From 109a75aac22463802f03dfc6588951ed0b04892a Mon Sep 17 00:00:00 2001
From: Egor Yusov <egor.yusov@gmail.com>
Date: Sat, 20 May 2017 14:00:37 -0700
Subject: Merge from dev branch

---
 .../GraphicsEngineD3D12/include/BufferD3D12Impl.h  |   3 +-
 .../include/BufferViewD3D12Impl.h                  |   3 +-
 .../GraphicsEngineD3D12/include/CommandContext.h   | 242 +--------------------
 .../include/CommandListD3D12Impl.h                 |   2 +-
 .../include/CommandListManager.h                   |  12 +-
 .../include/D3D12ResourceBase.h                    |   2 +-
 .../include/D3D12TypeConversions.h                 |   2 +-
 .../include/D3D12TypeDefinitions.h                 |   2 +-
 Graphics/GraphicsEngineD3D12/include/D3D12Utils.h  |   2 +-
 .../GraphicsEngineD3D12/include/DescriptorHeap.h   | 220 ++++++++++++++++---
 .../include/DeviceContextD3D12Impl.h               |   2 +-
 .../include/DynamicUploadHeap.h                    |   4 +-
 .../GraphicsEngineD3D12/include/GenerateMips.h     |   2 +-
 .../include/PipelineStateD3D12Impl.h               |   2 +-
 .../include/RenderDeviceD3D12Impl.h                |  87 ++++++--
 .../GraphicsEngineD3D12/include/RootSignature.h    |   9 +-
 .../GraphicsEngineD3D12/include/SamplerD3D12Impl.h |   2 +-
 .../GraphicsEngineD3D12/include/ShaderD3D12Impl.h  |   2 +-
 .../include/ShaderResourceBindingD3D12Impl.h       |   2 +-
 .../include/ShaderResourceCacheD3D12.h             |  69 +++---
 .../include/ShaderResourceLayoutD3D12.h            |  82 ++++---
 .../include/ShaderResourcesD3D12.h                 |   2 +-
 .../include/SwapChainD3D12Impl.h                   |   2 +-
 .../GraphicsEngineD3D12/include/TextureD3D12Impl.h |   4 +-
 .../include/TextureViewD3D12Impl.h                 |   5 +-
 Graphics/GraphicsEngineD3D12/include/pch.h         |   2 +-
 .../GraphicsEngineD3D12/interface/BufferD3D12.h    |   2 +-
 .../interface/BufferViewD3D12.h                    |   2 +-
 .../interface/PipelineStateD3D12.h                 |   2 +-
 .../interface/RenderDeviceD3D12.h                  |   2 +-
 .../interface/RenderDeviceFactoryD3D12.h           |   2 +-
 .../GraphicsEngineD3D12/interface/SamplerD3D12.h   |   2 +-
 .../GraphicsEngineD3D12/interface/ShaderD3D12.h    |   2 +-
 .../interface/ShaderResourceBindingD3D12.h         |   2 +-
 .../GraphicsEngineD3D12/interface/SwapChainD3D12.h |   2 +-
 .../GraphicsEngineD3D12/interface/TextureD3D12.h   |   2 +-
 .../interface/TextureViewD3D12.h                   |   2 +-
 .../GraphicsEngineD3D12/src/BufferD3D12Impl.cpp    |   4 +-
 .../src/BufferViewD3D12Impl.cpp                    |   2 +-
 .../GraphicsEngineD3D12/src/CommandContext.cpp     | 147 +------------
 .../GraphicsEngineD3D12/src/CommandListManager.cpp |  27 ++-
 .../GraphicsEngineD3D12/src/D3D12ResourceBase.cpp  |   2 +-
 .../src/D3D12TypeConversions.cpp                   |   2 +-
 Graphics/GraphicsEngineD3D12/src/D3D12Utils.cpp    |   2 +-
 Graphics/GraphicsEngineD3D12/src/DLLMain.cpp       |   2 +-
 .../GraphicsEngineD3D12/src/DescriptorHeap.cpp     | 122 +++++++++--
 .../src/DeviceContextD3D12Impl.cpp                 |   4 +-
 .../GraphicsEngineD3D12/src/DynamicUploadHeap.cpp  |  31 ++-
 Graphics/GraphicsEngineD3D12/src/GenerateMips.cpp  |   2 +-
 .../src/PipelineStateD3D12Impl.cpp                 |   5 +-
 .../src/RenderDeviceD3D12Impl.cpp                  | 195 +++++++++--------
 .../src/RenderDeviceFactoryD3D12.cpp               |   4 +-
 Graphics/GraphicsEngineD3D12/src/RootSignature.cpp |  70 ++++--
 .../GraphicsEngineD3D12/src/SamplerD3D12Impl.cpp   |   2 +-
 .../GraphicsEngineD3D12/src/ShaderD3D12Impl.cpp    |   3 +-
 .../src/ShaderResourceBindingD3D12Impl.cpp         |   3 +-
 .../src/ShaderResourceCacheD3D12.cpp               |   9 +-
 .../src/ShaderResourceLayoutD3D12.cpp              | 134 ++++++++----
 .../src/ShaderResourcesD3D12.cpp                   |   2 +-
 .../GraphicsEngineD3D12/src/SwapChainD3D12Impl.cpp |   2 +-
 .../GraphicsEngineD3D12/src/TextureD3D12Impl.cpp   |   2 +-
 .../src/TextureViewD3D12Impl.cpp                   |   2 +-
 Graphics/GraphicsEngineD3D12/src/pch.cpp           |   2 +-
 63 files changed, 826 insertions(+), 746 deletions(-)

(limited to 'Graphics/GraphicsEngineD3D12')

diff --git a/Graphics/GraphicsEngineD3D12/include/BufferD3D12Impl.h b/Graphics/GraphicsEngineD3D12/include/BufferD3D12Impl.h
index 9ee4e25d..289bf152 100644
--- a/Graphics/GraphicsEngineD3D12/include/BufferD3D12Impl.h
+++ b/Graphics/GraphicsEngineD3D12/include/BufferD3D12Impl.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -108,6 +108,7 @@ private:
 #endif
 
     friend class DeviceContextD3D12Impl;
+    // Array of dynamic allocations for every device context
     std::vector<DynamicAllocation,  STDAllocatorRawMem<DynamicAllocation> > m_DynamicData;
 };
 
diff --git a/Graphics/GraphicsEngineD3D12/include/BufferViewD3D12Impl.h b/Graphics/GraphicsEngineD3D12/include/BufferViewD3D12Impl.h
index f5aff0ab..0c102f41 100644
--- a/Graphics/GraphicsEngineD3D12/include/BufferViewD3D12Impl.h
+++ b/Graphics/GraphicsEngineD3D12/include/BufferViewD3D12Impl.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -53,6 +53,7 @@ public:
     virtual D3D12_CPU_DESCRIPTOR_HANDLE GetCPUDescriptorHandle()override{return m_DescriptorHandle.GetCpuHandle();}
    
 protected:
+    // Allocation in a CPU-only descriptor heap
     DescriptorHeapAllocation m_DescriptorHandle;
 };
 
diff --git a/Graphics/GraphicsEngineD3D12/include/CommandContext.h b/Graphics/GraphicsEngineD3D12/include/CommandContext.h
index 755e8076..41be0796 100644
--- a/Graphics/GraphicsEngineD3D12/include/CommandContext.h
+++ b/Graphics/GraphicsEngineD3D12/include/CommandContext.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -21,20 +21,6 @@
  *  of the possibility of such damages.
  */
 
-//
-// Copyright (c) Microsoft. All rights reserved.
-// This code is licensed under the MIT License (MIT).
-// THIS CODE IS PROVIDED *AS IS* WITHOUT WARRANTY OF
-// ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING ANY
-// IMPLIED WARRANTIES OF FITNESS FOR A PARTICULAR
-// PURPOSE, MERCHANTABILITY, OR NON-INFRINGEMENT.
-//
-// Developed by Minigraph
-//
-// Author:  James Stanard 
-//
-// Adapted to Diligent Engine: Egor Yusov
-//
 
 #pragma once
 
@@ -77,7 +63,7 @@ public:
 	CommandContext( IMemoryAllocator &MemAllocator,
                     class CommandListManager& CmdListManager, 
                     GPUDescriptorHeap GPUDescriptorHeaps[],
-                    Uint32 DynamicDescriptorAllocationChunkSize[]);
+                    const Uint32 DynamicDescriptorAllocationChunkSize[]);
 
     ~CommandContext(void);
 
@@ -97,25 +83,11 @@ public:
         m_pCommandList->CopyResource(pDstRes, pSrcRes);
     }
 
-	//void CopyBuffer( GpuResource& Dest, GpuResource& Src );
-	//void CopyBufferRegion( GpuResource& Dest, size_t DestOffset, GpuResource& Src, size_t SrcOffset, size_t NumBytes );
-	//void CopySubresource(GpuResource& Dest, UINT DestSubIndex, GpuResource& Src, UINT SrcSubIndex);
-	//void CopyCounter(GpuResource& Dest, size_t DestOffset, StructuredBuffer& Src);
-	//void ResetCounter(StructuredBuffer& Buf, uint32_t Value = 0);
-
-	//static void InitializeTextureArraySlice(GpuResource& Dest, UINT SliceIndex, GpuResource& Src);
-
     void TransitionResource(ITextureD3D12 *pTexture, D3D12_RESOURCE_STATES NewState, bool FlushImmediate = false);
     void TransitionResource(IBufferD3D12 *pBuffer, D3D12_RESOURCE_STATES NewState, bool FlushImmediate = false);
 	//void BeginResourceTransition(GpuResource& Resource, D3D12_RESOURCE_STATES NewState, bool FlushImmediate = false);
 	void FlushResourceBarriers();
 
-	//void InsertTimeStamp( ID3D12QueryHeap* pQueryHeap, uint32_t QueryIdx );
-	//void ResolveTimeStamps( ID3D12Resource* pReadbackHeap, ID3D12QueryHeap* pQueryHeap, uint32_t NumQueries );
-	//void PIXBeginEvent(const wchar_t* label);
-	//void PIXEndEvent(void);
-	//void PIXSetMarker(const wchar_t* label);
-
     struct ShaderDescriptorHeaps
     {
         ID3D12DescriptorHeap* pSrvCbvUavHeap;
@@ -144,7 +116,7 @@ public:
     void SetID(const Char* ID) { m_ID = ID; }
     ID3D12GraphicsCommandList *GetCommandList(){return m_pCommandList;}
     
-    void DiscardUsedDescriptorHeaps(Uint64 FrameNumber);
+    void DiscardDynamicDescriptors(Uint64 FrameNumber);
     DescriptorHeapAllocation AllocateDynamicGPUVisibleDescriptor( D3D12_DESCRIPTOR_HEAP_TYPE Type, UINT Count = 1 );
 
     void InsertUAVBarrier(D3D12ResourceBase& Resource, IDeviceObject &Object, bool FlushImmediate = false);
@@ -153,9 +125,6 @@ protected:
     void TransitionResource(D3D12ResourceBase& Resource, IDeviceObject &Object, D3D12_RESOURCE_STATES NewState, bool FlushImmediate);
     void InsertAliasBarrier(D3D12ResourceBase& Before, D3D12ResourceBase& After, IDeviceObject &BeforeObj, IDeviceObject &AfterObj, bool FlushImmediate = false);
 
-	//void FinishTimeStampQueryBatch();
-	//void BindDescriptorHeaps( void );
-
 	CComPtr<ID3D12GraphicsCommandList> m_pCommandList;
 	CComPtr<ID3D12CommandAllocator> m_pCurrentAllocator;
 
@@ -274,18 +243,11 @@ public:
 	    m_pCommandList->SetGraphicsRootConstantBufferView(RootIndex, CBV);
     }
 
-	//void SetDynamicConstantBufferView( UINT RootIndex, size_t BufferSize, const void* BufferData );
-	//void SetBufferSRV( UINT RootIndex, const GpuBuffer& SRV );
-	//void SetBufferUAV( UINT RootIndex, const GpuBuffer& UAV );
 	void SetDescriptorTable( UINT RootIndex, D3D12_GPU_DESCRIPTOR_HANDLE FirstHandle )
     {
 	    m_pCommandList->SetGraphicsRootDescriptorTable( RootIndex, FirstHandle );
     }
 
-
-	//void SetDynamicDescriptor( UINT RootIndex, UINT Offset, D3D12_CPU_DESCRIPTOR_HANDLE Handle );
-	//void SetDynamicDescriptors( UINT RootIndex, UINT Offset, UINT Count, const D3D12_CPU_DESCRIPTOR_HANDLE Handles[] );
-
 	void SetIndexBuffer( const D3D12_INDEX_BUFFER_VIEW& IBView )
     {
 	    m_pCommandList->IASetIndexBuffer(&IBView);
@@ -296,10 +258,6 @@ public:
 	    m_pCommandList->IASetVertexBuffers(StartSlot, Count, VBViews);
     }
 
-	//void SetDynamicVB( UINT Slot, size_t NumVertices, size_t VertexStride, const void* VBData );
-	//void SetDynamicIB( size_t IndexCount, const uint16_t* IBData );
-	//void SetDynamicSRV(UINT RootIndex, size_t BufferSize, const void* BufferData);
-
 	void Draw(UINT VertexCountPerInstance, UINT InstanceCount,
 	          UINT StartVertexLocation, UINT StartInstanceLocation)
     {
@@ -373,19 +331,11 @@ public:
 	    m_pCommandList->SetComputeRootConstantBufferView(RootIndex, CBV);
     }
 
-	//void SetDynamicConstantBufferView( UINT RootIndex, size_t BufferSize, const void* BufferData );
-	//void SetDynamicSRV( UINT RootIndex, size_t BufferSize, const void* BufferData ); 
-	//void SetBufferSRV( UINT RootIndex, const GpuBuffer& SRV );
-	//void SetBufferUAV( UINT RootIndex, const GpuBuffer& UAV );
 	void SetDescriptorTable( UINT RootIndex, D3D12_GPU_DESCRIPTOR_HANDLE FirstHandle )
     {
 	    m_pCommandList->SetComputeRootDescriptorTable( RootIndex, FirstHandle );
     }
 
-
-	//void SetDynamicDescriptor( UINT RootIndex, UINT Offset, D3D12_CPU_DESCRIPTOR_HANDLE Handle );
-	//void SetDynamicDescriptors( UINT RootIndex, UINT Offset, UINT Count, const D3D12_CPU_DESCRIPTOR_HANDLE Handles[] );
-
 	void Dispatch( size_t GroupCountX = 1, size_t GroupCountY = 1, size_t GroupCountZ = 1 )
     {
 	    FlushResourceBarriers();
@@ -403,112 +353,6 @@ inline ComputeContext& CommandContext::AsComputeContext()
     return static_cast<ComputeContext&>(*this);
 }
 
-#if 0
-
-inline void GraphicsContext::SetDynamicConstantBufferView( UINT RootIndex, size_t BufferSize, const void* BufferData )
-{
-	ASSERT(BufferData != nullptr && Math::IsAligned(BufferData, 16));
-	DynAlloc cb = m_CpuLinearAllocator.Allocate(BufferSize);
-	//SIMDMemCopy(cb.DataPtr, BufferData, Math::AlignUp(BufferSize, 16) >> 4);
-	memcpy(cb.DataPtr, BufferData, BufferSize);
-	m_pCommandList->SetGraphicsRootConstantBufferView(RootIndex, cb.GpuAddress);
-}
-
-inline void ComputeContext::SetDynamicConstantBufferView( UINT RootIndex, size_t BufferSize, const void* BufferData )
-{
-	ASSERT(BufferData != nullptr && Math::IsAligned(BufferData, 16));
-	DynAlloc cb = m_CpuLinearAllocator.Allocate(BufferSize);
-	//SIMDMemCopy(cb.DataPtr, BufferData, Math::AlignUp(BufferSize, 16) >> 4);
-	memcpy(cb.DataPtr, BufferData, BufferSize);
-	m_pCommandList->SetComputeRootConstantBufferView(RootIndex, cb.GpuAddress);
-}
-
-inline void GraphicsContext::SetDynamicVB( UINT Slot, size_t NumVertices, size_t VertexStride, const void* VertexData )
-{
-	ASSERT(VertexData != nullptr && Math::IsAligned(VertexData, 16));
-
-	size_t BufferSize = Math::AlignUp(NumVertices * VertexStride, 16);
-	DynAlloc vb = m_CpuLinearAllocator.Allocate(BufferSize);
-
-	SIMDMemCopy(vb.DataPtr, VertexData, BufferSize >> 4);
-
-	D3D12_VERTEX_BUFFER_VIEW VBView;
-	VBView.BufferLocation = vb.GpuAddress;
-	VBView.SizeInBytes = (UINT)BufferSize;
-	VBView.StrideInBytes = (UINT)VertexStride;
-
-	m_pCommandList->IASetVertexBuffers(Slot, 1, &VBView);
-}
-
-inline void GraphicsContext::SetDynamicIB( size_t IndexCount, const uint16_t* IndexData )
-{
-	ASSERT(IndexData != nullptr && Math::IsAligned(IndexData, 16));
-
-	size_t BufferSize = Math::AlignUp(IndexCount * sizeof(uint16_t), 16);
-	DynAlloc ib = m_CpuLinearAllocator.Allocate(BufferSize);
-
-	SIMDMemCopy(ib.DataPtr, IndexData, BufferSize >> 4);
-
-	D3D12_INDEX_BUFFER_VIEW IBView;
-	IBView.BufferLocation = ib.GpuAddress;
-	IBView.SizeInBytes = (UINT)(IndexCount * sizeof(uint16_t));
-	IBView.Format = DXGI_FORMAT_R16_UINT;
-
-	m_pCommandList->IASetIndexBuffer(&IBView);
-}
-
-inline void GraphicsContext::SetDynamicSRV(UINT RootIndex, size_t BufferSize, const void* BufferData)
-{
-	ASSERT(BufferData != nullptr && Math::IsAligned(BufferData, 16));
-	DynAlloc cb = m_CpuLinearAllocator.Allocate(BufferSize);
-	SIMDMemCopy(cb.DataPtr, BufferData, Math::AlignUp(BufferSize, 16) >> 4);
-	m_pCommandList->SetGraphicsRootShaderResourceView(RootIndex, cb.GpuAddress);
-}
-
-inline void ComputeContext::SetDynamicSRV(UINT RootIndex, size_t BufferSize, const void* BufferData)
-{
-	ASSERT(BufferData != nullptr && Math::IsAligned(BufferData, 16));
-	DynAlloc cb = m_CpuLinearAllocator.Allocate(BufferSize);
-	SIMDMemCopy(cb.DataPtr, BufferData, Math::AlignUp(BufferSize, 16) >> 4);
-	m_pCommandList->SetComputeRootShaderResourceView(RootIndex, cb.GpuAddress);
-}
-
-inline void GraphicsContext::SetBufferSRV( UINT RootIndex, const GpuBuffer& SRV )
-{
-	ASSERT((SRV.m_UsageState & (D3D12_RESOURCE_STATE_PIXEL_SHADER_RESOURCE | D3D12_RESOURCE_STATE_NON_PIXEL_SHADER_RESOURCE)) != 0);
-	m_pCommandList->SetGraphicsRootShaderResourceView(RootIndex, SRV.GetGpuVirtualAddress());
-}
-
-inline void ComputeContext::SetBufferSRV( UINT RootIndex, const GpuBuffer& SRV )
-{
-	ASSERT((SRV.m_UsageState & D3D12_RESOURCE_STATE_NON_PIXEL_SHADER_RESOURCE) != 0);
-	m_pCommandList->SetComputeRootShaderResourceView(RootIndex, SRV.GetGpuVirtualAddress());
-}
-
-inline void GraphicsContext::SetBufferUAV( UINT RootIndex, const GpuBuffer& UAV )
-{
-	ASSERT((UAV.m_UsageState & D3D12_RESOURCE_STATE_UNORDERED_ACCESS) != 0);
-	m_pCommandList->SetGraphicsRootUnorderedAccessView(RootIndex, UAV.GetGpuVirtualAddress());
-}
-
-inline void ComputeContext::SetBufferUAV( UINT RootIndex, const GpuBuffer& UAV )
-{
-	ASSERT((UAV.m_UsageState & D3D12_RESOURCE_STATE_UNORDERED_ACCESS) != 0);
-	m_pCommandList->SetComputeRootUnorderedAccessView(RootIndex, UAV.GetGpuVirtualAddress());
-}
-
-
-
-inline void CommandContext::SetDescriptorHeap( D3D12_DESCRIPTOR_HEAP_TYPE Type, ID3D12DescriptorHeap* HeapPtr )
-{
-	if (m_CurrentDescriptorHeaps[Type] != HeapPtr)
-	{
-		m_CurrentDescriptorHeaps[Type] = HeapPtr;
-		BindDescriptorHeaps();
-	}
-}
-#endif
-
 inline void CommandContext::SetDescriptorHeaps( ShaderDescriptorHeaps& Heaps )
 {
 #ifdef _DEBUG
@@ -530,84 +374,4 @@ inline void CommandContext::SetDescriptorHeaps( ShaderDescriptorHeaps& Heaps )
     }
 }
 
-#if 0
-inline void GraphicsContext::SetDynamicDescriptor( UINT RootIndex, UINT Offset, D3D12_CPU_DESCRIPTOR_HANDLE Handle )
-{
-	SetDynamicDescriptors(RootIndex, Offset, 1, &Handle);
-}
-
-inline void ComputeContext::SetDynamicDescriptor( UINT RootIndex, UINT Offset, D3D12_CPU_DESCRIPTOR_HANDLE Handle )
-{
-	SetDynamicDescriptors(RootIndex, Offset, 1, &Handle);
-}
-
-inline void GraphicsContext::SetDynamicDescriptors( UINT RootIndex, UINT Offset, UINT Count, const D3D12_CPU_DESCRIPTOR_HANDLE Handles[] )
-{
-	m_DynamicDescriptorHeap.SetGraphicsDescriptorHandles(RootIndex, Offset, Count, Handles);
-}
-
-inline void ComputeContext::SetDynamicDescriptors( UINT RootIndex, UINT Offset, UINT Count, const D3D12_CPU_DESCRIPTOR_HANDLE Handles[] )
-{
-	m_DynamicDescriptorHeap.SetComputeDescriptorHandles(RootIndex, Offset, Count, Handles);
-}
-
-
-inline void CommandContext::CopyBuffer( GpuResource& Dest, GpuResource& Src )
-{
-	TransitionResource(Dest, D3D12_RESOURCE_STATE_COPY_DEST);
-	TransitionResource(Src, D3D12_RESOURCE_STATE_COPY_SOURCE);
-	FlushResourceBarriers();
-	m_pCommandList->CopyResource(Dest.GetResource(), Src.GetResource());
-}
-
-
-inline void CommandContext::CopyCounter(GpuResource& Dest, size_t DestOffset, StructuredBuffer& Src)
-{
-	TransitionResource(Dest, D3D12_RESOURCE_STATE_COPY_DEST);
-	TransitionResource(Src.GetCounterBuffer(), D3D12_RESOURCE_STATE_COPY_SOURCE);
-	FlushResourceBarriers();
-	m_pCommandList->CopyBufferRegion(Dest.GetResource(), DestOffset, Src.GetCounterBuffer().GetResource(), 0, 4);
-}
-
-inline void CommandContext::ResetCounter(StructuredBuffer& Buf, uint32_t Value )
-{
-	FillBuffer(Buf.GetCounterBuffer(), 0, Value, sizeof(uint32_t));
-	TransitionResource(Buf.GetCounterBuffer(), D3D12_RESOURCE_STATE_UNORDERED_ACCESS);
-}
-
-inline void CommandContext::InsertTimeStamp(ID3D12QueryHeap* pQueryHeap, uint32_t QueryIdx)
-{
-	m_pCommandList->EndQuery(pQueryHeap, D3D12_QUERY_TYPE_TIMESTAMP, QueryIdx);
-}
-
-inline void CommandContext::ResolveTimeStamps(ID3D12Resource* pReadbackHeap, ID3D12QueryHeap* pQueryHeap, uint32_t NumQueries)
-{
-	m_pCommandList->ResolveQueryData(pQueryHeap, D3D12_QUERY_TYPE_TIMESTAMP, 0, NumQueries, pReadbackHeap, 0);
-}
-
-inline void CommandContext::PIXBeginEvent(const wchar_t* label)
-{
-#if defined(RELEASE) || _MSC_VER < 1800
-	(label);
-#else
-	::PIXBeginEvent(m_pCommandList, 0, label);
-#endif
-}
-
-inline void CommandContext::PIXEndEvent(void)
-{
-#if !defined(RELEASE) && _MSC_VER >= 1800
-	::PIXEndEvent(m_pCommandList);
-#endif
-}
-
-inline void CommandContext::PIXSetMarker(const wchar_t* label)
-{
-#if defined(RELEASE) || _MSC_VER < 1800
-	(label);
-#else
-	::PIXSetMarker(m_pCommandList, 0, label);
-#endif
-}
-#endif
 }
\ No newline at end of file
diff --git a/Graphics/GraphicsEngineD3D12/include/CommandListD3D12Impl.h b/Graphics/GraphicsEngineD3D12/include/CommandListD3D12Impl.h
index 00e5fcaa..e73e36d1 100644
--- a/Graphics/GraphicsEngineD3D12/include/CommandListD3D12Impl.h
+++ b/Graphics/GraphicsEngineD3D12/include/CommandListD3D12Impl.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/include/CommandListManager.h b/Graphics/GraphicsEngineD3D12/include/CommandListManager.h
index a9b79650..21866ad7 100644
--- a/Graphics/GraphicsEngineD3D12/include/CommandListManager.h
+++ b/Graphics/GraphicsEngineD3D12/include/CommandListManager.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -57,12 +57,16 @@ public:
     CommandListManager& operator = (CommandListManager&&) = delete;
 
     void CreateNewCommandList( ID3D12GraphicsCommandList** ppList, ID3D12CommandAllocator** ppAllocator );
-    void DiscardAllocator( Uint64 FenceValueForReset, ID3D12CommandAllocator* pAllocator );
+    
+    // Discards the allocator.
+    // CmdListNum is the serial number of the command list that was created by this allocator
+    void DiscardAllocator( Uint64 CmdListNum, ID3D12CommandAllocator* pAllocator );
+
     void RequestAllocator(ID3D12CommandAllocator** ppAllocator);
 
 private:
-	// Since there is only a "main pool" so far, everything below corresponds to that pool. It should be renamed and/or 
-	// restructured if we add other pools.
+    // fist    - the SERIAL NUMBER of command list that was created by the allocator 
+    // second  - the allocator to be discarded
     typedef std::pair<Uint64, CComPtr<ID3D12CommandAllocator> > DiscardedAllocatorQueueElemType;
 	std::deque< DiscardedAllocatorQueueElemType, STDAllocatorRawMem<DiscardedAllocatorQueueElemType> > m_DiscardedAllocators;
 
diff --git a/Graphics/GraphicsEngineD3D12/include/D3D12ResourceBase.h b/Graphics/GraphicsEngineD3D12/include/D3D12ResourceBase.h
index e8faa4a3..84629c48 100644
--- a/Graphics/GraphicsEngineD3D12/include/D3D12ResourceBase.h
+++ b/Graphics/GraphicsEngineD3D12/include/D3D12ResourceBase.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/include/D3D12TypeConversions.h b/Graphics/GraphicsEngineD3D12/include/D3D12TypeConversions.h
index d909bd42..d8741573 100644
--- a/Graphics/GraphicsEngineD3D12/include/D3D12TypeConversions.h
+++ b/Graphics/GraphicsEngineD3D12/include/D3D12TypeConversions.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/include/D3D12TypeDefinitions.h b/Graphics/GraphicsEngineD3D12/include/D3D12TypeDefinitions.h
index 892de4aa..761f750b 100644
--- a/Graphics/GraphicsEngineD3D12/include/D3D12TypeDefinitions.h
+++ b/Graphics/GraphicsEngineD3D12/include/D3D12TypeDefinitions.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/include/D3D12Utils.h b/Graphics/GraphicsEngineD3D12/include/D3D12Utils.h
index 64ee7c40..13dbd204 100644
--- a/Graphics/GraphicsEngineD3D12/include/D3D12Utils.h
+++ b/Graphics/GraphicsEngineD3D12/include/D3D12Utils.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/include/DescriptorHeap.h b/Graphics/GraphicsEngineD3D12/include/DescriptorHeap.h
index 4c4400ca..a9d895e3 100644
--- a/Graphics/GraphicsEngineD3D12/include/DescriptorHeap.h
+++ b/Graphics/GraphicsEngineD3D12/include/DescriptorHeap.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -21,6 +21,9 @@
  *  of the possibility of such damages.
  */
 
+// Descriptor heap management utilities. 
+// See http://diligentgraphics.com/diligent-engine/architecture/d3d12/managing-descriptor-heaps/ for details
+
 #pragma once
 
 #include <mutex>
@@ -47,9 +50,19 @@ public:
     virtual Uint32 GetDescriptorSize()const = 0;
 };
 
+
+// The class represents descriptor heap allocation (continuous descriptor range in a descriptor heap)
+// 
+//                  m_FirstCpuHandle
+//                   |
+//  | ~  ~  ~  ~  ~  X  X  X  X  X  X  X  ~  ~  ~  ~  ~  ~ |  D3D12 Descriptor Heap
+//                   |
+//                  m_FirstGpuHandle
+//
 class DescriptorHeapAllocation
 {
 public:
+    // Creates null allocation
 	DescriptorHeapAllocation() : 
         m_NumHandles(1), // One null descriptor handle
         m_pDescriptorHeap(nullptr),
@@ -59,20 +72,13 @@ public:
 		m_FirstGpuHandle.ptr = 0;
 	}
 
-	DescriptorHeapAllocation( IDescriptorAllocator *pAllocator, ID3D12DescriptorHeap *pHeap, D3D12_CPU_DESCRIPTOR_HANDLE CpuHandle, Uint32 NHandles ) : 
-        m_FirstCpuHandle(CpuHandle),
-        m_pAllocator(pAllocator),
-        m_pDescriptorHeap(pHeap),
-        m_NumHandles(NHandles)
-	{
-		m_FirstGpuHandle.ptr = 0;
-        VERIFY_EXPR(m_pAllocator != nullptr && m_pDescriptorHeap != nullptr);
-        auto DescriptorSize = m_pAllocator->GetDescriptorSize();
-        VERIFY(DescriptorSize < std::numeric_limits<Uint16>::max(), "DescriptorSize exceeds allowed limit")
-        m_DescriptorSize = static_cast<Uint16>( DescriptorSize );
-	}
-
-	DescriptorHeapAllocation( IDescriptorAllocator *pAllocator, ID3D12DescriptorHeap *pHeap, D3D12_CPU_DESCRIPTOR_HANDLE CpuHandle, D3D12_GPU_DESCRIPTOR_HANDLE GpuHandle, Uint32 NHandles, Uint16 AllocationManagerId = static_cast<Uint16>(-1) ) : 
+    // Initializes non-null allocation 
+	DescriptorHeapAllocation( IDescriptorAllocator *pAllocator, 
+                              ID3D12DescriptorHeap *pHeap, 
+                              D3D12_CPU_DESCRIPTOR_HANDLE CpuHandle, 
+                              D3D12_GPU_DESCRIPTOR_HANDLE GpuHandle, 
+                              Uint32 NHandles, 
+                              Uint16 AllocationManagerId = static_cast<Uint16>(-1) ) : 
         m_FirstCpuHandle(CpuHandle), 
         m_FirstGpuHandle(GpuHandle),
         m_pAllocator(pAllocator),
@@ -86,6 +92,7 @@ public:
         m_DescriptorSize = static_cast<Uint16>( DescriptorSize );
 	}
 
+    // Move constructor (copy is not allowed)
     DescriptorHeapAllocation(DescriptorHeapAllocation &&Allocation) : 
 	    m_FirstCpuHandle(Allocation.m_FirstCpuHandle),
 	    m_FirstGpuHandle(Allocation.m_FirstGpuHandle),
@@ -104,6 +111,7 @@ public:
         Allocation.m_AllocationManagerId = static_cast<Uint16>(-1);
     }
 
+    // Move assignment (assignment is not allowed)
     DescriptorHeapAllocation& operator = (DescriptorHeapAllocation &&Allocation)
     { 
 	    m_FirstCpuHandle = Allocation.m_FirstCpuHandle;
@@ -125,12 +133,16 @@ public:
         return *this;
     }
 
+    // Destructor automatically releases this allocation through the allocator
     ~DescriptorHeapAllocation()
     {
         if(!IsNull() && m_pAllocator)
             m_pAllocator->Free(std::move(*this));
+        // Allocation must have been disposed by the allocator
+        VERIFY(IsNull(), "Non-null descriptor is being destroyed")
     }
 
+    // Returns CPU descriptor handle at the specified offset
 	D3D12_CPU_DESCRIPTOR_HANDLE GetCpuHandle(Uint32 Offset = 0) const 
     { 
         VERIFY_EXPR(Offset >= 0 && Offset < m_NumHandles); 
@@ -143,6 +155,7 @@ public:
         return CPUHandle;
     }
 
+    // Returns GPU descriptor handle at the specified offset
 	D3D12_GPU_DESCRIPTOR_HANDLE GetGpuHandle(Uint32 Offset = 0) const
     { 
         VERIFY_EXPR(Offset >= 0 && Offset < m_NumHandles); 
@@ -154,9 +167,10 @@ public:
         return GPUHandle;
     }
 
+    // Returns pointer to D3D12 descriptor heap that contains this allocation
     ID3D12DescriptorHeap *GetDescriptorHeap(){return m_pDescriptorHeap;}
 
-    size_t GetNumHandles(){return m_NumHandles;}
+    size_t GetNumHandles()const{return m_NumHandles;}
 
 	bool IsNull() const { return m_FirstCpuHandle.ptr == 0; }
 	bool IsShaderVisible() const { return m_FirstGpuHandle.ptr != 0; }
@@ -164,29 +178,59 @@ public:
     UINT GetDescriptorSize()const{return m_DescriptorSize;}
 
 private:
+    // No copies, only moves are allowed
     DescriptorHeapAllocation(const DescriptorHeapAllocation&) = delete;
     DescriptorHeapAllocation& operator= (const DescriptorHeapAllocation&) = delete;
 
+    // First CPU descriptor handle in this allocation
 	D3D12_CPU_DESCRIPTOR_HANDLE m_FirstCpuHandle = {0};
+    
+    // First GPU descriptor handle in this allocation
 	D3D12_GPU_DESCRIPTOR_HANDLE m_FirstGpuHandle = {0};
+
     // Keep strong reference to the parent heap to make sure it is alive while allocation is alive - TOO EXPENSIVE
     //RefCntAutoPtr<IDescriptorAllocator> m_pAllocator;
+    
+    // Pointer to the descriptor heap allocator that created this allocation
     IDescriptorAllocator* m_pAllocator = nullptr;
+
+    // Pointer to the D3D12 descriptor heap that contains descriptors in this allocation
     ID3D12DescriptorHeap* m_pDescriptorHeap = nullptr;
+    
+    // Number of descriptors in the allocation
     Uint32 m_NumHandles = 0;
+
+    // Allocation manager ID. One allocator may support several 
+    // allocation managers. This field is required to identify
+    // the manager within the allocator that was used to create
+    // this allocation
     Uint16 m_AllocationManagerId = static_cast<Uint16>(-1);
+    
+    // Descriptor size 
     Uint16 m_DescriptorSize = 0;
 };
 
 
+// The class performs suballocations within one D3D12 descriptor heap. 
+// It uses VariableSizeGPUAllocationsManager to manage free space in the heap
+//
+// |  X  X  X  X  O  O  O  X  X  O  O  X  O  O  O  O  |  D3D12 descriptor heap
+//  
+//  X - used descriptor
+//  O - available descriptor
+//
 class DescriptorHeapAllocationManager
 {
 public:
+    // Creates a new D3D12 descriptor heap
     DescriptorHeapAllocationManager(IMemoryAllocator &Allocator, 
                                     RenderDeviceD3D12Impl *pDeviceD3D12Impl,
                                     IDescriptorAllocator *pParentAllocator,
                                     size_t ThisManagerId,
                                     const D3D12_DESCRIPTOR_HEAP_DESC &HeapDesc);
+
+    // Uses subrange of descriptors in the existing D3D12 descriptor heap
+    // that starts at offset FirstDescriptor and uses NumDescriptors descriptors
     DescriptorHeapAllocationManager(IMemoryAllocator &Allocator, 
                                     RenderDeviceD3D12Impl *pDeviceD3D12Impl,
                                     IDescriptorAllocator *pParentAllocator,
@@ -221,36 +265,83 @@ public:
         rhs.m_ThisManagerId = static_cast<size_t>(-1);
     }
 
+    // No copies or move-assignments
     DescriptorHeapAllocationManager& operator = (DescriptorHeapAllocationManager&& rhs) = delete;
     DescriptorHeapAllocationManager(const DescriptorHeapAllocationManager&) = delete;
     DescriptorHeapAllocationManager& operator = (const DescriptorHeapAllocationManager&) = delete;
 
     ~DescriptorHeapAllocationManager();
 
+    // Allocates Count descriptors
     DescriptorHeapAllocation Allocate( uint32_t Count );
+    
+    // Releases descriptor heap allocation. 
+    // Note that the allocation is not released immediately, but
+    // added to the release queue in the allocations manager
     void Free(DescriptorHeapAllocation&& Allocation);
-    void ReleaseStaleAllocations(Uint64 NumCompletedFrames);
+    
+    // Releases all stale allocation used by completed command lists
+	// The method takes the NUMBER of completed command lists (N)
+	// and releases all allocations whose number n < N 
+	// (cmd list n == N is NOT released)
+    void ReleaseStaleAllocations(Uint64 NumCompletedCmdLists);
+
     size_t GetNumAvailableDescriptors()const{return m_FreeBlockManager.GetFreeSize();}
+	size_t GetNumStaleDescriptors()const { return m_FreeBlockManager.GetStaleAllocationsSize(); }
+	Uint32 GetMaxDescriptors()const { return m_NumDescriptorsInAllocation; }
 
 private:
+    // Allocations manager used to handle descriptor allocations within the heap
     VariableSizeGPUAllocationsManager m_FreeBlockManager;
+    
+    // Heap description
     D3D12_DESCRIPTOR_HEAP_DESC m_HeapDesc;
+
+    // Strong reference to D3D12 descriptor heap object
 	CComPtr<ID3D12DescriptorHeap> m_pd3d12DescriptorHeap;
+    
+    // First CPU descriptor handle in the available descriptor range
 	D3D12_CPU_DESCRIPTOR_HANDLE m_FirstCPUHandle = {0};
+    
+    // First GPU descriptor handle in the available descriptor range
     D3D12_GPU_DESCRIPTOR_HANDLE m_FirstGPUHandle = {0};
+
     UINT m_DescriptorSize = 0;
+
+    // Number of descriptors in the allocation. 
+    // If this manager was initialized as a subrange in the existing heap,
+    // this value may be different from m_HeapDesc.NumDescriptors
     Uint32 m_NumDescriptorsInAllocation = 0;
+
     std::mutex m_AllocationMutex;
     RenderDeviceD3D12Impl *m_pDeviceD3D12Impl = nullptr;
     IDescriptorAllocator *m_pParentAllocator = nullptr;
+    
+    // External ID assigned to this descriptor allocations manager
     size_t m_ThisManagerId = static_cast<size_t>(-1);
 };
 
-// This is an unbounded resource descriptor heap.  It is intended to provide space for CPU-visible resource descriptors
-// as resources are created as well as for static and mutable shader descriptor tables.
+// CPU descriptor heap is intended to provide storage for resource view descriptor handles
+// It contains a pool of DescriptorHeapAllocationManager object instances, where every instance manages
+// its own CPU-only D3D12 descriptor heap:
+//
+//           m_HeapPool[0]                m_HeapPool[1]                 m_HeapPool[2]
+//   |  X  X  X  X  X  X  X  X |, |  X  X  X  O  O  X  X  O  |, |  X  O  O  O  O  O  O  O  |
+//
+//    X - used descriptor                m_AvailableHeaps = {1,2}
+//    O - available descriptor
+//
+// Allocation routine goes through the list of managers that have available descriptors and tries to process 
+// the request using every manager. If there are no available managers or no manager was able to handle the request, 
+// the function creates a new descriptor heap manager and lets it handle the request
+//
+// Render device contains four CPUDescriptorHeap object instances (one for each D3D12 heap type). The heaps are accessed
+// when a texture or a buffer view is created.
+//
 class CPUDescriptorHeap : public IDescriptorAllocator
 {
 public:
+    // Initializes the heap
 	CPUDescriptorHeap(IMemoryAllocator &Allocator, 
                       RenderDeviceD3D12Impl *pDeviceD3D12Impl, 
                       Uint32 NumDescriptorsInHeap, 
@@ -268,24 +359,71 @@ public:
     virtual void Free(DescriptorHeapAllocation&& Allocation)override;
     virtual Uint32 GetDescriptorSize()const override{return m_DescriptorSize;}
 
-    void ReleaseStaleAllocations(Uint64 NumCompletedFrames);
+	// Releases all stale allocation used by completed command lists
+	// The method takes the NUMBER of completed command lists (N)
+	// and releases all allocations whose number n < N 
+	// (cmd list n == N is NOT released)
+    void ReleaseStaleAllocations(Uint64 NumCompletedCmdLists);
 
 protected:
 
+    // Pool of descriptor heap managers
     std::vector<DescriptorHeapAllocationManager, STDAllocatorRawMem<DescriptorHeapAllocationManager> > m_HeapPool;
+    // Indices of available descriptor heap managers
     std::set<size_t, std::less<size_t>, STDAllocatorRawMem<size_t> > m_AvailableHeaps;
     IMemoryAllocator &m_MemAllocator;
  
 	std::mutex m_AllocationMutex;
 
     D3D12_DESCRIPTOR_HEAP_DESC m_HeapDesc;
+	RenderDeviceD3D12Impl *m_pDeviceD3D12Impl;
 	UINT m_DescriptorSize;
-    RenderDeviceD3D12Impl *m_pDeviceD3D12Impl;
-    Uint32 m_MaxHeapSize = 0;
+    
+    // Maximum heap size during the application lifetime - for statistic purposes
+	Uint32 m_MaxHeapSize = 0;
+	Uint32 m_MaxStaleSize = 0;
     Uint32 m_CurrentSize = 0; // This size does not count stale allocation
 };
 
-
+// GPU descriptor heap provides storage for shader-visible descriptors
+// The heap contains single D3D12 descriptor heap that is broken into two parts.
+// The first part stores static and mutable resource descriptor handles.
+// The second part is intended to provide temporary storage for dynamic resources
+// Space for dynamic resources is allocated in chunks, and then descriptors are suballocated within every
+// chunk. DynamicSuballocationsManager facilitates this process
+//
+//     
+//     static and mutable handles      ||                 dynamic space
+//                                     ||    chunk 0     chunk 1     chunk 2     unused
+//  | X O O X X O X O O O O X X X X O  ||  | X X X O | | X X O O | | O O O O |  O O O O  ||
+//                                               |         |
+//                                     suballocation       suballocation
+//                                    within chunk 0       within chunk 1
+//
+// Render device contains two GPUDescriptorHeap instances (CBV_SRV_UAV and SAMPLER). The heaps
+// are used to allocate GPU-visible descriptors for shader resource binding objects. The heaps
+// are also used by the command contexts (through DynamicSuballocationsManager to allocated dynamic descriptors)
+//
+//  _______________________________________________________________________________________________________________________________
+// | Render Device                                                                                                                 |
+// |                                                                                                                               |
+// | m_CPUDescriptorHeaps[CBV_SRV_UAV] |  X  X  X  X  X  X  X  X  |, |  X  X  X  X  X  X  X  X  |, |  X  O  O  X  O  O  O  O  |    |
+// | m_CPUDescriptorHeaps[SAMPLER]     |  X  X  X  X  O  O  O  X  |, |  X  O  O  X  O  O  O  O  |                                  |
+// | m_CPUDescriptorHeaps[RTV]         |  X  X  X  O  O  O  O  O  |, |  O  O  O  O  O  O  O  O  |                                  |
+// | m_CPUDescriptorHeaps[DSV]         |  X  X  X  O  X  O  X  O  |                                                                |
+// |                                                                               ctx1        ctx2                                |
+// | m_GPUDescriptorHeaps[CBV_SRV_UAV]  | X O O X X O X O O O O X X X X O  ||  | X X X O | | X X O O | | O O O O |  O O O O  ||    |
+// | m_GPUDescriptorHeaps[SAMPLER]      | X X O O X O X X X O O X O O O O  ||  | X X O O | | X O O O | | O O O O |  O O O O  ||    |
+// |                                                                                                                               |
+// |_______________________________________________________________________________________________________________________________|
+//  
+//  ________________________________________________               ________________________________________________ 
+// |Device Context 1                                |             |Device Context 2                                |
+// |                                                |             |                                                |
+// | m_DynamicGPUDescriptorAllocator[CBV_SRV_UAV]   |             | m_DynamicGPUDescriptorAllocator[CBV_SRV_UAV]   |
+// | m_DynamicGPUDescriptorAllocator[SAMPLER]       |             | m_DynamicGPUDescriptorAllocator[SAMPLER]       |
+// |________________________________________________|             |________________________________________________|
+//
 class GPUDescriptorHeap : public IDescriptorAllocator
 {
 public:
@@ -309,31 +447,52 @@ public:
 
     DescriptorHeapAllocation AllocateDynamic( uint32_t Count );
 
-    void ReleaseStaleAllocations(Uint64 NumCompletedFrames);
+	// Releases all stale allocation used by completed command lists
+	// The method takes the NUMBER of completed command lists (N)
+	// and releases all allocations whose number n < N 
+	// (cmd list n == N is NOT released)
+    void ReleaseStaleAllocations(Uint64 NumCompletedCmdLists);
 
-    D3D12_DESCRIPTOR_HEAP_DESC &GetHeapDesc(){return m_HeapDesc;}
+    const D3D12_DESCRIPTOR_HEAP_DESC &GetHeapDesc()const{return m_HeapDesc;}
+	Uint32 GetMaxStaticDescriptors()const { return m_HeapAllocationManager.GetMaxDescriptors(); }
+	Uint32 GetMaxDynamicDescriptors()const { return m_DynamicAllocationsManager.GetMaxDescriptors(); }
 
 protected:
 
     D3D12_DESCRIPTOR_HEAP_DESC m_HeapDesc;
     CComPtr<ID3D12DescriptorHeap> m_pd3d12DescriptorHeap;
 
-
     UINT m_DescriptorSize = 0;
 
-	std::mutex m_Mutex;
+	std::mutex m_AllocMutex, m_DynAllocMutex;
+    // Allocation manager for static/mutable part
     DescriptorHeapAllocationManager m_HeapAllocationManager;
+    
+    // Allocation manager for dynamic part
     DescriptorHeapAllocationManager m_DynamicAllocationsManager;
         
     RenderDeviceD3D12Impl *m_pDeviceD3D12;
     Uint32 m_CurrentSize = 0;
-    Uint32 m_MaxHeapSize = 0;
+    // Maximum static/mutable part size during the application lifetime - for statistic purposes
+	Uint32 m_MaxHeapSize = 0;
+	Uint32 m_MaxStaleSize = 0;
     Uint32 m_CurrentDynamicSize = 0;
-    Uint32 m_MaxDynamicSize = 0;
+    // Maximum dynamic part size during the application lifetime - for statistic purposes
+	Uint32 m_MaxDynamicSize = 0;
+	Uint32 m_MaxDynamicStaleSize = 0;
 };
 
 
+// The class facilitates allocation of dynamic descriptor handles. It requests a chunk of heap
+// from the master GPU descriptor heap and then performs linear suballocation within the chunk
+// At the end of the frame all allocations are disposed.
 
+//     static and mutable handles     ||                 dynamic space
+//                                    ||    chunk 0                 chunk 2           
+//  |                                 ||  | X X X O |             | O O O O |           || GPU Descriptor Heap
+//                                        |                       |
+//                                        m_Suballocations[0]     m_Suballocations[1]
+//
 class DynamicSuballocationsManager : public IDescriptorAllocator
 {
 public:
@@ -352,11 +511,14 @@ public:
     virtual Uint32 GetDescriptorSize()const override{return m_ParentGPUHeap.GetDescriptorSize();}
 
 private:
+    // List of chunks allocated from the master GPU descriptor heap. All chunks are disposed at the end
+    // of the frame
     std::vector<DescriptorHeapAllocation, STDAllocatorRawMem<DescriptorHeapAllocation> > m_Suballocations;
 
 	Uint32 m_CurrentSuballocationOffset = 0;
     Uint32 m_DynamicChunkSize = 0;
 
+    // Parent GPU descriptor heap that is used to allocate chunks
     GPUDescriptorHeap &m_ParentGPUHeap;
 };
 
diff --git a/Graphics/GraphicsEngineD3D12/include/DeviceContextD3D12Impl.h b/Graphics/GraphicsEngineD3D12/include/DeviceContextD3D12Impl.h
index ffe8598a..14555715 100644
--- a/Graphics/GraphicsEngineD3D12/include/DeviceContextD3D12Impl.h
+++ b/Graphics/GraphicsEngineD3D12/include/DeviceContextD3D12Impl.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/include/DynamicUploadHeap.h b/Graphics/GraphicsEngineD3D12/include/DynamicUploadHeap.h
index 6adefccf..00140f8d 100644
--- a/Graphics/GraphicsEngineD3D12/include/DynamicUploadHeap.h
+++ b/Graphics/GraphicsEngineD3D12/include/DynamicUploadHeap.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -126,7 +126,7 @@ public:
 private:
     const bool m_bIsCPUAccessible;
     // When a chunk of dynamic memory is requested, the heap first tries to allocate the memory in the largest GPU buffer. 
-    // If allocation fails, it a new ring buffer is created that provides enough space and requests memory from that buffer.
+    // If allocation fails, a new ring buffer is created that provides enough space and requests memory from that buffer.
     // Only the largest buffer is used for allocation and all other buffers are released when GPU is done with corresponding frames
     std::vector<GPURingBuffer, STDAllocatorRawMem<GPURingBuffer> > m_RingBuffers;
     IMemoryAllocator &m_Allocator;
diff --git a/Graphics/GraphicsEngineD3D12/include/GenerateMips.h b/Graphics/GraphicsEngineD3D12/include/GenerateMips.h
index 22e81589..109858a9 100644
--- a/Graphics/GraphicsEngineD3D12/include/GenerateMips.h
+++ b/Graphics/GraphicsEngineD3D12/include/GenerateMips.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/include/PipelineStateD3D12Impl.h b/Graphics/GraphicsEngineD3D12/include/PipelineStateD3D12Impl.h
index 1ac6564f..84e2fb09 100644
--- a/Graphics/GraphicsEngineD3D12/include/PipelineStateD3D12Impl.h
+++ b/Graphics/GraphicsEngineD3D12/include/PipelineStateD3D12Impl.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/include/RenderDeviceD3D12Impl.h b/Graphics/GraphicsEngineD3D12/include/RenderDeviceD3D12Impl.h
index 0294a8b8..c353f64e 100644
--- a/Graphics/GraphicsEngineD3D12/include/RenderDeviceD3D12Impl.h
+++ b/Graphics/GraphicsEngineD3D12/include/RenderDeviceD3D12Impl.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -32,6 +32,7 @@
 #include "CommandListManager.h"
 #include "CommandContext.h"
 #include "DynamicUploadHeap.h"
+#include "Atomics.h"
 
 /// Namespace for the Direct3D11 implementation of the graphics engine
 namespace Diligent
@@ -65,24 +66,22 @@ public:
     DescriptorHeapAllocation AllocateDescriptor( D3D12_DESCRIPTOR_HEAP_TYPE Type, UINT Count = 1 );
     DescriptorHeapAllocation AllocateGPUDescriptors( D3D12_DESCRIPTOR_HEAP_TYPE Type, UINT Count = 1 );
 
-    bool IsFenceComplete(Uint64 FenceValue);
-    bool IsFrameComplete(Uint64 Frame);
+    Uint64 GetNumCompletedCmdLists();
+	Uint64 GetNextCmdListNumber() const {return static_cast<Uint64>(m_NextCmdList);}
+	Uint64 GetCurrentFrameNumber()const {return static_cast<Uint64>(m_CurrentFrameNumber);}
 
     ID3D12CommandQueue *GetCmdQueue(){return m_pd3d12CmdQueue;}
 
-	Uint64 IncrementFence();
-	void WaitForFence(Uint64 FenceValue);
 	void IdleGPU(bool ReleasePendingObjects = false);
     CommandContext* AllocateCommandContext(const Char *ID = "");
-    Uint64 CloseAndExecuteCommandContext(CommandContext *pCtx);
+    void CloseAndExecuteCommandContext(CommandContext *pCtx);
     void DisposeCommandContext(CommandContext*);
 
     void SafeReleaseD3D12Object(ID3D12Object* pObj);
-    Uint64 FinishFrame();
+    void FinishFrame();
     
     DynamicUploadHeap* RequestUploadHeap();
     void ReleaseUploadHeap(DynamicUploadHeap* pUploadHeap);
-    Uint64 GetCurrentFrame()const {return m_CurrentFrame;}
 
 private:
     virtual void TestTextureFormat( TEXTURE_FORMAT TexFormat );
@@ -97,20 +96,64 @@ private:
     CPUDescriptorHeap m_CPUDescriptorHeaps[D3D12_DESCRIPTOR_HEAP_TYPE_NUM_TYPES];
     GPUDescriptorHeap m_GPUDescriptorHeaps[2]; // D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV == 0
                                                // D3D12_DESCRIPTOR_HEAP_TYPE_SAMPLER	 == 1
-
-	std::mutex m_FenceMutex;
-	std::mutex m_EventMutex;
-
-	CComPtr<ID3D12Fence> m_pFence;
-	Uint64 m_NextFenceValue;
-	Uint64 m_LastCompletedFenceValue;
-	HANDLE m_FenceEventHandle;
-
-    CComPtr<ID3D12Fence> m_pNumCompletedFramesFence;
-    Uint64 m_CurrentFrame = 0;
-    Uint64 m_NumCompletedFrames = 0;
-
-
+	
+	const Uint32 m_DynamicDescriptorAllocationChunkSize[2];
+
+	std::mutex m_CmdQueueMutex;
+
+	Atomics::AtomicInt64 m_CurrentFrameNumber;
+
+    // 0-based ordinal number of the command list that will be submitted to the GPU next time
+    Atomics::AtomicInt64 m_NextCmdList;
+
+    // Number of command lists that retired the GPU pipeline
+    //
+    //      To check if frame X is completed, 
+    //      strong inequality must be used:
+    //        X < m_NumCompletedCmdLists
+    //
+    volatile Uint64 m_NumCompletedCmdLists;
+
+    // The following basic requirement guarantees correctness of resource deallocation:
+    //
+    //        A resource is never released before the last draw command referencing it is invoked on the immediate context
+    //
+    // See http://diligentgraphics.com/diligent-engine/architecture/d3d12/managing-resource-lifetimes/
+
+    //
+    // CPU
+    //                       Last Reference
+    //                        of resource X
+    //                             |
+    //                             |     Submit Cmd       Submit Cmd            Submit Cmd
+    //                             |      List N           List N+1              List N+2
+    //                             V         |                |                     |
+    //    m_NextCmdList        |   *  N      |      N+1       |          N+2        |
+    //
+    //
+    //    m_NumCompletedCmdLists    |     N-2      |      N-1      |        N          |        N+1     |
+    //                              .              .               .                   .                .
+    // -----------------------------.--------------.---------------.-------------------.----------------.-------------
+    //                              .              .               .                   .                .
+    //       
+    // GPU                          | Cmd List N-2 | Cmd List N-1  |    Cmd List N     |   Cmd List N+1 |
+    //                                                                                 |
+    //                                                                                 |
+    //                                                                          Resource X can
+    //                                                                           be released
+    
+    // The fence is signaled right after the command list has been 
+    // submitted to the command queue for execution.
+    // Note that the meaning of the fence value is the TOTAL NUMBER OF COMPLETED COMMAND LISTS,
+    // NOT the ordinal number of the LAST completed cmd list
+    // If ordinal number of the current cmd list is N, then N+1 is signaled, so the
+    // cmd list X is complete when X < m_NumCompletedCmdLists
+    // This is convenient as the default fence value is 0, and hence 
+    // by default there are no completed cmd lists
+    CComPtr<ID3D12Fence> m_pCompletedCmdListFence;
+
+	HANDLE m_WaitForGPUEventHandle;
+    
     CommandListManager m_CmdListManager;
 
     typedef std::unique_ptr<CommandContext, STDDeleterRawMem<CommandContext> > ContextPoolElemType;
diff --git a/Graphics/GraphicsEngineD3D12/include/RootSignature.h b/Graphics/GraphicsEngineD3D12/include/RootSignature.h
index 750b2b9d..b0a9e2ce 100644
--- a/Graphics/GraphicsEngineD3D12/include/RootSignature.h
+++ b/Graphics/GraphicsEngineD3D12/include/RootSignature.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -272,8 +272,15 @@ private:
     };
 
     static const Uint8 InvalidRootTableIndex = static_cast<Uint8>(-1);
+    
+    // The array below contains array index of a CBV/SRV/UAV root table 
+    // in m_RootParams (NOT the Root Index!), for every variable type 
+    // (static, mutable, dynamic) and every shader type,
+    // or -1, if the table is not yet assigned to the combination
     Uint8 m_SrvCbvUavRootTablesMap[SHADER_VARIABLE_TYPE_NUM_TYPES * 6];
+    // This array contains the same data for Sampler root table
     Uint8 m_SamplerRootTablesMap[SHADER_VARIABLE_TYPE_NUM_TYPES * 6];
+
     RootParamsManager m_RootParams;
     
     struct StaticSamplerAttribs
diff --git a/Graphics/GraphicsEngineD3D12/include/SamplerD3D12Impl.h b/Graphics/GraphicsEngineD3D12/include/SamplerD3D12Impl.h
index 11226b64..fc920441 100644
--- a/Graphics/GraphicsEngineD3D12/include/SamplerD3D12Impl.h
+++ b/Graphics/GraphicsEngineD3D12/include/SamplerD3D12Impl.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/include/ShaderD3D12Impl.h b/Graphics/GraphicsEngineD3D12/include/ShaderD3D12Impl.h
index b39c70d6..79ef7fec 100644
--- a/Graphics/GraphicsEngineD3D12/include/ShaderD3D12Impl.h
+++ b/Graphics/GraphicsEngineD3D12/include/ShaderD3D12Impl.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/include/ShaderResourceBindingD3D12Impl.h b/Graphics/GraphicsEngineD3D12/include/ShaderResourceBindingD3D12Impl.h
index 025db186..b5824b17 100644
--- a/Graphics/GraphicsEngineD3D12/include/ShaderResourceBindingD3D12Impl.h
+++ b/Graphics/GraphicsEngineD3D12/include/ShaderResourceBindingD3D12Impl.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/include/ShaderResourceCacheD3D12.h b/Graphics/GraphicsEngineD3D12/include/ShaderResourceCacheD3D12.h
index aed6d32e..d82de76f 100644
--- a/Graphics/GraphicsEngineD3D12/include/ShaderResourceCacheD3D12.h
+++ b/Graphics/GraphicsEngineD3D12/include/ShaderResourceCacheD3D12.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -26,14 +26,15 @@
 /// \file
 /// Declaration of Diligent::ShaderResourceCacheD3D12 class
 
+// http://diligentgraphics.com/diligent-engine/architecture/d3d12/shader-resource-cache/
 
 // Shader resource cache stores D3D12 resources in a continuous chunk of memory:
 //   
 //
 //                                         __________________________________________________________
-//                                        |             m_pResources, m_NumResources                 |
-//  m_pMemory                             |                                                          |
-//  |                                     |                                                          V
+//  m_pMemory                             |             m_pResources, m_NumResources                 |
+//  |                                     |                                                          |
+//  V                                     |                                                          V
 //  |  RootTable[0]  |   ....    |  RootTable[Nrt-1]  |  Res[0]  |  ... |  Res[n-1]  |    ....     | Res[0]  |  ... |  Res[m-1]  |
 //       |                                                A \
 //       |                                                |  \
@@ -118,10 +119,11 @@ public:
 
     static const Uint32 InvalidDescriptorOffset = static_cast<Uint32>(-1);
 
+    //http://diligentgraphics.com/diligent-engine/architecture/d3d12/shader-resource-cache#Cache-Structure
     struct Resource
     {
         CachedResourceType Type = CachedResourceType::Unknown;
-        // CPU descriptor handle of a cached resource in external descriptor heap
+        // CPU descriptor handle of a cached resource in CPU-only descriptor heap
         // Note that for dynamic resources, this is the only available CPU descriptor handle
         D3D12_CPU_DESCRIPTOR_HANDLE CPUDescriptorHandle = {0};
         RefCntAutoPtr<IDeviceObject> pObject;
@@ -136,10 +138,10 @@ public:
         {}
 
         inline Resource& GetResource(Uint32 OffsetFromTableStart, 
-                                     const D3D12_DESCRIPTOR_HEAP_TYPE DescriptorHeapType, 
+                                     const D3D12_DESCRIPTOR_HEAP_TYPE dbgDescriptorHeapType, 
                                      const SHADER_TYPE dbgRefShaderType)
         {
-            VERIFY(m_dbgHeapType == DescriptorHeapType, "Incosistent descriptor heap type" )
+            VERIFY(m_dbgHeapType == dbgDescriptorHeapType, "Incosistent descriptor heap type" )
             VERIFY(m_dbgShaderType == dbgRefShaderType, "Incosistent shader type" )
 
             VERIFY(OffsetFromTableStart < m_NumResources, "Root table at index is not large enough to store descriptor at offset ", OffsetFromTableStart );
@@ -148,16 +150,16 @@ public:
 
         inline Uint32 GetSize()const{return m_NumResources; }
 
-        // Offset from the start of the descriptor heap alloction to the start of the table
-        Uint32 TableStartOffset = InvalidDescriptorOffset;
+        // Offset from the start of the descriptor heap allocation to the start of the table
+        Uint32 m_TableStartOffset = InvalidDescriptorOffset;
 
 #ifdef _DEBUG
         void SetDebugAttribs(Uint32 MaxOffset, 
-                             const D3D12_DESCRIPTOR_HEAP_TYPE DescriptorHeapType, 
+                             const D3D12_DESCRIPTOR_HEAP_TYPE dbgDescriptorHeapType, 
                              const SHADER_TYPE dbgRefShaderType)
         { 
             VERIFY_EXPR(m_NumResources == MaxOffset);
-            m_dbgHeapType = DescriptorHeapType;
+            m_dbgHeapType = dbgDescriptorHeapType;
             m_dbgShaderType = dbgRefShaderType;
         }
 
@@ -185,23 +187,23 @@ public:
 
     void SetDescriptorHeapSpace(DescriptorHeapAllocation &&CbcSrvUavHeapSpace, DescriptorHeapAllocation &&SamplerHeapSpace)
     {
-        VERIFY(m_SamplerHeapSpace.GetCpuHandle().ptr == 0 && m_CbcSrvUavHeapSpace.GetCpuHandle().ptr == 0, "Space has already been allocated in GPU descriptor heaps");
+        VERIFY(m_SamplerHeapSpace.GetCpuHandle().ptr == 0 && m_CbvSrvUavHeapSpace.GetCpuHandle().ptr == 0, "Space has already been allocated in GPU descriptor heaps");
 #ifdef _DEBUG
         Uint32 NumSamplerDescriptors = 0, NumSrvCbvUavDescriptors = 0;
         for (Uint32 rt = 0; rt < m_NumTables; ++rt)
         {
             auto &Tbl = GetRootTable(rt);
-            if(Tbl.TableStartOffset != InvalidDescriptorOffset)
+            if(Tbl.m_TableStartOffset != InvalidDescriptorOffset)
             {
                 if(Tbl.DbgGetHeapType() == D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV)
                 {
-                    VERIFY(Tbl.TableStartOffset == NumSrvCbvUavDescriptors, "Descriptor space allocation is not continuous")
-                    NumSrvCbvUavDescriptors = std::max(NumSrvCbvUavDescriptors, Tbl.TableStartOffset + Tbl.GetSize());
+                    VERIFY(Tbl.m_TableStartOffset == NumSrvCbvUavDescriptors, "Descriptor space allocation is not continuous")
+                    NumSrvCbvUavDescriptors = std::max(NumSrvCbvUavDescriptors, Tbl.m_TableStartOffset + Tbl.GetSize());
                 }
                 else
                 {
-                    VERIFY(Tbl.TableStartOffset == NumSamplerDescriptors, "Descriptor space allocation is not continuous")
-                    NumSamplerDescriptors = std::max(NumSamplerDescriptors, Tbl.TableStartOffset + Tbl.GetSize());
+                    VERIFY(Tbl.m_TableStartOffset == NumSamplerDescriptors, "Descriptor space allocation is not continuous")
+                    NumSamplerDescriptors = std::max(NumSamplerDescriptors, Tbl.m_TableStartOffset + Tbl.GetSize());
                 }
             }
         }
@@ -209,12 +211,12 @@ public:
         VERIFY(NumSamplerDescriptors == SamplerHeapSpace.GetNumHandles() || NumSamplerDescriptors == 0 && SamplerHeapSpace.GetCpuHandle(0).ptr == 0, "Unexpected descriptor heap allocation size" )
 #endif
 
-        m_CbcSrvUavHeapSpace = std::move(CbcSrvUavHeapSpace);
+        m_CbvSrvUavHeapSpace = std::move(CbcSrvUavHeapSpace);
         m_SamplerHeapSpace = std::move(SamplerHeapSpace);
     }
 
-    ID3D12DescriptorHeap* GetSrvCbvUavDescriptorHeap(){return m_CbcSrvUavHeapSpace.GetDescriptorHeap();}
-    ID3D12DescriptorHeap* GetSamplerDescriptorHeap(){return m_SamplerHeapSpace.GetDescriptorHeap();}
+    ID3D12DescriptorHeap* GetSrvCbvUavDescriptorHeap(){return m_CbvSrvUavHeapSpace.GetDescriptorHeap();}
+    ID3D12DescriptorHeap* GetSamplerDescriptorHeap()  {return m_SamplerHeapSpace.GetDescriptorHeap();}
 
     // Returns CPU descriptor handle of a shader visible descriptor heap allocation
     template<D3D12_DESCRIPTOR_HEAP_TYPE HeapType>
@@ -226,19 +228,19 @@ public:
         D3D12_CPU_DESCRIPTOR_HANDLE CPUDescriptorHandle = {0};
         // Descriptor heap allocation is not assigned for dynamic resources or 
         // in a special case when resource cache is used to store static 
-        // variable assignments for a shader
-        if( RootParam.TableStartOffset != InvalidDescriptorOffset )
+        // variable assignments for a shader. It is also not assigned to root views
+        if( RootParam.m_TableStartOffset != InvalidDescriptorOffset )
         {
-            VERIFY(RootParam.TableStartOffset + OffsetFromTableStart < RootParam.m_NumResources, "Offset is out of range");
+            VERIFY(RootParam.m_TableStartOffset + OffsetFromTableStart < RootParam.m_NumResources, "Offset is out of range");
             if( HeapType == D3D12_DESCRIPTOR_HEAP_TYPE_SAMPLER  )
             {
                 VERIFY_EXPR(!m_SamplerHeapSpace.IsNull());
-                CPUDescriptorHandle = m_SamplerHeapSpace.GetCpuHandle(RootParam.TableStartOffset + OffsetFromTableStart);
+                CPUDescriptorHandle = m_SamplerHeapSpace.GetCpuHandle(RootParam.m_TableStartOffset + OffsetFromTableStart);
             }
             else if( HeapType == D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV )
             {
-                VERIFY_EXPR(!m_CbcSrvUavHeapSpace.IsNull());
-                CPUDescriptorHandle = m_CbcSrvUavHeapSpace.GetCpuHandle(RootParam.TableStartOffset + OffsetFromTableStart);
+                VERIFY_EXPR(!m_CbvSrvUavHeapSpace.IsNull());
+                CPUDescriptorHandle = m_CbvSrvUavHeapSpace.GetCpuHandle(RootParam.m_TableStartOffset + OffsetFromTableStart);
             }
             else
             {
@@ -254,20 +256,20 @@ public:
     D3D12_GPU_DESCRIPTOR_HANDLE GetShaderVisibleTableGPUDescriptorHandle(Uint32 RootParamInd, Uint32 OffsetFromTableStart = 0)
     {
         auto &RootParam = GetRootTable(RootParamInd);
-        VERIFY_EXPR(RootParam.TableStartOffset != InvalidDescriptorOffset);
-        VERIFY(RootParam.TableStartOffset + OffsetFromTableStart < RootParam.m_NumResources, "Offset is out of range");
+        VERIFY(RootParam.m_TableStartOffset != InvalidDescriptorOffset, "GPU descriptor handle must never be requested for dynamic resources");
+        VERIFY(RootParam.m_TableStartOffset + OffsetFromTableStart < RootParam.m_NumResources, "Offset is out of range");
 
         D3D12_GPU_DESCRIPTOR_HANDLE GPUDescriptorHandle = {0};
         VERIFY( HeapType == RootParam.DbgGetHeapType(), "Invalid descriptor heap type");
         if( HeapType == D3D12_DESCRIPTOR_HEAP_TYPE_SAMPLER )
         {
             VERIFY_EXPR(!m_SamplerHeapSpace.IsNull());
-            GPUDescriptorHandle = m_SamplerHeapSpace.GetGpuHandle(RootParam.TableStartOffset + OffsetFromTableStart);
+            GPUDescriptorHandle = m_SamplerHeapSpace.GetGpuHandle(RootParam.m_TableStartOffset + OffsetFromTableStart);
         }
         else if( HeapType == D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV )
         {
-            VERIFY_EXPR(!m_CbcSrvUavHeapSpace.IsNull());
-            GPUDescriptorHandle = m_CbcSrvUavHeapSpace.GetGpuHandle(RootParam.TableStartOffset + OffsetFromTableStart);
+            VERIFY_EXPR(!m_CbvSrvUavHeapSpace.IsNull());
+            GPUDescriptorHandle = m_CbvSrvUavHeapSpace.GetGpuHandle(RootParam.m_TableStartOffset + OffsetFromTableStart);
         }
         else
         {
@@ -288,8 +290,11 @@ private:
     ShaderResourceCacheD3D12& operator = (const ShaderResourceCacheD3D12&) = delete;
     ShaderResourceCacheD3D12& operator = (ShaderResourceCacheD3D12&&) = delete;
 
+    // Allocation in a GPU-visible sampler descriptor heap
     DescriptorHeapAllocation m_SamplerHeapSpace;
-    DescriptorHeapAllocation m_CbcSrvUavHeapSpace;
+    
+    // Allocation in a GPU-visible CBV/SRV/UAV descriptor heap
+    DescriptorHeapAllocation m_CbvSrvUavHeapSpace;
 
     IMemoryAllocator *m_pAllocator=nullptr; 
     void *m_pMemory = nullptr;
diff --git a/Graphics/GraphicsEngineD3D12/include/ShaderResourceLayoutD3D12.h b/Graphics/GraphicsEngineD3D12/include/ShaderResourceLayoutD3D12.h
index 90d1ba27..038fd041 100644
--- a/Graphics/GraphicsEngineD3D12/include/ShaderResourceLayoutD3D12.h
+++ b/Graphics/GraphicsEngineD3D12/include/ShaderResourceLayoutD3D12.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -26,6 +26,7 @@
 /// \file
 /// Declaration of Diligent::ShaderResourceLayoutD3D12 class
 
+// http://diligentgraphics.com/diligent-engine/architecture/d3d12/shader-resource-layout/
 
 // All resources are stored in a single continuous chunk of memory using the following layout:
 //
@@ -51,9 +52,9 @@
 //
 //
 //   Every SRV_CBV_UAV and Sampler structure holds a reference to D3DShaderResourceAttribs structure from ShaderResources.
-//   ShaderResourceLayoutD3D12 holds shared pointer to ShaderResources instance. Note that ShaderResources::SamplerId references
-//   a sampler in ShaderResources, while SRV_CBV_UAV::SamplerId references a sampler in ShaderResourceLayoutD3D12, and the
-//   two are not the same
+//   ShaderResourceLayoutD3D12 holds shared pointer to ShaderResourcesD3D12 instance. Note that ShaderResources::SamplerId 
+//   references a sampler in ShaderResources, while SRV_CBV_UAV::SamplerId references a sampler in ShaderResourceLayoutD3D12, 
+//   and the two are not the same
 //
 //
 //                                                      ________________SamplerId____________________
@@ -77,19 +78,28 @@
 //   |                          |                 |                                                                        |                   
 //   | ShaderResourceCacheD3D12 |---------------->|                                   Resources                            | 
 //   |__________________________|                 |________________________________________________________________________|                   
-//                                                    
+//
+//   http://diligentgraphics.com/diligent-engine/architecture/d3d12/shader-resource-layout#Figure2
 //   Resources in the resource cache are identified by the root index and offset in the descriptor table
 //
 //                                
-//    ShaderResourceLayoutD3D12 is used by
-//      - ShaderD3D12Impl class instance to hold static resources of a shader; shader resource
-//        cache is used to store satatic resource bindings
-//      - PipelineStateD3D12Impl class instance to hold all kinds of resources. Root indices and
-//        descriptor table offsets are assigned during the initialization; no shader resource cache is used
-//      - ShaderResourceBindingD3D12Impl to hold all kind of resources; shader resource cache is assigned
+//    ShaderResourceLayoutD3D12 is used as follows:
+//    * Every pipeline state object (PipelineStateD3D12Impl) maintains shader resource layout for every active shader stage
+//      ** These resource layouts are not bound to a resource cache and are used as reference layouts for shader resource binding objects
+//      ** All variable types are preserved
+//      ** Root indices and descriptor table offsets are assigned during the initialization
+//      ** Resource cache is not assigned
+//    * Every shader object (ShaderD3D12Impl) contains shader resource layout that facilitates management of static shader resources
+//      ** The resource layout defines artificial layout and is bound to a resource cache that actually holds references to resources
+//      ** Resource cache is assigned and initialized
+//    * Every shader resource binding object (ShaderResourceBindingD3D12Impl) encompasses shader resource layout for every active shader 
+//      stage in the parent pipeline state
+//      ** Resource layouts are initialized by clonning reference layouts from the pipeline state object and are bound to the resource 
+//         cache that holds references to resources set by the application
+//      ** All shader variable types are clonned
+//      ** Resource cache is assigned, but not initialized; Initialization is performed by the root signature
 //
 
-
 // Set this define to 1 to use unordered_map to store shader variables. 
 // Note that sizeof(m_VariableHash)==128 (release mode, MS compiler, x64).
 #define USE_VARIABLE_HASH_MAP 0
@@ -118,7 +128,7 @@ public:
     ShaderResourceLayoutD3D12(IObject &Owner, IMemoryAllocator &ResourceLayoutDataAllocator);
 
     // This constructor is used by ShaderResourceBindingD3D12Impl to clone layout from the reference layout in PipelineStateD3D12Impl. 
-    // Root indices and descriptor table offsets must be correct. Resource cache is not initialized.
+    // Root indices and descriptor table offsets must be correct. Resource cache is assigned, but not initialized.
     ShaderResourceLayoutD3D12(IObject &Owner, 
                               const ShaderResourceLayoutD3D12& SrcLayout, 
                               IMemoryAllocator &ResourceLayoutDataAllocator,
@@ -136,8 +146,9 @@ public:
     //  The method is called by
     //  - ShaderD3D12Impl class instance to initialize static resource layout and initialize shader resource cache
     //    to hold static resources
-    //  - PipelineStateD3D12Impl class instance to hold all kind of resources. Root indices and
-    //    descriptor table offsets are assigned during the initialization; no shader resource cache is provided
+    //  - PipelineStateD3D12Impl class instance to reference all types of resources (static, mutable, dynamic). 
+    //    Root indices and descriptor table offsets are assigned during the initialization; 
+    //    no shader resource cache is provided
     void Initialize(ID3D12Device *pd3d12Device,
                     const std::shared_ptr<const ShaderResourcesD3D12>& pSrcResources, 
                     IMemoryAllocator &LayoutDataAllocator,
@@ -149,10 +160,10 @@ public:
     // sizeof(SRV_CBV_UAV) == 32 (x64)
     struct SRV_CBV_UAV : ShaderVariableD3DBase<ShaderResourceLayoutD3D12>
     {
-        SRV_CBV_UAV(const SRV_CBV_UAV&) = delete;
-        SRV_CBV_UAV(SRV_CBV_UAV&&) = delete;
+        SRV_CBV_UAV(const SRV_CBV_UAV&)              = delete;
+        SRV_CBV_UAV(SRV_CBV_UAV&&)                   = delete;
         SRV_CBV_UAV& operator = (const SRV_CBV_UAV&) = delete;
-        SRV_CBV_UAV& operator = (SRV_CBV_UAV&&) = delete;
+        SRV_CBV_UAV& operator = (SRV_CBV_UAV&&)      = delete;
 
         static const Uint32 ResTypeBits = 3;
         static const Uint32 RootIndBits = 16-ResTypeBits;
@@ -170,6 +181,8 @@ public:
         
         const Uint32 OffsetFromTableStart;
 
+        // Special copy constructor. Note that sampler ID refers to the ID of the sampler
+        // within THIS layout, and may not be the same as in original layout
         SRV_CBV_UAV(ShaderResourceLayoutD3D12 &ParentLayout, const SRV_CBV_UAV &rhs, Uint32 SamId ) :
             ResType_RootIndex(rhs.ResType_RootIndex),
             SamplerId(static_cast<Uint16>(SamId)),
@@ -182,8 +195,12 @@ public:
             VERIFY(IsValidRootIndex(), "Root index must be valid" )
         }
 
-        SRV_CBV_UAV(ShaderResourceLayoutD3D12 &ParentLayout, const D3DShaderResourceAttribs &_Attribs, 
-                    CachedResourceType ResType, Uint32 RootIndex, Uint32 _OffsetFromTableStart, Uint32 _SamplerId) :
+        SRV_CBV_UAV(ShaderResourceLayoutD3D12 &ParentLayout, 
+                    const D3DShaderResourceAttribs &_Attribs, 
+                    CachedResourceType ResType, 
+                    Uint32 RootIndex, 
+                    Uint32 _OffsetFromTableStart, 
+                    Uint32 _SamplerId) :
             ResType_RootIndex( (static_cast<Uint16>(ResType) << RootIndBits) | (RootIndex & RootIndMask)),
             SamplerId( static_cast<Uint16>(_SamplerId) ),
             OffsetFromTableStart(_OffsetFromTableStart),
@@ -206,9 +223,9 @@ public:
                 BindResource(ppObjects[Elem], FirstElement+Elem, nullptr);
         }
 
-        bool IsValidSampler()const{return GetSamplerId() != InvalidSamplerId;}
-        bool IsValidRootIndex()const{return GetRootIndex() != InvalidRootIndex;}
-        bool IsValidOffset()const{return OffsetFromTableStart != InvalidOffset;}
+        bool IsValidSampler()  const{return GetSamplerId()       != InvalidSamplerId;}
+        bool IsValidRootIndex()const{return GetRootIndex()       != InvalidRootIndex;}
+        bool IsValidOffset()   const{return OffsetFromTableStart != InvalidOffset;   }
 
         CachedResourceType GetResType()const
         {
@@ -231,7 +248,10 @@ public:
                                         // |  Root index  |   ResType   |
         const Uint16 SamplerId;
 
-        void CacheCB(IDeviceObject *pBuffer, ShaderResourceCacheD3D12::Resource& DstRes, Uint32 ArrayInd, D3D12_CPU_DESCRIPTOR_HANDLE ShdrVisibleHeapCPUDescriptorHandle);
+        void CacheCB(IDeviceObject *pBuffer, 
+                     ShaderResourceCacheD3D12::Resource& DstRes, 
+                     Uint32 ArrayInd, 
+                     D3D12_CPU_DESCRIPTOR_HANDLE ShdrVisibleHeapCPUDescriptorHandle);
 
         template<typename TResourceViewType, 
                  typename TViewTypeEnum,
@@ -247,16 +267,16 @@ public:
     // sizeof(Sampler) == 24 (x64)
     struct Sampler
     {
-        Sampler(const Sampler&) = delete;
-        Sampler(Sampler&&) = delete;
+        Sampler(const Sampler&)              = delete;
+        Sampler(Sampler&&)                   = delete;
         Sampler& operator = (const Sampler&) = delete;
-        Sampler& operator = (Sampler&&) = delete;
+        Sampler& operator = (Sampler&&)      = delete;
 
         const D3DShaderResourceAttribs &Attribs;
         ShaderResourceLayoutD3D12 &m_ParentResLayout;
 
         static const Uint32 InvalidRootIndex = static_cast<Uint32>(-1);
-        static const Uint32 InvalidOffset = static_cast<Uint32>(-1);
+        static const Uint32 InvalidOffset    = static_cast<Uint32>(-1);
 
         const Uint32 RootIndex;
         const Uint32 OffsetFromTableStart;
@@ -282,8 +302,8 @@ public:
             VERIFY(IsValidOffset(), "Offset must be valid" )
         }
 
-        bool IsValidRootIndex()const{return RootIndex != InvalidRootIndex;}
-        bool IsValidOffset()const{return OffsetFromTableStart != InvalidOffset;}
+        bool IsValidRootIndex()const{return RootIndex            != InvalidRootIndex;}
+        bool IsValidOffset()   const{return OffsetFromTableStart != InvalidOffset;   }
 
         void CacheSampler(class ITextureViewD3D12 *pTexViewD3D12, Uint32 ArrayIndex, D3D12_CPU_DESCRIPTOR_HANDLE ShdrVisibleHeapCPUDescriptorHandle);
     };
@@ -317,7 +337,7 @@ private:
     std::unique_ptr<void, STDDeleterRawMem<void> > m_ResourceBuffer;
     Sampler* m_Samplers = nullptr;
     Uint16 m_NumCbvSrvUav[SHADER_VARIABLE_TYPE_NUM_TYPES] = {0,0,0};
-    Uint16 m_NumSamplers[SHADER_VARIABLE_TYPE_NUM_TYPES] = {0,0,0};
+    Uint16 m_NumSamplers [SHADER_VARIABLE_TYPE_NUM_TYPES] = {0,0,0};
 
     Uint32 GetSrvCbvUavOffset(SHADER_VARIABLE_TYPE VarType, Uint32 r)const
     {
diff --git a/Graphics/GraphicsEngineD3D12/include/ShaderResourcesD3D12.h b/Graphics/GraphicsEngineD3D12/include/ShaderResourcesD3D12.h
index f58ce20d..940a1350 100644
--- a/Graphics/GraphicsEngineD3D12/include/ShaderResourcesD3D12.h
+++ b/Graphics/GraphicsEngineD3D12/include/ShaderResourcesD3D12.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/include/SwapChainD3D12Impl.h b/Graphics/GraphicsEngineD3D12/include/SwapChainD3D12Impl.h
index e7e8f312..197ccd68 100644
--- a/Graphics/GraphicsEngineD3D12/include/SwapChainD3D12Impl.h
+++ b/Graphics/GraphicsEngineD3D12/include/SwapChainD3D12Impl.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/include/TextureD3D12Impl.h b/Graphics/GraphicsEngineD3D12/include/TextureD3D12Impl.h
index 039de70f..29c0d117 100644
--- a/Graphics/GraphicsEngineD3D12/include/TextureD3D12Impl.h
+++ b/Graphics/GraphicsEngineD3D12/include/TextureD3D12Impl.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -44,11 +44,13 @@ class TextureD3D12Impl : public TextureBase<ITextureD3D12, TextureViewD3D12Impl,
 public:
     typedef TextureBase<ITextureD3D12, TextureViewD3D12Impl, FixedBlockMemoryAllocator, FixedBlockMemoryAllocator> TTextureBase;
 
+    // Creates a new D3D12 resource
     TextureD3D12Impl(FixedBlockMemoryAllocator &TexObjAllocator, 
                      FixedBlockMemoryAllocator &TexViewObjAllocator,
                      class RenderDeviceD3D12Impl *pDeviceD3D12, 
                      const TextureDesc& TexDesc, 
                      const TextureData &InitData = TextureData());
+    // Attaches to an existing D3D12 resource
     TextureD3D12Impl(FixedBlockMemoryAllocator &TexObjAllocator, 
                      FixedBlockMemoryAllocator &TexViewObjAllocator,
                      class RenderDeviceD3D12Impl *pDeviceD3D12, 
diff --git a/Graphics/GraphicsEngineD3D12/include/TextureViewD3D12Impl.h b/Graphics/GraphicsEngineD3D12/include/TextureViewD3D12Impl.h
index 6256ca0a..29bcbd9f 100644
--- a/Graphics/GraphicsEngineD3D12/include/TextureViewD3D12Impl.h
+++ b/Graphics/GraphicsEngineD3D12/include/TextureViewD3D12Impl.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -50,12 +50,9 @@ public:
 
     virtual void QueryInterface( const Diligent::INTERFACE_ID &IID, IObject **ppInterface )override;
 
-    //virtual ID3D12View* GetD3D12View()override;
-   
     void GenerateMips( IDeviceContext *pContext )override;
     
     virtual D3D12_CPU_DESCRIPTOR_HANDLE GetCPUDescriptorHandle()override{return m_Descriptor.GetCpuHandle();}
-    //virtual D3D12_GPU_DESCRIPTOR_HANDLE GetGPUDescriptorHandle()override{return m_Descriptor.GetGpuHandle();}
 
 protected:
     /// D3D12 view descriptor handle
diff --git a/Graphics/GraphicsEngineD3D12/include/pch.h b/Graphics/GraphicsEngineD3D12/include/pch.h
index f2f0b7f4..225f72b4 100644
--- a/Graphics/GraphicsEngineD3D12/include/pch.h
+++ b/Graphics/GraphicsEngineD3D12/include/pch.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/interface/BufferD3D12.h b/Graphics/GraphicsEngineD3D12/interface/BufferD3D12.h
index f3e69a13..823965a9 100644
--- a/Graphics/GraphicsEngineD3D12/interface/BufferD3D12.h
+++ b/Graphics/GraphicsEngineD3D12/interface/BufferD3D12.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/interface/BufferViewD3D12.h b/Graphics/GraphicsEngineD3D12/interface/BufferViewD3D12.h
index 7d9e45c9..a388e4c6 100644
--- a/Graphics/GraphicsEngineD3D12/interface/BufferViewD3D12.h
+++ b/Graphics/GraphicsEngineD3D12/interface/BufferViewD3D12.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/interface/PipelineStateD3D12.h b/Graphics/GraphicsEngineD3D12/interface/PipelineStateD3D12.h
index c31ea4cc..e978c014 100644
--- a/Graphics/GraphicsEngineD3D12/interface/PipelineStateD3D12.h
+++ b/Graphics/GraphicsEngineD3D12/interface/PipelineStateD3D12.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/interface/RenderDeviceD3D12.h b/Graphics/GraphicsEngineD3D12/interface/RenderDeviceD3D12.h
index 309d355e..3d37c0a8 100644
--- a/Graphics/GraphicsEngineD3D12/interface/RenderDeviceD3D12.h
+++ b/Graphics/GraphicsEngineD3D12/interface/RenderDeviceD3D12.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/interface/RenderDeviceFactoryD3D12.h b/Graphics/GraphicsEngineD3D12/interface/RenderDeviceFactoryD3D12.h
index f3aa45f4..2a81cf76 100644
--- a/Graphics/GraphicsEngineD3D12/interface/RenderDeviceFactoryD3D12.h
+++ b/Graphics/GraphicsEngineD3D12/interface/RenderDeviceFactoryD3D12.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/interface/SamplerD3D12.h b/Graphics/GraphicsEngineD3D12/interface/SamplerD3D12.h
index 4359fdc5..f8d98e69 100644
--- a/Graphics/GraphicsEngineD3D12/interface/SamplerD3D12.h
+++ b/Graphics/GraphicsEngineD3D12/interface/SamplerD3D12.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/interface/ShaderD3D12.h b/Graphics/GraphicsEngineD3D12/interface/ShaderD3D12.h
index 50aa22aa..c8bca697 100644
--- a/Graphics/GraphicsEngineD3D12/interface/ShaderD3D12.h
+++ b/Graphics/GraphicsEngineD3D12/interface/ShaderD3D12.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/interface/ShaderResourceBindingD3D12.h b/Graphics/GraphicsEngineD3D12/interface/ShaderResourceBindingD3D12.h
index 6038b88b..27162053 100644
--- a/Graphics/GraphicsEngineD3D12/interface/ShaderResourceBindingD3D12.h
+++ b/Graphics/GraphicsEngineD3D12/interface/ShaderResourceBindingD3D12.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/interface/SwapChainD3D12.h b/Graphics/GraphicsEngineD3D12/interface/SwapChainD3D12.h
index eacc0ef4..ab936019 100644
--- a/Graphics/GraphicsEngineD3D12/interface/SwapChainD3D12.h
+++ b/Graphics/GraphicsEngineD3D12/interface/SwapChainD3D12.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/interface/TextureD3D12.h b/Graphics/GraphicsEngineD3D12/interface/TextureD3D12.h
index 2fe585ce..449f2692 100644
--- a/Graphics/GraphicsEngineD3D12/interface/TextureD3D12.h
+++ b/Graphics/GraphicsEngineD3D12/interface/TextureD3D12.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/interface/TextureViewD3D12.h b/Graphics/GraphicsEngineD3D12/interface/TextureViewD3D12.h
index 967d28a1..f9c83a61 100644
--- a/Graphics/GraphicsEngineD3D12/interface/TextureViewD3D12.h
+++ b/Graphics/GraphicsEngineD3D12/interface/TextureViewD3D12.h
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/src/BufferD3D12Impl.cpp b/Graphics/GraphicsEngineD3D12/src/BufferD3D12Impl.cpp
index 1a516ad3..9f75d08e 100644
--- a/Graphics/GraphicsEngineD3D12/src/BufferD3D12Impl.cpp
+++ b/Graphics/GraphicsEngineD3D12/src/BufferD3D12Impl.cpp
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -367,7 +367,7 @@ void BufferD3D12Impl::CreateCBV(D3D12_CPU_DESCRIPTOR_HANDLE CBVDescriptor)
 void BufferD3D12Impl::DbgVerifyDynamicAllocation(Uint32 ContextId)
 {
     VERIFY(m_DynamicData[ContextId].GPUAddress != 0, "Dynamic buffer must be mapped before the first use");
-    auto CurrentFrame = ValidatedCast<RenderDeviceD3D12Impl>(GetDevice())->GetCurrentFrame();
+	auto CurrentFrame = ValidatedCast<RenderDeviceD3D12Impl>(GetDevice())->GetCurrentFrameNumber();
     VERIFY(m_DynamicData[ContextId].FrameNum == CurrentFrame, "Dynamic allocation is out-of-date. Dynamic buffer must be mapped in the same frame it is used.");
     VERIFY(GetState() == D3D12_RESOURCE_STATE_GENERIC_READ, "Dynamic buffers are expected to always be in D3D12_RESOURCE_STATE_GENERIC_READ state")
 }
diff --git a/Graphics/GraphicsEngineD3D12/src/BufferViewD3D12Impl.cpp b/Graphics/GraphicsEngineD3D12/src/BufferViewD3D12Impl.cpp
index e27c91ea..f0f7b2d7 100644
--- a/Graphics/GraphicsEngineD3D12/src/BufferViewD3D12Impl.cpp
+++ b/Graphics/GraphicsEngineD3D12/src/BufferViewD3D12Impl.cpp
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/src/CommandContext.cpp b/Graphics/GraphicsEngineD3D12/src/CommandContext.cpp
index 932eb333..9f689040 100644
--- a/Graphics/GraphicsEngineD3D12/src/CommandContext.cpp
+++ b/Graphics/GraphicsEngineD3D12/src/CommandContext.cpp
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -21,21 +21,6 @@
  *  of the possibility of such damages.
  */
 
-//
-// Copyright (c) Microsoft. All rights reserved.
-// This code is licensed under the MIT License (MIT).
-// THIS CODE IS PROVIDED *AS IS* WITHOUT WARRANTY OF
-// ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING ANY
-// IMPLIED WARRANTIES OF FITNESS FOR A PARTICULAR
-// PURPOSE, MERCHANTABILITY, OR NON-INFRINGEMENT.
-//
-// Developed by Minigraph
-//
-// Author:  James Stanard 
-//
-// Adapted to Diligent Engine: Egor Yusov
-//
-
 #include "pch.h"
 #include "CommandContext.h"
 #include "TextureD3D12Impl.h"
@@ -48,7 +33,7 @@ namespace Diligent
 CommandContext::CommandContext( IMemoryAllocator &MemAllocator,
                                 CommandListManager &CmdListManager, 
                                 GPUDescriptorHeap GPUDescriptorHeaps[],
-                                Uint32 DynamicDescriptorAllocationChunkSize[]) :
+                                const Uint32 DynamicDescriptorAllocationChunkSize[]) :
 	m_pCurGraphicsRootSignature( nullptr),
 	m_pCurGraphicsPipelineState( nullptr),
 	m_pCurComputeRootSignature( nullptr),
@@ -112,22 +97,6 @@ ID3D12GraphicsCommandList* CommandContext::Close(ID3D12CommandAllocator **ppAllo
 }
 
 
-#if 0
-void CommandContext::BindDescriptorHeaps( void )
-{
-	UINT NonNullHeaps = 0;
-	ID3D12DescriptorHeap* HeapsToBind[D3D12_DESCRIPTOR_HEAP_TYPE_NUM_TYPES];
-	for (UINT i = 0; i < D3D12_DESCRIPTOR_HEAP_TYPE_NUM_TYPES; ++i)
-	{
-		ID3D12DescriptorHeap* HeapIter = m_CurrentDescriptorHeaps[i];
-		if (HeapIter != nullptr)
-			HeapsToBind[NonNullHeaps++] = HeapIter;
-	}
-
-	if (NonNullHeaps > 0)
-		m_pCommandList->SetDescriptorHeaps(NonNullHeaps, HeapsToBind);
-}
-#endif 
 
 void GraphicsContext::SetRenderTargets( UINT NumRTVs, ITextureViewD3D12** ppRTVs, ITextureViewD3D12* pDSV )
 {
@@ -280,39 +249,6 @@ void CommandContext::TransitionResource(D3D12ResourceBase& Resource, IDeviceObje
         FlushResourceBarriers();
 }
 
-#if 0
-void CommandContext::BeginResourceTransition(GpuResource& Resource, D3D12_RESOURCE_STATES NewState, bool FlushImmediate)
-{
-	// If it's already transitioning, finish that transition
-	if (Resource.m_TransitioningState != (D3D12_RESOURCE_STATES)-1)
-		TransitionResource(Resource, Resource.m_TransitioningState);
-
-	D3D12_RESOURCE_STATES OldState = Resource.m_UsageState;
-
-	if (OldState != NewState)
-	{
-		ASSERT(m_NumBarriersToFlush < 16, "Exceeded arbitrary limit on buffered barriers");
-		D3D12_RESOURCE_BARRIER& BarrierDesc = m_ResourceBarrierBuffer[m_NumBarriersToFlush++];
-
-		BarrierDesc.Type = D3D12_RESOURCE_BARRIER_TYPE_TRANSITION;
-		BarrierDesc.Transition.pResource = Resource.GetResource();
-		BarrierDesc.Transition.Subresource = D3D12_RESOURCE_BARRIER_ALL_SUBRESOURCES;
-		BarrierDesc.Transition.StateBefore = OldState;
-		BarrierDesc.Transition.StateAfter = NewState;
-
-		BarrierDesc.Flags = D3D12_RESOURCE_BARRIER_FLAG_BEGIN_ONLY;
-
-		Resource.m_TransitioningState = NewState;
-	}
-
-	if (FlushImmediate || m_NumBarriersToFlush == 16)
-	{
-		m_pCommandList->ResourceBarrier(m_NumBarriersToFlush, m_ResourceBarrierBuffer);
-		m_NumBarriersToFlush = 0;
-	}
-}
-#endif
-
 void CommandContext::FlushResourceBarriers()
 {
 	if (m_PendingResourceBarriers.empty())
@@ -357,7 +293,7 @@ void CommandContext::InsertAliasBarrier(D3D12ResourceBase& Before, D3D12Resource
         FlushResourceBarriers();
 }
 
-void CommandContext::DiscardUsedDescriptorHeaps(Uint64 FrameNumber)
+void CommandContext::DiscardDynamicDescriptors(Uint64 FrameNumber)
 {
     for(size_t HeapType = 0; HeapType < _countof(m_DynamicGPUDescriptorAllocator); ++HeapType)
         m_DynamicGPUDescriptorAllocator[HeapType].DiscardAllocations(FrameNumber);
@@ -369,81 +305,4 @@ DescriptorHeapAllocation CommandContext::AllocateDynamicGPUVisibleDescriptor( D3
     return m_DynamicGPUDescriptorAllocator[Type].Allocate(Count);
 }
 
-#if 0
-
-void CommandContext::FillBuffer( GpuResource& Dest, size_t DestOffset, DWParam Value, size_t NumBytes )
-{
-	DynAlloc TempSpace = m_CpuLinearAllocator.Allocate( NumBytes, 512 );
-	__m128 VectorValue = _mm_set1_ps(Value.Float);
-	SIMDMemFill(TempSpace.DataPtr, VectorValue, Math::DivideByMultiple(NumBytes, 16));
-	CopyBufferRegion(Dest, DestOffset, TempSpace.Buffer, TempSpace.Offset, NumBytes );
-}
-
-void CommandContext::CopySubresource(GpuResource& Dest, UINT DestSubIndex, GpuResource& Src, UINT SrcSubIndex)
-{
-	// TODO:  Add a TransitionSubresource()?
-	TransitionResource(Dest, D3D12_RESOURCE_STATE_COPY_DEST);
-	TransitionResource(Src, D3D12_RESOURCE_STATE_COPY_SOURCE);
-	FlushResourceBarriers();
-
-	D3D12_TEXTURE_COPY_LOCATION DestLocation =
-	{
-		Dest.GetResource(),
-		D3D12_TEXTURE_COPY_TYPE_SUBRESOURCE_INDEX,
-		DestSubIndex
-	};
-
-	D3D12_TEXTURE_COPY_LOCATION SrcLocation =
-	{
-		Src.GetResource(),
-		D3D12_TEXTURE_COPY_TYPE_SUBRESOURCE_INDEX,
-		SrcSubIndex
-	};
-
-	m_pCommandList->CopyTextureRegion(&DestLocation, 0, 0, 0, &SrcLocation, nullptr);
-}
-
-void CommandContext::InitializeTextureArraySlice(GpuResource& Dest, UINT SliceIndex, GpuResource& Src)
-{
-	CommandContext& Context = CommandContext::Begin();
-
-	Context.TransitionResource(Dest, D3D12_RESOURCE_STATE_COPY_DEST);
-	Context.TransitionResource(Src, D3D12_RESOURCE_STATE_COPY_SOURCE);
-	Context.FlushResourceBarriers();
-
-	const D3D12_RESOURCE_DESC& DestDesc = Dest.GetResource()->GetDesc();
-	const D3D12_RESOURCE_DESC& SrcDesc = Src.GetResource()->GetDesc();
-
-	ASSERT(SliceIndex < DestDesc.DepthOrArraySize &&
-		SrcDesc.DepthOrArraySize == 1 &&
-		DestDesc.Width == SrcDesc.Width &&
-		DestDesc.Height == SrcDesc.Height &&
-		DestDesc.MipLevels <= SrcDesc.MipLevels
-		);
-
-	UINT SubResourceIndex = SliceIndex * DestDesc.MipLevels;
-
-	for (UINT i = 0; i < DestDesc.MipLevels; ++i)
-	{
-		D3D12_TEXTURE_COPY_LOCATION destCopyLocation =
-		{
-			Dest.GetResource(),
-			D3D12_TEXTURE_COPY_TYPE_SUBRESOURCE_INDEX,
-			SubResourceIndex + i
-		};
-
-		D3D12_TEXTURE_COPY_LOCATION srcCopyLocation =
-		{
-			Src.GetResource(),
-			D3D12_TEXTURE_COPY_TYPE_SUBRESOURCE_INDEX,
-			i
-		};
-
-		Context.m_pCommandList->CopyTextureRegion(&destCopyLocation, 0, 0, 0, &srcCopyLocation, nullptr);
-	}
-
-	Context.CloseAndExecute();
-}
-#endif
-
 }
diff --git a/Graphics/GraphicsEngineD3D12/src/CommandListManager.cpp b/Graphics/GraphicsEngineD3D12/src/CommandListManager.cpp
index 8ffc64ce..b9b10954 100644
--- a/Graphics/GraphicsEngineD3D12/src/CommandListManager.cpp
+++ b/Graphics/GraphicsEngineD3D12/src/CommandListManager.cpp
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -72,9 +72,23 @@ void CommandListManager::RequestAllocator(ID3D12CommandAllocator** ppAllocator)
 
     if (!m_DiscardedAllocators.empty())
 	{
+        // Pick the oldest allocator at the front of the deque
+        // If this allocator is not yet available, there is no sense in
+        // looking at the rest of allocators
 		auto& AllocatorPair = m_DiscardedAllocators.front();
-
-		if (m_pDeviceD3D12->IsFenceComplete(AllocatorPair.first))
+        
+        // Get the NUMBER OF COMPLETED cmd lists
+        auto NumCompeltedCmdLists = m_pDeviceD3D12->GetNumCompletedCmdLists();
+        // Note that NumCompeltedCmdLists only grows. So if after we queried
+        // the value, the actual value is increased in other thread, this will not
+        // be an issue as the only consequence is that the allocator that is 
+        // potentially available may not be used.
+
+        // AllocatorPair.first is the NUMBER of the command list.
+        // If command list number is N, it can be reused when
+        // NumCompeltedCmdLists is at least N+1
+        // (To reuse allocator used to create CmdList 0, NumCompeltedCmdLists must be at least 1)
+		if ( AllocatorPair.first < NumCompeltedCmdLists )
 		{
 			*ppAllocator = AllocatorPair.second.Detach();
 			auto hr = (*ppAllocator)->Reset();
@@ -95,12 +109,13 @@ void CommandListManager::RequestAllocator(ID3D12CommandAllocator** ppAllocator)
 	}
 }
 
-void CommandListManager::DiscardAllocator( Uint64 FenceValue, ID3D12CommandAllocator* pAllocator )
+void CommandListManager::DiscardAllocator( Uint64 CmdListNum, ID3D12CommandAllocator* pAllocator )
 {
 	std::lock_guard<std::mutex> LockGuard(m_AllocatorMutex);
 
-	// That fence value indicates we are free to reset the allocator
-	m_DiscardedAllocators.emplace_back( FenceValue, CComPtr<ID3D12CommandAllocator>(pAllocator) );
+    // CmdListNum is the number of the command list that was created by this allocator.
+    // This value is used to understand when it is safe to reuse the allocator
+	m_DiscardedAllocators.emplace_back( CmdListNum, CComPtr<ID3D12CommandAllocator>(pAllocator) );
 }
 
 }
diff --git a/Graphics/GraphicsEngineD3D12/src/D3D12ResourceBase.cpp b/Graphics/GraphicsEngineD3D12/src/D3D12ResourceBase.cpp
index b2e9f431..0744fda7 100644
--- a/Graphics/GraphicsEngineD3D12/src/D3D12ResourceBase.cpp
+++ b/Graphics/GraphicsEngineD3D12/src/D3D12ResourceBase.cpp
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/src/D3D12TypeConversions.cpp b/Graphics/GraphicsEngineD3D12/src/D3D12TypeConversions.cpp
index 738fbc98..68082795 100644
--- a/Graphics/GraphicsEngineD3D12/src/D3D12TypeConversions.cpp
+++ b/Graphics/GraphicsEngineD3D12/src/D3D12TypeConversions.cpp
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/src/D3D12Utils.cpp b/Graphics/GraphicsEngineD3D12/src/D3D12Utils.cpp
index a1f82e1c..c2428e16 100644
--- a/Graphics/GraphicsEngineD3D12/src/D3D12Utils.cpp
+++ b/Graphics/GraphicsEngineD3D12/src/D3D12Utils.cpp
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/src/DLLMain.cpp b/Graphics/GraphicsEngineD3D12/src/DLLMain.cpp
index fff890c0..94065164 100644
--- a/Graphics/GraphicsEngineD3D12/src/DLLMain.cpp
+++ b/Graphics/GraphicsEngineD3D12/src/DLLMain.cpp
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/src/DescriptorHeap.cpp b/Graphics/GraphicsEngineD3D12/src/DescriptorHeap.cpp
index a8ea6756..d226a3b8 100644
--- a/Graphics/GraphicsEngineD3D12/src/DescriptorHeap.cpp
+++ b/Graphics/GraphicsEngineD3D12/src/DescriptorHeap.cpp
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -29,7 +29,7 @@
 namespace Diligent
 {
 
-
+// Creates a new descriptor heap and reference the entire heap
 DescriptorHeapAllocationManager::DescriptorHeapAllocationManager(IMemoryAllocator &Allocator, 
                                                                  RenderDeviceD3D12Impl *pDeviceD3D12Impl,
                                                                  IDescriptorAllocator *pParentAllocator,
@@ -54,6 +54,8 @@ DescriptorHeapAllocationManager::DescriptorHeapAllocationManager(IMemoryAllocato
         m_FirstGPUHandle = m_pd3d12DescriptorHeap->GetGPUDescriptorHandleForHeapStart();
 }
 
+// Uses subrange of descriptors in the existing D3D12 descriptor heap
+// that starts at offset FirstDescriptor and uses NumDescriptors descriptors
 DescriptorHeapAllocationManager::DescriptorHeapAllocationManager(IMemoryAllocator &Allocator, 
                                                                  RenderDeviceD3D12Impl *pDeviceD3D12Impl,
                                                                  IDescriptorAllocator *pParentAllocator,
@@ -90,40 +92,59 @@ DescriptorHeapAllocationManager::~DescriptorHeapAllocationManager()
 DescriptorHeapAllocation DescriptorHeapAllocationManager::Allocate(uint32_t Count)
 {
     std::lock_guard<std::mutex> LockGuard(m_AllocationMutex);
+    // Methods of VariableSizeGPUAllocationsManager class are not thread safe!
 
+    // Use variable-size GPU allocations manager to allocate the requested number of descriptors
     auto DescriptorHandleOffset = m_FreeBlockManager.Allocate(Count);
     if (DescriptorHandleOffset == VariableSizeGPUAllocationsManager::InvalidOffset)
     {
         return DescriptorHeapAllocation();
     }
 
+    // Compute the first CPU and GPU descriptor handles in the allocation by
+    // offseting the first CPU and GPU descriptor handle in the range
     auto CPUHandle = m_FirstCPUHandle;
     CPUHandle.ptr += DescriptorHandleOffset * m_DescriptorSize;
 
-    auto GPUHandle = m_FirstGPUHandle;
+    auto GPUHandle = m_FirstGPUHandle; // Will be null if the heap is not GPU-visible
     if(m_HeapDesc.Flags & D3D12_DESCRIPTOR_HEAP_FLAG_SHADER_VISIBLE)
         GPUHandle.ptr += DescriptorHandleOffset * m_DescriptorSize;
 
-    VERIFY(m_ThisManagerId < std::numeric_limits<Uint16>::max(), "ManagerID exceed allowed limit");
-	DescriptorHeapAllocation Allocation( m_pParentAllocator, m_pd3d12DescriptorHeap, CPUHandle, GPUHandle, Count, static_cast<Uint16>(m_ThisManagerId));
-
-	return Allocation;
+    VERIFY(m_ThisManagerId < std::numeric_limits<Uint16>::max(), "ManagerID exceeds 16-bit range");
+	return DescriptorHeapAllocation( m_pParentAllocator, m_pd3d12DescriptorHeap, CPUHandle, GPUHandle, Count, static_cast<Uint16>(m_ThisManagerId));
 }
 
 void DescriptorHeapAllocationManager::Free(DescriptorHeapAllocation&& Allocation)
 {
     std::lock_guard<std::mutex> LockGuard(m_AllocationMutex);
+    // Methods of VariableSizeGPUAllocationsManager class are not thread safe!
 
     VERIFY(Allocation.GetAllocationManagerId() == m_ThisManagerId, "Invalid descriptor heap manager Id")
 
     auto DescriptorOffset = (Allocation.GetCpuHandle().ptr - m_FirstCPUHandle.ptr) / m_DescriptorSize;
-    m_FreeBlockManager.Free(DescriptorOffset, Allocation.GetNumHandles(), m_pDeviceD3D12Impl->GetCurrentFrame());
+    
+	// Note that the allocation is not released immediately, but added to the release queue in the allocations manager
+	
+    // The following basic requirement guarantees correctness of resource deallocation:
+    //
+    //        A resource is never released before the last draw command referencing it is invoked on the immediate context
+    //
+    // See http://diligentgraphics.com/diligent-engine/architecture/d3d12/managing-resource-lifetimes/
+    //
+    // If basic requirement is met, GetNextCmdListNumber() will never return a number that is less than the last
+    // command list number that references descriptors from the allocation
+    m_FreeBlockManager.Free(DescriptorOffset, Allocation.GetNumHandles(), m_pDeviceD3D12Impl->GetNextCmdListNumber());
+    
+	// Clear the allocation
     Allocation = DescriptorHeapAllocation();
 }
 
-void DescriptorHeapAllocationManager::ReleaseStaleAllocations(Uint64 NumCompletedFrames)
+void DescriptorHeapAllocationManager::ReleaseStaleAllocations(Uint64 NumCompletedCmdLists)
 {
-    m_FreeBlockManager.ReleaseCompletedFrames(NumCompletedFrames);
+    std::lock_guard<std::mutex> LockGuard(m_AllocationMutex);
+    // Methods of VariableSizeGPUAllocationsManager class are not thread safe!
+
+    m_FreeBlockManager.ReleaseStaleAllocations(NumCompletedCmdLists);
 }
 
 
@@ -151,33 +172,55 @@ CPUDescriptorHeap::~CPUDescriptorHeap()
     VERIFY(m_CurrentSize == 0, "Not all allocations released" );
     
     VERIFY(m_AvailableHeaps.size() == m_HeapPool.size(), "Not all descriptor heap pools are released");
+	Uint32 TotalDescriptors = 0;
     for (auto HeapPoolIt = m_HeapPool.begin(); HeapPoolIt != m_HeapPool.end(); ++HeapPoolIt)
     {
         VERIFY(HeapPoolIt->GetNumAvailableDescriptors() == m_HeapDesc.NumDescriptors, "Not all descriptors in the descriptor pool are released");
-    }
+		TotalDescriptors += HeapPoolIt->GetMaxDescriptors();
+	}
 
-    LOG_INFO_MESSAGE("Max ", GetD3D12DescriptorHeapTypeLiteralName(m_HeapDesc.Type), " CPU heap size: ", m_MaxHeapSize);
+    LOG_INFO_MESSAGE(GetD3D12DescriptorHeapTypeLiteralName(m_HeapDesc.Type), " CPU heap max size: ", m_MaxHeapSize, " (", m_MaxHeapSize*100/ TotalDescriptors, "%) "
+					 ". Max stale size: ", m_MaxStaleSize, " (", m_MaxStaleSize * 100 / TotalDescriptors, "%)");
 }
 
 DescriptorHeapAllocation CPUDescriptorHeap::Allocate( uint32_t Count )
 {
     std::lock_guard<std::mutex> LockGuard(m_AllocationMutex);
+    // Note that every DescriptorHeapAllocationManager object instance is itslef
+    // thread-safe. Nested mutexes cannot cause a deadlock
+
     DescriptorHeapAllocation Allocation;
+    // Go through all descriptor heap managers that have free descriptors
     for (auto AvailableHeapIt = m_AvailableHeaps.begin(); AvailableHeapIt != m_AvailableHeaps.end(); ++AvailableHeapIt)
     {
+        // Try to allocate descriptor using the current descriptor heap manager
         Allocation = m_HeapPool[*AvailableHeapIt].Allocate(Count);
+        // Remove the manager from the pool if it has no more available descriptors
         if(m_HeapPool[*AvailableHeapIt].GetNumAvailableDescriptors() == 0)
             m_AvailableHeaps.erase(*AvailableHeapIt);
 
+        // Terminate the loop if descriptor was successfully allocated, otherwise
+        // go to the next manager
         if(Allocation.GetCpuHandle().ptr != 0)
             break;
     }
 
+    // If there were no available descriptor heap managers or no manager was able 
+    // to suffice the allocation request, create a new manager
     if(Allocation.GetCpuHandle().ptr == 0)
     {
+        // Make sure the heap is large enough to accomodate the requested number of descriptors
+        if(Count > m_HeapDesc.NumDescriptors)
+        {
+            LOG_WARNING_MESSAGE("Number of requested descriptors exceeds the descriptor heap size. Increasing the number of descriptors in the heap")
+        }
+        m_HeapDesc.NumDescriptors = std::max(m_HeapDesc.NumDescriptors, static_cast<UINT>(Count));
+        // Create a new descriptor heap manager. Note that this constructor creates a new D3D12 descriptor
+        // heap and references the entire heap. Pool index is used as manager ID
         m_HeapPool.emplace_back(m_MemAllocator, m_pDeviceD3D12Impl, this, m_HeapPool.size(), m_HeapDesc);
         auto NewHeapIt = m_AvailableHeaps.insert(m_HeapPool.size()-1);
 
+        // Use the new manager to allocate descriptor handles
         Allocation = m_HeapPool[*NewHeapIt.first].Allocate(Count);
     }
 
@@ -189,21 +232,28 @@ DescriptorHeapAllocation CPUDescriptorHeap::Allocate( uint32_t Count )
 
 void CPUDescriptorHeap::Free(DescriptorHeapAllocation&& Allocation)
 {
+    // Method is called from ~DescriptorHeapAllocation()
     std::lock_guard<std::mutex> LockGuard(m_AllocationMutex);
     auto ManagerId = Allocation.GetAllocationManagerId();
     m_CurrentSize -= static_cast<Uint32>(Allocation.GetNumHandles());
     m_HeapPool[ManagerId].Free(std::move(Allocation));
 }
 
-void CPUDescriptorHeap::ReleaseStaleAllocations(Uint64 NumCompletedFrames)
+void CPUDescriptorHeap::ReleaseStaleAllocations(Uint64 NumCompletedCmdLists)
 {
     std::lock_guard<std::mutex> LockGuard(m_AllocationMutex);
+	size_t StaleSize = 0;
     for (size_t HeapManagerInd = 0; HeapManagerInd < m_HeapPool.size(); ++HeapManagerInd)
     {
-        m_HeapPool[HeapManagerInd].ReleaseStaleAllocations(NumCompletedFrames);
+		// Update size before releasing stale allocations	
+		StaleSize += m_HeapPool[HeapManagerInd].GetNumStaleDescriptors();
+
+        m_HeapPool[HeapManagerInd].ReleaseStaleAllocations(NumCompletedCmdLists);
+        // Return the manager to the pool of available managers if it has available descriptors
         if(m_HeapPool[HeapManagerInd].GetNumAvailableDescriptors() > 0)
             m_AvailableHeaps.insert(HeapManagerInd);
     }
+	m_MaxStaleSize = std::max(m_MaxStaleSize, static_cast<Uint32>(StaleSize));
 }
 
 
@@ -236,12 +286,19 @@ GPUDescriptorHeap::GPUDescriptorHeap(IMemoryAllocator &Allocator,
 
 GPUDescriptorHeap::~GPUDescriptorHeap()
 {
-    LOG_INFO_MESSAGE("Max ", GetD3D12DescriptorHeapTypeLiteralName(m_HeapDesc.Type), " GPU heap static/dynamic size: ", m_MaxHeapSize, "/", m_MaxDynamicSize);
+	auto StaticSize = m_HeapAllocationManager.GetMaxDescriptors();
+	auto DynamicSize = m_DynamicAllocationsManager.GetMaxDescriptors();
+    LOG_INFO_MESSAGE(GetD3D12DescriptorHeapTypeLiteralName(m_HeapDesc.Type), " GPU heap max allocated size (static|dynamic): ", 
+		            m_MaxHeapSize, " (", m_MaxHeapSize * 100 / StaticSize,"%) | ",
+					m_MaxDynamicSize, " (", m_MaxDynamicSize * 100 / DynamicSize, "%). Max stale size (static|dynamic): ", 
+		            m_MaxStaleSize, " (", m_MaxStaleSize * 100 / StaticSize, "%) | ", 
+					m_MaxDynamicStaleSize, " (", m_MaxDynamicStaleSize * 100 / DynamicSize, "%)");
 }
 
 DescriptorHeapAllocation GPUDescriptorHeap::Allocate(uint32_t Count)
 {
-    std::lock_guard<std::mutex> LockGuard(m_Mutex);
+    // Note: this mutex may be redundant as DescriptorHeapAllocationManager::Allocate() is itself thread-safe
+    std::lock_guard<std::mutex> LockGuard(m_AllocMutex);
     DescriptorHeapAllocation Allocation = m_HeapAllocationManager.Allocate(Count);
 
     m_CurrentSize += (Allocation.GetCpuHandle().ptr != 0) ? Count : 0;
@@ -252,7 +309,8 @@ DescriptorHeapAllocation GPUDescriptorHeap::Allocate(uint32_t Count)
 
 DescriptorHeapAllocation GPUDescriptorHeap::AllocateDynamic(uint32_t Count)
 {
-    std::lock_guard<std::mutex> LockGuard(m_Mutex);
+    // Note: this mutex may be redundant as DescriptorHeapAllocationManager::Allocate() is itself thread-safe
+    std::lock_guard<std::mutex> LockGuard(m_DynAllocMutex);
     DescriptorHeapAllocation Allocation = m_DynamicAllocationsManager.Allocate(Count);
 
     m_CurrentDynamicSize += (Allocation.GetCpuHandle().ptr != 0) ? Count : 0;
@@ -266,24 +324,34 @@ void GPUDescriptorHeap::Free(DescriptorHeapAllocation&& Allocation)
     auto MgrId = Allocation.GetAllocationManagerId();
     VERIFY(MgrId == 0 || MgrId == 1, "Unexpected allocation manager ID");
 
-    std::lock_guard<std::mutex> LockGuard(m_Mutex);
-
+    // Note: mutexex may be redundant as DescriptorHeapAllocationManager::Free() is itself thread-safe
     if(MgrId == 0)
     {
+        std::lock_guard<std::mutex> LockGuard(m_AllocMutex);
         m_CurrentSize -= static_cast<Uint32>(Allocation.GetNumHandles());
         m_HeapAllocationManager.Free(std::move(Allocation));
     }
     else
     {
+        std::lock_guard<std::mutex> LockGuard(m_DynAllocMutex);
         m_CurrentDynamicSize -= static_cast<Uint32>(Allocation.GetNumHandles());
         m_DynamicAllocationsManager.Free(std::move(Allocation));
     }
 }
 
-void GPUDescriptorHeap::ReleaseStaleAllocations(Uint64 NumCompletedFrames)
+void GPUDescriptorHeap::ReleaseStaleAllocations(Uint64 NumCompletedCmdLists)
 {
-    m_HeapAllocationManager.ReleaseStaleAllocations(NumCompletedFrames);
-    m_DynamicAllocationsManager.ReleaseStaleAllocations(NumCompletedFrames);
+    {
+        std::lock_guard<std::mutex> LockGuard(m_AllocMutex);
+		m_MaxStaleSize = std::max(m_MaxStaleSize, static_cast<Uint32>(m_HeapAllocationManager.GetNumStaleDescriptors()));
+        m_HeapAllocationManager.ReleaseStaleAllocations(NumCompletedCmdLists);
+    }
+
+    {
+        std::lock_guard<std::mutex> LockGuard(m_DynAllocMutex);
+		m_MaxDynamicStaleSize = std::max(m_MaxDynamicStaleSize, static_cast<Uint32>(m_DynamicAllocationsManager.GetNumStaleDescriptors()));
+        m_DynamicAllocationsManager.ReleaseStaleAllocations(NumCompletedCmdLists);
+    }
 }
 
 
@@ -299,14 +367,21 @@ DynamicSuballocationsManager::DynamicSuballocationsManager(IMemoryAllocator &All
 
 void DynamicSuballocationsManager::DiscardAllocations(Uint64 FrameNumber)
 {
+    // Clear the list and dispose all allocated chunks of GPU descriptor heap.
+    // The chunks will be added to the release queue in the allocations manager
     m_Suballocations.clear();
 }
 
 DescriptorHeapAllocation DynamicSuballocationsManager::Allocate(Uint32 Count)
 {
+    // This method is intentionally lock-free as it is expected to
+    // be called through device context from single thread only
+
+    // Check if there are no chunks or the last chunk does not have enough space
     if( m_Suballocations.empty() || 
         m_CurrentSuballocationOffset + Count > m_Suballocations.back().GetNumHandles() )
     {
+        // Request a new chunk from the parent GPU descriptor heap
         auto SuballocationSize = std::max(m_DynamicChunkSize, Count);
         auto NewDynamicSubAllocation = m_ParentGPUHeap.AllocateDynamic(SuballocationSize);
         if (NewDynamicSubAllocation.GetCpuHandle().ptr == 0)
@@ -318,6 +393,7 @@ DescriptorHeapAllocation DynamicSuballocationsManager::Allocate(Uint32 Count)
         m_CurrentSuballocationOffset = 0;
     }
 
+    // Perform suballocation from the last chunk
     auto &CurrentSuballocation = m_Suballocations.back();
     
     auto ManagerId = CurrentSuballocation.GetAllocationManagerId();
@@ -335,7 +411,7 @@ DescriptorHeapAllocation DynamicSuballocationsManager::Allocate(Uint32 Count)
 
 void DynamicSuballocationsManager::Free(DescriptorHeapAllocation&& Allocation)
 {
-    // Do nothing
+    // Do nothing. Dynamic allocations are not disposed individually, but as whole chunks at the end of the frame
     Allocation = DescriptorHeapAllocation();
 }
 
diff --git a/Graphics/GraphicsEngineD3D12/src/DeviceContextD3D12Impl.cpp b/Graphics/GraphicsEngineD3D12/src/DeviceContextD3D12Impl.cpp
index 5ebfb4b4..003a464b 100644
--- a/Graphics/GraphicsEngineD3D12/src/DeviceContextD3D12Impl.cpp
+++ b/Graphics/GraphicsEngineD3D12/src/DeviceContextD3D12Impl.cpp
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -507,7 +507,7 @@ namespace Diligent
     {
         if( m_pCurrCmdCtx )
         {
-            VERIFY(!m_bIsDeferred, "Deferred contexts cannot executre command lists directly");
+            VERIFY(!m_bIsDeferred, "Deferred contexts cannot execute command lists directly");
             ValidatedCast<RenderDeviceD3D12Impl>(m_pDevice.RawPtr())->CloseAndExecuteCommandContext(m_pCurrCmdCtx);
         }
 
diff --git a/Graphics/GraphicsEngineD3D12/src/DynamicUploadHeap.cpp b/Graphics/GraphicsEngineD3D12/src/DynamicUploadHeap.cpp
index c747a731..12622465 100644
--- a/Graphics/GraphicsEngineD3D12/src/DynamicUploadHeap.cpp
+++ b/Graphics/GraphicsEngineD3D12/src/DynamicUploadHeap.cpp
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -72,15 +72,22 @@ namespace Diligent
 	    m_pBuffer->SetName(L"Upload Ring Buffer");
         
         m_GpuVirtualAddress = m_pBuffer->GetGPUVirtualAddress();
-
-	    if (AllowCPUAccess)
+        
+        if (AllowCPUAccess)
         {
 	        m_pBuffer->Map(0, nullptr, &m_CpuVirtualAddress);
         }
+
+        LOG_INFO_MESSAGE("GPU ring buffer created. Size: ", MaxSize, "; GPU virtual address 0x", std::hex, m_GpuVirtualAddress)
     }
 
     void GPURingBuffer::Destroy()
     {
+        if(m_pBuffer)
+        {
+            LOG_INFO_MESSAGE("Destroying GPU ring buffer. Size: ", m_pBuffer->GetDesc().Width, "; GPU virtual address 0x", std::hex, m_GpuVirtualAddress)
+        }
+
 	    if (m_CpuVirtualAddress)
         {
 	        m_pBuffer->Unmap(0, nullptr);
@@ -106,11 +113,15 @@ namespace Diligent
 
     DynamicAllocation DynamicUploadHeap::Allocate(size_t SizeInBytes, size_t Alignment /*= DEFAULT_ALIGN*/)
     {
-        // This is very expensive! Currently other threads cannot allocate dynamic 
-        // data while frame is being finished.
+        // Every device context has its own upload heap, so there is no need to lock
 
         //std::lock_guard<std::mutex> Lock(m_Mutex);
 
+        //
+        //      Deferred contexts must not update resources or map dynamic buffers
+        //      across several frames!
+        //
+
 	    const size_t AlignmentMask = Alignment - 1;
 	    // Assert that it's a power of two.
 	    VERIFY_EXPR((AlignmentMask & Alignment) == 0);
@@ -125,15 +136,21 @@ namespace Diligent
             DynAlloc = m_RingBuffers.back().Allocate(AlignedSize);
         }
 #ifdef _DEBUG
-        DynAlloc.FrameNum = m_pDeviceD3D12->GetCurrentFrame();
+		DynAlloc.FrameNum = m_pDeviceD3D12->GetCurrentFrameNumber();
 #endif
         return DynAlloc;
     }
 
     void DynamicUploadHeap::FinishFrame(Uint64 FrameNum, Uint64 NumCompletedFrames)
     {
+        // Every device context has its own upload heap, so there is no need to lock
         //std::lock_guard<std::mutex> Lock(m_Mutex);
 
+        //
+        //      Deferred contexts must not update resources or map dynamic buffers
+        //      across several frames!
+        //
+
         size_t NumBuffsToDelete = 0;
         for(size_t Ind = 0; Ind < m_RingBuffers.size(); ++Ind)
         {
@@ -145,7 +162,7 @@ namespace Diligent
                 ++NumBuffsToDelete;
             }
         }
-
+        
         if(NumBuffsToDelete)
             m_RingBuffers.erase(m_RingBuffers.begin(), m_RingBuffers.begin()+NumBuffsToDelete);
     }
diff --git a/Graphics/GraphicsEngineD3D12/src/GenerateMips.cpp b/Graphics/GraphicsEngineD3D12/src/GenerateMips.cpp
index 1784a89c..5ef672d4 100644
--- a/Graphics/GraphicsEngineD3D12/src/GenerateMips.cpp
+++ b/Graphics/GraphicsEngineD3D12/src/GenerateMips.cpp
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/src/PipelineStateD3D12Impl.cpp b/Graphics/GraphicsEngineD3D12/src/PipelineStateD3D12Impl.cpp
index c2ed2d83..c5e2cf4b 100644
--- a/Graphics/GraphicsEngineD3D12/src/PipelineStateD3D12Impl.cpp
+++ b/Graphics/GraphicsEngineD3D12/src/PipelineStateD3D12Impl.cpp
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -282,6 +282,8 @@ ShaderResourceCacheD3D12* PipelineStateD3D12Impl::CommitAndTransitionShaderResou
     }
 #endif
 
+    // If the shaders contain no resources or static resources only, shader resource binding may be null. 
+    // In this case use special internal SRB object
     auto *pResBindingD3D12Impl = pShaderResourceBinding ? ValidatedCast<ShaderResourceBindingD3D12Impl>(pShaderResourceBinding) : m_pDefaultShaderResBinding.get();
     
 #ifdef VERIFY_SHADER_BINDINGS
@@ -295,6 +297,7 @@ ShaderResourceCacheD3D12* PipelineStateD3D12Impl::CommitAndTransitionShaderResou
     }
 #endif
 
+    // First time only, copy static shader resources to the cache
     if(!pResBindingD3D12Impl->StaticResourcesInitialized())
         pResBindingD3D12Impl->InitializeStaticResources(this);
 
diff --git a/Graphics/GraphicsEngineD3D12/src/RenderDeviceD3D12Impl.cpp b/Graphics/GraphicsEngineD3D12/src/RenderDeviceD3D12Impl.cpp
index 51c89306..d9fc8265 100644
--- a/Graphics/GraphicsEngineD3D12/src/RenderDeviceD3D12Impl.cpp
+++ b/Graphics/GraphicsEngineD3D12/src/RenderDeviceD3D12Impl.cpp
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -41,9 +41,10 @@ RenderDeviceD3D12Impl :: RenderDeviceD3D12Impl(IMemoryAllocator &RawMemAllocator
     m_pd3d12Device(pd3d12Device),
     m_pd3d12CmdQueue(pd3d12CmdQueue),
     m_EngineAttribs(CreationAttribs),
-    m_NextFenceValue(1),
-    m_LastCompletedFenceValue(0),
-    m_FenceEventHandle( CreateEvent(nullptr, false, false, nullptr) ),
+	m_CurrentFrameNumber(0),
+    m_NextCmdList(0),
+    m_NumCompletedCmdLists(0),
+    m_WaitForGPUEventHandle( CreateEvent(nullptr, false, false, nullptr) ),
     m_CmdListManager(this),
     m_CPUDescriptorHeaps
     {
@@ -57,6 +58,11 @@ RenderDeviceD3D12Impl :: RenderDeviceD3D12Impl(IMemoryAllocator &RawMemAllocator
         {RawMemAllocator, this, CreationAttribs.GPUDescriptorHeapSize[0], CreationAttribs.GPUDescriptorHeapDynamicSize[0], D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV, D3D12_DESCRIPTOR_HEAP_FLAG_SHADER_VISIBLE},
         {RawMemAllocator, this, CreationAttribs.GPUDescriptorHeapSize[1], CreationAttribs.GPUDescriptorHeapDynamicSize[1], D3D12_DESCRIPTOR_HEAP_TYPE_SAMPLER,     D3D12_DESCRIPTOR_HEAP_FLAG_SHADER_VISIBLE}
     },
+	m_DynamicDescriptorAllocationChunkSize
+	{
+		CreationAttribs.DynamicDescriptorAllocationChunkSize[0], // D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV
+		CreationAttribs.DynamicDescriptorAllocationChunkSize[1]  // D3D12_DESCRIPTOR_HEAP_TYPE_SAMPLER
+	},
     m_ContextPool(STD_ALLOCATOR_RAW_MEM(ContextPoolElemType, GetRawAllocator(), "Allocator for vector<unique_ptr<CommandContext>>")),
     m_AvailableContexts(STD_ALLOCATOR_RAW_MEM(CommandContext*, GetRawAllocator(), "Allocator for vector<CommandContext*>")),
     m_D3D12ObjReleaseQueue(STD_ALLOCATOR_RAW_MEM(ReleaseQueueElemType, GetRawAllocator(), "Allocator for queue<ReleaseQueueElemType>")),
@@ -68,22 +74,17 @@ RenderDeviceD3D12Impl :: RenderDeviceD3D12Impl(IMemoryAllocator &RawMemAllocator
     m_DeviceCaps.bSeparableProgramSupported = True;
     m_DeviceCaps.bMultithreadedResourceCreationSupported = True;
 
-    VERIFY_EXPR(m_FenceEventHandle != INVALID_HANDLE_VALUE);
-
-    auto hr = pd3d12Device->CreateFence(0, D3D12_FENCE_FLAG_NONE, __uuidof(m_pFence), reinterpret_cast<void**>(static_cast<ID3D12Fence**>(&m_pFence)));
-    VERIFY(SUCCEEDED(hr), "Failed to create fence");
-	m_pFence->SetName(L"CommandListManager::m_pFence");
-	m_pFence->Signal(m_LastCompletedFenceValue);
+    VERIFY_EXPR(m_WaitForGPUEventHandle != INVALID_HANDLE_VALUE);
 
-    hr = pd3d12Device->CreateFence(0, D3D12_FENCE_FLAG_NONE, __uuidof(m_pNumCompletedFramesFence), reinterpret_cast<void**>(static_cast<ID3D12Fence**>(&m_pNumCompletedFramesFence)));
-    VERIFY(SUCCEEDED(hr), "Failed to create fence");
-	m_pNumCompletedFramesFence->SetName(L"Last completed frame fence");
-	m_pNumCompletedFramesFence->Signal(m_NumCompletedFrames);
+    auto hr = pd3d12Device->CreateFence(0, D3D12_FENCE_FLAG_NONE, __uuidof(m_pCompletedCmdListFence), reinterpret_cast<void**>(static_cast<ID3D12Fence**>(&m_pCompletedCmdListFence)));
+    VERIFY(SUCCEEDED(hr), "Failed to create the fence");
+	m_pCompletedCmdListFence->SetName(L"RenderDeviceD3D12Impl::m_pCompletedCmdListFence fence");
+	m_pCompletedCmdListFence->Signal(m_NumCompletedCmdLists); // 0 cmd lists are completed
 }
 
 RenderDeviceD3D12Impl::~RenderDeviceD3D12Impl()
 {
-    // Finish current frame. This will release resources taken by previous frames, and
+	// Finish current frame. This will release resources taken by previous frames, and
     // will signal current frame as completed. If we do not call FinishFrame(), then
     // current frame will not be signaled as completed and the second call to FinishFrame()
     // will not release current frame's resources.
@@ -92,7 +93,7 @@ RenderDeviceD3D12Impl::~RenderDeviceD3D12Impl()
     IdleGPU();
     // Call FinishFrame() again to release all resources associated with the current frame
     FinishFrame();
-    CloseHandle(m_FenceEventHandle);
+    CloseHandle(m_WaitForGPUEventHandle);
 
 	//LinearAllocator::DestroyAll();
 	//DynamicDescriptorHeap::DestroyAll();
@@ -105,49 +106,69 @@ void RenderDeviceD3D12Impl::DisposeCommandContext(CommandContext* pCtx)
     m_AvailableContexts.push_back(pCtx);
 }
 
-Uint64 RenderDeviceD3D12Impl::CloseAndExecuteCommandContext(CommandContext *pCtx)
+void RenderDeviceD3D12Impl::CloseAndExecuteCommandContext(CommandContext *pCtx)
 {
     CComPtr<ID3D12CommandAllocator> pAllocator;
 	auto *pCmdList = pCtx->Close(&pAllocator);
 
-	uint64_t FenceValue = 0;
+    Uint64 SubmittedCmdListNum = 0;
     {
-	    std::lock_guard<std::mutex> LockGuard(m_FenceMutex);
+	    std::lock_guard<std::mutex> LockGuard(m_CmdQueueMutex);
 
-	    // Kickoff the command list
+	    // Submit the command list to the queue
         ID3D12CommandList *const ppCmdLists[] = {pCmdList};
 	    m_pd3d12CmdQueue->ExecuteCommandLists(1, ppCmdLists);
 
-	    // Signal the next fence value (with the GPU)
-	    m_pd3d12CmdQueue->Signal(m_pFence, m_NextFenceValue);
+        // Increment the counter before signaling the fence.
+		SubmittedCmdListNum = m_NextCmdList;
+		Atomics::AtomicIncrement(m_NextCmdList);
 
-	    // And increment the fence value.  
-	    FenceValue = m_NextFenceValue++;
+	    // Signal the fence value. Note that for cmd list N that has just been submitted,
+        // we are signaling value N+1, that has a meaning of the TOTAL NUMBER OF COMPLETED 
+        // cmd lists rather than the index number of the LAST completed cmd list.
+        // This is convenient as the natural default fence value of 0
+        // corresponds to no completed cmd lists
+	    m_pd3d12CmdQueue->Signal(m_pCompletedCmdListFence, m_NextCmdList);
     }
 
-	m_CmdListManager.DiscardAllocator(FenceValue, pAllocator);
-    pCtx->DiscardUsedDescriptorHeaps(m_CurrentFrame);
+    // DiscardAllocator() is thread-safe
+	m_CmdListManager.DiscardAllocator(SubmittedCmdListNum, pAllocator);
+    
+    // m_NextCmdList may be different at this point, which does not matter.
+    // SubmittedCmdListNum stores the actual number when the command list
+    // was sent for executrion
+    pCtx->DiscardDynamicDescriptors(SubmittedCmdListNum);
 
     {
 	    std::lock_guard<std::mutex> LockGuard(m_ContextAllocationMutex);
     	m_AvailableContexts.push_back(pCtx);
     }
-
-	return FenceValue;
 }
 
 
-Uint64 RenderDeviceD3D12Impl::IncrementFence(void)
-{
-	std::lock_guard<std::mutex> LockGuard(m_FenceMutex);
-    m_pd3d12CmdQueue->Signal(m_pFence, m_NextFenceValue);
-	return m_NextFenceValue++;
-}
-
 void RenderDeviceD3D12Impl::IdleGPU(bool ReleasePendingObjects) 
 { 
-    auto FenceValue = IncrementFence();
-    WaitForFence(FenceValue); 
+    // We must lock the command queue to avoid other threads interfering with the GPU
+    std::lock_guard<std::mutex> LockGuard(m_CmdQueueMutex);
+
+	// Simulate execution of an empty command list
+
+	// Increment the counter before signaling the fence.
+	Atomics::AtomicIncrement(m_NextCmdList);
+
+	// Signal the fence value. Note that for cmd list N that has just been submitted, 
+	// we are signaling value N+1, that has a meaning of the TOTAL NUMBER OF COMPLETED cmd lists
+	m_pd3d12CmdQueue->Signal(m_pCompletedCmdListFence, m_NextCmdList);
+	
+	// Wait for the fence
+	m_pCompletedCmdListFence->SetEventOnCompletion(m_NextCmdList, m_WaitForGPUEventHandle);
+	WaitForSingleObject(m_WaitForGPUEventHandle, INFINITE);
+
+	VERIFY(GetNumCompletedCmdLists() == m_NextCmdList, "Unexpected number of completed cmd lists");
+
+    // Note: release queues may now contain objects released during the current frame
+	// that have cmd list number (m_NextCmdList-1)
+
     if(ReleasePendingObjects)
     {
         // Do not wait until the end of the frame and force deletion. 
@@ -158,74 +179,63 @@ void RenderDeviceD3D12Impl::IdleGPU(bool ReleasePendingObjects)
     }
 }
 
-
-bool RenderDeviceD3D12Impl::IsFenceComplete(Uint64 FenceValue)
+Uint64 RenderDeviceD3D12Impl::GetNumCompletedCmdLists()
 {
-	// Avoid querying the fence value by testing against the last one seen.
-	// The max() is to protect against an unlikely race condition that could cause the last
-	// completed fence value to regress.
-	if (FenceValue > m_LastCompletedFenceValue)
-		m_LastCompletedFenceValue = std::max(m_LastCompletedFenceValue, m_pFence->GetCompletedValue());
+    auto NumCompletedCmdLists = m_pCompletedCmdListFence->GetCompletedValue();
+    if(NumCompletedCmdLists > m_NumCompletedCmdLists)
+        m_NumCompletedCmdLists = NumCompletedCmdLists;
 
-	return FenceValue <= m_LastCompletedFenceValue;
+    return m_NumCompletedCmdLists;
 }
 
-Uint64 RenderDeviceD3D12Impl::FinishFrame()
+void RenderDeviceD3D12Impl::FinishFrame()
 {
-    m_NumCompletedFrames = std::max(m_NumCompletedFrames, m_pNumCompletedFramesFence->GetCompletedValue());
-    for (auto &UploadHeap : m_UploadHeaps)
+    auto NumCompletedCmdLists = GetNumCompletedCmdLists();
+
     {
-        // Currently upload heaps are free-threaded, so other threads must not allocate
-        // resources at the same time
-        UploadHeap->FinishFrame(m_CurrentFrame, m_NumCompletedFrames);
+        // There is no need to lock as new heaps are only created during initialization
+        // time for every context
+        //std::lock_guard<std::mutex> LockGuard(m_UploadHeapMutex);
+        
+        // Upload heaps are used to update resource contents as well as to allocate
+        // space for dynamic resources.
+        // Initial resource data is uploaded using temporary one-time upload buffers, so can 
+        // performed in parallel across frame boundaries
+        for (auto &UploadHeap : m_UploadHeaps)
+        {
+            // Currently upload heaps are free-threaded, so other threads must not allocate
+            // resources at the same time. This means that all dynamic buffers must be unmaped 
+            // in the same frame and all resources must be updated within boundaries of a single frame.
+            //
+            //   worker thread 2    | pDevice->CrateTexture(InitData) |    | pDevice->CrateBuffer(InitData) |    | pDevice->CrateTexture(InitData) |
+            //                                                                                               
+            //    worker thread 2     | pDfrdCtx2->UpdateResource()  |                                              ||
+            //                                                                                                      ||
+            //    worker thread 1       |  pDfrdCtx1->Map(WRITE_DISCARD) |    | pDfrdCtx1->UpdateResource()  |      ||
+            //                                                                                                      ||
+            //    main thread        |  pCtx->Map(WRITE_DISCARD )|  | pCtx->UpdateResource()  |                     ||   | Present() |
+            //
+            //
+            UploadHeap->FinishFrame(GetNextCmdListNumber(), NumCompletedCmdLists);
+        }
     }
 
     for(Uint32 CPUHeap=0; CPUHeap < _countof(m_CPUDescriptorHeaps); ++CPUHeap)
     {
-        m_CPUDescriptorHeaps[CPUHeap].ReleaseStaleAllocations(m_NumCompletedFrames);
+        // This is OK if other thread disposes descriptor heap allocation at this time
+        // The allocation will be registered as part of the current frame
+        m_CPUDescriptorHeaps[CPUHeap].ReleaseStaleAllocations(NumCompletedCmdLists);
     }
         
     for(Uint32 GPUHeap=0; GPUHeap < _countof(m_GPUDescriptorHeaps); ++GPUHeap)
     {
-        m_GPUDescriptorHeaps[GPUHeap].ReleaseStaleAllocations(m_NumCompletedFrames);
+        m_GPUDescriptorHeaps[GPUHeap].ReleaseStaleAllocations(NumCompletedCmdLists);
     }
 
 
     ProcessReleaseQueue();
 
-    // How does this work in a multi-threaded environment??
-    auto CompletedFrame = m_CurrentFrame++;
-    m_pd3d12CmdQueue->Signal(m_pNumCompletedFramesFence, m_CurrentFrame);
-	return CompletedFrame;
-}
-
-bool RenderDeviceD3D12Impl::IsFrameComplete(Uint64 Frame)
-{
-	// Avoid querying the fence value by testing against the last one seen.
-	// The max() is to protect against an unlikely race condition that could cause the last
-	// completed fence value to regress.
-	if (Frame > m_NumCompletedFrames)
-		m_NumCompletedFrames = std::max(m_NumCompletedFrames, m_pNumCompletedFramesFence->GetCompletedValue());
-
-	return Frame <= m_NumCompletedFrames;
-}
-
-void RenderDeviceD3D12Impl::WaitForFence(Uint64 FenceValue)
-{
-	if (IsFenceComplete(FenceValue))
-		return;
-
-	// TODO:  Think about how this might affect a multi-threaded situation.  Suppose thread A
-	// wants to wait for fence 100, then thread B comes along and wants to wait for 99.  If
-	// the fence can only have one event set on completion, then thread B has to wait for 
-	// 100 before it knows 99 is ready.  Maybe insert sequential events?
-	{
-		std::lock_guard<std::mutex> LockGuard(m_EventMutex);
-
-		m_pFence->SetEventOnCompletion(FenceValue, m_FenceEventHandle);
-		WaitForSingleObject(m_FenceEventHandle, INFINITE);
-		m_LastCompletedFenceValue = FenceValue;
-	}
+    Atomics::AtomicIncrement(m_CurrentFrameNumber);
 }
 
 DynamicUploadHeap* RenderDeviceD3D12Impl::RequestUploadHeap()
@@ -257,10 +267,9 @@ CommandContext* RenderDeviceD3D12Impl::AllocateCommandContext(const Char *ID)
 	CommandContext* ret = nullptr;
 	if (m_AvailableContexts.empty())
 	{
-        Uint32 DynamicDescriptorAllocationChunkSize[] = {256, 32};
         auto &CmdCtxAllocator = GetRawAllocator();
         auto *pRawMem = ALLOCATE(CmdCtxAllocator, "CommandContext instance", sizeof(CommandContext));
-		ret = new (pRawMem) CommandContext( GetRawAllocator(), m_CmdListManager, m_GPUDescriptorHeaps, DynamicDescriptorAllocationChunkSize);
+		ret = new (pRawMem) CommandContext( GetRawAllocator(), m_CmdListManager, m_GPUDescriptorHeaps, m_DynamicDescriptorAllocationChunkSize);
 		m_ContextPool.emplace_back(ret, STDDeleterRawMem<CommandContext>(CmdCtxAllocator) );
 	}
 	else
@@ -280,19 +289,21 @@ CommandContext* RenderDeviceD3D12Impl::AllocateCommandContext(const Char *ID)
 void RenderDeviceD3D12Impl::SafeReleaseD3D12Object(ID3D12Object* pObj)
 {
     std::lock_guard<std::mutex> LockGuard(m_ReleasedObjectsMutex);
-    m_D3D12ObjReleaseQueue.emplace_back( m_CurrentFrame, CComPtr<ID3D12Object>(pObj) );
+    m_D3D12ObjReleaseQueue.emplace_back( GetNextCmdListNumber(), CComPtr<ID3D12Object>(pObj) );
 }
 
 void RenderDeviceD3D12Impl::ProcessReleaseQueue(bool ForceRelease)
 {
     std::lock_guard<std::mutex> LockGuard(m_ReleasedObjectsMutex);
 
-    // Release all objects whose frame number value < number of completed frames
-    while (m_D3D12ObjReleaseQueue.size())
+	auto NumCompletedCmdLists = GetNumCompletedCmdLists();
+    // Release all objects whose cmd list number value < number of completed cmd lists
+    // See http://diligentgraphics.com/diligent-engine/architecture/d3d12/managing-resource-lifetimes/
+    while (!m_D3D12ObjReleaseQueue.empty())
     {
         auto &FirstObj = m_D3D12ObjReleaseQueue.front();
         // GPU must have been idled when ForceRelease == true 
-        if (FirstObj.first < m_NumCompletedFrames || ForceRelease)
+        if (FirstObj.first < NumCompletedCmdLists || ForceRelease)
             m_D3D12ObjReleaseQueue.pop_front();
         else
             break;
diff --git a/Graphics/GraphicsEngineD3D12/src/RenderDeviceFactoryD3D12.cpp b/Graphics/GraphicsEngineD3D12/src/RenderDeviceFactoryD3D12.cpp
index 762e8a03..db7164dc 100644
--- a/Graphics/GraphicsEngineD3D12/src/RenderDeviceFactoryD3D12.cpp
+++ b/Graphics/GraphicsEngineD3D12/src/RenderDeviceFactoryD3D12.cpp
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -179,7 +179,7 @@ void CreateDeviceAndContextsD3D12( const EngineD3D12Attribs& CreationAttribs,
 
 #ifndef RELEASE
 	    // Prevent the GPU from overclocking or underclocking to get consistent timings
-	    d3d12Device->SetStablePowerState(TRUE);
+	    //d3d12Device->SetStablePowerState(TRUE);
 #endif
 
 	    // Describe and create the command queue.
diff --git a/Graphics/GraphicsEngineD3D12/src/RootSignature.cpp b/Graphics/GraphicsEngineD3D12/src/RootSignature.cpp
index 2cecfdac..8be68df4 100644
--- a/Graphics/GraphicsEngineD3D12/src/RootSignature.cpp
+++ b/Graphics/GraphicsEngineD3D12/src/RootSignature.cpp
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -74,7 +74,7 @@ D3D12_DESCRIPTOR_RANGE* RootSignature::RootParamsManager::Extend(Uint32 NumExtra
         pCurrDescriptorRangePtr += NumRanges;
     }
 
-    // Copy existing root view to new memory
+    // Copy existing root views to new memory
     for (Uint32 rv = 0; rv < m_NumRootViews; ++rv)
     {
         const auto &SrcView = GetRootView(rv);
@@ -236,47 +236,72 @@ void RootSignature::InitStaticSampler(SHADER_TYPE ShaderType, const String &Text
     }
 }
 
-void RootSignature::AllocateResourceSlot(SHADER_TYPE ShaderType, const D3DShaderResourceAttribs &ShaderResAttribs, D3D12_DESCRIPTOR_RANGE_TYPE RangeType, Uint32 &RootIndex, Uint32 &OffsetFromTableStart)
+// http://diligentgraphics.com/diligent-engine/architecture/d3d12/shader-resource-layout#Initializing-Shader-Resource-Layouts-and-Root-Signature-in-a-Pipeline-State-Object
+void RootSignature::AllocateResourceSlot(SHADER_TYPE ShaderType, 
+                                         const D3DShaderResourceAttribs &ShaderResAttribs, 
+                                         D3D12_DESCRIPTOR_RANGE_TYPE RangeType, 
+                                         Uint32 &RootIndex, // Output parameter
+                                         Uint32 &OffsetFromTableStart // Output parameter
+                                        )
 {
     auto ShaderInd = GetShaderTypeIndex(ShaderType);
     auto ShaderVisibility = GetShaderVisibility(ShaderType);
     if (RangeType == D3D12_DESCRIPTOR_RANGE_TYPE_CBV && ShaderResAttribs.BindCount == 1)
     {
-        // Allocate CBV directly in the root signature
-        RootIndex = m_RootParams.GetNumRootTables() +  m_RootParams.GetNumRootViews();
+        // Allocate single CBV directly in the root signature
+
+        // Get the next available root index past all allocated tables and root views
+        RootIndex = m_RootParams.GetNumRootTables() + m_RootParams.GetNumRootViews();
         OffsetFromTableStart = 0;
 
+        // Add new root view to existing root parameters
         m_RootParams.AddRootView(D3D12_ROOT_PARAMETER_TYPE_CBV, RootIndex, ShaderResAttribs.BindPoint, ShaderVisibility, ShaderResAttribs.GetVariableType());
     }
     else
     {
-        // Use the same table for static and mutable resources. Mark table type as static (mutable is an equivalent option)
+        // Use the same table for static and mutable resources. Treat both as static
         auto RootTableType = (ShaderResAttribs.GetVariableType() == SHADER_VARIABLE_TYPE_DYNAMIC) ? SHADER_VARIABLE_TYPE_DYNAMIC : SHADER_VARIABLE_TYPE_STATIC;
         auto TableIndKey = ShaderInd * SHADER_VARIABLE_TYPE_NUM_TYPES + RootTableType;
-        auto &RootTableInd = (( RangeType == D3D12_DESCRIPTOR_RANGE_TYPE_SAMPLER ) ? m_SamplerRootTablesMap : m_SrvCbvUavRootTablesMap)[ TableIndKey ];
-        if (RootTableInd == InvalidRootTableIndex)
+        // Get the table array index (this is not the root index!)
+        auto &RootTableArrayInd = (( RangeType == D3D12_DESCRIPTOR_RANGE_TYPE_SAMPLER ) ? m_SamplerRootTablesMap : m_SrvCbvUavRootTablesMap)[ TableIndKey ];
+        if (RootTableArrayInd == InvalidRootTableIndex)
         {
+            // Root table has not been assigned to this combination yet
+
+            // Get the next available root index past all allocated tables and root views
             RootIndex = m_RootParams.GetNumRootTables() +  m_RootParams.GetNumRootViews();
             VERIFY_EXPR(m_RootParams.GetNumRootTables() < 255);
-            RootTableInd = static_cast<Uint8>( m_RootParams.GetNumRootTables() );
+            RootTableArrayInd = static_cast<Uint8>( m_RootParams.GetNumRootTables() );
+            // Add root table with one single-descriptor range
             m_RootParams.AddRootTable(RootIndex, ShaderVisibility, RootTableType, 1);
         }
         else
         {
-            m_RootParams.AddDescriptorRanges(RootTableInd, 1);
+            // Add a new single-descriptor range to the existing table at index RootTableArrayInd
+            m_RootParams.AddDescriptorRanges(RootTableArrayInd, 1);
         }
-
-        auto &CurrParam = m_RootParams.GetRootTable(RootTableInd);
+        
+        // Reference to either existing or just added table
+        auto &CurrParam = m_RootParams.GetRootTable(RootTableArrayInd);
         RootIndex = CurrParam.GetRootIndex();
 
         const auto& d3d12RootParam = static_cast<const D3D12_ROOT_PARAMETER&>(CurrParam);
 
         VERIFY( d3d12RootParam.ShaderVisibility == ShaderVisibility, "Shader visibility is not correct" );
         
+        // Descriptors are tightly packed, so the next descriptor offset is the
+        // current size of the table
         OffsetFromTableStart = CurrParam.GetDescriptorTableSize();
 
+        // New just added range is the last range in the descriptor table
         Uint32 NewDescriptorRangeIndex = d3d12RootParam.DescriptorTable.NumDescriptorRanges-1;
-        CurrParam.SetDescriptorRange(NewDescriptorRangeIndex, RangeType, ShaderResAttribs.BindPoint, ShaderResAttribs.BindCount, 0, OffsetFromTableStart);
+        CurrParam.SetDescriptorRange(NewDescriptorRangeIndex, 
+                                     RangeType, // Range type (CBV, SRV, UAV or SAMPLER)
+                                     ShaderResAttribs.BindPoint, // Shader register
+                                     ShaderResAttribs.BindCount, // Number of registers used (1 for non-array resources)
+                                     0, // Register space. Always 0 for now
+                                     OffsetFromTableStart // Offset in descriptors from the table start
+                                     );
     }
 }
 
@@ -465,8 +490,12 @@ void RootSignature::Finalize(ID3D12Device *pd3d12Device)
     }
 }
 
+//http://diligentgraphics.com/diligent-engine/architecture/d3d12/shader-resource-cache#Initializing-the-Cache-for-Shader-Resource-Binding-Object
 void RootSignature::InitResourceCache(RenderDeviceD3D12Impl *pDeviceD3D12Impl, ShaderResourceCacheD3D12& ResourceCache, IMemoryAllocator &CacheMemAllocator)const
 {
+    // Get root table size for every root index
+    // m_RootParams keeps root tables sorted by the array index, not the root index
+    // Root views are treated as one-descriptor tables
     std::vector<Uint32, STDAllocatorRawMem<Uint32> > CacheTableSizes(m_RootParams.GetNumRootTables() + m_RootParams.GetNumRootViews(), 0, STD_ALLOCATOR_RAW_MEM(Uint32, GetRawAllocator(), "Allocator for vector<Uint32>") );
     for(Uint32 rt = 0; rt < m_RootParams.GetNumRootTables(); ++rt)
     {
@@ -479,8 +508,10 @@ void RootSignature::InitResourceCache(RenderDeviceD3D12Impl *pDeviceD3D12Impl, S
         auto &RootParam = m_RootParams.GetRootView(rv);
         CacheTableSizes[RootParam.GetRootIndex()] = 1;
     }
+    // Initialize resource cache to hold root tables 
     ResourceCache.Initialize(CacheMemAllocator, static_cast<Uint32>(CacheTableSizes.size()), CacheTableSizes.data());
 
+    // Allocate space in GPU-visible descriptor heap for static and mutable variables only
     Uint32 TotalSrvCbvUavDescriptors =
                 m_TotalSrvCbvUavSlots[SHADER_VARIABLE_TYPE_STATIC] + 
                 m_TotalSrvCbvUavSlots[SHADER_VARIABLE_TYPE_MUTABLE];
@@ -495,6 +526,10 @@ void RootSignature::InitResourceCache(RenderDeviceD3D12Impl *pDeviceD3D12Impl, S
     if(TotalSamplerDescriptors)
         SamplerHeapSpace = pDeviceD3D12Impl->AllocateGPUDescriptors(D3D12_DESCRIPTOR_HEAP_TYPE_SAMPLER, TotalSamplerDescriptors);
 
+    // Iterate through all root static/mutable tables and assign start offsets. The tables are tightly packed, so
+    // start offset of table N+1 is start offset of table N plus the size of table N.
+    // Root tables with dynamic resources as well as root views are not assigned space in GPU-visible allocation
+    // (root views are simply not processed)
     Uint32 SrvCbvUavTblStartOffset = 0;
     Uint32 SamplerTblStartOffset = 0;
     for(Uint32 rt = 0; rt < m_RootParams.GetNumRootTables(); ++rt)
@@ -523,18 +558,18 @@ void RootSignature::InitResourceCache(RenderDeviceD3D12Impl *pDeviceD3D12Impl, S
         {
             if( HeapType == D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV )
             {
-                RootTableCache.TableStartOffset = SrvCbvUavTblStartOffset;
+                RootTableCache.m_TableStartOffset = SrvCbvUavTblStartOffset;
                 SrvCbvUavTblStartOffset += TableSize;
             }
             else
             {
-                RootTableCache.TableStartOffset = SamplerTblStartOffset;
+                RootTableCache.m_TableStartOffset = SamplerTblStartOffset;
                 SamplerTblStartOffset += TableSize;
             }
         }
         else
         {
-            VERIFY_EXPR(RootTableCache.TableStartOffset == ShaderResourceCacheD3D12::InvalidDescriptorOffset)
+            VERIFY_EXPR(RootTableCache.m_TableStartOffset == ShaderResourceCacheD3D12::InvalidDescriptorOffset)
         }
     }
 
@@ -544,7 +579,8 @@ void RootSignature::InitResourceCache(RenderDeviceD3D12Impl *pDeviceD3D12Impl, S
         auto &RootParam = m_RootParams.GetRootView(rv);
         const auto& D3D12RootParam = static_cast<const D3D12_ROOT_PARAMETER&>(RootParam);
         auto &RootTableCache = ResourceCache.GetRootTable(RootParam.GetRootIndex());
-        VERIFY_EXPR(RootTableCache.TableStartOffset == ShaderResourceCacheD3D12::InvalidDescriptorOffset)
+        // Root views are not assigned valid table start offset
+        VERIFY_EXPR(RootTableCache.m_TableStartOffset == ShaderResourceCacheD3D12::InvalidDescriptorOffset)
         
         SHADER_TYPE dbgShaderType = ShaderTypeFromShaderVisibility(D3D12RootParam.ShaderVisibility);
         VERIFY_EXPR(D3D12RootParam.ParameterType == D3D12_ROOT_PARAMETER_TYPE_CBV);
diff --git a/Graphics/GraphicsEngineD3D12/src/SamplerD3D12Impl.cpp b/Graphics/GraphicsEngineD3D12/src/SamplerD3D12Impl.cpp
index e6e95bac..0d443e85 100644
--- a/Graphics/GraphicsEngineD3D12/src/SamplerD3D12Impl.cpp
+++ b/Graphics/GraphicsEngineD3D12/src/SamplerD3D12Impl.cpp
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/src/ShaderD3D12Impl.cpp b/Graphics/GraphicsEngineD3D12/src/ShaderD3D12Impl.cpp
index fd43fa49..6e2b7484 100644
--- a/Graphics/GraphicsEngineD3D12/src/ShaderD3D12Impl.cpp
+++ b/Graphics/GraphicsEngineD3D12/src/ShaderD3D12Impl.cpp
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -50,6 +50,7 @@ ShaderD3D12Impl::ShaderD3D12Impl(FixedBlockMemoryAllocator& ShaderObjAllocator,
     m_pShaderResources.reset(pResources, STDDeleterRawMem<ShaderResourcesD3D12>(Allocator));
 
     // Clone only static resources that will be set directly in the shader
+    // http://diligentgraphics.com/diligent-engine/architecture/d3d12/shader-resource-layout#Initializing-Special-Resource-Layout-for-Managing-Static-Shader-Resources
     SHADER_VARIABLE_TYPE VarTypes[] = {SHADER_VARIABLE_TYPE_STATIC};
     m_StaticResLayout.Initialize(pRenderDeviceD3D12->GetD3D12Device(), m_pShaderResources, GetRawAllocator(), VarTypes, _countof(VarTypes), &m_ConstResCache, nullptr);
 }
diff --git a/Graphics/GraphicsEngineD3D12/src/ShaderResourceBindingD3D12Impl.cpp b/Graphics/GraphicsEngineD3D12/src/ShaderResourceBindingD3D12Impl.cpp
index 118707a2..737fd6f7 100644
--- a/Graphics/GraphicsEngineD3D12/src/ShaderResourceBindingD3D12Impl.cpp
+++ b/Graphics/GraphicsEngineD3D12/src/ShaderResourceBindingD3D12Impl.cpp
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -51,6 +51,7 @@ ShaderResourceBindingD3D12Impl::ShaderResourceBindingD3D12Impl( FixedBlockMemory
         
         auto &ShaderResLayoutDataAllocator = pPSO->GetShaderResourceLayoutDataAllocator(ShaderInd);
 
+        // http://diligentgraphics.com/diligent-engine/architecture/d3d12/shader-resource-layout#Initializing-Resource-Layouts-in-a-Shader-Resource-Binding-Object
         SHADER_VARIABLE_TYPE Types[] = {SHADER_VARIABLE_TYPE_STATIC, SHADER_VARIABLE_TYPE_MUTABLE, SHADER_VARIABLE_TYPE_DYNAMIC};
         const auto &SrcLayout = pPSO->GetShaderResLayout(ShaderType);
         new (m_pResourceLayouts + s) ShaderResourceLayoutD3D12(*this, SrcLayout, ShaderResLayoutDataAllocator, Types, _countof(Types), m_ShaderResourceCache);
diff --git a/Graphics/GraphicsEngineD3D12/src/ShaderResourceCacheD3D12.cpp b/Graphics/GraphicsEngineD3D12/src/ShaderResourceCacheD3D12.cpp
index 700b49b5..0ac5ac16 100644
--- a/Graphics/GraphicsEngineD3D12/src/ShaderResourceCacheD3D12.cpp
+++ b/Graphics/GraphicsEngineD3D12/src/ShaderResourceCacheD3D12.cpp
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -27,13 +27,14 @@
 
 namespace Diligent
 {
+    // http://diligentgraphics.com/diligent-engine/architecture/d3d12/shader-resource-cache#Cache-Structure
     void ShaderResourceCacheD3D12::Initialize(IMemoryAllocator &MemAllocator, Uint32 NumTables, Uint32 TableSizes[])
     {
         // Memory layout:
         //                                         __________________________________________________________
-        //                                        |             m_pResources, m_NumResources                 |
-        //  m_pMemory                             |                                                          |
-        //  |                                     |                                                          V
+        //  m_pMemory                             |             m_pResources, m_NumResources                 |
+        //  |                                     |                                                          |
+        //  V                                     |                                                          V
         //  |  RootTable[0]  |   ....    |  RootTable[Nrt-1]  |  Res[0]  |  ... |  Res[n-1]  |    ....     | Res[0]  |  ... |  Res[m-1]  |
         //       |                                                A  
         //       |                                                |   
diff --git a/Graphics/GraphicsEngineD3D12/src/ShaderResourceLayoutD3D12.cpp b/Graphics/GraphicsEngineD3D12/src/ShaderResourceLayoutD3D12.cpp
index 924131e4..092111f7 100644
--- a/Graphics/GraphicsEngineD3D12/src/ShaderResourceLayoutD3D12.cpp
+++ b/Graphics/GraphicsEngineD3D12/src/ShaderResourceLayoutD3D12.cpp
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -50,7 +50,12 @@ ShaderResourceLayoutD3D12::ShaderResourceLayoutD3D12(IObject &Owner,
 
 ShaderResourceLayoutD3D12::~ShaderResourceLayoutD3D12()
 {
+    // For some reason MS compiler generates this false warning:
+    // warning C4189: 'CbvSrvUav': local variable is initialized but not referenced
+#pragma warning(push)
+#pragma warning(disable : 4189)
     auto* CbvSrvUav = reinterpret_cast<SRV_CBV_UAV*>(m_ResourceBuffer.get());
+#pragma warning(pop)
     for(Uint32 r=0; r < GetTotalSrvCbvUavCount(); ++r)
         CbvSrvUav[r].~SRV_CBV_UAV();
 
@@ -92,9 +97,10 @@ void ShaderResourceLayoutD3D12::AllocateMemory(IMemoryAllocator &Allocator)
         m_Samplers = reinterpret_cast<Sampler*>(reinterpret_cast<SRV_CBV_UAV*>(pRawMem) + TotalSrvCbvUav);
 }
 
-// Clones layout from the reference layout
+// Clones layout from the reference layout maintained by the pipeline state
 // Root indices and descriptor table offsets must be correct
 // Resource cache is not initialized.
+// http://diligentgraphics.com/diligent-engine/architecture/d3d12/shader-resource-layout#Initializing-Resource-Layouts-in-a-Shader-Resource-Binding-Object
 ShaderResourceLayoutD3D12::ShaderResourceLayoutD3D12(IObject &Owner,
                                                      const ShaderResourceLayoutD3D12& SrcLayout, 
                                                      IMemoryAllocator &ResourceLayoutDataAllocator,
@@ -164,6 +170,8 @@ ShaderResourceLayoutD3D12::ShaderResourceLayoutD3D12(IObject &Owner,
 #endif
 }
 
+// http://diligentgraphics.com/diligent-engine/architecture/d3d12/shader-resource-layout#Initializing-Shader-Resource-Layouts-and-Root-Signature-in-a-Pipeline-State-Object
+// http://diligentgraphics.com/diligent-engine/architecture/d3d12/shader-resource-cache#Initializing-Shader-Resource-Layouts-in-a-Pipeline-State
 void ShaderResourceLayoutD3D12::Initialize(ID3D12Device *pd3d12Device,
                                            const std::shared_ptr<const ShaderResourcesD3D12>& pSrcResources, 
                                            IMemoryAllocator &LayoutDataAllocator,
@@ -180,6 +188,7 @@ void ShaderResourceLayoutD3D12::Initialize(ID3D12Device *pd3d12Device,
 
     Uint32 AllowedTypeBits = GetAllowedTypeBits(AllowedVarTypes, NumAllowedTypes);
 
+    // Count number of resources to allocate all needed memory
     m_pResources->ProcessResources(
         AllowedVarTypes, NumAllowedTypes,
 
@@ -226,7 +235,7 @@ void ShaderResourceLayoutD3D12::Initialize(ID3D12Device *pd3d12Device,
 
     Uint32 CurrCbvSrvUav[SHADER_VARIABLE_TYPE_NUM_TYPES] = {0,0,0};
     Uint32 CurrSampler[SHADER_VARIABLE_TYPE_NUM_TYPES] = {0,0,0};
-    int MaxBindPoint[4] = {-1, -1, -1, -1};
+    Uint32 StaticResCacheTblSizes[4] = {0, 0, 0, 0};
 
     auto AddResource = [&](const D3DShaderResourceAttribs &Attribs, CachedResourceType ResType, Uint32 SamplerId = SRV_CBV_UAV::InvalidSamplerId)
     {
@@ -241,13 +250,20 @@ void ShaderResourceLayoutD3D12::Initialize(ID3D12Device *pd3d12Device,
         else
         {
             // If root signature is not provided - use artifial root signature to store
-            // static shader resources
+            // static shader resources:
+            // SRVs at root index D3D12_DESCRIPTOR_RANGE_TYPE_SRV (0)
+            // UAVs at root index D3D12_DESCRIPTOR_RANGE_TYPE_UAV (1)
+            // CBVs at root index D3D12_DESCRIPTOR_RANGE_TYPE_CBV (2)
+            // Samplers at root index D3D12_DESCRIPTOR_RANGE_TYPE_SAMPLER (3)
+
+            // http://diligentgraphics.com/diligent-engine/architecture/d3d12/shader-resource-layout#Initializing-Special-Resource-Layout-for-Managing-Static-Shader-Resources
+
             VERIFY_EXPR(m_pResourceCache != nullptr);
 
             RootIndex = DescriptorRangeType;
             Offset = Attribs.BindPoint;
             // Resources in the static resource cache are indexed by the bind point
-            MaxBindPoint[RootIndex] = std::max(MaxBindPoint[RootIndex], static_cast<int>(Offset + Attribs.BindCount));
+            StaticResCacheTblSizes[RootIndex] = std::max(StaticResCacheTblSizes[RootIndex], Offset + Attribs.BindCount);
         }
         VERIFY(RootIndex != SRV_CBV_UAV::InvalidRootIndex, "Root index must be valid")
         VERIFY(Offset != SRV_CBV_UAV::InvalidOffset, "Offset must be valid")
@@ -299,15 +315,15 @@ void ShaderResourceLayoutD3D12::Initialize(ID3D12Device *pd3d12Device,
                         VERIFY_EXPR(m_pResourceCache != nullptr);
 
                         // We use the following artifial root signature:
-                        // CBVs at root index D3D12_DESCRIPTOR_RANGE_TYPE_CBV,
-                        // SRVs at root index D3D12_DESCRIPTOR_RANGE_TYPE_SRV,
-                        // UAVs at root index D3D12_DESCRIPTOR_RANGE_TYPE_UAV, and
-                        // Samplers at root index D3D12_DESCRIPTOR_RANGE_TYPE_SAMPLER
+                        // SRVs at root index D3D12_DESCRIPTOR_RANGE_TYPE_SRV (0)
+                        // UAVs at root index D3D12_DESCRIPTOR_RANGE_TYPE_UAV (1)
+                        // CBVs at root index D3D12_DESCRIPTOR_RANGE_TYPE_CBV (2)
+                        // Samplers at root index D3D12_DESCRIPTOR_RANGE_TYPE_SAMPLER (3)
                         // Every resource is stored at offset that equals its bind point
                         SamplerRootIndex = D3D12_DESCRIPTOR_RANGE_TYPE_SAMPLER; 
                         SamplerOffset = SrcSamplerAttribs.BindPoint;
                         // Resources in the static resource cache are indexed by the bind point
-                        MaxBindPoint[SamplerRootIndex] = std::max(MaxBindPoint[SamplerRootIndex], static_cast<int>(SamplerOffset + SrcSamplerAttribs.BindCount));
+                        StaticResCacheTblSizes[SamplerRootIndex] = std::max(StaticResCacheTblSizes[SamplerRootIndex], SamplerOffset + SrcSamplerAttribs.BindCount);
                     }
                     VERIFY(SamplerRootIndex != Sampler::InvalidRootIndex, "Sampler root index must be valid")
                     VERIFY(SamplerOffset != Sampler::InvalidOffset, "Sampler offset must be valid")
@@ -346,20 +362,16 @@ void ShaderResourceLayoutD3D12::Initialize(ID3D12Device *pd3d12Device,
 
     if(m_pResourceCache)
     {
+        // Initialize resource cache to store static resources
+        // http://diligentgraphics.com/diligent-engine/architecture/d3d12/shader-resource-cache#Initializing-the-Cache-for-Static-Shader-Resources
+        // http://diligentgraphics.com/diligent-engine/architecture/d3d12/shader-resource-cache#Initializing-Shader-Objects
         VERIFY_EXPR(pRootSig == nullptr);
-        Uint32 CachedTblSizes[4] = 
-        {
-            static_cast<Uint32>(MaxBindPoint[D3D12_DESCRIPTOR_RANGE_TYPE_SRV] + 1),
-            static_cast<Uint32>(MaxBindPoint[D3D12_DESCRIPTOR_RANGE_TYPE_UAV] + 1),
-            static_cast<Uint32>(MaxBindPoint[D3D12_DESCRIPTOR_RANGE_TYPE_CBV] + 1),
-            static_cast<Uint32>(MaxBindPoint[D3D12_DESCRIPTOR_RANGE_TYPE_SAMPLER] + 1)
-        };
-        m_pResourceCache->Initialize(GetRawAllocator(), _countof(CachedTblSizes), CachedTblSizes);
+        m_pResourceCache->Initialize(GetRawAllocator(), _countof(StaticResCacheTblSizes), StaticResCacheTblSizes);
 #ifdef _DEBUG
-        m_pResourceCache->GetRootTable(D3D12_DESCRIPTOR_RANGE_TYPE_SRV).SetDebugAttribs(MaxBindPoint[D3D12_DESCRIPTOR_RANGE_TYPE_SRV] + 1, D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV, m_pResources->GetShaderType());
-        m_pResourceCache->GetRootTable(D3D12_DESCRIPTOR_RANGE_TYPE_UAV).SetDebugAttribs(MaxBindPoint[D3D12_DESCRIPTOR_RANGE_TYPE_UAV] + 1, D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV, m_pResources->GetShaderType());
-        m_pResourceCache->GetRootTable(D3D12_DESCRIPTOR_RANGE_TYPE_CBV).SetDebugAttribs(MaxBindPoint[D3D12_DESCRIPTOR_RANGE_TYPE_CBV] + 1, D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV, m_pResources->GetShaderType());
-        m_pResourceCache->GetRootTable(D3D12_DESCRIPTOR_RANGE_TYPE_SAMPLER).SetDebugAttribs(MaxBindPoint[D3D12_DESCRIPTOR_RANGE_TYPE_SAMPLER] + 1, D3D12_DESCRIPTOR_HEAP_TYPE_SAMPLER, m_pResources->GetShaderType());
+        m_pResourceCache->GetRootTable(D3D12_DESCRIPTOR_RANGE_TYPE_SRV).SetDebugAttribs(StaticResCacheTblSizes[D3D12_DESCRIPTOR_RANGE_TYPE_SRV], D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV, m_pResources->GetShaderType());
+        m_pResourceCache->GetRootTable(D3D12_DESCRIPTOR_RANGE_TYPE_UAV).SetDebugAttribs(StaticResCacheTblSizes[D3D12_DESCRIPTOR_RANGE_TYPE_UAV], D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV, m_pResources->GetShaderType());
+        m_pResourceCache->GetRootTable(D3D12_DESCRIPTOR_RANGE_TYPE_CBV).SetDebugAttribs(StaticResCacheTblSizes[D3D12_DESCRIPTOR_RANGE_TYPE_CBV], D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV, m_pResources->GetShaderType());
+        m_pResourceCache->GetRootTable(D3D12_DESCRIPTOR_RANGE_TYPE_SAMPLER).SetDebugAttribs(StaticResCacheTblSizes[D3D12_DESCRIPTOR_RANGE_TYPE_SAMPLER], D3D12_DESCRIPTOR_HEAP_TYPE_SAMPLER, m_pResources->GetShaderType());
 #endif
     }
 
@@ -392,6 +404,8 @@ void ShaderResourceLayoutD3D12::InitVariablesHashMap()
 
 void ShaderResourceLayoutD3D12::SRV_CBV_UAV::CacheCB(IDeviceObject *pBuffer, ShaderResourceCacheD3D12::Resource& DstRes, Uint32 ArrayInd, D3D12_CPU_DESCRIPTOR_HANDLE ShdrVisibleHeapCPUDescriptorHandle)
 {
+    // http://diligentgraphics.com/diligent-engine/architecture/d3d12/shader-resource-cache#Binding-Objects-to-Shader-Variables
+
     // We cannot use ValidatedCast<> here as the resource retrieved from the
     // resource mapping can be of wrong type
     RefCntAutoPtr<BufferD3D12Impl> pBuffD3D12(pBuffer, IID_BufferD3D12);
@@ -399,10 +413,17 @@ void ShaderResourceLayoutD3D12::SRV_CBV_UAV::CacheCB(IDeviceObject *pBuffer, Sha
     {
         if( pBuffD3D12->GetDesc().BindFlags & BIND_UNIFORM_BUFFER )
         {
-            if( Attribs.GetVariableType() != SHADER_VARIABLE_TYPE_DYNAMIC && DstRes.pObject != nullptr && DstRes.pObject != pBuffD3D12)
+            if( Attribs.GetVariableType() != SHADER_VARIABLE_TYPE_DYNAMIC && DstRes.pObject != nullptr )
             {
-                auto VarTypeStr = GetShaderVariableTypeLiteralName(Attribs.GetVariableType());
-                LOG_ERROR_MESSAGE( "Non-null constant buffer is already bound to ", VarTypeStr, " shader variable \"", Attribs.GetPrintName(ArrayInd), "\" in shader \"", m_ParentResLayout.GetShaderName(), "\". Attempring to bind another constant buffer is an error and may cause unpredicted behavior. Use another shader resource binding instance or mark shader variable as dynamic." )
+                if(DstRes.pObject != pBuffD3D12)
+                {
+                    auto VarTypeStr = GetShaderVariableTypeLiteralName(Attribs.GetVariableType());
+                    LOG_ERROR_MESSAGE( "Non-null constant buffer is already bound to ", VarTypeStr, " shader variable \"", Attribs.GetPrintName(ArrayInd), "\" in shader \"", m_ParentResLayout.GetShaderName(), "\". Attempring to bind another constant buffer is an error and will be ignored. Use another shader resource binding instance or mark shader variable as dynamic." )
+                }
+
+                // Do not update resource if one is already bound unless it is dynamic. This may be 
+                // dangerous as CopyDescriptorsSimple() may interfere with GPU reading the same descriptor.
+                return;
             }
 
             DstRes.Type = GetResType();
@@ -411,6 +432,10 @@ void ShaderResourceLayoutD3D12::SRV_CBV_UAV::CacheCB(IDeviceObject *pBuffer, Sha
             
             if(ShdrVisibleHeapCPUDescriptorHandle.ptr != 0 )
             {
+                // Dynamic resources are assigned descriptor in the GPU-visible heap at every draw call, and
+                // the descriptor is copied by the RootSignature when resources are committed
+                VERIFY(DstRes.pObject == nullptr, "Static and mutable resource descriptors must be copied only once");
+
                 ID3D12Device *pd3d12Device = m_ParentResLayout.m_pd3d12Device;
                 pd3d12Device->CopyDescriptorsSimple(1, ShdrVisibleHeapCPUDescriptorHandle, DstRes.CPUDescriptorHandle, D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV);
             }
@@ -477,22 +502,33 @@ void ShaderResourceLayoutD3D12::SRV_CBV_UAV::CacheResourceView(IDeviceObject *pV
             return;
         }
 #endif
-        if( Attribs.GetVariableType() != SHADER_VARIABLE_TYPE_DYNAMIC && DstRes.pObject != nullptr && DstRes.pObject != pViewD3D12)
+        if( Attribs.GetVariableType() != SHADER_VARIABLE_TYPE_DYNAMIC && DstRes.pObject != nullptr )
         {
-            auto VarTypeStr = GetShaderVariableTypeLiteralName(Attribs.GetVariableType());
-            LOG_ERROR_MESSAGE( "Non-null resource is already bound to ", VarTypeStr, " shader variable \"", Attribs.GetPrintName(ArrayIndex), "\" in shader \"", m_ParentResLayout.GetShaderName(), "\". Attempting to bind another resource or null is an error and may cause unpredicted behavior. Use another shader resource binding instance or mark shader variable as dynamic." );
+            if(DstRes.pObject != pViewD3D12)
+            {
+                auto VarTypeStr = GetShaderVariableTypeLiteralName(Attribs.GetVariableType());
+                LOG_ERROR_MESSAGE( "Non-null resource is already bound to ", VarTypeStr, " shader variable \"", Attribs.GetPrintName(ArrayIndex), "\" in shader \"", m_ParentResLayout.GetShaderName(), "\". Attempting to bind another resource or null is an error and will be ignored. Use another shader resource binding instance or mark shader variable as dynamic." );
+            }
+
+            // Do not update resource if one is already bound unless it is dynamic. This may be 
+            // dangerous as CopyDescriptorsSimple() may interfere with GPU reading the same descriptor.
+            return;
         }
 
         DstRes.Type = GetResType();
-        DstRes.pObject = pViewD3D12;
         DstRes.CPUDescriptorHandle = pViewD3D12->GetCPUDescriptorHandle();
         VERIFY(DstRes.CPUDescriptorHandle.ptr != 0, "No relevant D3D12 view")
 
         if(ShdrVisibleHeapCPUDescriptorHandle.ptr != 0)
         {
+            // Dynamic resources are assigned descriptor in the GPU-visible heap at every draw call, and
+            // the descriptor is copied by the RootSignature when resources are committed
+            VERIFY(DstRes.pObject == nullptr, "Static and mutable resource descriptors must be copied only once");
+
             ID3D12Device *pd3d12Device = m_ParentResLayout.m_pd3d12Device;
             pd3d12Device->CopyDescriptorsSimple(1, ShdrVisibleHeapCPUDescriptorHandle, DstRes.CPUDescriptorHandle, D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV);
         }
+        DstRes.pObject = pViewD3D12;
 
         BindSamplerProc(pViewD3D12);
     }
@@ -504,7 +540,7 @@ void ShaderResourceLayoutD3D12::SRV_CBV_UAV::CacheResourceView(IDeviceObject *pV
 
 void ShaderResourceLayoutD3D12::Sampler::CacheSampler(ITextureViewD3D12 *pTexViewD3D12, Uint32 ArrayIndex, D3D12_CPU_DESCRIPTOR_HANDLE ShdrVisibleHeapCPUDescriptorHandle)
 {
-    auto &pResourceCache = m_ParentResLayout.m_pResourceCache;
+    auto *pResourceCache = m_ParentResLayout.m_pResourceCache;
     VERIFY(pResourceCache, "Resource cache is null");
     VERIFY(Attribs.IsValidBindPoint(), "Invalid bind point");
     VERIFY_EXPR(ArrayIndex < Attribs.BindCount);
@@ -536,10 +572,17 @@ void ShaderResourceLayoutD3D12::Sampler::CacheSampler(ITextureViewD3D12 *pTexVie
         auto pSampler = pTexViewD3D12->GetSampler();
         if( pSampler )
         {
-            if( Attribs.GetVariableType() != SHADER_VARIABLE_TYPE_DYNAMIC && DstSam.pObject != nullptr && DstSam.pObject != pSampler)
+            if( Attribs.GetVariableType() != SHADER_VARIABLE_TYPE_DYNAMIC && DstSam.pObject != nullptr)
             {
-                auto VarTypeStr = GetShaderVariableTypeLiteralName(Attribs.GetVariableType());
-                LOG_ERROR_MESSAGE( "Non-null sampler is already bound to ", VarTypeStr, " shader variable \"", Attribs.GetPrintName(ArrayIndex), "\" in shader \"", m_ParentResLayout.GetShaderName(), "\". Attempting to bind another sampler is an error and may cause unpredicted behavior. Use another shader resource binding instance or mark shader variable as dynamic." )
+                if(DstSam.pObject != pSampler)
+                {
+                    auto VarTypeStr = GetShaderVariableTypeLiteralName(Attribs.GetVariableType());
+                    LOG_ERROR_MESSAGE( "Non-null sampler is already bound to ", VarTypeStr, " shader variable \"", Attribs.GetPrintName(ArrayIndex), "\" in shader \"", m_ParentResLayout.GetShaderName(), "\". Attempting to bind another sampler is an error and will be ignored. Use another shader resource binding instance or mark shader variable as dynamic." )
+                }
+                
+                // Do not update resource if one is already bound unless it is dynamic. This may be 
+                // dangerous as CopyDescriptorsSimple() may interfere with GPU reading the same descriptor.
+                return;
             }
 
             DstSam.Type = CachedResourceType::Sampler;
@@ -550,6 +593,10 @@ void ShaderResourceLayoutD3D12::Sampler::CacheSampler(ITextureViewD3D12 *pTexVie
 
             if(ShdrVisibleHeapCPUDescriptorHandle.ptr != 0)
             {
+                // Dynamic resources are assigned descriptor in the GPU-visible heap at every draw call, and
+                // the descriptor is copied by the RootSignature when resources are committed
+                VERIFY(DstSam.pObject == nullptr, "Static and mutable resource descriptors must be copied only once");
+
                 ID3D12Device *pd3d12Device = m_ParentResLayout.m_pd3d12Device;
                 pd3d12Device->CopyDescriptorsSimple(1, ShdrVisibleHeapCPUDescriptorHandle, DstSam.CPUDescriptorHandle, D3D12_DESCRIPTOR_HEAP_TYPE_SAMPLER);
             }
@@ -581,7 +628,7 @@ ShaderResourceLayoutD3D12::Sampler &ShaderResourceLayoutD3D12::GetAssignedSample
 
 void ShaderResourceLayoutD3D12::SRV_CBV_UAV::BindResource(IDeviceObject *pObj, Uint32 ArrayIndex, const ShaderResourceLayoutD3D12 *dbgResLayout)
 {
-    auto &pResourceCache = m_ParentResLayout.m_pResourceCache;
+    auto *pResourceCache = m_ParentResLayout.m_pResourceCache;
     VERIFY(pResourceCache, "Resource cache is null");
     VERIFY(dbgResLayout == nullptr || pResourceCache == dbgResLayout->m_pResourceCache, "Invalid resource cache");
     VERIFY_EXPR(ArrayIndex < Attribs.BindCount);
@@ -674,7 +721,7 @@ void ShaderResourceLayoutD3D12::SRV_CBV_UAV::BindResource(IDeviceObject *pObj, U
 
 bool ShaderResourceLayoutD3D12::SRV_CBV_UAV::IsBound(Uint32 ArrayIndex)
 {
-    auto &pResourceCache = m_ParentResLayout.m_pResourceCache;
+    auto *pResourceCache = m_ParentResLayout.m_pResourceCache;
     VERIFY(pResourceCache, "Resource cache is null");
     VERIFY_EXPR(ArrayIndex < Attribs.BindCount);
 
@@ -708,7 +755,6 @@ void ShaderResourceLayoutD3D12::BindResources( IResourceMapping* pResourceMappin
         return;
     }
 
-    // Bind constant buffers
     Uint32 TotalResources = GetTotalSrvCbvUavCount();
     for(Uint32 r=0; r < TotalResources; ++r)
     {
@@ -793,16 +839,21 @@ void ShaderResourceLayoutD3D12::CopyStaticResourceDesriptorHandles(const ShaderR
 
     for(Uint32 r=0; r < m_NumCbvSrvUav[SHADER_VARIABLE_TYPE_STATIC]; ++r)
     {
+        // Get resource attributes
         const auto &res = GetSrvCbvUav(SHADER_VARIABLE_TYPE_STATIC, r);
         VERIFY(SrcLayout.m_pResources->GetShaderType() == m_pResources->GetShaderType(), "Incosistent shader types")
         auto RangeType = GetDescriptorRangeType(res.GetResType());
         for(Uint32 ArrInd = 0; ArrInd < res.Attribs.BindCount; ++ArrInd)
         {
             auto BindPoint = res.Attribs.BindPoint + ArrInd;
-            // Static resources are indexed in the resource cache by its bind point
+            // Source resource in the static resource cache is in the root table at index RangeType, at offset BindPoint 
+            // D3D12_DESCRIPTOR_RANGE_TYPE_SRV = 0,
+            // D3D12_DESCRIPTOR_RANGE_TYPE_UAV = 1
+            // D3D12_DESCRIPTOR_RANGE_TYPE_CBV = 2
             const auto &SrcRes = SrcLayout.m_pResourceCache->GetRootTable(RangeType).GetResource(BindPoint, D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV, SrcLayout.m_pResources->GetShaderType());
             if( !SrcRes.pObject )
                 LOG_ERROR_MESSAGE( "No resource assigned to static shader variable \"", res.Attribs.GetPrintName(ArrInd), "\" in shader \"", GetShaderName(), "\"." );
+            // Destination resource is at the root index and offset defined by the resource layout
             auto &DstRes = m_pResourceCache->GetRootTable(res.GetRootIndex()).GetResource(res.OffsetFromTableStart + ArrInd, D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV, m_pResources->GetShaderType());
         
             if(DstRes.pObject != SrcRes.pObject)
@@ -815,6 +866,7 @@ void ShaderResourceLayoutD3D12::CopyStaticResourceDesriptorHandles(const ShaderR
 
                 auto ShdrVisibleHeapCPUDescriptorHandle = m_pResourceCache->GetShaderVisibleTableCPUDescriptorHandle<D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV>(res.GetRootIndex(), res.OffsetFromTableStart + ArrInd);
                 VERIFY_EXPR(ShdrVisibleHeapCPUDescriptorHandle.ptr != 0 || DstRes.Type == CachedResourceType::CBV);
+                // Root views are not assigned space in the GPU-visible descriptor heap allocation
                 if (ShdrVisibleHeapCPUDescriptorHandle.ptr != 0)
                 {
                     m_pd3d12Device->CopyDescriptorsSimple(1, ShdrVisibleHeapCPUDescriptorHandle, SrcRes.CPUDescriptorHandle, D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV);
@@ -840,7 +892,8 @@ void ShaderResourceLayoutD3D12::CopyStaticResourceDesriptorHandles(const ShaderR
             for(Uint32 ArrInd = 0; ArrInd < SamInfo.Attribs.BindCount; ++ArrInd)
             {
                 auto BindPoint = SamInfo.Attribs.BindPoint + ArrInd;
-                // Static resources are indexed by the bind point in the resource cache
+                // Source sampler in the static resource cache is in the root table at index 3 
+                // (D3D12_DESCRIPTOR_RANGE_TYPE_SAMPLER = 3), at offset BindPoint 
                 auto& SrcSampler = SrcLayout.m_pResourceCache->GetRootTable(D3D12_DESCRIPTOR_RANGE_TYPE_SAMPLER).GetResource(BindPoint, D3D12_DESCRIPTOR_HEAP_TYPE_SAMPLER, SrcLayout.m_pResources->GetShaderType());
                 if( !SrcSampler.pObject )
                     LOG_ERROR_MESSAGE( "No sampler assigned to static shader variable \"", res.Attribs.GetPrintName(ArrInd), "\" in shader \"", GetShaderName(), "\"." );
@@ -894,7 +947,8 @@ void ShaderResourceLayoutD3D12::dbgVerifyBindings()const
                     VERIFY(CachedRes.Type == CachedResourceType::Unknown, "Unexpected cached resource types")
 
                 if( !CachedRes.pObject || 
-                     (CachedRes.CPUDescriptorHandle.ptr == 0 && ValidatedCast<const BufferD3D12Impl>(CachedRes.pObject.RawPtr())->GetDesc().Usage != USAGE_DYNAMIC) )
+                     // Dynamic buffers do not have CPU descriptor handle as they do not keep D3D12 buffer, and space is allocated from the GPU ring buffer
+                     CachedRes.CPUDescriptorHandle.ptr == 0 && !(CachedRes.Type==CachedResourceType::CBV && ValidatedCast<const BufferD3D12Impl>(CachedRes.pObject.RawPtr())->GetDesc().Usage == USAGE_DYNAMIC) )
                     LOG_ERROR_MESSAGE( "No resource is bound to ", GetShaderVariableTypeLiteralName(res.Attribs.GetVariableType()), " variable \"", res.Attribs.GetPrintName(ArrInd), "\" in shader \"", GetShaderName(), "\"" )
                 
                 if (res.Attribs.BindCount > 1 && res.IsValidSampler())
@@ -944,7 +998,7 @@ void ShaderResourceLayoutD3D12::dbgVerifyBindings()const
 
             if (res.IsValidSampler())
             {
-                VERIFY(res.GetResType() == CachedResourceType::TexSRV, "Sampler can only be assigned to texture SRV" );
+                VERIFY(res.GetResType() == CachedResourceType::TexSRV, "Sampler can only be assigned to a texture SRV" );
                 const auto &SamInfo = const_cast<ShaderResourceLayoutD3D12*>(this)->GetAssignedSampler(res);
                 VERIFY( !SamInfo.Attribs.IsStaticSampler(), "Static samplers should never be assigned space in the cache" )
                 VERIFY(SamInfo.Attribs.IsValidBindPoint(), "Sampler bind point must be valid")
diff --git a/Graphics/GraphicsEngineD3D12/src/ShaderResourcesD3D12.cpp b/Graphics/GraphicsEngineD3D12/src/ShaderResourcesD3D12.cpp
index e7543ce6..c42f663e 100644
--- a/Graphics/GraphicsEngineD3D12/src/ShaderResourcesD3D12.cpp
+++ b/Graphics/GraphicsEngineD3D12/src/ShaderResourcesD3D12.cpp
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/src/SwapChainD3D12Impl.cpp b/Graphics/GraphicsEngineD3D12/src/SwapChainD3D12Impl.cpp
index dad6639f..2e42ca44 100644
--- a/Graphics/GraphicsEngineD3D12/src/SwapChainD3D12Impl.cpp
+++ b/Graphics/GraphicsEngineD3D12/src/SwapChainD3D12Impl.cpp
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/src/TextureD3D12Impl.cpp b/Graphics/GraphicsEngineD3D12/src/TextureD3D12Impl.cpp
index d5ce27d7..8361421f 100644
--- a/Graphics/GraphicsEngineD3D12/src/TextureD3D12Impl.cpp
+++ b/Graphics/GraphicsEngineD3D12/src/TextureD3D12Impl.cpp
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/src/TextureViewD3D12Impl.cpp b/Graphics/GraphicsEngineD3D12/src/TextureViewD3D12Impl.cpp
index 0b93926b..57749298 100644
--- a/Graphics/GraphicsEngineD3D12/src/TextureViewD3D12Impl.cpp
+++ b/Graphics/GraphicsEngineD3D12/src/TextureViewD3D12Impl.cpp
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
diff --git a/Graphics/GraphicsEngineD3D12/src/pch.cpp b/Graphics/GraphicsEngineD3D12/src/pch.cpp
index 997e0f4a..d5f45c6a 100644
--- a/Graphics/GraphicsEngineD3D12/src/pch.cpp
+++ b/Graphics/GraphicsEngineD3D12/src/pch.cpp
@@ -1,4 +1,4 @@
-/*     Copyright 2015-2016 Egor Yusov
+/*     Copyright 2015-2017 Egor Yusov
  *  
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
-- 
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