Added DRAW_FLAG_RESOURCE_BUFFERS_INTACT flag (API Version 240036)

7 files changed, 70 insertions, 16 deletions

diff --git a/Graphics/GraphicsEngine/interface/APIInfo.h b/Graphics/GraphicsEngine/interface/APIInfo.h
index 36cb5c36..74e125ca 100644
--- a/Graphics/GraphicsEngine/interface/APIInfo.h
+++ b/Graphics/GraphicsEngine/interface/APIInfo.h
@@ -26,7 +26,7 @@
 /// \file
 /// Diligent API information
 
-#define DILIGENT_API_VERSION 240035
+#define DILIGENT_API_VERSION 240036
 
 #include "../../../Primitives/interface/BasicTypes.h"
 
diff --git a/Graphics/GraphicsEngine/interface/DeviceContext.h b/Graphics/GraphicsEngine/interface/DeviceContext.h
index 45f057c9..1e50262e 100644
--- a/Graphics/GraphicsEngine/interface/DeviceContext.h
+++ b/Graphics/GraphicsEngine/interface/DeviceContext.h
@@ -70,7 +70,40 @@ enum DRAW_FLAGS : Uint8
     DRAW_FLAG_VERIFY_RENDER_TARGETS           = 0x04,
 
     /// Perform all state validation checks
-    DRAW_FLAG_VERIFY_ALL                      = DRAW_FLAG_VERIFY_STATES | DRAW_FLAG_VERIFY_DRAW_ATTRIBS | DRAW_FLAG_VERIFY_RENDER_TARGETS
+    DRAW_FLAG_VERIFY_ALL                      = DRAW_FLAG_VERIFY_STATES | DRAW_FLAG_VERIFY_DRAW_ATTRIBS | DRAW_FLAG_VERIFY_RENDER_TARGETS,
+
+    /// Indicates that none of the resource buffers used by the draw command
+    /// have been modified by the CPU since the last command.
+    ///
+    /// \remarks D3D12 and Vulkan back-ends have to perform some work to make data in buffers
+    ///          available to draw commands. By default the engine assumes that the CPU may
+    ///          change the data after every command. For example, if a draw command uses a constant
+    ///          buffer, the engine assumes that the CPU may write new data to the buffer (for example, new
+    ///          transformation matrices), before every draw call. This is not always the case, however,
+    ///          and the application may inform the engine that the data in the buffer stay intact to avoid
+    ///          extra work.\n
+    ///          This flag is most useful when application issues a series of draw commands that use the same
+    ///          resources that do not change between the commands.\n
+    ///          Note that after a new PSO is bound or an SRB is committed, the engine will always set all
+    ///          required buffers regardless of the flag. The flag will only take effect on the second and
+    ///          susbequent draw calls that use the same PSO and SRB.\n
+    ///          The flag has no effect in D3D11 and OpenGL backends.
+    ///
+    ///          Technical details
+    ///         
+    ///          Vulkan backend allocates VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC descriptors for uniform (constant), 
+    ///          buffers and VK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC descritptors for storage buffers.
+    ///          Note that HLSL structured buffers are mapped to read-only storage buffers in SPIRV and RW buffers
+    ///          are mapped to RW-storage buffers.
+    ///          By default, all dynamic descriptor sets are updated every time a draw command is issued (see
+    ///          PipelineStateVkImpl::BindDescriptorSetsWithDynamicOffsets). When DRAW_FLAG_RESOURCE_BUFFERS_INTACT is
+    ///          specified, dynamic descriptor sets are only be bound by the first draw command that uses the PSO and the SRB.
+    ///
+    ///          Direct3D12 backend binds constant buffers to root views. By default the engine assumes that the buffers
+    ///          may be modified by the CPU between draw commands and always commits root views (see RootSignature::CommitRootViews).
+    ///          When DRAW_FLAG_RESOURCE_BUFFERS_INTACT is set, root views are only committed by the first draw command that uses
+    ///          the PSO and the SRB pair.
+    DRAW_FLAG_RESOURCE_BUFFERS_INTACT         = 0x08
 };
 DEFINE_FLAG_ENUM_OPERATORS(DRAW_FLAGS)
 
diff --git a/Graphics/GraphicsEngineD3D12/include/DeviceContextD3D12Impl.h b/Graphics/GraphicsEngineD3D12/include/DeviceContextD3D12Impl.h
index 2bcb8004..b9561b3b 100644
--- a/Graphics/GraphicsEngineD3D12/include/DeviceContextD3D12Impl.h
+++ b/Graphics/GraphicsEngineD3D12/include/DeviceContextD3D12Impl.h
@@ -288,12 +288,16 @@ private:
         VALUE_TYPE              CommittedIBFormat                  = VT_UNDEFINED;
         Uint32                  CommittedD3D12IndexDataStartOffset = 0;
 
-        // Flag indicating if currently committed D3D12 vertex buffers are up to date
+        // Indicates if currently committed D3D12 vertex buffers are up to date
         bool bCommittedD3D12VBsUpToDate = false;
 
-        // Fl indicating if currently committed D3D11 index buffer is up to date
+        // Indicates if currently committed D3D11 index buffer is up to date
         bool bCommittedD3D12IBUpToDate  = false;
 
+        // Indicates if root views have been committed since the time SRB
+        // has been committed.
+        bool bRootViewsCommitted        = false;
+
         class ShaderResourceCacheD3D12* pCommittedResourceCache = nullptr;
     }m_State;
 
diff --git a/Graphics/GraphicsEngineD3D12/src/DeviceContextD3D12Impl.cpp b/Graphics/GraphicsEngineD3D12/src/DeviceContextD3D12Impl.cpp
index 1a3a4985..c1608c4a 100644
--- a/Graphics/GraphicsEngineD3D12/src/DeviceContextD3D12Impl.cpp
+++ b/Graphics/GraphicsEngineD3D12/src/DeviceContextD3D12Impl.cpp
@@ -229,6 +229,7 @@ namespace Diligent
             }
         }
         m_State.pCommittedResourceCache = nullptr;
+        m_State.bRootViewsCommitted     = false;
     }
 
     void DeviceContextD3D12Impl::TransitionShaderResources(IPipelineState* pPipelineState, IShaderResourceBinding* pShaderResourceBinding)
@@ -250,6 +251,7 @@ namespace Diligent
             m_pPipelineState->CommitAndTransitionShaderResources(pShaderResourceBinding, Ctx, true,
                     StateTransitionMode == RESOURCE_STATE_TRANSITION_MODE_TRANSITION,
                     StateTransitionMode == RESOURCE_STATE_TRANSITION_MODE_VERIFY);
+        m_State.bRootViewsCommitted = false;
     }
 
     void DeviceContextD3D12Impl::SetStencilRef(Uint32 StencilRef)
@@ -392,7 +394,11 @@ namespace Diligent
 
         if (m_State.pCommittedResourceCache != nullptr)
         {
-            m_pPipelineState->GetRootSignature().CommitRootViews(*m_State.pCommittedResourceCache, GraphCtx, false, this);
+            if (!m_State.bRootViewsCommitted || (Flags & DRAW_FLAG_RESOURCE_BUFFERS_INTACT) == 0)
+            {
+                m_pPipelineState->GetRootSignature().CommitRootViews(*m_State.pCommittedResourceCache, GraphCtx, false, this);
+                m_State.bRootViewsCommitted = true;
+            }
         }
 #ifdef DEVELOPMENT
         else
diff --git a/Graphics/GraphicsEngineVulkan/include/PipelineLayout.h b/Graphics/GraphicsEngineVulkan/include/PipelineLayout.h
index 902dcdd4..e34ee108 100644
--- a/Graphics/GraphicsEngineVulkan/include/PipelineLayout.h
+++ b/Graphics/GraphicsEngineVulkan/include/PipelineLayout.h
@@ -90,10 +90,11 @@ public:
     {
         std::vector<VkDescriptorSet> vkSets;
         std::vector<uint32_t>        DynamicOffsets;
-        const ShaderResourceCacheVk* pResourceCache     = nullptr;
-        VkPipelineBindPoint          BindPoint          = VK_PIPELINE_BIND_POINT_MAX_ENUM;
-        Uint32                       SetCout            = 0;
-        Uint32                       DynamicOffsetCount = 0;
+        const ShaderResourceCacheVk* pResourceCache          = nullptr;
+        VkPipelineBindPoint          BindPoint               = VK_PIPELINE_BIND_POINT_MAX_ENUM;
+        Uint32                       SetCout                 = 0;
+        Uint32                       DynamicOffsetCount      = 0;
+        bool                         DynamicDescriptorsBound = false;
 #ifdef _DEBUG
         const PipelineLayout*        pDbgPipelineLayout = nullptr;
 #endif
@@ -105,16 +106,17 @@ public:
 
         void Reset()
         {
-            SetCout            = 0;
-            DynamicOffsetCount = 0;
+            pResourceCache          = nullptr;
+            BindPoint               = VK_PIPELINE_BIND_POINT_MAX_ENUM;
+            SetCout                 = 0;
+            DynamicOffsetCount      = 0;
+            DynamicDescriptorsBound = false;
+
 #ifdef _DEBUG
             // In release mode, do not clear vectors as this causes unnecessary work
             vkSets.clear();
             DynamicOffsets.clear();
-#endif
-            pResourceCache = nullptr;
-            BindPoint = VK_PIPELINE_BIND_POINT_MAX_ENUM;
-#ifdef _DEBUG
+
             pDbgPipelineLayout = nullptr;
 #endif
         }
@@ -246,6 +248,8 @@ __forceinline void PipelineLayout::BindDescriptorSetsWithDynamicOffsets(VulkanUt
                                  // dynamicOffsetCount must equal the total number of dynamic descriptors in the sets being bound (13.2.5)
                                  BindInfo.DynamicOffsetCount,
                                  BindInfo.DynamicOffsets.data());
+
+    BindInfo.DynamicDescriptorsBound = true;
 }
 
 }
diff --git a/Graphics/GraphicsEngineVulkan/src/DeviceContextVkImpl.cpp b/Graphics/GraphicsEngineVulkan/src/DeviceContextVkImpl.cpp
index 2bc18ce1..454429b8 100644
--- a/Graphics/GraphicsEngineVulkan/src/DeviceContextVkImpl.cpp
+++ b/Graphics/GraphicsEngineVulkan/src/DeviceContextVkImpl.cpp
@@ -421,7 +421,12 @@ namespace Diligent
 #endif
 
         if (m_DescrSetBindInfo.DynamicOffsetCount != 0)
-            m_pPipelineState->BindDescriptorSetsWithDynamicOffsets(GetCommandBuffer(), m_ContextId, this, m_DescrSetBindInfo);
+        {
+            if (!m_DescrSetBindInfo.DynamicDescriptorsBound || (Flags & DRAW_FLAG_RESOURCE_BUFFERS_INTACT) == 0)
+            {
+                m_pPipelineState->BindDescriptorSetsWithDynamicOffsets(GetCommandBuffer(), m_ContextId, this, m_DescrSetBindInfo);
+            }
+        }
 #if 0
 #ifdef _DEBUG
         else
diff --git a/Graphics/GraphicsEngineVulkan/src/PipelineLayout.cpp b/Graphics/GraphicsEngineVulkan/src/PipelineLayout.cpp
index b978f3c6..b3b97ec6 100644
--- a/Graphics/GraphicsEngineVulkan/src/PipelineLayout.cpp
+++ b/Graphics/GraphicsEngineVulkan/src/PipelineLayout.cpp
@@ -499,6 +499,8 @@ void PipelineLayout::PrepareDescriptorSets(DeviceContextVkImpl*          pCtxVkI
                                      0, 
                                      nullptr);
     }
+
+    BindInfo.DynamicDescriptorsBound = false;
 }
 
 }