From 64888e8097027b9becb6ab4def09b510d291cf64 Mon Sep 17 00:00:00 2001
From: assiduous <assiduous@diligentgraphics.com>
Date: Tue, 19 May 2020 23:13:41 -0700
Subject: Improved latency handling in D3D11 and D3D12 (API 240061, fixed
 https://github.com/DiligentGraphics/DiligentEngine/issues/81)

---
 .../include/SwapChainD3D11Impl.hpp                 |  5 ++--
 .../GraphicsEngineD3D11/src/EngineFactoryD3D11.cpp |  6 +++--
 .../GraphicsEngineD3D11/src/SwapChainD3D11Impl.cpp | 31 +++++++++++++++++++++-
 3 files changed, 37 insertions(+), 5 deletions(-)

(limited to 'Graphics/GraphicsEngineD3D11')

diff --git a/Graphics/GraphicsEngineD3D11/include/SwapChainD3D11Impl.hpp b/Graphics/GraphicsEngineD3D11/include/SwapChainD3D11Impl.hpp
index 2e6efb6a..0c36c5d3 100644
--- a/Graphics/GraphicsEngineD3D11/include/SwapChainD3D11Impl.hpp
+++ b/Graphics/GraphicsEngineD3D11/include/SwapChainD3D11Impl.hpp
@@ -37,10 +37,10 @@ namespace Diligent
 {
 
 /// Swap chain implementation in Direct3D11 backend.
-class SwapChainD3D11Impl final : public SwapChainD3DBase<ISwapChainD3D11, IDXGISwapChain>
+class SwapChainD3D11Impl final : public SwapChainD3DBase<ISwapChainD3D11, IDXGISwapChain2>
 {
 public:
-    using TSwapChainBase = SwapChainD3DBase<ISwapChainD3D11, IDXGISwapChain>;
+    using TSwapChainBase = SwapChainD3DBase<ISwapChainD3D11, IDXGISwapChain2>;
 
     SwapChainD3D11Impl(IReferenceCounters*           pRefCounters,
                        const SwapChainDesc&          SCDesc,
@@ -70,6 +70,7 @@ public:
 private:
     virtual void UpdateSwapChain(bool CreateNew) override final;
     void         CreateRTVandDSV();
+    virtual void SetDXGIDeviceMaximumFrameLatency() override final;
 
     RefCntAutoPtr<ITextureViewD3D11> m_pRenderTargetView;
     RefCntAutoPtr<ITextureViewD3D11> m_pDepthStencilView;
diff --git a/Graphics/GraphicsEngineD3D11/src/EngineFactoryD3D11.cpp b/Graphics/GraphicsEngineD3D11/src/EngineFactoryD3D11.cpp
index d82f0668..4d7c1321 100644
--- a/Graphics/GraphicsEngineD3D11/src/EngineFactoryD3D11.cpp
+++ b/Graphics/GraphicsEngineD3D11/src/EngineFactoryD3D11.cpp
@@ -29,6 +29,10 @@
 /// Routines that initialize D3D11-based engine implementation
 
 #include "pch.h"
+
+#include <Windows.h>
+#include <dxgi1_3.h>
+
 #include "EngineFactoryD3D11.h"
 #include "RenderDeviceD3D11Impl.hpp"
 #include "DeviceContextD3D11Impl.hpp"
@@ -36,8 +40,6 @@
 #include "D3D11TypeConversions.hpp"
 #include "EngineMemory.h"
 #include "EngineFactoryD3DBase.hpp"
-#include <Windows.h>
-#include <dxgi1_2.h>
 
 namespace Diligent
 {
diff --git a/Graphics/GraphicsEngineD3D11/src/SwapChainD3D11Impl.cpp b/Graphics/GraphicsEngineD3D11/src/SwapChainD3D11Impl.cpp
index d65df7f3..d10aa2d1 100644
--- a/Graphics/GraphicsEngineD3D11/src/SwapChainD3D11Impl.cpp
+++ b/Graphics/GraphicsEngineD3D11/src/SwapChainD3D11Impl.cpp
@@ -26,10 +26,11 @@
  */
 
 #include "pch.h"
+#include <dxgi1_3.h>
+
 #include "SwapChainD3D11Impl.hpp"
 #include "RenderDeviceD3D11Impl.hpp"
 #include "DeviceContextD3D11Impl.hpp"
-#include <dxgi1_2.h>
 
 namespace Diligent
 {
@@ -143,6 +144,11 @@ void SwapChainD3D11Impl::Present(Uint32 SyncInterval)
         // as this can explicitly be done by the user
     }
 
+    // In contrast to MSDN sample, we wait for the frame as late as possible - right
+    // before presenting.
+    // https://docs.microsoft.com/en-us/windows/uwp/gaming/reduce-latency-with-dxgi-1-3-swap-chains#step-4-wait-before-rendering-each-frame
+    WaitForFrame();
+
     m_pSwapChain->Present(SyncInterval, 0);
 }
 
@@ -218,4 +224,27 @@ void SwapChainD3D11Impl::Resize(Uint32 NewWidth, Uint32 NewHeight, SURFACE_TRANS
     }
 }
 
+void SwapChainD3D11Impl::SetDXGIDeviceMaximumFrameLatency()
+{
+    VERIFY(m_FrameLatencyWaitableObject == NULL, "This method should only be used as a workaround for swap chains that are not waitable");
+
+    auto* pd3d11Device = m_pRenderDevice.RawPtr<IRenderDeviceD3D11>()->GetD3D11Device();
+
+    CComPtr<IDXGIDevice1> pDXGIDevice;
+
+    auto hr = pd3d11Device->QueryInterface(__uuidof(pDXGIDevice), reinterpret_cast<void**>(static_cast<IDXGIDevice1**>(&pDXGIDevice)));
+    if (SUCCEEDED(hr) && pDXGIDevice)
+    {
+        hr = pDXGIDevice->SetMaximumFrameLatency(m_MaxFrameLatency);
+        if (FAILED(hr))
+        {
+            LOG_ERROR_MESSAGE("Failed to set the maximum frame latency for DXGI device");
+        }
+    }
+    else
+    {
+        LOG_ERROR("Failed to query IDXGIDevice1 interface from D3D11 device");
+    }
+}
+
 } // namespace Diligent
-- 
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