Use D3DSWAPEFFECT_FLIPEX on Windows 7.
Reduces frame rate jitters on Windows 7 reported in crbug.com/82925
Review URL: http://codereview.appspot.com/4517096
git-svn-id: https://angleproject.googlecode.com/svn/trunk@654 736b8ea6-26fd-11df-bfd4-992fa37f6226
diff --git a/src/libEGL/Surface.cpp b/src/libEGL/Surface.cpp
index bbdd412..3ab15d2 100644
--- a/src/libEGL/Surface.cpp
+++ b/src/libEGL/Surface.cpp
@@ -145,7 +145,14 @@
D3DPRESENT_PARAMETERS presentParameters = {0};
HRESULT result;
+ bool useFlipEx = LOWORD(GetVersion()) >= 0x61;
+
presentParameters.AutoDepthStencilFormat = mConfig->mDepthStencilFormat;
+ // We set BackBufferCount = 1 even when we use D3DSWAPEFFECT_FLIPEX.
+ // We do this because DirectX docs are a bit vague whether to set this to 1
+ // or 2. The runtime seems to accept 1, so we speculate that either it is
+ // forcing it to 2 without telling us, or better, doing something smart
+ // behind the scenes knowing that we don't need more.
presentParameters.BackBufferCount = 1;
presentParameters.BackBufferFormat = mConfig->mRenderTargetFormat;
presentParameters.EnableAutoDepthStencil = FALSE;
@@ -154,7 +161,11 @@
presentParameters.MultiSampleQuality = 0; // FIXME: Unimplemented
presentParameters.MultiSampleType = D3DMULTISAMPLE_NONE; // FIXME: Unimplemented
presentParameters.PresentationInterval = mPresentInterval;
- presentParameters.SwapEffect = D3DSWAPEFFECT_DISCARD;
+ // Use flipEx on Win7 or greater.
+ if(useFlipEx)
+ presentParameters.SwapEffect = D3DSWAPEFFECT_FLIPEX;
+ else
+ presentParameters.SwapEffect = D3DSWAPEFFECT_DISCARD;
presentParameters.Windowed = TRUE;
presentParameters.BackBufferWidth = backbufferWidth;
presentParameters.BackBufferHeight = backbufferHeight;
