CPU optimisations

apps/LoopThroughWithOpenGLCompositing/gl/OpenGLComposite.cpp

@@ -35,7 +35,7 @@ OpenGLComposite::OpenGLComposite(HWND hWnd, HDC hDC, HGLRC hRC) :
 		*mRuntimeHost,
 		[this]() { renderEffect(); },
 		[this]() { ProcessScreenshotRequest(); },
-		[this]() { paintGL(); });
+		[this]() { paintGL(false); });
 	mVideoIOBridge = std::make_unique<OpenGLVideoIOBridge>(
 		*mVideoIO,
 		*mRenderer,
@@ -156,8 +156,26 @@ error:
 	return false;
 }
 
-void OpenGLComposite::paintGL()
+void OpenGLComposite::paintGL(bool force)
 {
+	if (!force)
+	{
+		if (IsIconic(hGLWnd))
+			return;
+
+		const unsigned previewFps = mRuntimeHost ? mRuntimeHost->GetPreviewFps() : 30u;
+		if (previewFps == 0)
+			return;
+
+		const auto now = std::chrono::steady_clock::now();
+		const auto minimumInterval = std::chrono::microseconds(1000000 / (previewFps == 0 ? 1u : previewFps));
+		if (mLastPreviewPresentTime != std::chrono::steady_clock::time_point() &&
+			now - mLastPreviewPresentTime < minimumInterval)
+		{
+			return;
+		}
+	}
+
 	if (!TryEnterCriticalSection(&pMutex))
 	{
 		ValidateRect(hGLWnd, NULL);
@@ -165,6 +183,7 @@ void OpenGLComposite::paintGL()
 	}
 
 	mRenderer->PresentToWindow(hGLDC, mVideoIO->OutputFrameWidth(), mVideoIO->OutputFrameHeight());
+	mLastPreviewPresentTime = std::chrono::steady_clock::now();
 	ValidateRect(hGLWnd, NULL);
 	LeaveCriticalSection(&pMutex);
 }
@@ -314,15 +333,35 @@ void OpenGLComposite::renderEffect()
 	}
 	else if (mRuntimeHost)
 	{
-		if (mRuntimeHost->TryGetLayerRenderStates(mVideoIO->InputFrameWidth(), mVideoIO->InputFrameHeight(), layerStates))
-		{
-			mCachedLayerRenderStates = layerStates;
-		}
-		else
+		const unsigned renderWidth = mVideoIO->InputFrameWidth();
+		const unsigned renderHeight = mVideoIO->InputFrameHeight();
+		const uint64_t renderStateVersion = mRuntimeHost->GetRenderStateVersion();
+		const bool renderStateCacheValid =
+			!mCachedLayerRenderStates.empty() &&
+			mCachedRenderStateVersion == renderStateVersion &&
+			mCachedRenderStateWidth == renderWidth &&
+			mCachedRenderStateHeight == renderHeight;
+
+		if (renderStateCacheValid)
 		{
 			layerStates = mCachedLayerRenderStates;
 			mRuntimeHost->RefreshDynamicRenderStateFields(layerStates);
 		}
+		else
+		{
+			if (mRuntimeHost->TryGetLayerRenderStates(renderWidth, renderHeight, layerStates))
+			{
+				mCachedLayerRenderStates = layerStates;
+				mCachedRenderStateVersion = renderStateVersion;
+				mCachedRenderStateWidth = renderWidth;
+				mCachedRenderStateHeight = renderHeight;
+			}
+			else
+			{
+				layerStates = mCachedLayerRenderStates;
+				mRuntimeHost->RefreshDynamicRenderStateFields(layerStates);
+			}
+		}
 	}
 	const unsigned historyCap = mRuntimeHost ? mRuntimeHost->GetMaxTemporalHistoryFrames() : 0;
 	mRenderPass->Render(