Revert "preview changes"

This reverts commit 98f5cbe309.

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);
 }

apps/LoopThroughWithOpenGLCompositing/gl/OpenGLComposite.h

@@ -23,6 +23,7 @@
 #include <string>
 #include <vector>
 #include <deque>
+#include <chrono>
 
 class VideoIODevice;
 class OpenGLVideoIOBridge;
@@ -64,7 +65,7 @@ public:
 	std::string GetOscAddress() const;
 
 	void resizeGL(WORD width, WORD height);
-	void paintGL();
+	void paintGL(bool force = false);
 
 private:
 	void resizeWindow(int width, int height);
@@ -92,6 +93,7 @@ private:
 	unsigned								mCachedRenderStateHeight = 0;
 	std::atomic<bool>						mUseCommittedLayerStates;
 	std::atomic<bool>						mScreenshotRequested;
+	std::chrono::steady_clock::time_point	mLastPreviewPresentTime;
 
 	bool InitOpenGLState();
 	void renderEffect();