Don't discard frames which are decoded before the video display becomes visible

Originally committed to SVN as r6950.

aegisub/src/video_display.cpp

@@ -69,6 +69,7 @@
 #include "utils.h"
 #include "video_out_gl.h"
 #include "video_context.h"
+#include "video_frame.h"
 #include "visual_tool.h"
 
 /// Attribute list for gl canvases; set the canvases to doublebuffered rgba with an 8 bit stencil buffer
@@ -158,11 +159,14 @@ bool VideoDisplay::InitContext() {
 }
 
 void VideoDisplay::UploadFrameData(FrameReadyEvent &evt) {
-	if (!InitContext()) {
+	pending_frame = evt.frame;
-		evt.Skip();
+	Render();
-		return;
 }
 
+void VideoDisplay::Render() try {
+	if (!con->videoController->IsLoaded() || !InitContext() || (!videoOut && !pending_frame))
+		return;
+
 	if (!videoOut)
 		videoOut.reset(new VideoOutGL);
 
@@ -170,7 +174,10 @@ void VideoDisplay::UploadFrameData(FrameReadyEvent &evt) {
 		cmd::call("video/tool/cross", con);
 
 	try {
-		videoOut->UploadFrameData(*evt.frame);
+		if (pending_frame) {
+			videoOut->UploadFrameData(*pending_frame);
+			pending_frame.reset();
+		}
 	}
 	catch (const VideoOutInitException& err) {
 		wxLogError(
@@ -179,19 +186,15 @@ void VideoDisplay::UploadFrameData(FrameReadyEvent &evt) {
 			"Error message reported: %s",
 			err.GetMessage());
 		con->videoController->SetVideo("");
+		return;
 	}
 	catch (const VideoOutRenderException& err) {
 		wxLogError(
 			"Could not upload video frame to graphics card.\n"
 			"Error message reported: %s",
 			err.GetMessage());
-	}
-	Render();
-}
-
-void VideoDisplay::Render() try {
-	if (!con->videoController->IsLoaded() || !videoOut || !InitContext() )
 		return;
+	}
 
 	if (!viewport_height || !viewport_width)
 		PositionVideo();
@@ -428,6 +431,7 @@ void VideoDisplay::Unload() {
 	glContext.reset();
 	videoOut.reset();
 	tool.reset();
+	pending_frame.reset();
 }
 
 void VideoDisplay::OnSubtitlesSave() {

aegisub/src/video_display.h

@@ -37,6 +37,7 @@
 
 #ifndef AGI_PRE
 #include <list>
+#include <tr1/memory>
 
 #include <wx/glcanvas.h>
 #endif
@@ -49,6 +50,7 @@
 #include "vector2d.h"
 
 // Prototypes
+class AegiVideoFrame;
 class FrameReadyEvent;
 class VideoContext;
 class VideoOutGL;
@@ -114,6 +116,9 @@ class VideoDisplay : public wxGLCanvas {
 	/// Whether the display can be freely resized by the user
 	bool freeSize;
 
+	/// Frame which will replace the currently visible frame on the next render
+	std::tr1::shared_ptr<AegiVideoFrame> pending_frame;
+
 	/// @brief Draw an overscan mask
 	/// @param horizontal_percent The percent of the video reserved horizontally
 	/// @param vertical_percent The percent of the video reserved vertically