From df5ada10067c24ce697dcb99946d5541970e2288 Mon Sep 17 00:00:00 2001
From: Thomas Goyne <plorkyeran@aegisub.org>
Date: Tue, 20 Oct 2009 19:07:18 +0000
Subject: [PATCH] Make the video display only upload texture data when the
 frame has changed rather than every time Render is called.

Originally committed to SVN as r3726.
---
 aegisub/src/video_display.cpp |  3 ++-
 aegisub/src/video_out_gl.cpp  | 20 +++++++++++++-------
 aegisub/src/video_out_gl.h    |  8 +++++++-
 3 files changed, 22 insertions(+), 9 deletions(-)

diff --git a/aegisub/src/video_display.cpp b/aegisub/src/video_display.cpp
index fde75aef6..3ea91506b 100644
--- a/aegisub/src/video_display.cpp
+++ b/aegisub/src/video_display.cpp
@@ -193,6 +193,7 @@ void VideoDisplay::SetFrame(int frameNumber) {
 	if (IsShownOnScreen() && visual) visual->Refresh();
 
 	// Render the new frame
+	videoOut->InvalidateFrame();
 	Render(frameNumber);
 
 	currentFrame = frameNumber;
@@ -274,7 +275,7 @@ void VideoDisplay::Render(int frameNumber) try {
 	glDisable(GL_BLEND);
 	if (glGetError()) throw _T("Error disabling blending.");
 
-	videoOut->DisplayFrame(context->GetFrame(frameNumber), sw, sh);
+	videoOut->DisplayFrame(context->GetFrame(frameNumber), frameNumber, sw, sh);
 
 	DrawTVEffects();
 
diff --git a/aegisub/src/video_out_gl.cpp b/aegisub/src/video_out_gl.cpp
index 3df30f3fc..26ddefd0f 100644
--- a/aegisub/src/video_out_gl.cpp
+++ b/aegisub/src/video_out_gl.cpp
@@ -111,7 +111,8 @@ VideoOutGL::VideoOutGL()
 	textureList(),
 	textureCount(0),
 	textureRows(0),
-	textureCols(0)
+	textureCols(0),
+	lastFrame(-1)
 { }
 
 /// @brief Runtime detection of required OpenGL capabilities
@@ -218,9 +219,8 @@ void VideoOutGL::InitTextures(int width, int height, GLenum format, int bpp) {
 				ti.texTop = 1.0f / (2 * h);
 			}
 
-			// Calculate what percent of the texture is actually used
-			ti.texRight = float(ti.sourceW) / w - ti.texLeft;
-			ti.texBottom = float(ti.sourceH) / h - ti.texTop;
+			ti.texRight = 1.0f - ti.texLeft;
+			ti.texBottom = 1.0f - ti.texTop;
 
 			// destW/H is the percent of the output which this texture covers
 			ti.destW = float(w) / width;
@@ -259,9 +259,11 @@ void VideoOutGL::InitTextures(int width, int height, GLenum format, int bpp) {
 	frameFormat = format;
 }
 
-void VideoOutGL::DisplayFrame(AegiVideoFrame frame, int sw, int sh) {
+void VideoOutGL::DisplayFrame(AegiVideoFrame frame, int frameNumber, int sw, int sh) {
 	if (frame.h == 0 || frame.w == 0) return;
 
+	if (frameNumber == -1) frameNumber = lastFrame;
+
 	glEnable(GL_TEXTURE_2D);
 	if (GLenum err = glGetError()) throw VideoOutOpenGLException(L"glEnable(GL_TEXTURE_2d)", err);
 
@@ -283,8 +285,10 @@ void VideoOutGL::DisplayFrame(AegiVideoFrame frame, int sw, int sh) {
 		glBindTexture(GL_TEXTURE_2D, ti.textureID);
 		if (GLenum err = glGetError()) throw VideoOutOpenGLException(L"glBindTexture", err);
 
-		glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, ti.sourceW, ti.sourceH, format, GL_UNSIGNED_BYTE, frame.data[0] + ti.dataOffset);
-		if (GLenum err = glGetError()) throw VideoOutOpenGLException(L"glTexSubImage2D", err);
+		if (lastFrame != frameNumber) {
+			glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, ti.sourceW, ti.sourceH, format, GL_UNSIGNED_BYTE, frame.data[0] + ti.dataOffset);
+			if (GLenum err = glGetError()) throw VideoOutOpenGLException(L"glTexSubImage2D", err);
+		}
 
 		glColor4f(1.0f, 1.0f, 1.0f, 1.0f);
 		if (GLenum err = glGetError()) throw VideoOutOpenGLException(L"glColor4f", err);
@@ -313,6 +317,8 @@ void VideoOutGL::DisplayFrame(AegiVideoFrame frame, int sw, int sh) {
 
 	glDisable(GL_TEXTURE_2D);
 	if (GLenum err = glGetError()) throw VideoOutOpenGLException(L"glDisable(GL_TEXTURE_2d)", err);
+
+	lastFrame = frameNumber;
 }
 
 VideoOutGL::~VideoOutGL() {
diff --git a/aegisub/src/video_out_gl.h b/aegisub/src/video_out_gl.h
index 309224d1c..2d6d9c4da 100644
--- a/aegisub/src/video_out_gl.h
+++ b/aegisub/src/video_out_gl.h
@@ -74,6 +74,8 @@ private:
 	int textureRows;
 	/// The number of columns of textures
 	int textureCols;
+	/// The frame currently displayed
+	int lastFrame;
 
 	void DetectOpenGLCapabilities();
 	void InitTextures(int width, int height, GLenum format, int bpp);
@@ -83,9 +85,13 @@ private:
 public:
 	/// @brief Render a frame
 	/// @param frame The frame to be displayed
+	/// @param frameNumber The frame number of the frame to be displayed
 	/// @param sw The current script width
 	/// @param sh The current script height
-	void DisplayFrame(AegiVideoFrame frame, int sw, int sh);
+	void DisplayFrame(AegiVideoFrame frame, int frameNumber, int sw, int sh);
+
+	/// @brief Force the redisplay of the frame the next time DisplayFrame is called even if the frame number has not changed
+	void InvalidateFrame() { lastFrame = -1; }
 
 	/// @brief Constructor
 	VideoOutGL();