From 1837acd0dd4d557276b761fb2846a8b7d6d8beb7 Mon Sep 17 00:00:00 2001
From: plombo <plombo@users.sf.net>
Date: Wed, 9 Feb 2011 05:05:13 +0000
Subject: [PATCH] sdl: Attempt to fix flickering garbage data in OpenGL
 fullscreen mode with fglrx (and possibly other drivers using page flipping)

---
 src/drivers/sdl/sdl-opengl.cpp | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/drivers/sdl/sdl-opengl.cpp b/src/drivers/sdl/sdl-opengl.cpp
index 02b38cc1..ebb1116d 100644
--- a/src/drivers/sdl/sdl-opengl.cpp
+++ b/src/drivers/sdl/sdl-opengl.cpp
@@ -90,6 +90,7 @@ SetOpenGLPalette(uint8 *data)
 void
 BlitOpenGL(uint8 *buf)
 {
+    p_glClear(GL_COLOR_BUFFER_BIT);
     p_glBindTexture(GL_TEXTURE_2D, textures[0]);
     if(HiBuffer) {
         Blit8ToHigh(buf, (uint8*)HiBuffer, 256, 240, 256*4, 1, 1);
@@ -277,11 +278,16 @@ InitOpenGL(int l,
  p_glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S,GL_CLAMP);
  p_glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T,GL_CLAMP);
  p_glEnable(GL_TEXTURE_2D);
+ p_glDisable(GL_DEPTH_TEST);
  p_glClearColor(0.0f, 0.0f, 0.0f, 0.0f);	// Background color to black.
  p_glMatrixMode(GL_MODELVIEW);
-
- p_glClear(GL_COLOR_BUFFER_BIT);
  p_glLoadIdentity();
 
+ // In a double buffered setup with page flipping, be sure to clear both buffers.
+ p_glClear(GL_COLOR_BUFFER_BIT);
+ SDL_GL_SwapBuffers();
+ p_glClear(GL_COLOR_BUFFER_BIT);
+ SDL_GL_SwapBuffers();
+
  return(1);
 }