From 6e12a127dc4bb8a6337a316bc28d09e1086ff51d Mon Sep 17 00:00:00 2001
From: Michael Sartain <mikesart@valvesoftware.com>
Date: Thu, 11 Oct 2012 09:41:43 -0700
Subject: [PATCH] Add GLX_X_VISUAL_TYPE_EXT so created window will use
 DirectColor if available (instead of TrueColor). Our new X11 window was being
 created with the TrueColor attribute, and trying to set the gamma on that
 would fail. This change checks for the visual_info extension, and uses that
 to ask for DirectColor if available.

---
 src/video/x11/SDL_x11opengl.c | 24 +++++++++++++++++++++++-
 src/video/x11/SDL_x11opengl.h |  1 +
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/src/video/x11/SDL_x11opengl.c b/src/video/x11/SDL_x11opengl.c
index c05ccefa2..2899ac288 100644
--- a/src/video/x11/SDL_x11opengl.c
+++ b/src/video/x11/SDL_x11opengl.c
@@ -60,6 +60,12 @@
 #define GLX_NON_CONFORMANT_VISUAL_EXT      0x800D
 #endif
 
+#ifndef GLX_EXT_visual_info
+#define GLX_EXT_visual_info
+#define GLX_X_VISUAL_TYPE_EXT              0x22
+#define GLX_DIRECT_COLOR_EXT               0x8003
+#endif
+
 #ifndef GLX_ARB_create_context
 #define GLX_ARB_create_context
 #define GLX_CONTEXT_MAJOR_VERSION_ARB      0x2091
@@ -353,6 +359,11 @@ X11_GL_InitExtensions(_THIS)
         _this->gl_data->HAS_GLX_EXT_visual_rating = SDL_TRUE;
     }
 
+    /* Check for GLX_EXT_visual_info */
+    if (HasExtension("GLX_EXT_visual_info", extensions)) {
+        _this->gl_data->HAS_GLX_EXT_visual_info = SDL_TRUE;
+    }
+
     if (context) {
         _this->gl_data->glXMakeCurrent(display, None, NULL);
         _this->gl_data->glXDestroyContext(display, context);
@@ -368,9 +379,10 @@ int
 X11_GL_GetAttributes(_THIS, Display * display, int screen, int * attribs, int size, Bool for_FBConfig)
 {
     int i = 0;
+	const int MAX_ATTRIBUTES = 64;
 
     /* assert buffer is large enough to hold all SDL attributes. */ 
-    SDL_assert(size >= 32);
+    SDL_assert(size >= MAX_ATTRIBUTES);
 
     /* Setup our GLX attributes according to the gl_config. */
     if( for_FBConfig ) {
@@ -448,7 +460,17 @@ X11_GL_GetAttributes(_THIS, Display * display, int screen, int * attribs, int si
                                                       GLX_SLOW_VISUAL_EXT;
     }
 
+    // If we're supposed to use DirectColor visuals, and we've got the EXT_visual_info
+    //  extension, then add GLX_X_VISUAL_TYPE_EXT.
+    if (X11_UseDirectColorVisuals() &&
+        _this->gl_data->HAS_GLX_EXT_visual_info) {
+        attribs[i++] = GLX_X_VISUAL_TYPE_EXT;
+        attribs[i++] = GLX_DIRECT_COLOR_EXT;
+    }
+
     attribs[i++] = None;
+
+    SDL_assert(i <= MAX_ATTRIBUTES);
  
     return i;
 }
diff --git a/src/video/x11/SDL_x11opengl.h b/src/video/x11/SDL_x11opengl.h
index c87fbc2fe..a786b773e 100644
--- a/src/video/x11/SDL_x11opengl.h
+++ b/src/video/x11/SDL_x11opengl.h
@@ -30,6 +30,7 @@
 struct SDL_GLDriverData
 {
     SDL_bool HAS_GLX_EXT_visual_rating;
+    SDL_bool HAS_GLX_EXT_visual_info;
     SDL_bool HAS_GLX_EXT_swap_control_tear;
 
     void *(*glXGetProcAddress) (const GLubyte*);