Index: GL/canvas_opengl.cpp
===================================================================
--- GL/canvas_opengl.cpp	(revision 168)
+++ GL/canvas_opengl.cpp	(working copy)
@@ -176,52 +176,58 @@
 #ifdef __APPLE__
 		// todo: add AGL pbuffer code
 #else
-		if (glXCreateGLXPbufferSGIX == 0)
-		{
-			throw CL_Error("GLX_SGIX_pbuffer OpenGL extension not supported by this card");
-		}
+   int scrnum;
+   GLXFBConfig *fbconfig;
+   XVisualInfo *visinfo;
+   int nitems;
 
-		int configAttribs[] =
-		{
-//			GLX_DOUBLEBUFFER,        False,
-			GLX_RED_SIZE,            8,
-			GLX_GREEN_SIZE,          8,
-			GLX_BLUE_SIZE,           8,
-			GLX_ALPHA_SIZE,          8,
-			GLX_DRAWABLE_TYPE_SGIX,  GLX_PBUFFER_BIT_SGIX,
-			(int) None
-		};
+   int attrib[] = {
+      GLX_DOUBLEBUFFER,  False,
+      GLX_RED_SIZE,      1,
+      GLX_GREEN_SIZE,    1,
+      GLX_BLUE_SIZE,     1,
+      GLX_DEPTH_SIZE,    1,
+      GLX_RENDER_TYPE,   GLX_RGBA_BIT,
+      GLX_DRAWABLE_TYPE, GLX_PBUFFER_BIT | GLX_WINDOW_BIT,
+      None
+   };
+   int pbufAttrib[] = {
+     GLX_PBUFFER_WIDTH,   selected_surface->surface_size.width,
+     GLX_PBUFFER_HEIGHT,  selected_surface->surface_size.height,
+     GLX_LARGEST_PBUFFER, False,
+     None
+   };
 
-		int num_configs_returned = 0;
 
-		GLXFBConfig *config = glXChooseFBConfigSGIX(
-			CL_DisplayWindow_OpenGL::get_display(),
-			DefaultScreen(CL_DisplayWindow_OpenGL::get_display()),
-			configAttribs,
-			&num_configs_returned);
+   scrnum   = DefaultScreen( CL_DisplayWindow_OpenGL::get_display() );
 
-		if (num_configs_returned == 0 || config == 0)
-		{
-			throw CL_Error("glXChooseFBConfigSGIX could not find any suitable pbuffer pixel formats on this card!");
-		}
+   fbconfig = glXChooseFBConfig(CL_DisplayWindow_OpenGL::get_display(),
+                                scrnum,
+                                attrib,
+                                &nitems);
+   if (NULL == fbconfig) {
+      fprintf(stderr,"Error: couldn't get fbconfig\n");
+      exit(1);
+   }
 
-		int pbufAttribs[] = {
-			GLX_PRESERVED_CONTENTS, True,
-			(int) None };
+   pbuffer = glXCreatePbuffer(CL_DisplayWindow_OpenGL::get_display(), fbconfig[0], pbufAttrib);
 
-		pbuffer = glXCreateGLXPbufferSGIX(
-			CL_DisplayWindow_OpenGL::get_display(),
-			*config,
-			selected_surface->surface_size.width,
-			selected_surface->surface_size.height,
-			pbufAttribs);
+   visinfo = glXGetVisualFromFBConfig(CL_DisplayWindow_OpenGL::get_display(), fbconfig[0]);
+   if (!visinfo) {
+      fprintf(stderr, "Error: couldn't get an RGBA, double-buffered visual\n");
+      exit(1);
+   }
 
-		pbuffer_context = glXCreateContextWithConfigSGIX(
-			CL_DisplayWindow_OpenGL::get_display(),
-			config[0],
-			GLX_RGBA_TYPE,
-			CL_DisplayWindow_OpenGL::share_context,
-			True);
+   pbuffer_context = glXCreateContext( CL_DisplayWindow_OpenGL::get_display(), visinfo, 
+                                       dynamic_cast<CL_GraphicContext_OpenGL*>(CL_Display::get_current_window()->get_gc()->impl)->get_context(), GL_TRUE );
+   if (!pbuffer_context) {
+      fprintf(stderr, "Error: glXCreateContext failed\n");
+      exit(1);
+   }
+
+   XFree(fbconfig);
+   XFree(visinfo);
+
 #endif
 #endif