/**

  * $Id: video_gl.c,v 1.2 2007-01-15 12:57:12 nkeynes Exp $

  *

  * Common GL code that doesn't depend on a specific implementation

  *

  * Copyright (c) 2005 Nathan Keynes.

  *

  * This program is free software; you can redistribute it and/or modify

  * it under the terms of the GNU General Public License as published by

  * the Free Software Foundation; either version 2 of the License, or

  * (at your option) any later version.

  *

  * This program is distributed in the hope that it will be useful,

  * but WITHOUT ANY WARRANTY; without even the implied warranty of

  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

  * GNU General Public License for more details.

  */

 #include "dream.h"

 #include "drivers/video_gl.h"

 #include <GL/gl.h>

 char *required_extensions[] = { "GL_EXT_framebuffer_object", NULL };

 /**

  * Test if a specific extension is supported. From opengl.org

  * @param extension extension name to check for

  * @return TRUE if supported, otherwise FALSE.

  */

 gboolean isGLExtensionSupported( const char *extension )

 {

     const GLubyte *extensions = NULL;

     const GLubyte *start;

     GLubyte *where, *terminator;

     /* Extension names should not have spaces. */

     where = (GLubyte *) strchr(extension, ' ');

     if (where || *extension == '\0')

 	return 0;

     extensions = glGetString(GL_EXTENSIONS);

     /* It takes a bit of care to be fool-proof about parsing the

        OpenGL extensions string. Don't be fooled by sub-strings,

        etc. */

     start = extensions;

     for (;;) {

 	where = (GLubyte *) strstr((const char *) start, extension);

 	if (!where)

 	    break;

 	terminator = where + strlen(extension);

 	if (where == start || *(where - 1) == ' ')

 	    if (*terminator == ' ' || *terminator == '\0')

 		return TRUE;

 	start = terminator;

     }

     return FALSE;

 }

 gboolean hasRequiredGLExtensions( ) 

 {

     int i;

     gboolean isOK = TRUE;

     for( i=0; required_extensions[i] != NULL; i++ ) {

 	if( !isGLExtensionSupported(required_extensions[i]) ) {

 	    ERROR( "Required OpenGL extension not supported: %s", required_extensions[i] );

 	    isOK = FALSE;

 	}

     }

     return isOK;

 }