/**

  * $Id$

  *

  * GL-based support functions 

  *

  * 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 <string.h>

 #include "pvr2/glutil.h"

 /**

  * 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);

     if( extensions == NULL ) {

 	/* No GL available, so we're pretty sure the extension isn't

 	 * available either. */

 	return FALSE;

     }

     /* 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;

 }