nkeynes@280: /**
nkeynes@290:  * $Id: video_gl.c,v 1.2 2007-01-15 12:57:12 nkeynes Exp $
nkeynes@280:  *
nkeynes@280:  * Common GL code that doesn't depend on a specific implementation
nkeynes@280:  *
nkeynes@280:  * Copyright (c) 2005 Nathan Keynes.
nkeynes@280:  *
nkeynes@280:  * This program is free software; you can redistribute it and/or modify
nkeynes@280:  * it under the terms of the GNU General Public License as published by
nkeynes@280:  * the Free Software Foundation; either version 2 of the License, or
nkeynes@280:  * (at your option) any later version.
nkeynes@280:  *
nkeynes@280:  * This program is distributed in the hope that it will be useful,
nkeynes@280:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
nkeynes@280:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
nkeynes@280:  * GNU General Public License for more details.
nkeynes@280:  */
nkeynes@280: 
nkeynes@280: #include "dream.h"
nkeynes@280: #include "drivers/video_gl.h"
nkeynes@280: #include <GL/gl.h>
nkeynes@280: 
nkeynes@280: char *required_extensions[] = { "GL_EXT_framebuffer_object", NULL };
nkeynes@280: 
nkeynes@280: /**
nkeynes@280:  * Test if a specific extension is supported. From opengl.org
nkeynes@280:  * @param extension extension name to check for
nkeynes@280:  * @return TRUE if supported, otherwise FALSE.
nkeynes@280:  */
nkeynes@280: gboolean isGLExtensionSupported( const char *extension )
nkeynes@280: {
nkeynes@280:     const GLubyte *extensions = NULL;
nkeynes@280:     const GLubyte *start;
nkeynes@280:     GLubyte *where, *terminator;
nkeynes@280: 
nkeynes@280:     /* Extension names should not have spaces. */
nkeynes@280:     where = (GLubyte *) strchr(extension, ' ');
nkeynes@280:     if (where || *extension == '\0')
nkeynes@280: 	return 0;
nkeynes@280:     extensions = glGetString(GL_EXTENSIONS);
nkeynes@280:     /* It takes a bit of care to be fool-proof about parsing the
nkeynes@280:        OpenGL extensions string. Don't be fooled by sub-strings,
nkeynes@280:        etc. */
nkeynes@280:     start = extensions;
nkeynes@280:     for (;;) {
nkeynes@280: 	where = (GLubyte *) strstr((const char *) start, extension);
nkeynes@280: 	if (!where)
nkeynes@280: 	    break;
nkeynes@280: 	terminator = where + strlen(extension);
nkeynes@280: 	if (where == start || *(where - 1) == ' ')
nkeynes@280: 	    if (*terminator == ' ' || *terminator == '\0')
nkeynes@280: 		return TRUE;
nkeynes@280: 	start = terminator;
nkeynes@280:     }
nkeynes@280:     return FALSE;
nkeynes@280: }
nkeynes@280: 
nkeynes@280: gboolean hasRequiredGLExtensions( ) 
nkeynes@280: {
nkeynes@280:     int i;
nkeynes@280:     gboolean isOK = TRUE;
nkeynes@280: 
nkeynes@280:     for( i=0; required_extensions[i] != NULL; i++ ) {
nkeynes@280: 	if( !isGLExtensionSupported(required_extensions[i]) ) {
nkeynes@280: 	    ERROR( "Required OpenGL extension not supported: %s", required_extensions[i] );
nkeynes@280: 	    isOK = FALSE;
nkeynes@280: 	}
nkeynes@280:     }
nkeynes@280:     return isOK;
nkeynes@280: }