Use glGetStringi() for extension lookup on OpenGL contexts >= version 3.0.
Fixes Bugzilla #1620.
--- a/src/video/SDL_video.c Tue May 21 22:04:14 2013 -0700
+++ b/src/video/SDL_video.c Wed May 22 01:31:04 2013 -0400
@@ -2347,6 +2347,12 @@
}
}
+static __inline__ SDL_bool
+isAtLeastGL3(const char *verstr)
+{
+ return ( verstr && (SDL_atoi(verstr) >= 3) );
+}
+
SDL_bool
SDL_GL_ExtensionSupported(const char *extension)
{
@@ -2366,13 +2372,40 @@
if (start && *start == '0') {
return SDL_FALSE;
}
+
/* Lookup the available extensions */
+
glGetStringFunc = SDL_GL_GetProcAddress("glGetString");
- if (glGetStringFunc) {
- extensions = (const char *) glGetStringFunc(GL_EXTENSIONS);
- } else {
- extensions = NULL;
+ if (!glGetStringFunc) {
+ return SDL_FALSE;
}
+
+ if (isAtLeastGL3((const char *) glGetStringFunc(GL_VERSION))) {
+ const GLubyte *(APIENTRY * glGetStringiFunc) (GLenum, GLuint);
+ void (APIENTRY * glGetIntegervFunc) (GLenum pname, GLint * params);
+ GLint num_exts = 0;
+ GLint i;
+
+ glGetStringiFunc = SDL_GL_GetProcAddress("glGetStringi");
+ glGetIntegervFunc = SDL_GL_GetProcAddress("glGetIntegerv");
+ if ((!glGetStringiFunc) || (!glGetIntegervFunc)) {
+ return SDL_FALSE;
+ }
+
+ glGetIntegervFunc(GL_NUM_EXTENSIONS, &num_exts);
+ for (i = 0; i < num_exts; i++) {
+ const char *thisext = (const char *) glGetStringiFunc(GL_EXTENSIONS, i);
+ if (SDL_strcmp(thisext, extension) == 0) {
+ return SDL_TRUE;
+ }
+ }
+
+ return SDL_FALSE;
+ }
+
+ /* Try the old way with glGetString(GL_EXTENSIONS) ... */
+
+ extensions = (const char *) glGetStringFunc(GL_EXTENSIONS);
if (!extensions) {
return SDL_FALSE;
}