Re: [PATCH 3/5] opengl32: Fix extension checks on OpenGL core profile contexts.

[Matteo Bruni]

2015-01-05 18:33 GMT+01:00 Henri Verbeet :
> On 5 January 2015 at 17:17, Matteo Bruni  wrote:
> > static BOOL has_extension( const char *list, const char *ext, size_t len )
> >  {
> > - if (!list)
> > - {
> > -
> >    const struct opengl_funcs *funcs = NtCurrentTeb()->glTable;
> > -
> >    const char *gl_ext;
> > -
> >    unsigned int i;
> > -
> >    GLint extensions_count;
> > -
> > -
> >    glGetIntegerv(GL_NUM_EXTENSIONS, &extensions_count);
> > -
> >    for (i = 0; i < extensions_count; ++i)
> > -
> >    {
> > -
> >        gl_ext = (const char *)funcs->ext.p_glGetStringi(GL_EXTENSIONS, i);
> > -
> >        if (!strncmp(gl_ext, ext, len) && !gl_ext[len])
> > -
> >            return TRUE;
> > -
> >    }
> > -
> >    return FALSE;
> > - }
> > -
>
> If I'm reading this correctly, this effectively ignores
> DisabledExtensions for anything newer than GL 3.0. (And at least as
> far as wglGetProcAddress() is concerned it affects both compatibility
> and core contexts.)

Hmm, it should still work via filter_extensions(). On the other hand
we don't filter the extensions the application queries through
glGetStringi(GL_EXTENSIONS, i), so yeah, that is missing and I should
add that (maybe in a separate patch?)
> > - gl_version = (const char *)glGetString(GL_VERSION);
> > - sscanf(gl_version, "%u", &major);
> > - if (major >= 3)
> > - {
>
> It seems tempting to just flag the context in
> wglCreateContextAttribsARB() under the appropriate conditions, perhaps
> in a similar way to wgl_handle_type. Not sure if it would really make
> it better though.

I'm going to give it a try and see how it looks.
> As an aside, note that winex11.drv also uses
> "glGetString(GL_EXTENSIONS);" in X11DRV_WineGL_InitOpenglInfo().

That should be fine, that's always a compatibility context created
with glXCreateContext().