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

[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.)
> - 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.

As an aside, note that winex11.drv also uses
"glGetString(GL_EXTENSIONS);" in X11DRV_WineGL_InitOpenglInfo().