[Mesa-dev] [PATCH] Allow setting GL_TEXTURE_COMPARE_MODE on a sampler object without ARB_shadow support.

[Henri Verbeet]

On 26 June 2015 at 17:38, Brian Paul <brianp at vmware.com> wrote:
> Digging up the patch from March for reference:
>
>> This fixes a GL error warning on r200 in Wine.
>>
>> The GL_ARB_sampler_objects extension does not specify a dependency on
>> GL_ARB_shadow or GL_ARB_depth_texture for this value. Just set the value
>> and don't do anything else. It won't matter without a depth texture
>> being assigned anyway.
>
> So I take it that Wine calls glSamplerParameteri(s, GL_TEXTURE_COMPARE_MODE,
> mode) even when GL_ARB_shadow is not supported and you get a bunch of GL
> errors?
>
> Has this been reported upstream to Wine so they can fix it?
>
Stefan is part of upstream, so yeah, we're aware of this.

> I see this sort of thing all the time in Windows OpenGL apps and it's
> tempting to just silence some obscure GL errors, but it's a slippery slope.
> When I'm debugging a new GL app, seeing GL errors for all the corner cases
> can actually be very helpful and I'd hate to lose that.
>
Well, the argument is that it's actually a bug in Mesa (if perhaps an
obscure one) to generate an GL error in this case. We could add a
workaround in Wine if we really have to, but the way we're reading the
ARB_sampler_objects spec that shouldn't be needed.