[Mesa-dev] [PATCH 6/7] st/mesa: convert GLSL image intrinsics into TGSI

[Ilia Mirkin]

On Sun, Jan 31, 2016 at 3:26 PM, Dave Airlie <airlied at gmail.com> wrote:
> On 31 January 2016 at 23:39, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
>> On Sun, Jan 31, 2016 at 2:37 AM, Dave Airlie <airlied at gmail.com> wrote:
>>>> +   for (i = 0; i < program->shader->NumImages; i++) {
>>>> +      if (program->images_used & (1 << i)) {
>>>> +         t->images[i] = ureg_DECL_image(ureg, i,
>>>> +                                        program->image_targets[i],
>>>> +                                        program->image_formats[i],
>>>> +                                        true, false);
>>>
>>> Can we not know if the image is writable from the GL level?
>>
>> Yes, we can. But do we care? It was there already so I kept the flag,
>> but I'd be fully in favor of removing it...
>>
>> layout(writeonly) in GLSL lets you not specify a format, which would
>> come through as PIPE_FORMAT_NONE in here. But beyond validation, I
>> don't see what the use is. Something like layout(readonly) just causes
>> imageStore() to error out...
>
> I think on radeon it might let us not bind the image to the CB, but just
> texture loads on it directly.

Wouldn't you want to do that anyways, even if it's not marked
readonly? (This reminds me - I forgot all about the caching modifiers
on image declarations. Oops. But I'll add those later.)

  -ilia