[Mesa-dev] Help! CopyImageSubData is defeating me

[Ilia Mirkin]

On Sun, Jun 25, 2017 at 5:25 PM, Jason Ekstrand <jason at jlekstrand.net> wrote:
> On June 25, 2017 1:40:09 PM Ilia Mirkin <imirkin at alum.mit.edu> wrote:
>
>> On Sun, Jun 25, 2017 at 4:33 PM, Jason Ekstrand <jason at jlekstrand.net>
>> wrote:
>>>>
>>>> Anyone have thoughts on this? Am I being foolish for trying to hold
>>>> onto GL_RGBA4 texturing? (Any decision here also affects st/nine.)
>>>
>>>
>>>
>>> Yes.  Chances are that you're also doing texture views wrong.  Are there
>>> any
>>> 4444 formats supported on nvidia hardware?
>>
>>
>> Well, any permutation of a 4444 format is easily supportable for
>> texturing.
>>
>> What's wrong with the texture views? Should be fine... unless I'm
>> missing something. It's really just this issue with RB <-> Texture
>> copies where the RB's internal format is GL_RGBA4 while the *real*
>> internal format is RGBA8. Texture views between e.g. RGB565 and
>> RGBA4444 should work fine (and the fb will fail to validate as one
>> might expect if one were to attach a GL_RGBA4 texture view of a
>> GL_RGB565 texture).
>
>
> But what if you have a 4444 and you render to as 4444 and then try to
> texture from it as 565?

If you have a 4444 texture and attach it to a FB, then that FB will
not be complete. So you can't render to it in the first place.

  -ilia