[Mesa-dev] ARB_copy_image support in Gallium

[Roland Scheidegger]

Am 20.07.2015 um 22:46 schrieb Ilia Mirkin:
> On Mon, Jul 20, 2015 at 3:53 PM, Brian Paul <brianp at vmware.com> wrote:
>> On 07/20/2015 01:19 PM, Ilia Mirkin wrote:
>>
>>> On Mon, Jul 20, 2015 at 2:44 PM, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
>>>>
>>>> Hi Brian,
>>>>
>>>> You marked off ARB_copy_image (and ARB_clear_texture) as in-progress
>>>> by VMware some months ago -- has there been any movement on that? It
>>>> appears that Bioshock Infinite requires ARB_copy_image so might be
>>>> nice to get that added in.
>>>>
>>>> The complication in implementing ARB_copy_image was that st/mesa will
>>>> pick potentially different PIPE_FORMAT enums for the same internal
>>>> format, depending on the parameters to the glTexImage call. A
>>>> developer (irc handle Leftmost, I forget his real name, sorry) tried
>>>> to wrestle with the issues this presents, but as I recall ended up
>>>> coming up short.
>>>>
>>>> The final implementation probably needs some combination of
>>>> resource_copy_region and blit. I think resource_copy_region currently
>>>> is spec'd to require identical formats in src and dst, but that could
>>>> be relaxed.
>>>>
>>>> Anyways, would be interested in hearing whether you guys have made any
>>>> progress, or if you had thoughts on proper implementation.
>>>>
>>>> Cheers,
>>>>
>>>>    -ilia
>>>
>>>
>>> As an aside, here's a very naive implementation of the ext, which
>>> fails for lots of reasons not the least of which is that we default to
>>> BGRA instead of RGBA. Perhaps we could create a resource_copy_region
>>> version that also takes (or knows about) swizzles... that should also
>>> cover many (all?) of the situations I think.
>>
>>
>> One of our interns did the implementation (with some contributions from me).
>> I need to do a lot of clean-up before posting the patches here though.  I
>> was hoping to do that in the next month or two.  If you need it sooner, I'll
>> can see what I can do.
> 
> As there's a decent chance that tessellation and subroutine support
> will land in the next release (thus exposing GL 4.1 in several
> drivers), and there is an actual released game that requires
> ARB_copy_image, it would definitely be nice to see support land before
> the next mesa release is branched off, which should happen in about a
> month's time I guess.
> 
Are you sure it actually requires ARB_copy_image (not just optionally
uses it)? Seems like it shouldn't be, since officially it only needs GL
4.1, and this extension only became core with 4.3.
(There's also a mac version which doesn't support that feature neither).

Roland