[v3 PATCH 3/3] wined3d: Use EXT_framebuffer_multisample_blit_scaled extension.

[Paul Gofman]

On 3/11/20 18:25, Henri Verbeet wrote:
> On Wed, 11 Mar 2020 at 16:30, Paul Gofman <gofmanp at gmail.com> wrote:
>>>
>> No, we have to. Scaled resolve allows to scale from multisampled
>> texture, but if destination is multisampled it always fails for me.
>> There is explicit check for zero samples count on destination I spotted
>> in Mesa code, and it seems to fail the same way on Nvidia.
>>
> Right, I checked the spec and it does say that. That limits the
> benefit of EXT_framebuffer_multisample_blit_scaled a bit, but I guess
> it's fine.

I can guess it was not immediately clear how and why resample coverage
masks other than resolve it first and then stretch. I hope even with
this limitation it is still beneficial for the majority of practical
cases as resolving source to destination is probably a more common use
case (for which it works). Also if the destination surface is fully
overwritten we avoid an extra blit for resolving destination surface by
using _prepare_location() instead of _load_location() in
texture2d_blt_fbo().