[Mesa-dev] EXT_multisampled_render_to_texture support in gallium

[Ilia Mirkin]

This extension allows the same thing you can do with MSAA visuals, but
with actual textures. Additionally it allows a tiler's pipeline to
stay MSAA until the end, at which point the resolve happens to slower
memory (and it's thus advantageous for that to not be multisampled).

I've had a few thoughts about how to implement it, but nothing too
actionable thus far. The main issue is in conveying the desire to
perform MS operations without actually supplying MS cbufs. My current
thinking is to switch the "multisample" rasterizer bit to be wider and
supply the # of samples to it.

I'm not sure if GLES3.1 will interfere with this, since it seems to
support MS textures, but something like this would be useful for
freedreno and probably other tiling drivers.

Thoughts appreciated.

  -ilia