[Mesa-dev] [PATCH] gallium: add MULTISAMPLE_Z_RESOLVE cap

[Axel Davy]

On 19/01/2015 11:59, Roland Scheidegger wrote :
> I always thought you can't resolve z because such an operation just
> makes no sense at all. What the hell does it even mean and how do you do
> it? Color resolve you just interpolate between the value to get rid of
> the aliased edges. But in the depth buffer, these values represent the
> depth information for different objects, an "averaged depth value"
> doesn't really make any sense. Or do you blit not by interpolating but
> taking the most common value per pixel or something?
> bind_sampler_view flag with depth textures OTOH is definitely something
> which can be done and should already work with the existing
> infrastructure, if drivers don't advertize it correctly that's their fault.
>
> Roland
>
When a multisampled depth buffer is resolved to a single sample depth 
buffer,
only the first sample is copied.

Perhaps is makes sense to add the cap just to say this behaviour is what 
happens with a pipe_blit,
since it is different than the ability to read the texture in a shader, 
like the is_format_supported would indicate.

Axel Davy