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

[Marek Olšák]

BTW, this is the same as the glBlitFramebuffer behavior for MSAA depth buffers.

Marek

On Mon, Jan 19, 2015 at 2:18 PM, Axel Davy <axel.davy at ens.fr> wrote:
> 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
>
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