[Mesa-dev] Making ext_framebuffer_multisample-accuracy run on non-i965 drivers

[Ilia Mirkin]

Aha, apparently there's a 'depthstencil' option that uses a combined
RB. Nevermind! Didn't realize that was the case.

On Wed, Sep 9, 2015 at 3:24 PM, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
> Both st/mesa and the NVIDIA fail framebuffer completeness on this
> command sequence:
>
> 270 glRenderbufferStorageMultisample(target = GL_RENDERBUFFER, samples
> = 0, internalformat = GL_RGBA, width = 256, height = 256)
> 272 glFramebufferRenderbuffer(target = GL_DRAW_FRAMEBUFFER, attachment
> = GL_COLOR_ATTACHMENT0, renderbuffertarget = GL_RENDERBUFFER,
> renderbuffer = 1)
> 273 glBindRenderbuffer(target = GL_RENDERBUFFER, renderbuffer = 10)
> 274 glRenderbufferStorageMultisample(target = GL_RENDERBUFFER, samples
> = 0, internalformat = GL_STENCIL_INDEX8, width = 256, height = 256)
> 275 glFramebufferRenderbuffer(target = GL_DRAW_FRAMEBUFFER, attachment
> = GL_STENCIL_ATTACHMENT, renderbuffertarget = GL_RENDERBUFFER,
> renderbuffer = 10)
> 276 glBindRenderbuffer(target = GL_RENDERBUFFER, renderbuffer = 9)
> 277 glRenderbufferStorageMultisample(target = GL_RENDERBUFFER, samples
> = 0, internalformat = GL_DEPTH_COMPONENT24, width = 256, height = 256)
> 278 glFramebufferRenderbuffer(target = GL_DRAW_FRAMEBUFFER, attachment
> = GL_DEPTH_ATTACHMENT, renderbuffertarget = GL_RENDERBUFFER,
> renderbuffer = 9)
> 279 glCheckFramebufferStatus(target = GL_DRAW_FRAMEBUFFER) =
> GL_FRAMEBUFFER_UNSUPPORTED
>
> This is because (in the case of st/mesa), the depth and stencil
> backing textures are different, which is not something that the
> gallium API allows (nor does NVIDIA hardware handle).
>
> For textures this is handled by merging attachment points when the
> textures are identical, but this is harder to do with renderbuffers
> since they're allocated implicitly, and can be attached/detached
> individually.
>
> I'm not sure that there's a clean way to fix this. I think that the
> piglit should be fixed instead to not do this. However I know these
> sorts of suggestions are often frowned upon, so I'm asking here.
>
>   -ilia