[Mesa-dev] [PATCH 1/2] gallium: add PIPE_CAP_MIXED_FRAMEBUFFER_SIZES

[Marek Olšák]

On r300, colorbuffers can have different pitches, therefore each of
them can be of arbitrary size. Other than that, there is a separate
framebuffer width and height state, which applies to all colorbuffers
(it's usually set to the minimum of all widths and heights as in
OpenGL).

r300 doesn't support mixed formats (r500 does), but it does support
mixed sizes and various other features like MSAA.

PIPE_CAP_MIXED_COLORBUFFER_FORMATS doesn't affect exposed extensions,
but it affects FBO completeness.

Marek

On Mon, Sep 9, 2013 at 2:36 PM, Roland Scheidegger <sroland at vmware.com> wrote:
> Am 09.09.2013 13:55, schrieb Erik Faye-Lund:
>> On Mon, Sep 9, 2013 at 1:31 PM, Roland Scheidegger <sroland at vmware.com> wrote:
>>> I'm not really convinced of this idea.
>>> There's already PIPE_CAP_MIXED_COLORBUFFER_FORMATS which is sort of
>>> similar - a "requirement" of ARB_fbo, but it isn't used to determine
>>> support of ARB_fbo or not (my guess is drivers want to advertize ARB_fbo
>>> even if they can't do it, and ARB_fbo doesn't really have a hard
>>> requirement for anything as you always can say "no" to fb supported).
>>> So I can't see why not supporting different width/height is treated
>>> different to not supporting different formats.
>>
>> Actually, ARB_framebuffer_object does have a hard requirement on
>> rendering to differently sized attachments. FRAMEBUFFER_UNSUPPORTED is
>> only allowed for format-issues. EXT_framebuffer_objects can still be
>> supported on hardware that cannot meet this requirement
>>
>
> Ah you're right. For some reason I thought it would be permitted for a
> driver to return unsupported framebuffer for any reason.
> So this makes sense then.
> (Though I'm wondering if we really need the
> PIPE_CAP_MIXED_COLORBUFFER_FORMATS then since I don't think there's any
> driver which can do different width/height hence support ARB_fbo but not
> actually support mixed formats, r300 and softpipe might be candidates
> though I don't know why the latter wouldn't support mixed formats as it
> claims not to and have no idea if the former can support different
> width/height.)
>
> Roland
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