[Mesa-dev] Mesa (master): mesa: Allow querying the system FBO in GetFramebufferAttachmentParameteriv

[Kristian Høgsberg]

On Tue, Jun 22, 2010 at 10:42 AM, Brian Paul <brianp at vmware.com> wrote:
> Kristian Høgsberg wrote:
>>
>> Module: Mesa
>> Branch: master
>> Commit: 80dfec3e53fd5b5c8c31fb16376c9910258c91b0
>> URL:
>>  http://cgit.freedesktop.org/mesa/mesa/commit/?id=80dfec3e53fd5b5c8c31fb16376c9910258c91b0
>>
>> Author: Kristian Høgsberg <krh at bitplanet.net>
>> Date:   Tue Jun 15 13:07:01 2010 -0400
>>
>> mesa: Allow querying the system FBO in GetFramebufferAttachmentParameteriv
>>
>>        If the default framebuffer is bound to <target>, then
>>        <attachment> must be one of FRONT_LEFT, FRONT_RIGHT, BACK_LEFT,
>>        BACK_RIGHT, AUXi, DEPTH_BUFFER, or STENCIL_BUFFER, identifying a
>>        color buffer, the depth buffer, or the stencil buffer, and
>>        <pname> may be FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE or
>>        FRAMEBUFFER_ATTACHMENT_OBJECT_NAME.
>>
>> as well as these <pname> values
>>
>>        FRAMEBUFFER_ATTACHMENT_RED_SIZE,
>>        FRAMEBUFFER_ATTACHMENT_GREEN_SIZE,
>>        FRAMEBUFFER_ATTACHMENT_BLUE_SIZE,
>>        FRAMEBUFFER_ATTACHMENT_ALPHA_SIZE,
>>        FRAMEBUFFER_ATTACHMENT_DEPTH_SIZE,
>>        FRAMEBUFFER_ATTACHMENT_STENCIL_SIZE,
>>        FRAMEBUFFER_ATTACHMENT_COMPONENT_TYPE, or
>>        FRAMEBUFFER_ATTACHMENT_COLOR_ENCODING.
>>
>> https://bugs.freedesktop.org/show_bug.cgi?id=28551
>
>
> This isn't quite correct.
>
> If glGetFramebufferAttachmentParameteriv() is called on the window-system
> FBO we need to disallow querying attachments such as
> GL_COLOR_ATTACHMENT0_EXT and GL_DEPTH_STENCIL_ATTACHMENT.
>
> Similarly, if glGetFramebufferAttachmentParameteriv() is called on a
> user-created FBO we need to disallow querying attachments such as
> GL_FRONT_LEFT and GL_AUX0.
>
> The attached patch fixes this by adding a new _mesa_get_fb0_attachment()
> function.  Pretty simple.  I'll commit later if there's no other concerns.

Yes, that looks good, thanks for catching it.  I believe I had it in
mind when I wrote the patch, but it slipped my mind.  I did check that
we only allow valid pname values though.  All the invalid ones are
texture attachments, which never happens for fb 0, so we reject those
automatically.

Kristian