[Mesa-dev] [PATCH 05/14] meta: Abort meta pbo path if readpixels need signed-unsigned conversion

[Iago Toral]

On Fri, 2015-06-19 at 13:40 -0700, Anuj Phogat wrote:
> On Tue, Jun 16, 2015 at 9:21 PM, Jason Ekstrand <jason at jlekstrand.net> wrote:
> >
> > On Jun 16, 2015 11:15, "Anuj Phogat" <anuj.phogat at gmail.com> wrote:
> >>
> >> Without this patch, piglit test fbo_integer_readpixels_sint_uint fails,
> >> when
> >> forced to use the meta pbo path.
> >>
> >> Signed-off-by: Anuj Phogat <anuj.phogat at gmail.com>
> >> Cc: <mesa-stable at lists.freedesktop.org>
> >> ---
> >>  src/mesa/drivers/common/meta_tex_subimage.c | 3 +++
> >>  1 file changed, 3 insertions(+)
> >>
> >> diff --git a/src/mesa/drivers/common/meta_tex_subimage.c
> >> b/src/mesa/drivers/common/meta_tex_subimage.c
> >> index 00364f8..84cbc50 100644
> >> --- a/src/mesa/drivers/common/meta_tex_subimage.c
> >> +++ b/src/mesa/drivers/common/meta_tex_subimage.c
> >> @@ -283,6 +283,9 @@ _mesa_meta_pbo_GetTexSubImage(struct gl_context *ctx,
> >> GLuint dims,
> >>
> >>        if (_mesa_need_rgb_to_luminance_conversion(rb->Format, format))
> >>           return false;
> >> +
> >> +      if (_mesa_need_signed_unsigned_int_conversion(rb->Format, format,
> >> type))
> >> +         return false;
> >
> > Hrm... This seems fishy.  Isn't glBlitFramebuffers supposed to handle format
> > conversion with integers?  If so we should probably fix it rather than just
> > skip it for the meta pbo path.
> >
> As discussed offline, here is relevant text for glBlitFrameBuffer() from
> OpenGL 4.5 spec, section 18.3.1:
> "An INVALID_OPERATION error is generated if format conversions are not
> supported, which occurs under any of the following conditions:
> -The read buffer contains fixed-point or floating-point values and any draw
>   buffer contains neither fixed-point nor floating-point values.
> -The read buffer contains unsigned integer values and any draw buffer does
>   not contain unsigned integer values.
> - The read buffer contains signed integer values and any draw buffer does
>   not contain signed integer values."
> 
> I'll add a comment here explaining the reason to avoid meta path.

Is this code going to run only for glBlitFramebuffer? I see this
function being called from code paths that implement glReadPixels and
glGetTexImage too.

Iago

> >>     }
> >>
> >>     /* For arrays, use a tall (height * depth) 2D texture but taking into
> >> --
> >> 1.9.3
> >>
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