[Mesa-dev] [PATCH 11/11] mesa: fix error value in GetFramebufferAttachmentParameteriv for OpenGL ES 3.0

[Ian Romanick]

On 01/19/2015 03:32 AM, Eduardo Lima Mitev wrote:
> From: Samuel Iglesias Gonsalvez <siglesias at igalia.com>
> 
> Section 6.1.13 "Framebuffer Object Queries" of OpenGL ES 3.0 spec:
> 
>  "If the default framebuffer is bound to target, then attachment must be
>   BACK, identifying the color buffer; DEPTH, identifying the depth buffer; or
>   STENCIL, identifying the stencil buffer."
> 
> But the spec doesn't state which kind of error to return. GL_EXT_draw_buffers,
> section "Errors" says the following:
> 
>   "The INVALID_ENUM error is generated by GetFramebufferAttachmentParameteriv
>    if the <attachment> parameter is not one of the values listed in Table 4.x."
> 
> Due to the ambiguity of OpenGL ES 3.0 spec on this regard and because
> GL_EXT_draw_buffers returns INVALID_ENUM in a related case, then
> change the returned error to INVALID_ENUM.

This is another section 2.3.1 (Errors) case:

    "If a command that requires an enumerated value is passed a
    symbolic constant that is not one of those specified as allowable
    for that command, an INVALID_ENUM error is generated."

The ES3.1 spec is also specific on this point:

    An INVALID_ENUM error is generated by any combinations of
    framebuffer type and pname not described above.

I'm not sure why we were generating INVALID_OPERATION previously.  This came
from

commit 2f2801f876a4c637273bd3ddefb8a5b7a840e604
Author: Anuj Phogat <anuj.phogat at gmail.com>
Date:   Tue Dec 11 20:08:13 2012 -0800

    mesa: Fix GL error generation in _mesa_GetFramebufferAttachmentParameteriv()
    
    This allows query on default framebuffer in
    glGetFramebufferAttachmentParameteriv() for gles3. Fixes unexpected GL
    errors in gles3 conformance test case:
    framebuffer_blit_functionality_multisampled_to_singlesampled_blit
    
    V2: Use _mesa_is_gles3() check to restrict allowed attachment types to
    specific APIs.
    
    Signed-off-by: Anuj Phogat <anuj.phogat at gmail.com>
    Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>
    Reviewed-by: Ian Romanick <ian.d.romanick at intel.com>

So... I wonder if framebuffer_blit_functionality_multisampled_to_singlesampled_blit
checks for INVALID_OPERATION here.  Either that or the error was just
copy-and-pasted from the previous case.  Anuj, do you recall?

> More info:
> 
> http://lists.freedesktop.org/archives/mesa-dev/2015-January/074447.html
> 
> Fixes:
> 
> dEQP-GLES3.functional.fbo.api.attachment_query_default_fbo
> 
> Signed-off-by: Samuel Iglesias Gonsalvez <siglesias at igalia.com>
> ---
>  src/mesa/main/fbobject.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/src/mesa/main/fbobject.c b/src/mesa/main/fbobject.c
> index 80dc353..99ecee8 100644
> --- a/src/mesa/main/fbobject.c
> +++ b/src/mesa/main/fbobject.c
> @@ -2790,7 +2790,7 @@ _mesa_GetFramebufferAttachmentParameteriv(GLenum target, GLenum attachment,
>  
>        if (_mesa_is_gles3(ctx) && attachment != GL_BACK &&
>            attachment != GL_DEPTH && attachment != GL_STENCIL) {
> -         _mesa_error(ctx, GL_INVALID_OPERATION,
> +         _mesa_error(ctx, GL_INVALID_ENUM,
>                       "glGetFramebufferAttachmentParameteriv(attachment)");
>           return;
>        }
>