[Mesa-dev] [PATCH] st/mesa: disallow mixed formats in a FBO

[Christoph Bumiller]

On 28.03.2011 02:51, Marek Olšák wrote:
> Some GPUs can't do it (I think most of DX9 ones).
>
> We should later decide how Gallium will expose this feature.
How about you just add a PIPE_CAP_FRAMEBUFFE_MIXED_FORMATS and
PIPE_CAP_FRAMEBUFFER_MIXED_DIMENSIONS ?
And if those aren't present you only expose GL_EXT_framebuffer_object
and not the ARB version.

Or alternatively a pipe_context.validate_framebuffer_configuration where
more advanced cards can just return TRUE ?

I'd rather avoid breaking applications that use this feature for an
undefined amount of time.

> ---
>  src/mesa/state_tracker/st_cb_fbo.c |   21 ++++++++++++++++++++-
>  1 files changed, 20 insertions(+), 1 deletions(-)
>
> diff --git a/src/mesa/state_tracker/st_cb_fbo.c b/src/mesa/state_tracker/st_cb_fbo.c
> index 0df0428..e1057b1 100644
> --- a/src/mesa/state_tracker/st_cb_fbo.c
> +++ b/src/mesa/state_tracker/st_cb_fbo.c
> @@ -529,6 +529,7 @@ st_validate_framebuffer(struct gl_context *ctx, struct gl_framebuffer *fb)
>     const struct gl_renderbuffer_attachment *stencil =
>           &fb->Attachment[BUFFER_STENCIL];
>     GLuint i;
> +   enum pipe_format first_format = PIPE_FORMAT_NONE;
>  
>     if (depth->Type && stencil->Type && depth->Type != stencil->Type) {
>        fb->_Status = GL_FRAMEBUFFER_UNSUPPORTED_EXT;
> @@ -562,13 +563,31 @@ st_validate_framebuffer(struct gl_context *ctx, struct gl_framebuffer *fb)
>        return;
>     }
>     for (i = 0; i < ctx->Const.MaxColorAttachments; i++) {
> +      struct gl_renderbuffer_attachment *att =
> +            &fb->Attachment[BUFFER_COLOR0 + i];
> +      enum pipe_format format;
> +
>        if (!st_validate_attachment(ctx,
>                                    screen,
> -				  &fb->Attachment[BUFFER_COLOR0 + i],
> +				  att,
>  				  PIPE_BIND_RENDER_TARGET)) {
>  	 fb->_Status = GL_FRAMEBUFFER_UNSUPPORTED_EXT;
>  	 return;
>        }
> +
> +      /* Disallow mixed formats. This may be revisited later. */
> +      if (att->Type != GL_NONE) {
> +         format = st_renderbuffer(att->Renderbuffer)->surface->format;
> +      } else {
> +         continue;
> +      }
> +
> +      if (first_format == PIPE_FORMAT_NONE) {
> +         first_format = format;
> +      } else if (format != first_format) {
> +         fb->_Status = GL_FRAMEBUFFER_UNSUPPORTED_EXT;
> +         return;
> +      }
>     }
>  }
>