[Mesa-dev] [PATCH 1/4] gallium: add new pipe_screen::legal_resource_size() function

[Jose Fonseca]

----- Original Message -----
> On 09/17/2012 08:12 AM, Brian Paul wrote:
> > On 09/17/2012 04:16 AM, Jose Fonseca wrote:
> >>
> >>
> >> ----- Original Message -----
> >>> From: Brian Paul<brianp at vmware.com>
> >>>
> >>> To implement proxy textures. If a gallium driver doesn't
> >>> implement
> >>> this function we'll just continue to use the core Mesa fallback
> >>> code.
> >>>
> >>> Without this hook we really have no good way to implement OpenGL
> >>> proxy
> >>> textures with gallium drivers.
> >>
> >> Brian,
> >>
> >> This interface seems a good thing to add. A just have a few
> >> suggestion/remarks below.
> >>
> >>> ---
> >>> src/gallium/include/pipe/p_screen.h | 8 ++++++++
> >>> 1 files changed, 8 insertions(+), 0 deletions(-)
> >>>
> >>> diff --git a/src/gallium/include/pipe/p_screen.h
> >>> b/src/gallium/include/pipe/p_screen.h
> >>> index fdf6fa2..718a72b 100644
> >>> --- a/src/gallium/include/pipe/p_screen.h
> >>> +++ b/src/gallium/include/pipe/p_screen.h
> >>> @@ -138,6 +138,14 @@ struct pipe_screen {
> >>> enum pipe_video_profile
> >>> profile );
> >>>
> >>> /**
> >>> + * Check the size of the resource/texture given by 'res'.
> >>> + * Used to implement proxy textures.
> >>> + * \return TRUE if size is OK, FALSE if too large.
> >>> + */
> >>> + boolean (*legal_resource_size)(struct pipe_screen *screen,
> >>
> >> I think the name would benefit from a verb somewhere in it, e.g.,
> >> is_resource_size_legal.
> >>
> >> I suspect this function will check more than size (e.g., number of
> >> samples, format). If so, then I'd suggest a more generic name,
> >> such
> >> as, "can_create_resource".
> >>
> >> Also, shouldn't this interface return an enum (e.g., pipe_error),
> >> so
> >> that one can distinguish between "can't create a texture because
> >> not
> >> enough memory now", vs "can't create this texture ever because of
> >> HW
> >> limitations", or is such distinction useless for GL proxy
> >> textures?
> 
> Oops, I missed this part.  We could certainly return a pipe error to
> give more info, but at the OpenGL level it won't matter.  I'd say
> let's keep it as a boolean for now until we find a reason that more
> info is needed.

Ok, sounds good.

Jose