[Mesa-dev] [PATCH] st/mesa: check shader image format support before using PBO download

[Ilia Mirkin]

AMD folk - can you confirm that this will work with radeonsi?
Unfortunately we don't support all RT formats as images in nvc0 right
now.

On Mon, Jun 6, 2016 at 10:10 AM, Samuel Pitoiset
<samuel.pitoiset at gmail.com> wrote:
> This fixes the following piglits on nvc0 (tested on GK106, and should work
> like a charm on Fermi as well):
>
> - spec/mesa_pack_invert/mesa_pack_invert-readpixels/PBO unorm BGRA
> - spec/arb_pixel_buffer_object/fbo-pbo-readpixels-small
> - spec/arb_pixel_buffer_object/pbo-read-argb8888
> - spec/arb_pixel_buffer_object/pbo-readpixels-small
>
> Tested-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>
>
>
> On 06/06/2016 12:59 AM, Ilia Mirkin wrote:
>>
>> ARB_shader_image_load_store only requires a very fixed list of formats
>> to be supported, while textures may be in all kinds of formats, like
>> BGRA which are presently not supported on at least Kepler.
>>
>> Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
>> ---
>>  src/mesa/state_tracker/st_cb_readpixels.c | 6 ++++++
>>  1 file changed, 6 insertions(+)
>>
>> diff --git a/src/mesa/state_tracker/st_cb_readpixels.c
>> b/src/mesa/state_tracker/st_cb_readpixels.c
>> index 6df3a39..09450c9 100644
>> --- a/src/mesa/state_tracker/st_cb_readpixels.c
>> +++ b/src/mesa/state_tracker/st_cb_readpixels.c
>> @@ -79,6 +79,7 @@ try_pbo_readpixels(struct st_context *st, struct
>> st_renderbuffer *strb,
>>                     const struct gl_pixelstore_attrib *pack, void *pixels)
>>  {
>>     struct pipe_context *pipe = st->pipe;
>> +   struct pipe_screen *screen = pipe->screen;
>>     struct cso_context *cso = st->cso_context;
>>     struct pipe_surface *surface = strb->surface;
>>     struct pipe_resource *texture = strb->texture;
>> @@ -91,6 +92,11 @@ try_pbo_readpixels(struct st_context *st, struct
>> st_renderbuffer *strb,
>>     if (texture->nr_samples > 1)
>>        return false;
>>
>> +   if (!screen->is_format_supported(screen, dst_format, PIPE_TEXTURE_2D,
>> +                                    texture->nr_samples,
>> +                                    PIPE_BIND_SHADER_IMAGE))
>> +      return false;
>> +
>>     desc = util_format_description(dst_format);
>>
>>     /* Compute PBO addresses */
>>
>
> --
> -Samuel