[Mesa-dev] [PATCH 7/9] gallium/u_tests: test a NULL texture sampler view

[Roland Scheidegger]

Looks good to me. We may need to tighten that up at some point but I
wouldn't know how yet.

Roland

Am 06.02.2015 um 20:08 schrieb Marek Olšák:
> The updated patch is attached. It allows both (0,0,0,0) and (0,0,0,1).
> 
> Marek
> 
> On Mon, Feb 2, 2015 at 5:19 PM, Roland Scheidegger <sroland at vmware.com> wrote:
>> Actually, since ARB_robust_buffer_access_behavior, GL requires some
>> specfic values, but it's - odd...
>> "In all the above cases, if the context was created with robust buffer
>> access enabled then instead of undefined behavior the result of the
>> texel fetch is zero. For the case of a texel fetch on an incomplete
>> texture the result is a texture source color of (0, 0, 0, 1)."
>> So, it seems if the texture was incomplete, then 0/0/0/1 has to be
>> returned, but if it was unbound, then all zeros is the right answer.
>> However, this is only true for textures _fetches_, not ordinary sampling
>> (it is described in the vertex shader functionality). I would assume
>> this to be the case for ordinary sampling too, but there the spec only
>> describes the 0/0/0/1 behavior for incomplete textures, not the behavior
>> for unbound ones...
>>
>> Roland
>>
>>
>>
>> Am 02.02.2015 um 16:51 schrieb Roland Scheidegger:
>>> I don't think this is really correct. llvmpipe will return all zeros on
>>> purpose, because this is d3d10 behavior (and dummy textures cannot work
>>> correctly with d3d10). Traditionally both d3d9 and gl state trackers
>>> used dummy textures, though I'm unsure what values they required (if
>>> any). (For d3d9 though 0/0/0/1 would be somewhat odd since it would be
>>> different to what bound textures but unused channels have to return, but
>>> d3d9 is sometimes odd so it's possible. Well in that way d3d10 is odd
>>> too...)
>>> I certainly do agree though with the "don't crash" part.
>>>
>>> Am 01.02.2015 um 18:15 schrieb Marek Olšák:
>>>> From: Marek Olšák <marek.olsak at amd.com>
>>>>
>>>> It shouldn't crash the GPU and it should return (0, 0, 0, 1).
>>>>
>>>> This is r300 behavior, so I assume it's also DX9 behavior.
>>>> Radeonsi can support this easily.
>>>> ---
>>>>  src/gallium/auxiliary/util/u_tests.c | 39 ++++++++++++++++++++++++++++++++++++
>>>>  1 file changed, 39 insertions(+)
>>>>
>>>> diff --git a/src/gallium/auxiliary/util/u_tests.c b/src/gallium/auxiliary/util/u_tests.c
>>>> index 89ae840..9c8514c 100644
>>>> --- a/src/gallium/auxiliary/util/u_tests.c
>>>> +++ b/src/gallium/auxiliary/util/u_tests.c
>>>> @@ -304,6 +304,44 @@ tgsi_vs_window_space_position(struct pipe_context *ctx)
>>>>     util_report_result(pass);
>>>>  }
>>>>
>>>> +static void
>>>> +null_sampler_view(struct pipe_context *ctx)
>>>> +{
>>>> +   struct cso_context *cso;
>>>> +   struct pipe_resource *cb;
>>>> +   void *fs, *vs;
>>>> +   bool pass = true;
>>>> +   static const float expected[] = {0, 0, 0, 1};
>>>> +
>>>> +   cso = cso_create_context(ctx);
>>>> +   cb = util_create_texture2d(ctx->screen, 256, 256,
>>>> +                              PIPE_FORMAT_R8G8B8A8_UNORM);
>>>> +   util_set_common_states_and_clear(cso, ctx, cb);
>>>> +
>>>> +   ctx->set_sampler_views(ctx, PIPE_SHADER_FRAGMENT, 0, 1, NULL);
>>>> +
>>>> +   /* Fragment shader. */
>>>> +   fs = util_make_fragment_tex_shader(ctx, TGSI_TEXTURE_2D,
>>>> +                                      TGSI_INTERPOLATE_LINEAR);
>>>> +   cso_set_fragment_shader_handle(cso, fs);
>>>> +
>>>> +   /* Vertex shader. */
>>>> +   vs = util_set_passthrough_vertex_shader(cso, ctx, false);
>>>> +   util_draw_fullscreen_quad(cso);
>>>> +
>>>> +   /* Probe pixels. */
>>>> +   pass = pass && util_probe_rect_rgba(ctx, cb, 0, 0,
>>>> +                                       cb->width0, cb->height0, expected);
>>>> +
>>>> +   /* Cleanup. */
>>>> +   cso_destroy_context(cso);
>>>> +   ctx->delete_vs_state(ctx, vs);
>>>> +   ctx->delete_fs_state(ctx, fs);
>>>> +   pipe_resource_reference(&cb, NULL);
>>>> +
>>>> +   util_report_result(pass);
>>>> +}
>>>> +
>>>>  /**
>>>>   * Run all tests. This should be run with a clean context after
>>>>   * context_create.
>>>> @@ -314,6 +352,7 @@ util_run_tests(struct pipe_screen *screen)
>>>>     struct pipe_context *ctx = screen->context_create(screen, NULL);
>>>>
>>>>     tgsi_vs_window_space_position(ctx);
>>>> +   null_sampler_view(ctx);
>>>>
>>>>     ctx->destroy(ctx);
>>>>
>>>>
>>>
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>>