[Piglit] [PATCH 3/4] arb_texture_view: Pass correct layer index to shader

[Jon Ashburn]

Okay I misunderstood that the shader access was relative to the view.
Looks like your patch is a good bug fix.

My original test code on master branch did work on Nvidia.

Jon
On 01/14/2014 12:06 PM, Chris Forbes wrote:
> Could do that, but one side or the other *must* account for the view
> having a nonzero MinLayer.
>
> Colors[] is indexed based on the layer index relative to the
> underlying texture; expectedLayer is currently relative to the
> underlying texture; the value used in the shader needs to be relative
> to the view [so expectedLayer - view's MinLayer]
>
> Did this actually work on nvidia on master?
>
>
> On Wed, Jan 15, 2014 at 5:36 AM, Jon Ashburn <jon at lunarg.com> wrote:
>> see inline
>>
>> On 01/11/2014 05:39 PM, Chris Forbes wrote:
>>> We want to sample from the last layer in the view, but we were actually
>>> trying to sample from a layer beyond that [by the texture's minimum
>>> layer].
>>>
>>> This might have worked on hardware where the sampler clamps the layer
>>> index before sampling [NV?], but that relies on undefined behavior.
>>>
>>> Signed-off-by: Chris Forbes <chrisf at ijw.co.nz>
>>> ---
>>>    tests/spec/arb_texture_view/rendering_levels.c | 2 +-
>>>    1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/tests/spec/arb_texture_view/rendering_levels.c
>>> b/tests/spec/arb_texture_view/rendering_levels.c
>>> index ef29f78..86bf055 100644
>>> --- a/tests/spec/arb_texture_view/rendering_levels.c
>>> +++ b/tests/spec/arb_texture_view/rendering_levels.c
>>> @@ -205,7 +205,7 @@ test_render_layers(void)
>>>                  glClear(GL_COLOR_BUFFER_BIT);
>>>                  expectedLayer = l + numLayers[l] - 1;
>>> -               draw_3d_depth(-1.0, -1.0, 2.0, 2.0, expectedLayer);
>>> +               draw_3d_depth(-1.0, -1.0, 2.0, 2.0, numLayers[l] - 1);
>>>
>> with this change  then the draw depth is inconsistent with the indexing into
>> the Colors array
>> how about this:
>> expectedLayer = numLayers[l] - 1;
>>
>>
>>>                  expected[0] = Colors[expectedLayer][0] / 255.0;
>>>                  expected[1] = Colors[expectedLayer][1] / 255.0;
>>
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