On 11/14/2011 6:40 PM, Brian Paul wrote:
> On 11/14/2011 10:24 AM, Morgan Armand wrote:
>> On 11/14/2011 3:44 PM, Brian Paul wrote:
>>> On 11/13/2011 03:24 AM, Morgan Armand wrote:
>>>> ---
>>>> src/gallium/drivers/softpipe/sp_tex_sample.c | 7 ++++---
>>>> 1 files changed, 4 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/src/gallium/drivers/softpipe/sp_tex_sample.c
>>>> b/src/gallium/drivers/softpipe/sp_tex_sample.c
>>>> index 72629a0..9b0e54e1 100644
>>>> --- a/src/gallium/drivers/softpipe/sp_tex_sample.c
>>>> +++ b/src/gallium/drivers/softpipe/sp_tex_sample.c
>>>> @@ -491,7 +491,8 @@ wrap_linear_unorm_clamp(const float s[4], unsigned
>>>> size,
>>>> uint ch;
>>>> for (ch = 0; ch< 4; ch++) {
>>>> /* Not exactly what the spec says, but it matches NVIDIA output */
>>>> - float u = CLAMP(s[ch] - 0.5F, 0.0f, (float) size - 1.0f);
>>>> + float u = CLAMP(s[ch], 0.0f, (float) size);
>>>> + u -= 0.5F;
>>>> icoord0[ch] = util_ifloor(u);
>>>
>>> If s=0, then icoord0 = -1 and that's not right. The 'i' coordinates must
>>> be in the range [0,size-1].
>>>
>>> Are you trying to fix a specific bug or piglit test?
>>>
>>>
>>>> icoord1[ch] = icoord0[ch] + 1;
>>>> w[ch] = frac(u);
>>>> @@ -512,8 +513,8 @@ wrap_linear_unorm_clamp_to_border(const float s[4],
>>>> unsigned size,
>>>> u -= 0.5F;
>>>> icoord0[ch] = util_ifloor(u);
>>>> icoord1[ch] = icoord0[ch] + 1;
>>>> - if (icoord1[ch]> (int) size - 1)
>>>> - icoord1[ch] = size - 1;
>>>> + if (icoord1[ch]> (int) size)
>>>> + icoord1[ch] = size;
>>>> w[ch] = frac(u);
>>>> }
>>>> }
>>>
>>> -Brian
>>
>> Yes, sorry, I forgot to mention it. This patch fixes
>> texwrap-RECT-bordercolor and texwrap-RECT-proj-bordercolor.
>>
>> From what I understand from the spec, we expect to get the border color
>> when sampling with out-of-range coordinates, or the
>> correct interpolation between the border color and the texel color when
>> sampling with coordinates in the range [0; 1/2N[ or
>> [1-1/2N; max[. That's why I converted the coordinates to [-1;size] instead.
>> get_texel_*d functions handle the case when a texture
>> coordinate is out-of-range but it may not the case of all functions so I
>> probably need to check that carefully.
>> Please correct me if I misunderstood something.
>
> I think I was wrong above. I thought you were changing the clamp-to-edge
> behaviour, but that case is implemented in the
> wrap_linear_unorm_clamp_to_edge() function.
>
> In any case, I remember that implementing what the spec says didn't match the
> output from NVIDIA's driver (hence the comment there).
>
> Do you have an NVIDIA GPU to compare against?
>
> I could do some testing/comparing later...
>
> -Brian
Yes I have, and AFAICT the results are identical (pixel-perfect, in fact). I've
made the test on a windows machine, with the last
drivers.
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