[Mesa-dev] [PATCH] i965/gen5+: Fix incorrect miptree layout for non-power-of-two cubemaps.

[Kenneth Graunke]

On 07/31/2011 07:25 PM, Eric Anholt wrote:
> On Sat, 30 Jul 2011 21:35:52 -0700, Kenneth Graunke <kenneth at whitecape.org> wrote:
>> For power-of-two sizes, h0 == mt->height0 since it's already a multiple
>> of two.  However, for NPOT, they're different; h1 should be computed
>> based on the original size.
>>
>> Fixes piglit test "cubemap npot" and oglconform_31 test "textureNPOT".
>>
>> NOTE: This is a candidate for stable release branches.
>>
>> Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
>> ---
>>  src/mesa/drivers/dri/i965/brw_tex_layout.c |    2 +-
>>  1 files changed, 1 insertions(+), 1 deletions(-)
>>
>> Note that the piglit test referenced isn't committed yet; I sent it to the
>> piglit mailing list.
>>
>> diff --git a/src/mesa/drivers/dri/i965/brw_tex_layout.c b/src/mesa/drivers/dri/i965/brw_tex_layout.c
>> index f462f32..46a417a 100644
>> --- a/src/mesa/drivers/dri/i965/brw_tex_layout.c
>> +++ b/src/mesa/drivers/dri/i965/brw_tex_layout.c
>> @@ -60,7 +60,7 @@ GLboolean brw_miptree_layout(struct intel_context *intel,
>>  	   * given in Volume 1 of the BSpec.
>>  	   */
>>  	  h0 = ALIGN(mt->height0, align_h);
>> -	  h1 = ALIGN(minify(h0), align_h);
>> +	  h1 = ALIGN(minify(mt->height0), align_h);
>>  	  qpitch = (h0 + h1 + (intel->gen >= 7 ? 12 : 11) * align_h);
>>            if (mt->compressed)
>>  	     qpitch /= 4;
> 
> 
> This looks wrong to me.  The height of a level L is ALIGN(height0 >> L,
> j) according to SNB PRM vol1, 6.17.3.1 "Computing MIP level sizes".
> Note that our calculation of j is wrong for a bunch of hardware/format
> combos -- I wonder if that was the issue you were looking at?

Just for the record, I talked with Eric about this in person, and he
agreed that my patch is correct.  mt->height0 is H_0 (actual height) in
the PRM, while h0 is h_0 (aligned).  We were using the wrong one.  Also,
for the case I was looking at, j == 2, so that wasn't the issue.