[Mesa-dev] [Mesa-stable] [PATCH] st/mesa: use first image's dimensions when finalizing texture

[Ilia Mirkin]

On Mon, Jun 6, 2016 at 11:37 AM, Brian Paul <brianp at vmware.com> wrote:
> On 06/05/2016 12:24 AM, Ilia Mirkin wrote:
>>
>> In the case where we can't guess the base level size, just use the first
>> image's dims. The width0/height0/depth0 on stObj may not have been set
>> at this point. Observed in a trace that set up levels 2..9 of a 2d
>> texture,
>> and set the base level to 2, with height 1. This made the guess logic
>> always bail.
>>
>> Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
>> Cc: "12.0" <mesa-stable at lists.freedesktop.org>
>> ---
>>   src/mesa/state_tracker/st_cb_texture.c | 6 +++---
>>   1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/src/mesa/state_tracker/st_cb_texture.c
>> b/src/mesa/state_tracker/st_cb_texture.c
>> index d38f24c..1dd1ef6 100644
>> --- a/src/mesa/state_tracker/st_cb_texture.c
>> +++ b/src/mesa/state_tracker/st_cb_texture.c
>> @@ -2463,9 +2463,9 @@ st_finalize_texture(struct gl_context *ctx,
>>                                    firstImage->base.Depth2,
>>                                    firstImage->base.Level,
>>                                    &width, &height, &depth)) {
>> -         width = stObj->width0;
>> -         height = stObj->height0;
>> -         depth = stObj->depth0;
>> +         width = stObj->width0 = firstImage->base.Width2;
>> +         height = stObj->height0 = firstImage->base.Height2;
>> +         depth = stObj->depth0 = firstImage->base.Depth2;
>>         } else {
>>            /* The width/height/depth may have been previously reset in
>>             * guess_and_alloc_texture. */
>>
>
> Does this fix a crash or glitch or something else?
>
> The state tracker's texture code is pretty delicate so I'd like to fully
> understand the change.

Yes, this fixes a trace that was supplied by someone on IRC. The
situation was that the texture only ever had levels 2..9 (or 10?) set,
and its base level was set to 2. And each level was Nx1 (but
GL_TEXTURE_2D). So all the guessing logic always bailed, which means
that the stObj->width/height/depth were set to 0, which caused asserts
on the next line. (And I assume it wouldn't have rendered correctly
either, but it can be hard to tell in a large scene.)

>
> Maybe we should have a piglit test for this?

I can try to whip something up, not sure when I'll get to it though.
Definitely not today, and probably not for a few at least.

  -ilia