[Mesa-dev] [PATCH 2/2] mesa: rearrange texture error checking order

[Ilia Mirkin]

On Thu, Jul 23, 2015 at 6:34 PM, Brian Paul <brianp at vmware.com> wrote:
> On 07/23/2015 04:24 PM, Ilia Mirkin wrote:
>>
>> On Wed, Jul 22, 2015 at 1:44 PM, Brian Paul <brianp at vmware.com> wrote:
>>>
>>> On 07/22/2015 11:29 AM, Ilia Mirkin wrote:
>>>>
>>>>
>>>> On Wed, Jul 22, 2015 at 1:20 PM, Brian Paul <brianp at vmware.com> wrote:
>>>>>
>>>>>
>>>>> On 07/22/2015 11:02 AM, Ilia Mirkin wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>> This moves the width/height/depth == 0 check to the front and avoids
>>>>>> doing any other checking when that is the case.
>>>>>>
>>>>>> Also moves the dimensions check after the format/type checks so that
>>>>>> we
>>>>>> don't bail out with success on a width/height/depth == 0 request when
>>>>>> the format/type don't match.
>>>>>>
>>>>>> Bugzilla:
>>>>>>
>>>>>>
>>>>>> https://urldefense.proofpoint.com/v2/url?u=https-3A__bugs.freedesktop.org_show-5Fbug.cgi-3Fid-3D91425&d=BQIBAg&c=Sqcl0Ez6M0X8aeM67LKIiDJAXVeAw-YihVMNtXt-uEs&r=T0t4QG7chq2ZwJo6wilkFznRSFy-8uDKartPGbomVj8&m=Y1TotaJmX1E7sCopvmMJc8PQKFXlHu6QxfcYOydKuII&s=L0lmmuk31G6M4hZEiwnX-IC4CPhW7rsrSCgEYtDgXjw&e=
>>>>>> Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> I suspect this isn't really needed in light of my patch to
>>>>> getteximage-invalid-format-for-packed-type.c
>>>>>
>>>>> I believe the test was in error, or at least sloppy, in that it was
>>>>> calling
>>>>> glGetTexImage to test format/type validation when there wasn't even a
>>>>> texture image to return.  The OpenGL spec doesn't specify an order for
>>>>> error
>>>>> checking multiple things, so if there's multiple errors, you can't be
>>>>> sure
>>>>> which one will be reported first.  My patch to the test removes that
>>>>> ambiguity.
>>>>
>>>>
>>>>
>>>> Well, irrespective of the piglit test, the current code is a little
>>>> suspect -- it does the width/height/depth == 0 checks after it ensures
>>>> that height == 1 for 1d and depth == 1 for 2d. Any thoughts on that?
>>>
>>>
>>>
>>> Yeah, that makes sense.  I guess we don't have any tests that exercise
>>> getting a 0 x 0 texture image.
>>>
>>> Reviewed-by: Brian Paul <brianp at vmware.com>
>>
>>
>> Ugh, so Dylan points out that this breaks
>>
>> bin/arb_direct_state_access-get-textures
>>
>> (which I didn't notice, because I guess it got recently enabled on mesa)
>>
>> It has this check:
>>
>>          /* No Storage
>>           *
>>           * The spec doesn't say what should happen in this case.  This is
>>           * addressed by Khronos Bug 13223.
>>           */
>>          glCreateTextures(GL_TEXTURE_CUBE_MAP, 1, &name);
>>          glGetTextureImage(name, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0, data);
>>          pass &= piglit_check_gl_error(GL_INVALID_OPERATION);
>>          glDeleteTextures(1, &name);
>>
>> But my width == 0 || ... check at the top of dimensions_error_check
>> short-circuits all that.
>>
>> Brian, what situation is the "width == 0 || height == 0 || depth == 0"
>> supposed to account for?
>
>
> After error checking, it just lets up skip all the
> ctx->Driver.GetTexSubImage() calls and associated stuff (mapping PBOs, etc).

But some of the error checking makes sure that width/height/depth
aren't 0. And in case of a missing image, width/height/depth are all
set to 0. That was my confusion.