[Piglit] [PATCH] fs-texelFetchOffset-2D: don't assume undefined values to be solid black

[Roland Scheidegger]

Am 27.11.2012 08:25, schrieb Eric Anholt:
> sroland at vmware.com writes:
> 
>> From: Roland Scheidegger <sroland at vmware.com>
>>
>> core GL specifies out-of-bound accesses have undefined behavior,
>> which includes crashes.
>> Crashes are very much undesired, but ARB_robustness still allows undefined
>> values to be returned (with a recommendation to return 0).
>> Only ARB_robust_buffer_access_behavior would require to return zero, but the
>> test doesn't need this extension. In any case even returning zero is not what
>> the test expected, since it wanted [0,0,0,1].
>> (With this change softpipe passes the test, as it clamps the coords.)
> 
> Are you saying texelFetch is supposed to not do wrap modes?
> 
Yes. From the OpenGL specification 4.3 compatibility profile, page 387
(in a section you'd never find it..., subsection 11.1.3.2 Texel Fetches).
FWIW the DX10 equivalent (ld opcode) doesn't even have any sampler state
(and hence clamping behavior) associated with it.


Roland