[Piglit] [PATCH] fbo-maxsize: minor test improvements

[Brian Paul]

On 03/04/2013 04:30 PM, Eric Anholt wrote:
> Brian Paul<brianp at vmware.com>  writes:
>
>> Clear the large FBO to a non-black color and probe for it in the
>> final test.
>>
>> This uncovers a bug in Mesa's llvmpipe driver where we ran out of
>> bin commmand memory and skipped some tiles, leaving them black.
>>
>> Setting the clear color to white (and actually clearing the FBO)
>> helps to detect that.
>
> Was this unique to clear operations?

No.  There'd be other ways to trigger this, but clearing is the 
simplest way.  I also thought it was kind of unusual for us to be 
drawing to an FBO that was never cleared in the first place.


> Otherwise, why change from 4 pixel
> probes to 5, instead of just doing some drawing that covers the whole
> screen and probing the whole screen?

That'd be another approach, but glClear + another probe was the 
simplest thing.

I might have some additional enhancements down the road...

-Brian