[PD] [GEM-dev] gl stack underflow

[chris clepper]

pix_snap is probably using texunit 0 which is the default for any texturing
call.  pix_snap actually uses a function called glReadPixels(), and that
might use texture units internally to grab the frame and store it before
read back to main memory.

Also, you cannot use any value for the texunit pix_texture uses most GPUs
have at least 8 so texunits 0 to 7 are valid.  Lots of GPUs have much more
than 8 so you have to figure out where they end.

On Fri, Jan 1, 2010 at 1:38 PM, Matteo Sisti Sette <
matteosistisette at gmail.com> wrote:

> Thank you for pointing me to the examples, but it definitely seems there is
> some kind of interaction with [pix_snap]: even if I force [gemframebuffer]
> to use texunit 0 and my textures to use texunits 1,2,3 and 4, I still get
> under/overflows as soon as pix_snap takes a snap, and my shader is using a
> snapped picture (which does not correspond to any other texture) instead of
> the texture I expect it to use.......
>
> Well I will try to post a simplified patch because this explanation of mine
> is a mess, but it seems I have to figure out how to avoid pixsnap to mess
> with textures. It does not accept a texunit message (dunnow if it would make
> any sense)......
>
> cyrille henry escribió:
>
>
>>
>> Matteo Sisti Sette a écrit :
>>
>>> cyrille henry escribió:
>>>
>>>> there is an exemple of how to use multiple texture / textunit in the gem
>>>> exemple folder, in directory 10.GLSL
>>>>
>>>>
>>>>
>>> You mean 05.multitexture.pd?
>>>
>>> Yes I've seen it (it is thanks to that example that I have been able to
>>> do something - btw iirc it is yours, so thank you).
>>>
>>> But that doesn't show any interaction with [gemframebuffer] nor
>>> [pix_snap]. That's where my troubles begin (apparently)
>>>
>> the exemple 06 show how to use gemframebuffer and multiple texture.
>>
>> exemple 07 is also usefull for you.
>>
>> c
>>
>>
>>
>
> --
> Matteo Sisti Sette
> matteosistisette at gmail.com
> http://www.matteosistisette.com
>
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