Well it seems that:
- by avoiding texunit 0 and (probably unnecessarily) 1, I have actually
resolved the weird interactions with [pix_snap]
- I still have stack underflows and overflows printed at each frame
which I'll investigate but it's probably not causing any "visible" issue
- What was still driving me crazy is that I didn't know that I have to
take into account that the texture size is actually the next power of two of the expected image size.
Since using [pix_texture] you don't have to worry about "padded" image size, AND since ALL glsl examples in Gem use 512x512 images, gently "avoiding" the problem, I naively thought that a MxN image used as a texture would simply have its M pixels spanning the [0,1] range in the x axis (and same for N on y).
Is there some "standard" way, some utility function or something, to deal with non-power-of-two size textures? or have I to explicitely write the calculations to get the correct coordinates? I think I can do that, but if I can have the machine do it for me I prefer that :)
Thanks m.
chris clepper escribió:
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@gmail.com mailto:matteosistisette@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@gmail.com <mailto:matteosistisette@gmail.com> http://www.matteosistisette.com _______________________________________________ Pd-list@iem.at <mailto:Pd-list@iem.at> mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list