[PD] pix_mask and gemframebuffer

[ub at xdv.org]

hey there,

On 09.11.2011 15:53, Max wrote:
> i remember someone said that he was working on making glsl abstractions to replace some of the pix_ es
some time ago, i have made a video-mixer to replace the example in 
04.pix/12.blending.pd, that routes the signal into each appropriate pix,
with one shader program, initially because i wanted to have hard-light 
blending and writing a shader seemed easier than adding a pix_ object.
i then added some effects to it, so i kind of have replaced some pixes 
with shaders, but in one rather large fragment shader program, rather than
single abstractions.

following your suggestion, i moved some code into individual 
abstractions and it basically works to prove the concept, but there's 
some limitations.
every abstraction needs to render its output into a frambuffer with a 
texunit assgined to it as input for the fragment program, but afaik the 
number
of texunits is limited[1] and you need to track their index globally.
some pix operation will need more than one texunit and the number or the 
overall memory of framebuffers might as well be limited.

anyway i will continue to experiment on that, but if something in the 
direction of pix replacement (or frei0r replacement for that matter) has 
already been done,
i'd be curious to see it. :)

ciao,
ub

[1] http://www.opengl.org/wiki/GLSL_Sampler#Binding_textures_to_samplers