[PD] Gem / glsl_fragment

ub at xdv.org ub at xdv.org
Sat Jul 30 01:42:28 CEST 2011


hey there again,

i basically got my shader running, it was a bit of a challenge, because 
i realized i had to use rectangle texunits, as the input is classic 4:3 
video frames.

so fine, i did this, but now  the output of pix_progam is acting kind of 
weird.
it seems to be a proper pix structure, when i attach a pix_info to it, 
it's the correct resolution and type.
it is possible that it is still an bug in my shader, but for instance i 
see in the example patch 06.rectangle_multitexture that there is a 
pix_set right after the pix_program and also in my patch things dont 
work correctly when i don't put it there.
i wonder what it's needed for.

still with the thing in place, the texturing behaves strange. for 
example, if i put an object like pix_contrast or pix_add in it's way, i 
only see some blue flashing. the flashing seems like one pixel of the 
texture magnified to the whole surface.
so i thought it's the texture coordinates and i tried pix_coordinates to 
correct them without success.

then the texture won't display on pix_draw at all, which is fine, i can 
live without it.

pix_flip doesn't do anything but it doesn't screw up the texture.

when i use the output of the rectangle_multitexture example i have 
basically the same effects slightly different in some cases.

maybe i'm missing something obvious, i have tried a lot and i will 
continue to look, but if someone knows more about this i'd be happy with 
some explanations.

thanks+ciao,
ub



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