first thanks both for your help. i was tired yesterday evening. jack , i have a problem with your patch. i had already similar problems before, that's why i wanted to use some shader in the feedback chain .
it works ok BUT with very long feedback ( 0.999 alpha ) values i get a ghost image, the point never diseappears( because perhaps of a bad approximation in opengl ) . ie : color 1 1 1 0.995 leaves traces is that a problem with my graphics card ? i don't think so . i join a clumsy correction test , with makes things flicker a bit too much . do you have a better workaround? 2013/10/2 Jack <[email protected]>: > Le 02/10/2013 20:10, Py Fave a écrit : >> Hello list , >> >> i'm currently trying to understand a bit more glsl , >> and am tearing my hairs >> >> i have a scene with some moving geometry (torus) >> on this geometry i use successfully a simple shader to plot a moving circle. >> >> Then >> i try to make the classical feedback effect , but i need to use glsl >> because i want to control precisely the adding of the image at time >> and at time+1 >> >> here is the feedback shader i try to use . >> ---- >> uniform sampler2D tex1,tex2; >> uniform float motionblurstrenght; >> vec2 coord = gl_TexCoord[0].st; >> void main() >> { >> vec4 t1 = texture(tex1, coord);//new frame >> vec4 t2 = texture(tex2, coord);//acumulated frame >> gl_FragColor = vec4(t1.r); >> float r = ((1.-motionblurstrenght)*t2.r) + (t1.r);//motion blur >> gl_FragColor = vec4(r); >> } >> ---------------------- >> >> >> do you have a clean example or hints on how to implement this ? >> i am currently fighting with gemframebuffer and pix_texture >> and rendering order and texunits . >> and i feel i'm missing something .. >> >> i would like , if possible to keep this as an effect i can turn on and >> off , without modifing my current gem chains . >> >> i think i need two gem chains ,one early and one at last in the frame >> drawing chronology , but i can't make it though i tried a lot >> >> any help appreciated . >> >> Pierre-Yves >> >> _______________________________________________ >> [email protected] mailing list >> UNSUBSCRIBE and account-management -> >> http://lists.puredata.info/listinfo/pd-list > > This example could help, see attached. > ++ > > Jack > > > > _______________________________________________ > [email protected] mailing list > UNSUBSCRIBE and account-management -> > http://lists.puredata.info/listinfo/pd-list >
feedback_and_glsl2.pd
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_______________________________________________ [email protected] mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
