Video Feedback (was [PD] feedback in gem, any tips)

[IOhannes m zmoelnig]

Ian Smith-Heisters wrote:
> its input and you've essentially got a feedback loop. I don't think you can do this in GEM though.
> 

i am happy to inform you, that this is wrong ;-)

for several years there is an object [pix_snapshot] which will capture 
the current rendering-buffer into pix-space (so you can edit it with 
various [pix_-objects)

since this is quite inefficient (the client-server model of openGL is 
not optimized for storing back the render-buffer (on the server) into 
client-memory) there is (for several months now) a [pix_snap2tex] object 
that allows capture of the current render-buffer into a texture (since 
this takes place entirely on the server it is fast)


the example of ben bogart that was using this technique is below.

mfg.a.sdr
IOhannes


#N canvas 610 316 525 271 10;
#X obj 365 135 pix_texture;
#X msg 458 64 snap;
#X obj 365 40 render_trigger;
#X obj 365 16 gemhead 15;
#X obj 388 64 gemhead 5;
#X obj 365 112 pix_snap 0 0 512 512;
#X obj 174 22 gemhead 10;
#X obj 174 84 scaleXYZ 6 0.1 6;
#X obj 190 53 hsl 128 15 0.02 1.53 0 0 empty empty empty -2 -6 0 8
-262144 -1 -1 2600 1;
#X obj 174 107 cube 0.34;
#X obj 365 228 sphere 3.64;
#X msg 437 208 50;
#X obj 365 188 rotateXYZ;
#X obj 379 165 hsl 128 15 0 34 0 0 empty empty empty -2 -6 0 8 -262144
-1 -1 12700 1;
#X obj 17 122 gemwin 60;
#N canvas 525 586 276 170 init 0;
#X obj 65 128 outlet;
#X obj 59 25 loadbang;
#X msg 94 69 dimen 512 512;
#X msg 14 68 lighting 1;
#X connect 1 0 2 0;
#X connect 1 0 3 0;
#X connect 2 0 0 0;
#X connect 3 0 0 0;
#X restore 50 80 pd init;
#X obj 175 185 gemhead 70;
#X obj 175 231 light;
#X msg 17 19 create \, 1;
#X msg 37 49 0 \, destroy;
#X obj 175 208 translateXYZ 0 0 4;
#X obj 437 188 loadbang;
#X connect 0 0 12 0;
#X connect 1 0 5 0;
#X connect 2 0 5 0;
#X connect 2 2 1 0;
#X connect 3 0 2 0;
#X connect 4 0 5 0;
#X connect 5 0 0 0;
#X connect 6 0 7 0;
#X connect 7 0 9 0;
#X connect 8 0 7 2;
#X connect 11 0 10 2;
#X connect 12 0 10 0;
#X connect 13 0 12 2;
#X connect 15 0 14 0;
#X connect 16 0 20 0;
#X connect 18 0 14 0;
#X connect 19 0 14 0;
#X connect 20 0 17 0;
#X connect 21 0 11 0;