I made a little time domain iir-filter example for images using proce55ing (link below). though I know nothing about GEM, if it can operate on individual pixels then it shouldn't be too hard to store previous values in a buffer?? in this example there are 3-taps (so 3 buffers). sorry if this is no help at all.

Matt

-=-=-=-=-=-=-=-=-=-=-=-=- http://www.loopit.org/ -=-=-=-=-=-=-=-=-=-=-=-=-

----- Original Message ----- From: "Ian Smith-Heisters" heisters@0x09.com To: type_non@yahoo.com Cc: pd-list@iem.at Sent: Tuesday, April 06, 2004 1:19 PM Subject: RE: Video Feedback (was [PD] feedback in gem, any tips)

I've only seen video feedback done in analog. Take a camera, hook it to a

TV, so the TV shows what you're

filming, and then film the TV screen. I would guess that the delays on

processing digital data on a computer

would make it impossible to do on a computer, but I may be very, very

wrong. Try hooking any object's output to

its input and you've essentially got a feedback loop. I don't think you

can do this in GEM though.

-Ian

...

-------- Original Message -------- Subject: Re: [PD] feedback in gem, any tips From: "=?iso-8859-1?q?type=5Fnon?=" type_non@yahoo.com Date: Tue, April 06, 2004 3:56 am To: PD-list@iem.at

I didn't saw that graphic... but i'm very interested in this kind of "visual feedback" patches too. So if someone has more info about this, it would be cool to know how to do that.

Nicholas Ward niward@cs.tcd.ie wrote: Hi, Im new to this gem and pd stuff and loving it! I saw a graphic that someone had made using gem that used "visual feedback". Just wondering

if anyone had a patch that could show what this technique means. Its kinda like a shadow of an object remains as it moves through the space. Thanks nicky

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;