Processing 1.0 - Processing Discourse

We closed this forum 18 June 2010. It has served us well since 2005 as the ALPHA forum did before it from 2002 to 2005. New discussions are ongoing at the new URL http://forum.processing.org. You'll need to sign up and get a new user account. We're sorry about that inconvenience, but we think it's better in the long run. The content on this forum will remain online.

Index › Discussion › Exhibition › Motion trails

‹ Previous Topic | Next Topic ›

Pages: 1

Motion trails (Read 2838 times)

jimblibs

Motion trails
Oct 13^th, 2008, 3:05am

Hi All

I've been having a tinker with my webcam and have produced a piece that records motion in the form of trails of coloured cicles. This allows the participant to "paint" using their bodies and any objects around them.

Have a look at some footage and/or get the source code at http://jamesalliban.wordpress.com/2008/10/13/motion-trails-v01/

Cheers

Jim

introspector Junior Member Offline Posts: 54	Re: Motion trails Reply #1 - Oct 14^th, 2008, 9:51pm lovely idea. source works great. Maybe you could fade them out over time. or make the fade also dependant on the amount of movement etc.
	http://www.introspector.be && http://www.fabriek.org/ && http://www.flickr.com/photos/21825226@N05 && http://www.mmblog.be/

jimblibs

Re: Motion trails
Reply #2 - Oct 15^th, 2008, 11:02am

Thanks for the comments/suggestions introspector. I tried to fade them out by adding a new rect every frame (or whenever there is movement):

fill(255, 3);
rect(0, 0, width, height);

This faded up to a point but you could still see the circles. Here is an example:

http://jamesalliban.co.uk/blogContent/image/motionTest.jpg

I've had this problem before on previous projects and had to up the opacity. This solution wouldn't work here. Anyone know a way round this?

EDIT: One thing I can't do is keep references to each circle and redraw them with adifferent opacity each time as there are so many and the sketch is already straining my system enough as it is. Any suggestions on how to optimise the code would be very useful btw.

introspector Junior Member Offline Posts: 54	Re: Motion trails Reply #3 - Oct 15^th, 2008, 11:29am i had the same problem with some sketches. there is some explanation in the hacks section: http://processing.org/hacks/doku.php?id=hacks:fading on the bottom of the page there is a link to a working solution: http://www.tom-carden.co.uk/p5/fade2anycolour/applet/
	http://www.introspector.be && http://www.fabriek.org/ && http://www.flickr.com/photos/21825226@N05 && http://www.mmblog.be/

JoostSpanjerberg

Re: Motion trails
Reply #4 - Nov 2^nd, 2008, 9:26pm

I'm liking this. Really beautiful effect. Haven't looked at your code, but have you thought about making the speed at which the screen updates variable? Or is that webcam dependant?

Right now it seems perfect for slow movements; if you move your face from left to right, it takes 5-10 seconds before you can start to see a face. It gets real blurry when you up your movement speed.

jimblibs

Re: Motion trails
Reply #5 - Nov 5^th, 2008, 11:48pm

Thanks. In terms of framerate, it runs quite slowly even on a fairly powerful computer. I'm sure the code could be optimised but I've tried several approaches and the current one is the fastest.

@introspector. Thanks for the link. I integrated a slightly different approach into the sketch. The following is called every frame:

void fadescr() {
loadPixels();
for (int i = 0; i < pixels.length; i++) {
int currR = (pixels[i] >> 16) & 0xFF; // Like red(), but faster
int currG = (pixels[i] >> 8) & 0xFF;
int currB = pixels[i] & 0xFF;
pixels[i] = color(currR + 5, currG + 5, currB + 5);
}
updatePixels();
}

kadavy YaBB Newbies Offline Posts: 2	Re: Motion trails Reply #6 - Nov 30^th, 2008, 6:26am Thanks for a great script. I was able to tinker with it and make a few changes, and make this video: http://www.vimeo.com/2382875

Jack Perkins Junior Member Offline Posts: 99	Re: Motion trails Reply #7 - Jan 8^th, 2009, 2:00pm This is fantastic! Thanks so much for this.

Pages: 1

‹ Previous Topic | Next Topic ›