I missed out on the April Recreational Programming Group because I was at PyCon. He presented on a really cool texture genreator. It’s written in Processing so I decided to see how easy it is to run it using processing.js. TL;DR - Really easy.

The only necessary change I had to make to the code was to add a note to preload the image. Normally processing will execute assuming that the image file is local, but the DOM hasn’t yet loaded the image. To do this you just add a comment to preload the image:

/* @pjs preload="13940260644_7fe66ea59c_c.jpg" */;
String source_image_file = "13940260644_7fe66ea59c_c.jpg";
int xdim = 300;//1400;
int ydim = 300;//700;
int nparticles = 50000;

I also resized it and changed the image. I wanted to add the ability to input an image url via a text field and so that any visitors can change the image. This, it turns out isn’t possible. The preload string cannot use a javascript variable. Also since the image is loaded via ajax, cross site scripting considerations prevent it. I could do this using a django app that would dynamically rewrite the pde file, but I don’t want to host a place for people to randomly upload images. If Steve is impressed with this I might do it, bu it hardly seems worth booting up a VPS.

Also I added a button for freezing the image so that you can easily save the image. I might eventually create a txrxlabs.org subdomain for hosting this and other projects, but for now this is all I’m doing:


19 April 2014