We had some difficulties on Wednesday afternoon, which stemmed from a bug in Processing’s offscreen drawing code. We are drawing our kaleidoscope images offscreen in order to avoid the overhead of computing the positions of all of the “particles” in our system. By drawing a small particle system offscreen and capturing the bitmap image of it each frame, we can manipulate the bitmap using Processing’s image handling functions and avoid iterating through massive collections of particle objects.

Shawn Van Every came to our assistance and helped me dig through some of the Processing source code in order to locate a potential workaround. He found that by changing the offscreen rendering method from P2D to Java2D, we could safely use the “rect” function which had previously caused Processing to choke.

This week, I created some water droplets. In the process, I found a really obscure compiler error. Word to the wise: don’t use “#define” in Processing. It doesn’t work and the message the compiler returns (something dealing with “webcolor” and “preproc” is not at all helpful in narrowing things down. James Kolstad and I stared at this for a while before I commented out just about every line of my program.