If your bandwidth profiler is up then this would cause the problem due to the stage bounds being offset when the profiler opens and the constraints written in the code relating to the initial stage size.

I love this, very interesting using brightness to offset movement. Would be interesting to see generated art over a photograph or other piece of art. Maybe mix with music to generate over the course of a song for velocity and direction using brightness and color change. hmm…

Should try Perlin Noise function using frocessing library ( frocessing.math.PerlinNoise )
It’s a simple mathematic function that do the same , much more faster !

It should be keeping the agents within the stage bounds. perhaps they’re getting stuck as It’s these lines that are handling the boundaries (they check if the agent is off the left of stage and if so move it to the right of stage – same principle with the Y axis)

private static const MARGIN:int = 10;

if ( particle.x < -MARGIN ) particle.x = stage.stageWidth + MARGIN;
else if ( particle.x > stage.stageWidth + MARGIN ) particle.x = -MARGIN;

if ( particle.y < -MARGIN ) particle.y = stage.stageHeight + MARGIN;
else if ( particle.y > stage.stageHeight + MARGIN ) particle.y = -MARGIN;

It’s pretty rudimentary. If you want to add your own logic it works along these lines though – i.e. check an agents position and if its x is less than the left of stage – its width, either remove it and spawn a new one or move it somewhere on stage.