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Showing posts from January, 2005

Profiling + Vector Math = Performance

So there was a student who implemented a flocking simulation for a virtual fishtank using Croquet. Worked fine with 20 fishes. With 50 fishes it became rather sluggish. Putting in more than 100 fishes the framerate could be measured in seconds per frame. So the rendering in Croquet is too slow, right? Not quite. There are two things you have to keep in mind when it comes to performance: When in doubt, measure. You are in doubt. So we fired up a message tally (world menu - debug - start MessageTally). Turns out only 12 percent of the time were spent in rendering. So it's not the rendering at all. A whopping 80 percent was taken by the flock's step methods. The leaves of the message tally showed that 15 percent of the time went into each of the methods #x , #y , and #z ! So we looked at the code. Every fish was told to swim in the main direction of its neighbors, that is the fishes within a certain radius. Processing continued only for those fishes in range. Sounds quite r