Best way to avoid repeatedly computing the pixels' spherical coordinates?

[wizard]

See also this thread

Does Caching work?

The question of caching usefulness was raised. It obviously depends on how much math/etc you are doing, but, even in the case of a simple bit of math, on a small number of LEDs, I see sufficient improvements to make it seem worthwhile, so more math, more LEDs, it would only improve. var cache = array(pixelCount) var usecache = 0 for (i = 0; i < pixelCount; i++){ cache[i] = array(3) // to ensure it's a "array within an array" cache, // a simple array lookup might be even faster, but this…

Generally, the trig math is extremely fast, its all optimized for speed, and the rest of your pattern code will down out the cost of the trig calls.

There’s also overhead in doing the cache, unless you do a trick with swapping out render functions like @jeff mentions, you can easily erase any gains with extra if() checks, thats how fast they are.

You might want to use the “Performance test framework” pattern if you want to experiment with micro-optimizations. (Currently on page 5):
Performance test framework.epe (3.8 KB)

Using this I measure that calling atan2 and hypot 384 times will add about 0.57ms per animation frame more than looking up a value from a cache array (assuming perfectly optimized with no checks). Given all the added complexity of a cache, I would personally opt for the much shorter simpler code.