Cache Voronoi source points.

[player-03]

This requires some input from the user but seriously improves performance. Basically it looks like this:

var module = new Voronoi(0.02, 1, 234, false);
module.cache(0, 0, 0, 100, 100, 100);

// The cached area is faster to calculate:
module.getValue(10, 20, 30);
module.getValue(50, 50, 50);
module.getValue(100, 0, 100);
module.getValue(40, 50, 60);

// You can still get values outside the area, but they aren't faster:
module.getValue(200, 0, 0);
module.getValue(-1, -1, -1);

Tested primarily in HashLink and HTML5. In HashLink it shaves off about 33% of the time required, while in HTML5 it shaves off about 66%.

[player-03]

The currently-submitted version is the best I could come up with, but I also tried some alternatives. For the record:

• I tried storing data in one big haxe.io.Bytes object, and while this helped a little in JavaScript, it noticeably hurt C++, HashLink, and Neko. (Maybe a 33% slowdown? I forget exactly.)
• I tried Array<Array<Array<Float>>> (with the innermost array storing 3x as many Floats) instead of Array<Array<Array<Site>>> (where Site is a class with three Float variables), with the same results.
• It feels like iteration order (x→y→z vs. z→y→x) should matter for cache misses, but I tried it and it seemed to make no difference.
• Optional arguments are incredibly slow in C++, HashLink, and Neko. By which I mean they're comparable to two calls to Utils.ValueNoise3D. So instead of the cache speeding things up by 33%, it slowed everything down by 100%.