Shrink polygon to more closely meet minimum

[gordonwoodhull]

Since the number of tiles more than doubles each iteration, each triangle being split into 2 or 3, the result is often more than twice as large as needed.

[gordonwoodhull]

This is a significant problem for use in hexapipes, because it means a huge variation in difficulty for a specific grid size.

Generating tiles just to throw them away is sad, but I think the right solution is to shrink the polygon after generation to get closer to the target.

[gordonwoodhull]

The fill algorithm could be more efficient / elegant if it has "leftover" rhombs to work with, instead of having to run additional passes of generateTriangles().

That elegance would be offset by the bookkeeping for keeping track of a graph of neighboring rhombs where some are included and others are leftovers, but it's worth doing somewhat right. (No need to get into metagraphs here. 😉)