Height Mapped Polyhedra in OpenScad

I want to do height mapping in OpenScad. The easiest way to do it is to generate little cubes for each offset. That's a good start, but I wanted more. What I really want is the ability to layout a polyhedron mesh use a height map to alter the vertices of that mesh.

This thing is just the latest incarnation of the library. With it, you can do the following:

display_mesh_height([32,32], [2,2], heightmap=checker_image);

That is, specify a size in millimeters for the mesh [32,32], then a resolution [2,2], and the height map, our checker image.

The work is actually located in the test_mesh.scad file. It will do the height, but not do the color. That will come next.

Another thing that I'm doing in this incarnation of the library is separating out this thing called glsl.scad Basically, recognizing that there's a lot of stuff that I'm doing that mirrors what I would be doing in 3D graphics. A lot of this stuff is like vertex and shader programming, so I figured I'd model