Per-Block Dichromatic Directional Coloring with Automatic Color Variation

This is an extremely significant accomplishment for the game's progress! There is now per-block dichromatic directional coloring (so that blocks have "direction": forward, backward, left, right, up, or down) with automatic color variation (for distinguishment between adjacent same-colored blocks).

It's also noteworthy that:

1. Variance of transparency levels within a block (between its two colors) is possible and is demonstrated in the first two pictures below.
2. All color variations and directions are automatically calculated in the GPU (in other words it's fast).
3. Wireframe mode is possible (and was possible since the last update, but I forgot to demonstrate it) and is shown in the third picture.
4. In the last three pictures:
1. The camera is rotating around the blocks while simultaneously shifting up and down.
2. There are 4 different colors (and associated transparencies) being drawn, two of which are for a single cube color combo (green and red).
3. Though the facing of all of the green and red blocks is specified explicitly, 5 of the 6 possible directions for a block to face are depicted.

Fourteenth step complete:

I am very happy to see these results. Up next is probably lighting or anti-aliasing.