The project is using nobuild build system.

$ cc -o nobuild nobuild.c
$ ./nobuild
$ ./wang -live

Trying to generate a random grid of 2-colored Wang Tiles based on a single function definition:

typedef struct { float c[2]; } Vec2f;
typedef struct { float c[3]; } Vec3f;
typedef Vec2f UV;
typedef Vec3f RGB;
typedef uint32_t BLTR;

RGB wang(BLTR bltr, UV uv);

where

• bltr is a 4 bit mask encoding the specific Wang Tile. Each bit represents a side of the tile in the following order: Bottom, Left, Top, Right. 0 is the first color, 1 is the second one.
• uv is a 2D vector that represents a point on the tile. Top-Left corner is [0.0, 0.0], Bottom-Right corner is [1.0, 1.0]. Coordinates are normalized and resolution-independant.
• The result of the function is a 3D vector that represents an RGB color of a pixel on the tile bltr at uv.

Think of it as a Fragment Shader that generates a Texture for a Wang Tile based on its bitmask description.

The whole rendering is split into roughly 3 phases and done entirely on CPU.

Given the "Shader" function described in the Goal section we generate an atlas (spritesheet) of all 16 Wang Tiles. (4 sides, 2 colors, 2⁴ = 16)

Given the size of the grid in tiles we generate 2D array of BLTR-s (defined in the Goal section) satisfying the Wang Tile constraints between the tiles (the adjacent side of the tiles must have the same color).

After the Atlas and the Grid are generated we iterate over each BLTR in the Grid and copy the corresponding tiles from the Atlas into the final Grid image.

The development was streamed on Twitch. Here is an archive of screencasts: https://www.youtube.com/playlist?list=PLpM-Dvs8t0VYgJXZyQzWjfYUm3MxcvqR0