LVL Format
From ASSS Wiki
asss only wiki or all of ss dev? --smong
See http://www4.ncsu.edu/~rniyenga/subspace/old/lvlformat.html
Basically it is a bitmap with tile data appended to it. Each tile is represented in this format: (little endian)
struct { unsigned long x : 12; unsigned long y : 12; unsigned long tile : 8; };
The x and y must not exceed 1023. The tileset can be any bit depth, but history puts it at 8bit since the original Subspace uses an 8bit palette.