Starfield Mod:Biome File Format

'BIOME files are found in one of Starfield's ESM file and appear to contain data related to the biomes of each planet.

Overall Structure
Header (14-54 bytes) Color Data 1 (262144 bytes) Index Data 1 (65536 + 4 bytes) Color Data 2 (262144 bytes) Index Data 2 (65536 + 4 bytes)

The two image sections appear to form the top half and bottom half of a rectangular 256x512 image matching the aspect ratio of the planet textures.

Header
The first 14-54 bytes at the start of the file is a variable sized header: word U1        (261) dword Count    (1-8) dword U3[Count] (color RGB, same as in data?) dword U4       (2, flags?)

U3 appears to match the "default" color in the color data. U4 is usually 2 but takes on a wide variety of other values, potentially flags.

Count appears to correlate to the possible file sizes:
 * 655,406 bytes = 1
 * 655,410 bytes = 2
 * 655,414 bytes = 3
 * 655,418 bytes = 4
 * 655,422 bytes = 5
 * 655,426 bytes = 6
 * 655,430 bytes = 7
 * 655,434 bytes = 8

Color Data
Appears to be color RGBA values, 4 bytes per pixel. Has a 12 byte header indicating the image/data size. dword Width (256) dword Height (256) dword Size  (65546) rgba_t Color[Size]

== Index Data Appears to be indexed or bitflag value, usually lower numbers starting at 0, 1 byte per pixel. Has a 4 byte head indicating the size in bytes. dword Size  (65546) byte Index[Size]