Two claims in the previous commit were wrong and are retracted here rather than
left standing for the next person to build on.
"382 records of 64 bytes" and "byte +3 is 0x48 in every record" were both
artefacts. The 0x48 at that offset is simply the most common byte in the region --
945 of 2000 sampled slots -- not a marker. Over 33,091 slots at that position
only 4,127 hold 0x48. The pattern holds for the first 382 records and then
breaks, which is exactly how a coincidence of a dense byte value masquerades as
structure.
"The coordinates are fixed-point s16 with a scale of 8" is also not supported.
It rested on one coincidence: 17,496 / 8 = 2,187, the planet radius. No grouping
of the record into coordinate triples produces points on a sphere of that radius.
Tested every stride from 2 to 16 bytes at every starting offset, with three and
four components; the best result is 5.0% of points on-sphere, which is chance.
What is now established, and holds on all 27 levels:
core_data region layout, as strictly increasing offsets
tfrag [0, occlusion)
occlusion [occlusion, sky)
sky [sky, collision)
collision [collision, textures_base)
Ruled out the competing reading where 0x0c/0x10/0x14 are sizes laid end to end:
the cumulative total misses textures_base on every level and the leading bytes
of each supposed region are not plausible structures.
Also new: terrain carries its texels inline. A scan for the PS2 texel pattern
18 18 18 80 finds 6,739 occurrences in 138 clusters starting at 0xd9f8, well
inside the tfrag region, so textures_base names something other than terrain
textures.
The vertex format remains unrecovered and the record says so. The next attempt
should look for a longer run of plausible vertices rather than re-deriving a
framing from one record.
ReaperOfVeriod
3ec548efe8