M3 texel decode: the game's own textures recovered from the wire

Action 0x1a carries the textures: header[32] {handle, byte_size, u, v, mode}
+ v rows of 256 bytes, texels in 0x00BBGGRR words. The netdeath session's 20
textures decode to real game art -- 'PLAYER 1/5' HUD labels, a squadron
dragon emblem, metal-panel/grating/terrain surfaces, and the pilot callsign
'Cyd' (texsheet.png in the session scratchpad). The M3 texel FORMAT is
solved; texstore.py builds the handle->RGB store. Remaining: per-quad texid
binding + (texu,texv) sampling to skin the geometry.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

emulator/firmware-decomp/emu860c/texstore.py

@@ -0,0 +1,30 @@
+"""M3 texel store: parse the game wire's action-0x1a texture uploads into a
+handle -> (u_size, v_size, mode, RGB array) dict. Format: header[32] =
+{handle, byte_size, u, v, mode, ...}, then v rows of 256 bytes, texels in
+0x00BBGGRR little-endian words (bytes R,G,B,0). Verified: decodes to the real
+game textures (HUD 'PLAYER n' labels, squadron emblem, panel/terrain art)."""
+import struct
+import numpy as np
+
+
+def build_texstore(recs):
+    store = {}
+    i = 0
+    while i < len(recs):
+        a, p = recs[i]
+        if a == 0x1a and len(p) == 32:
+            h = [struct.unpack_from('<I', p, 4 * k)[0] for k in range(8)]
+            handle, u, v, mode = h[0], h[2], h[3], h[4]
+            rb = b''
+            j = i + 1
+            while j < len(recs) and recs[j][0] == 0x1a and len(recs[j][1]) == 256:
+                rb += bytes(recs[j][1]); j += 1
+            n = u * v
+            if n and len(rb) >= n * 4:
+                arr = np.frombuffer(rb[:n * 4], dtype=np.uint8).reshape(v, u, 4)
+                # v-flip (rows arrive bottom-up: 'PLAYER' reads mirrored otherwise)
+                store[handle] = (u, v, mode, arr[::-1, :, :3].copy())
+            i = j
+        else:
+            i += 1
+    return store