The opaque BLACK rectangle under a destroyed truck was basev:bvx9_mtl (the
MECHMD wreck's 4-vtx scorch base): the material authors NO diffuse, ambient
(0,0,0), texture bexp9_tex (MAP 'bexp' slice 8, BEXP.BSL) + ramp cdusty.
collectMaterials' AMBIENT fallback took the all-zero ambient as a REAL
colour (hasDiffuse=true, black) and tinted the whole quad black regardless
of its texture. An all-zero ambient means UNSET, not 'tint black' (a black
tint renders geometry invisible -- never authored intent): the fallback now
requires r+g+b > 0.001. Pixel-verified (BT_SHOT ram run): the scorch base
draws as the authored charred burn patch under the wreck debris.
Also: cross-library TEXTURE registry (globalTexMaps, BT_TEX_XLIB=0
disables) mirroring the existing globalRamps -- material libs reference
textures DEFINED in other libs (bexp9_tex is defined in BTARENA/BTFX, not
BASEV.BMF); a per-file texMaps miss left such batches untextured. Same
first-wins sweep of the indexed BMFs on first miss.
Regression scope: only materials authoring a zero ambient AND no diffuse
change (they now ramp/texture instead of black); cross-lib refs that
previously resolved keep their same-file definitions (checked first).
Awaiting human verification in a live session (issue #3 stays open).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
