The gauge framebuffer is PLANE-PACKED: L4GAUGE.CFG gives each port a bit
mask, not a rectangle, so all six heads share the same x/y and are separated
only by bit -- the packing the VDB splits into the pod's physical screens.
Comparing RGB was therefore measuring nothing useful; the "magenta artifact"
just meant the wrong heads were lit at that pixel.
New instruments (emulator/render-bridge/gauge-ab/, with a README):
planes.py per-head scoreboard -- shipped vs ours, missing vs extra, per
port mask, recovering the 16-bit word from DOSBox's RGB565
BT_VIS_LOG a complete cockpit widget map from the single dispatch every
gauge widget is built through (MethodDescription::Execute),
printing name + port + authored position
ab.sh stages the fresh build over BTL4REC.EXE and kills any running
DOSBox before launching -- see below
The fix: the Comm page's pilot roster is the POD roster (the viewpoint mech's
ControlsMapper pilot array, mapper attributes 15/16), not the mission's
player list. It is zero in a solo mission, so the shipped page draws empty;
ours resolved the local player and painted its icon in colour 0xff. The gate
belongs in the row source, not PilotList::Execute -- Execute's empty branch
still has to run, because erasing is what the shipped page draws.
head shipped ours missing extra (was)
Eng1 17981 17981 0 0 (0 / 1030)
Eng2 17981 17981 0 0
Eng3 17981 17981 0 0
Comm 15656 13557 2099 0 (2099 / 1253)
Heat 21374 20913 566 105 (566 / 990)
Title-band magenta 404 -> 0. The 2099 Comm pixels we are missing were
missing before the gate, so it is a strict improvement.
Method note, which cost more than the bug: the rig's confs run BTL4REC.EXE
out of the mount while the build writes build410/btl4opt.exe, and nothing
connected the two. Three measurements ran an hour-old binary, so a change
that "did nothing" three times had never been tested -- and the correct first
hypothesis was discarded on that evidence. ab.sh now re-stages every launch.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>