backward-firing rack
User report (madcat): missiles sometimes leave the mech BACKWARD; lasers
always fine. Root cause: only missiles fly the authored MuzzleVelocity
vector, and BTPushProjectile rotated it through the mech BODY basis
(localToWorld) -- but the madcat's racks ride the TORSO. The muzzle POINT
was segment-resolved (tracked the twist) while the launch DIRECTION followed
the LEGS: twist the torso far enough and rounds left the back. Lasers/ACs
aim straight at the designated pick (no launch vector) -- unaffected, exactly
as observed.
Binary ground truth [T1]: the fire builder FUN_004bcc60 spawns the missile
with the FULL muzzle-segment frame (the real GetMuzzlePoint fills an
AffineMatrix into the descriptor, :8762-8764), composes the authored MV with
the z-NEGATION (:8759-8761 -- confirming the 2026-07-12 telemetry finding)
onto the mech's own localVelocity (FUN_004b9cbc = owner+0x1c4), and the dumb
seeker re-aims 100u ahead of the MISSILE's own frame each frame (0x4be9a0
disasm) -- the mount orientation IS the launch direction.
Port: BTPushProjectile takes muzzle_seg and rotates the launch vector through
the mount segment's world frame (segment-to-entity x localToWorld, the same
matrix the muzzle point already used), keeping the z-negation convention, and
inherits the shooter's world velocity; body-basis fallback for callers
without a segment. All four call sites pass GetSegmentIndex().
Bonus decode banked for the full Missile-entity revival (KB-worthy): the
three authentic performances -- Seeker 0x4be9a0 (aim = target-frame offset /
100u-ahead dumb + loft/lead 0x4beae4), Thruster 0x4be474 (quaternion-slerp
BODY TURN toward the aim at turnRate deg/s), MoveAndCollide 0x4bef78
(velocity aerodynamically aligned to thrust via signed-square per-axis gains,
ballistic droop as fuel burns, PROXIMITY FUSE on seeker rangeToTarget,
max-range + altitude-floor retire).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
