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Missiles (task #67): launch through the WEAPON MOUNT frame -- the

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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>
This commit is contained in:
arcattack
2026-07-16 16:46:56 -05:00
co-authored by Claude Opus 4.8
parent c51d64a6b8
commit ab6ea83e3b
3 changed files with 48 additions and 15 deletions
Download Patch File Download Diff File Expand all files Collapse all files
game/reconstructed/projweap.cpp
+3 -2
View File
@@ -95,7 +95,7 @@
extern void BTPushProjectile(const Point3D &muzzle, void *shooter, void *target,
const Point3D &targetPos, Scalar speed, Scalar damage,
const Vector3D *launch_velocity = 0, int guided = 1,
int weapon_subsys = -1, int splash_burst = 0); // AC: no cluster splash (default 0)
int weapon_subsys = -1, int splash_burst = 0, int muzzle_seg = -1); // AC: no cluster splash (default 0)
//#############################################################################
@@ -846,7 +846,8 @@ void
|| rec->fireTarget.z != 0.0f);
BTPushProjectile(mz, owner, 0 /*aim point only, no entity*/, rec->fireTarget,
spd, 0.0f /*VISUAL*/,
haveAim ? 0 : &launchVelocity, 0 /*ballistic*/, subsystemID);
haveAim ? 0 : &launchVelocity, 0 /*ballistic*/, subsystemID,
0, GetSegmentIndex() /*task #67 mount frame*/);
const char *mzf = getenv("BT_MUZZLE"); // default ON; =0 disables
if (mzf == 0 || mzf[0] != '0')