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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/mislanch.cpp
+5 -3
View File
@@ -73,7 +73,7 @@
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);
int weapon_subsys = -1, int splash_burst = 0, int muzzle_seg = -1);
//###########################################################################
// Port-side salvo replication state (missile-visibility wave).
@@ -317,7 +317,8 @@ void MissileLauncher::FireWeapon()
(i == 0) ? damageData.damageAmount : 0.0f,
&launchVelocity, 1,
subsystemID /*messmgr explosion bundling at impact (task #7)*/,
(i == 0) ? nmiss : 0 /*salvo-lead: cluster splash baseBurst*/);
(i == 0) ? nmiss : 0 /*salvo-lead: cluster splash baseBurst*/,
GetSegmentIndex() /*task #67: launch through the MOUNT frame (torso twist)*/);
// Salvo replication (missile-visibility wave): bump the fire counter + stamp
// the aim point; the extended update record carries both to peer nodes.
@@ -389,7 +390,8 @@ void
for (int i = 0; i < n; ++i)
BTPushProjectile(mz, owner, 0 /*no entity: aim point only*/,
rec->salvoTarget, spd, 0.0f /*VISUAL*/, &launchVelocity, 1,
subsystemID /*per-round detonation resolve on this node*/);
subsystemID /*per-round detonation resolve on this node*/,
0, GetSegmentIndex() /*task #67 mount frame*/);
if (getenv("BT_PROJ_LOG"))
DEBUG_STREAM << "[projectile] REPLICANT salvo x" << n
<< " at(" << rec->salvoTarget.x << "," << rec->salvoTarget.y