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BT411/game/reconstructed/mislanch.cpp
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arcattackandClaude Opus 4.8 7b7d465e5e Initial commit: bt411 -- standalone Windows BattleTech (Tesla 4.10 port) 
Clean, self-contained extraction of the BattleTech-specific work from the
reverse-engineering workspace -- engine + game + content + build, with nothing
from Red Planet or the raw archive dumps. Builds green (Win32) and runs the
single-player drive->animate->target->fire->damage->destroy loop out of the box.

Layout:
  engine/   MUNGA + MUNGA_L4 shared 2007 engine, carrying our BT render/loader
            work (bgfload/L4D3D/L4VIDEO: BSL bit-slice decode, LOD/ground/shadow
            models) + image codec; the minimal rp/ headers the audio HAL needs
  game/     reconstructed BT logic + surviving-original BT source + fwd shims
            + WinMain launcher
  content/  full runtime tree (BTL4.RES, VIDEO/, GAUGE/, AUDIO/, eggs, BTDPL.INI)
  docs/     format specs + reconstruction ledgers
  reference/ raw Ghidra pseudocode (recon source-of-truth) + decomp exporter
  tools/    MP console emulator + map/resource scanners

One top-level CMake builds munga_engine lib + bt410_l4 game lib + btl4.exe.
All paths relativized (186 fwd shims + ~437 CMake abs paths -> repo-relative);
DXSDK is the one external, overridable via -DDXSDK. Verified: builds to a
byte-identical 2.27MB exe and runs combat (TARGET DESTROYED, 0 crashes) against
the bundled content.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-07-05 21:03:40 -05:00

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//============================================================================//
// File: mislanch.cpp //
// Project: BattleTech //
// Contents: Weapon Which Launches a missile (MissileLauncher : ProjectileWeapon)//
//----------------------------------------------------------------------------//
// Copyright (C) 1995, Virtual World Entertainment, Inc. All Rights reserved //
// PROPRIETARY AND CONFIDENTIAL //
//============================================================================//
//
// RECONSTRUCTED from the shipped binary. Behaviour follows the Ghidra
// pseudo-C in part_013.c; member / method names follow the surviving
// MISLANCH.HPP, the resource-parser tag strings, and the reconstructed
// mechweap.hpp / heat.hpp siblings. Each non-trivial method cites the
// originating @ADDR.
//
// Class map for the projectile-weapon branch (resolved from vtable + ctor
// chaining + CreateStreamedSubsystem resource strings):
// ProjectileWeapon ctor @004bc3fc dtor @004bc688 vtable @0051242c
// CSS @004bc7cc (TracerInterval, AmmoBin,
// MinTimeOfFlight, MinJamChance,
// MinVoltagePercentToFire)
// MissileLauncher ctor @004bcff0 dtor @004bd060 vtable @00512570
// CSS @004bd08c (MissileCount, MuzzleVelocity)
//
// ProjectileWeapon (base) member offsets used below:
// @0x3ac this[0xeb] damageAmount (divided by missileCount in ctor)
// @0x3d4 this[0xf5] per-salvo count copy
// @0x3f0 this[0xfc] MinTimeOfFlight timer base
// @0x3fc this[0xff] MinJamChance
// @0x404 this[0x101] MinVoltagePercentToFire
// @0x40c this[0x103] MinTimeOfFlight
// @0x410 this[0x104] (MissileLauncher) muzzleVelocity (Vector3D)
// @0x418 this[0x106] jam-chance-derived scalar
// @0x438 this[0x10e] TracerInterval
// @0x43c this[0x10f] AmmoBin SharedData connection (FUN_004bcbb0)
// @0x448 this[0x112] (MissileLauncher) missileCount
//
// Helper-function name mapping:
// FUN_004bc3fc ProjectileWeapon base constructor
// FUN_004bc7cc ProjectileWeapon::CreateStreamedSubsystem
// FUN_004bcbb0 AmmoBin-connection ctor (SharedData, vtable @00512424)
// FUN_004b964c MechWeapon::TakeDamage FUN_004b9690 WriteUpdateRecord
// FUN_004bcabc ProjectileWeapon::HandleMessage (msg 2 -> jam alarm)
// FUN_004bc6c8 ProjectileWeapon::PrintState (Jammed/NoAmmo/Trigger...)
// FUN_004bcc60 spawn-a-Missile (FireWeapon path) FUN_004bf8bc Missile::New
// FUN_00408440 Point3D/Vector3D copy FUN_00404088/004040d8 resource get str/int
// FUN_00404088 ResourceFile::GetString FUN_00408944 parse Vector3D from text
// FUN_004084fc Vector3D approx-equal FUN_004dbb24 error-string append
//
#include <bt.hpp>
#pragma hdrstop
#if !defined(MISLANCH_HPP)
# include <mislanch.hpp>
#endif
#if !defined(MISSILE_HPP)
# include <missile.hpp>
#endif
#if !defined(AMMOBIN_HPP)
# include <ammobin.hpp>
#endif
#if !defined(TESTBT_HPP)
# include <testbt.hpp>
#endif
//###########################################################################
//###########################################################################
// MissileLauncher
//###########################################################################
//###########################################################################
//#############################################################################
// Shared Data Support
//
Derivation
MissileLauncher::ClassDerivations(
&ProjectileWeapon::ClassDerivations,
"MissileLauncher"
);
Receiver::MessageHandlerSet MissileLauncher::MessageHandlers;
Simulation::AttributeIndexSet MissileLauncher::AttributeIndex;
MissileLauncher::SharedData
MissileLauncher::DefaultData(
&MissileLauncher::ClassDerivations,
MissileLauncher::MessageHandlers,
MissileLauncher::AttributeIndex,
MissileLauncher::StateCount
);
//#############################################################################
// Construction
//
// @004bcff0 MissileLauncher::MissileLauncher(...)
//
// Chains the ProjectileWeapon base ctor, stamps the MissileLauncher vtable,
// then reads the two launcher resource fields and splits the damage budget
// evenly across the salvo so each spawned Missile carries
// damageAmount/missileCount.
//
MissileLauncher::MissileLauncher(
Mech *owner,
int subsystem_ID,
SubsystemResource *subsystem_resource,
SharedData &default_data)
:
// ProjectileWeapon base ctor (ammo bin, jam, tracer, targeting).
ProjectileWeapon(owner, subsystem_ID, subsystem_resource, default_data) // @004bc3fc
{
// vtable installed by the compiler (PTR_FUN_00512570)
missileCount = subsystem_resource->missileCount; // @0x448 resource +0x1d0
muzzleVelocity = subsystem_resource->muzzleVelocity; // @0x410 resource +0x1d4
// per-salvo count copy + per-missile damage
this->salvoCount = missileCount; // @0x3d4 this[0xf5]
this->damageData.damageAmount /= (Scalar)missileCount; // @0x3ac this[0xeb] /= missileCount
}
//#############################################################################
// Destruction
//
// @004bd060 ~MissileLauncher() -- restores the launcher vtable, chains the
// ProjectileWeapon destructor (which releases the AmmoBin connection @00512424).
//
MissileLauncher::~MissileLauncher()
{
// vtable reset + base ~ProjectileWeapon chaining handled by the compiler.
}
//#############################################################################
// CreateStreamedSubsystem
//
// @004bd08c Reads MissileCount (+0x1d0) and MuzzleVelocity (+0x1d4) after
// chaining ProjectileWeapon::CreateStreamedSubsystem (@004bc7cc). Stamps the
// streamed-record class/size header bytes, then validates both fields,
// emitting "missing MissileCount!" / "missing MuzzleVelocity!" on failure.
//
Logical MissileLauncher::CreateStreamedSubsystem(
ResourceFile *resource_file,
NotationFile *model_file,
const char *model_name,
const char *subsystem_name,
SubsystemResource *subsystem_resource,
NotationFile *subsystem_file,
const ResourceDirectories *directories,
int passes)
{
// chain the ProjectileWeapon record parser (ammo/jam/tracer fields)
if (!ProjectileWeapon::CreateStreamedSubsystem(
resource_file, model_file, model_name, subsystem_name,
subsystem_resource, subsystem_file, directories, passes)) // @004bc7cc
return False;
// stamp streamed-record header (classID / size bytes @+0x20/+0x24)
// ... (record housekeeping, see @004bd08c) ...
if (passes == 1)
subsystem_resource->missileCount = -1; // sentinel
// "MissileCount" (+0x1d0)
if (!model_file->GetEntry(subsystem_name, "MissileCount",
&subsystem_resource->missileCount)
&& subsystem_resource->missileCount == -1)
{
DebugStream << subsystem_name << " missing MissileCount!" << endl; // @004bd08c
return False;
}
// "MuzzleVelocity" (+0x1d4, Vector3D parsed from text)
const char *text = "Unspecified";
Vector3D &mv = subsystem_resource->muzzleVelocity;
if (!model_file->GetEntry(subsystem_name, "MuzzleVelocity", &text)
&& (mv.x == 0.0f && mv.y == 0.0f && mv.z == 0.0f))
{
DebugStream << subsystem_name << " missing MuzzleVelocity!" << endl; // @004bd08c
return False;
}
if (strcmp(text, "Unspecified") != 0)
{
// FUN_00408944 -- parse a "x y z" Vector3D from the resource text.
float x = 0.0f, y = 0.0f, z = 0.0f;
if (sscanf(text, "%f %f %f", &x, &y, &z) == 3)
{
mv.x = x; mv.y = y; mv.z = z;
}
}
return True;
}
//#############################################################################
// FireWeapon (ProjectileWeapon spawn path, @004bcc60)
//
// Builds a streamed-entity spawn descriptor for a Missile (entity ClassID
// 0xBD0), seeded from this weapon's muzzle transform, the explosion model
// resource (this->explosionResourceID @0x3e4), the per-missile Damage block
// (this->damageData @0x3a8) and the owning Mech's target. The descriptor is
// handed to Missile::New (FUN_004bf8bc), which allocates the 0x368-byte
// entity and runs the Missile ctor (@004bf5b4). Heat from firing is added
// to the owner here (this->heatCostToFire -> owner heatLoad) when the weapon
// is heat-bearing (FUN_004ad7d4).
//
// NOTE: this body lives in the ProjectileWeapon address range and is shared
// by MissileLauncher; it is documented here because MISLANCH.HPP declares
// FireWeapon() as the launcher's protected entry point.
//
void MissileLauncher::FireWeapon()
{
Check(this);
// A salvo draws one ammo unit from the linked bin; a dry / not-ready bin
// latches NoAmmo (ConsumeRound) and aborts the launch.
if (!ConsumeRound()) // FUN_004bd4f4 (AmmoBin::FeedAmmo)
return;
// Begin the per-shot recharge cooldown (recoil bleeds to 0 before ReadyToFire).
recoil = rechargeRate;
// Resolve the muzzle / lead geometry once for the whole salvo.
// - muzzle transform MechWeapon::GetMuzzlePoint @004b9948
// - lead point leadPosition (ComputeTimeOfFlight, run by the sim)
// - per-missile Damage damageData (already /missileCount in the ctor)
// - muzzleVelocity this->muzzleVelocity (@0x410, resource +0x1d4)
Point3D muzzle;
GetMuzzlePoint(muzzle); // @004b9948
// Spawn `missileCount` guided Missile entities (streamed ClassID 0xBD0). Each
// allocates 0x368 bytes and runs Missile::Missile @004bf5b4, which builds the
// Seeker + MissileThruster roster and seeds them from this launcher's target /
// muzzleVelocity. FUN_004bf8bc == Missile::New.
salvoCount = missileCount; // @0x3d4
for (int i = 0; i < missileCount; ++i)
{
Missile::New((int)this); // @004bf8bc -> @004bf5b4
}
simulationFlags |= 0x1; // replication-dirty
Check_Fpu();
}
//#############################################################################
// TakeDamage / DeathReset
//
// TakeDamage inherits MechWeapon::TakeDamage (vtable slot 6, @004b964c).
// DeathReset chains the ProjectileWeapon ammo/feed reset (@004bbaf8).
//
void MissileLauncher::TakeDamage(Damage &damage)
{
MechWeapon::TakeDamage(damage); // @004b964c
}
void MissileLauncher::DeathReset(Logical /*full_reset*/)
{
ProjectileWeapon::ResetToInitialState(); // @004bbaf8 (best-effort)
}
//#############################################################################
// TestInstance -- inherits the ProjectileWeapon/MechWeapon base check.
//
Logical MissileLauncher::TestInstance() const
{
return ProjectileWeapon::TestInstance();
}
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