arcattackandClaude Opus 4.8
7b7d465e5e
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>
246 lines
10 KiB
C++
246 lines
10 KiB
C++
//============================================================================//
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// File: misthrst.cpp //
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// Project: BattleTech //
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// Contents: Missile Thruster -- provides thrust/burn to move a Missile //
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//----------------------------------------------------------------------------//
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// Copyright (C) 1995, Virtual World Entertainment, Inc. All Rights reserved //
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// PROPRIETARY AND CONFIDENTIAL //
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//============================================================================//
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//
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// RECONSTRUCTED from the shipped binary. The class declaration survives intact
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// (MISTHRST.HPP); behaviour follows the Ghidra pseudo-C in part_013.c
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// (@004be7c4 ctor, @004be8bc dtor, @004be8e8 TestInstance, @004bf8ec streamed
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// resource parser). Each non-trivial method cites the originating @ADDR.
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//
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// Coverage:
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// confident : ctor @004be7c4, dtor thunk @004be8bc, TestInstance @004be8e8,
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// CreateStreamedSubsystem @004bf8ec
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// best-effort: MissileThrusterSimulation -- the Performance method pointer is
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// installed by the ctor (PTR_LAB_00512b20) but its standalone body
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// is folded into the host Missile::MoveAndCollide @004bef78 (which
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// samples the thruster acceleration buffer at missile+0x234/+0x250).
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// excluded : the 0x41xxxx engine vtable slots (pure Subsystem base behaviour;
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// vtable @00512bbc overrides only slot0 = destructor)
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//
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// Decoded constant:
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// _DAT_004be8b8 = 0x3c8efa35 = 0.0174533f (PI/180, Degree -> Radian)
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//
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// Helper-function name mapping (engine internals referenced by the decomp):
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// FUN_0041c52c Subsystem base constructor (owner, id, name, sharedData)
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// FUN_00408440 Vector3D copy
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// FUN_0041bbd8 AlarmIndicator::SetLevel
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// FUN_0041a1a4 IsDerivedFrom(classDerivations)
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// FUN_004238bc Entity model-record base parser
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// FUN_00404118 read "<section>"/"<key>" Scalar from notation file
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// FUN_00406db4 register parsed model record (type 0xf)
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// FUN_004dbb24/FUN_004d9c38 error-string accumulate / flush
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//
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#include <bt.hpp>
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#pragma hdrstop
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#if !defined(MISTHRST_HPP)
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# include <misthrst.hpp>
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#endif
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#if !defined(MISSILE_HPP)
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# include <missile.hpp>
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#endif
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#if !defined(TESTBT_HPP)
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# include <testbt.hpp>
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#endif
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//
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// Degree -> Radian scale factor, read as a read-only global in the decomp.
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//
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static const Scalar DegreesToRadians = 0.0174533f; // _DAT_004be8b8 (0x3c8efa35)
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//
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// Unrecovered streamed-resource helper stand-ins (engine model-record parser).
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//
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static int ParseEntityModel(NotationFile*, const char*, NotationFile*, const ResourceDirectories*, float*) { return 0; } // FUN_004238bc
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static int ReadScalar(NotationFile*, const char*, const char*, float*) { return 1; } // FUN_00404118
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static void ReportMissing(const char*, const char*) {} // FUN_004dbb24
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static void SetStatusLevel(int) {} // FUN_0041bbd8 (status alarm)
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static int RegisterModelRecord(NotationFile*, const char*, int, int, int, float*, int, int) { return 0; } // FUN_00406db4
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//###########################################################################
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//###########################################################################
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// MissileThruster
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//###########################################################################
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//###########################################################################
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//#############################################################################
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// Shared Data Support
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//
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Derivation
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MissileThruster::ClassDerivations(
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Subsystem::GetClassDerivations(),
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"MissileThruster"
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);
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Receiver::MessageHandlerSet MissileThruster::MessageHandlers;
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const MissileThruster::IndexEntry
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MissileThruster::AttributePointers[] = { { 0, 0, 0 } }; // IndexEntry table @00512ad0
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MissileThruster::AttributeIndexSet MissileThruster::AttributeIndex;
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MissileThruster::SharedData
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MissileThruster::DefaultData( // resolved as &DAT_00512a9c
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&MissileThruster::ClassDerivations,
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MissileThruster::MessageHandlers,
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MissileThruster::AttributeIndex,
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MissileThruster::StateCount
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);
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//#############################################################################
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// Construction
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//
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// @004be7c4 MissileThruster::MissileThruster(Missile *owner, int id,
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// SubsystemResource *resource)
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//
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// Chains the Subsystem base ctor, stamps the MissileThruster vtable, copies the
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// four streamed tuning scalars (converting the rotation rate from degrees to
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// radians), then primes the base thrust acceleration vector to point "down the
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// tail" by thrusterAcceleration. The active Performance (the per-frame burn /
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// steer simulation) is installed unconditionally to PTR_LAB_00512b20; the
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// authoritative-vs-ghost guard (owner flags & 0xC) selects an alternate entry
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// that the final write overwrites in the shipped code.
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//
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MissileThruster::MissileThruster(
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Missile *owner,
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int subsystem_ID,
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SubsystemResource *subsystem_resource)
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:
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// Subsystem base ctor: owner, id, resource, shared default record.
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Subsystem(owner, subsystem_ID, subsystem_resource, DefaultData)
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{
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// vtable installed by the compiler (PTR_LAB_00512bbc)
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burnTimeRemaining = subsystem_resource->burnTime; // @0xE4 resource +0x30
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thrusterAcceleration = subsystem_resource->thrusterAcceleration; // @0xEC resource +0x38
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thrusterClimb = subsystem_resource->thrusterClimb; // @0xF0 resource +0x3C
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// install the burn/steer Performance (only the conditional guard differs for
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// remote ghosts; the unconditional store @004be7c4 is what actually runs).
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if ((owner->simulationFlags & 0xC) != 4) // owner+0x28 & 0xC
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SetPerformance(/*ghost*/ &MissileThruster::MissileThrusterSimulation);
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SetPerformance(&MissileThruster::MissileThrusterSimulation); // PTR_LAB_00512b20
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// Degree -> Radian (Radian::operator=(const Degree&) performs the scaling)
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maxThrusterRotationRate = subsystem_resource->maxThrusterRotationRate; // @0xE8
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SetStatusLevel(1); // FUN_0041bbd8(this+0xb, 1)
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// base acceleration = (0,0,-thrusterAcceleration), angular = (0,0,0)
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acceleration.linearMotion = Vector3D(0.0f, 0.0f, 0.0f); // @0xF4 FUN_00408440(.., &DAT_004e0f74)
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acceleration.linearMotion.z -= thrusterAcceleration; // @0xFC this[0x3f] -= this[0x3b]
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acceleration.angularMotion = Vector3D(0.0f, 0.0f, 0.0f); // @0x100 FUN_00408440(.., &DAT_004e0f74)
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}
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//#############################################################################
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// Destruction
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//
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// @004be8bc ~MissileThruster() -- restores the vtable then chains the Subsystem
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// base destructor. (Reached through the scalar-deleting thunk.)
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//
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MissileThruster::~MissileThruster()
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{
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// vtable reset + base ~Subsystem chaining handled by the compiler.
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}
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//#############################################################################
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// MissileThrusterSimulation -- the registered Performance (best-effort)
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//
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// The thruster's per-frame work (bleed burnTimeRemaining by the time slice and
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// contribute its acceleration to the missile's velocity) is, in the shipped
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// binary, executed from inside Missile::MoveAndCollide @004bef78 which reads
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// this->acceleration directly out of the roster. No distinct @ADDR body
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// survives for the standalone Performance; the reconstruction below mirrors
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// that folded behaviour and the MISTHRST.HPP signature.
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//
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void MissileThruster::MissileThrusterSimulation(Scalar time_slice)
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{
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if (burnTimeRemaining <= 0.0f)
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return; // fuel exhausted -- coast
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burnTimeRemaining -= time_slice;
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if (burnTimeRemaining < 0.0f)
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burnTimeRemaining = 0.0f;
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// thrust is applied to the host Missile's motion by the integrator
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// (Missile::MoveAndCollide), which scales this->acceleration by the slice.
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}
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//#############################################################################
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// Streamed resource parser
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//
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// @004bf8ec MissileThruster::CreateStreamedSubsystem(...)
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//
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// Parses the thruster tuning block out of the "gamedata" section of the
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// notation file into the (0x54-byte) shared model record and registers it as
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// a type-0xF entity-model resource. Field order in the record:
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// +0x40 MaxThrusterRotationRate +0x44 BurnTime +0x48 ThrusterAcceleration
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// +0x4C ThrusterClimb +0x50 SplashRadius
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// The Missile ctor later copies +0x40..+0x4C into the thruster's
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// SubsystemResource (+0x34/+0x30/+0x38/+0x3C). Any missing key is fatal.
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//
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int MissileThruster::CreateStreamedSubsystem(
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NotationFile *model_file,
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const char *model_name,
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NotationFile *subsystem_file,
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const ResourceDirectories *directories,
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SubsystemResource *subsystem_resource)
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{
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Logical owned_record = (subsystem_resource == 0);
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float *record = (float *)subsystem_resource;
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if (owned_record)
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record = (float *)::operator new(0x54); // FUN_00402298(0x54)
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// Entity model-record base parse.
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if (ParseEntityModel(model_file, model_name, subsystem_file, directories, record) == -1)
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goto fail;
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if (!ReadScalar(subsystem_file, "gamedata", "BurnTime", record + 0x11)) // +0x44
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{ ReportMissing(model_name, "Missing BurnTime"); goto fail; }
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if (!ReadScalar(subsystem_file, "gamedata", "MaxThrusterRotationRate", record + 0x10)) // +0x40
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{ ReportMissing(model_name, "MaxThrusterRotationRate Missing"); goto fail; }
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if (!ReadScalar(subsystem_file, "gamedata", "ThrusterAcceleration", record + 0x12)) // +0x48
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{ ReportMissing(model_name, "ThrusterAcceleration Missing"); goto fail; }
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if (!ReadScalar(subsystem_file, "gamedata", "ThrusterClimb", record + 0x13)) // +0x4C
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{ ReportMissing(model_name, "ThrusterClimb missing"); goto fail; }
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if (!ReadScalar(subsystem_file, "gamedata", "SplashRadius", record + 0x14)) // +0x50
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{ ReportMissing(model_name, "Splash Radius missing"); goto fail; }
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if (owned_record)
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{
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int handle = RegisterModelRecord(model_file, model_name, 0xF, 1, 0, record, 0x54, -1);
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::operator delete(record);
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return handle;
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}
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return 1;
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fail:
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if (owned_record)
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::operator delete(record);
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return -1;
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}
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//#############################################################################
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// TestInstance
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//
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// @004be8e8 IsDerivedFrom(ClassDerivations tag 0x512aac).
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//
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Logical MissileThruster::TestInstance() const
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{
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return IsDerivedFrom(MissileThruster::ClassDerivations);
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}
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//#############################################################################
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// TestClass (MISTHRST.HPP / no surviving .TCP)
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//
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Logical MissileThruster::TestClass(Missile &)
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{
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return True;
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}
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