Engine Initialization Chain

Overview

WA.exe initializes the engine through a chain of constructor calls that build the DDGame monolith and its subsystems. The top-level entry is ConstructDDGameWrapper which allocates DDGame and wires up all subsystems.

Call Chain

WinMain / CRT startup (0x5D8B6C)
  └─ ConstructDDGameWrapper (0x56DEF0)
       ├─ Allocates DDGameWrapper (vtable 0x66A30C)
       ├─ DDGame__Constructor (0x56E220)
       │    ├─ Allocates 0x98B8 bytes for DDGame
       │    ├─ DDDisplay__Init (0x569D00)
       │    │    └─ Sets display mode, dimensions, palette, HWND
       │    ├─ GfxHandler x2 (vtable 0x66B280, 0x19C bytes each)
       │    ├─ Task state machines x5 (vtable 0x664118)
       │    └─ Game state pointer at DDGame+0x24
       ├─ PCLandscape__Constructor (0x57ACB0)
       │    ├─ vtable 0x66B208, parent = DDGame
       │    ├─ Allocates terrain buffer (0x60000 bytes) at +0x8E8
       │    ├─ Creates WaterEffect object (vtable 0x66B268) at +0xC8
       │    ├─ Creates LandscapeShader (vtable 0x66B1DC) at +0x93C
       │    └─ Loads Water.dir, Level.dir from data\Gfx\
       ├─ DSSound__Constructor (0x573D50)
       │    ├─ vtable 0x66AF20
       │    ├─ Master volume = Fixed(0x10000) = 1.0 at +0x8A4
       │    └─ 500 sound channel slots
       └─ OpenGLCPU__Constructor (0x5A0850) [conditional]
            ├─ vtable 0x6774C0, 0x48 bytes
            ├─ Width at +0x10, Height at +0x24
            └─ OpenGL__Init (0x59F000) stores HDC/HGLRC in DDDisplay

DDGameWrapper Layout

DDGameWrapper is a thin wrapper (~0x500 bytes) around DDGame:

Offset	Field	Notes
0x000	vtable	0x66A30C
0x488	DDGame ptr	Allocated 0x98B8-byte object
0x48C	DDGame secondary	Optional 0x2C-byte struct
0x4C0	GfxHandler 0	0x19C bytes, vtable 0x66B280
0x4C4	GfxHandler 1	Optional
0x4C8	GfxMode	Graphics mode flag
0x4CC	PCLandscape	Pointer to landscape subsystem

DDGame Key Offsets

DDGame is a ~39KB (0x98B8 bytes) monolithic object. Known landmark fields:

Offset	Field	Notes
0x0024	game_state	Global game state pointer
0x0028	param	Constructor parameter
0x11B0	task_ptrs[5]	5 task state machine pointers
0x3548	display_mode	Display mode pointer
0x354C	display_width	Screen width
0x3560	display_center_x	Screen center X
0x3564	display_center_y	Screen center Y
0x3578	hwnd	Window handle
0x358D	palette	256-color palette (0x400 bytes)
0x3D98	gfx_objects[4]	Graphics object pointers

Ghidra Offset Convention

Ghidra's decompiler shows DWORD-indexed offsets for struct access:

param_1[0x122] → byte offset 0x122 * 4 = 0x488
param_1[0x133] → byte offset 0x133 * 4 = 0x4CC
Always multiply DWORD index by 4 to get the true byte offset.