| # 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. |
|
|
