| # RenderQueue System |
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| ## Overview |
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| WA.exe uses a deferred rendering queue. Game logic enqueues draw commands into a per-frame buffer, then `RQ_RenderDrawingQueue` (0x542350) processes them all at once, sorted by priority/layer. |
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| The RenderQueue lives at DDGame+0x524 (see `ddgame_offsets::RENDER_QUEUE`). |
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| ## RenderQueue struct (0x12008 bytes) |
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| | Offset | Size | Field | |
| |--------|------|-------| |
| | 0x00000 | 4 | `buffer_offset` — write position (grows downward from 0x10000) | |
| | 0x00004 | 0x10000 | `_buffer` — command data storage | |
| | 0x10004 | 4 | `entry_count` — number of enqueued commands | |
| | 0x10008 | 0x2000 | `entry_ptrs[0x800]` — pointers to command entries | |
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| Max 2048 (0x800) entries per frame. Buffer grows downward; each alloc subtracts from `buffer_offset`. |
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| ## Command Types (0–14) |
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| The dequeue function uses a switch on command type (first DWORD of each entry). |
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| ### Enqueue functions (standalone, all ported to Rust) |
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| | Type | Function | Address | DDDisplay vtable | Purpose | |
| |------|----------|---------|------------------|---------| |
| | 0 | RQ_DrawRect | 0x541F40 | [0x48] | Filled rectangle (clipped) | |
| | 1 | RQ_DrawBitmapGlobal | 0x542170 | [0x50] | Bitmap at world position | |
| | 2 | RQ_DrawTextboxLocal | 0x542200 | [0x50] | Text box (optional clipping) | |
| | 4 | RQ_DrawSpriteGlobal | 0x541FE0 | [0x4C] | Sprite at world position | |
| | 5 | RQ_DrawSpriteLocal | 0x542060 | [0x4C] | Sprite at screen position (camera-adjusted) | |
| | 6 | RQ_DrawSpriteOffset | 0x5420E0 | [0x4C] | Sprite with optional clipping/rotation | |
| | 8 | RQ_DrawLineStrip | 0x541DD0 | [0x38] | Connected line segments (variable-size) | |
| | 9 | RQ_DrawPolygon | 0x541E50 | [0x34] | Filled polygon edges (variable-size) | |
| | 0xB | RQ_DrawScaled | 0x541ED0 | [0x40] | Scaled sprite | |
| | 0xD | RQ_DrawPixel | 0x541D60 | [0x2C] | Single pixel | |
| | 0xE | RQ_DrawClippedSprite_Maybe | 0x5422A0 | [0x58] | Sprite with complex clipping (like type 6 but different vtable slot) | |
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| ### Types without standalone enqueue functions |
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| These types exist in the dequeue switch but have no standalone enqueue function in the binary. Their enqueue code is either inlined at call sites or unused in WA 3.8.1. |
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| | Type | DDDisplay vtable | Dequeue behavior | |
| |------|------------------|------------------| |
| | 3 | [0x54] | Coord-clipped, 5 params | |
| | 7 | [0x30] | Direct command struct pass, 3 params | |
| | 10 | [0x3C] | Camera-adjusted + pixel offset, 6 params | |
| | 12 | [0x44] | Like type 0xB but different vtable slot | |
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| ## DDDisplay Drawing Vtable |
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| The dequeue function dispatches draw calls through a DDDisplay vtable. Slot offsets: |
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| | Offset | Method | Used by types | |
| |--------|--------|---------------| |
| | 0x2C | PutPixel | 0xD | |
| | 0x30 | (unknown) | 7 | |
| | 0x34 | DrawPolygonEdge | 9 | |
| | 0x38 | DrawLineSegment | 8 | |
| | 0x3C | (unknown) | 10 | |
| | 0x40 | DrawScaledSprite | 0xB | |
| | 0x44 | (unknown) | 12 | |
| | 0x48 | DrawClippedRect | 0 | |
| | 0x4C | DrawSprite | 4, 5, 6 | |
| | 0x50 | DrawBitmap | 1, 2 | |
| | 0x54 | (unknown) | 3 | |
| | 0x58 | DrawClippedSprite | 0xE | |
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| ## Helper Functions |
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| | Address | Name | Purpose | |
| |---------|------|---------| |
| | 0x542B10 | RQ_GetCameraOffset_Maybe | Returns camera/viewport offset for screen-space conversion | |
| | 0x542BA0 | RQ_ClipCoordinates | Main 16.16 fixed-point coordinate clipping | |
| | 0x542C70 | RQ_ClipWithRefOffset_Maybe | Clipping with reference offset transform (type 6 flag 0x04) | |
| | 0x542D50 | RQ_TransformWithZoom_Maybe | Coordinate transformation with zoom/scale | |
| | 0x542E60 | RQ_SmoothInterpolate_Maybe | Linear interpolation with threshold (smooth scrolling) | |
| | 0x542F10 | RQ_UpdateClipBounds_Maybe | Viewport bounding box constraint updater | |
| | 0x542F70 | RQ_SaturateClipBounds_Maybe | Clipping with overflow saturation | |
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| ## Render Pipeline |
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| | Address | Name | Role | |
| |---------|------|------| |
| | 0x56E040 | RenderFrame_Maybe | Top-level render frame dispatcher | |
| | 0x533DC0 | GameRender_Maybe | Core game render: resets queue, processes scene, calls RQ_RenderDrawingQueue | |
| | 0x535000 | RenderTerrain_Maybe | Terrain/landscape viewport rendering | |
| | 0x534F20 | RenderHUD_Maybe | HUD/timer display | |
| | 0x534E00 | RenderTurnStatus_Maybe | Turn state/status text | |
| | 0x533C80 | PaletteManage_Maybe | Palette/color management | |
| | 0x533A80 | PaletteAnimate_Maybe | Palette animation/cycling (3 color palettes) | |
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| ## Higher-Level Drawing Functions |
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| These are not RenderQueue enqueue methods but call them: |
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| | Address | Name | Notes | |
| |---------|------|-------| |
| | 0x500720 | DrawBungeeTrail | Uses DrawSpriteLocal + DrawPolygon/DrawLineStrip | |
| | 0x5197D0 | DrawCrosshairLine | Uses DrawPolygon + DrawSpriteLocal | |
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| ## Dequeue Processing (0x542350) |
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| `RQ_RenderDrawingQueue` sorts entries by priority field (DWORD at entry+4) via `qsort`, then iterates in reverse order (highest priority last = drawn on top). Each command is dispatched through the type switch, with coordinate clipping applied before calling the DDDisplay vtable method. |
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| Fixed-point coordinates (16.16) are right-shifted to pixel values (`>> 0x10`) before passing to DDDisplay methods. |
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