Caution
This project is an early, experimental prototype.
- It is not stable: expect crashes, rendering glitches, broken features and missing functionality.
- It is not a release, not a beta, and not production-ready in any form.
- Everything here may change, break or be removed at any time.
- Do not rely on this for anything — use the official OpenTTD for actual gameplay.
Experimental 3D camera and depth rendering for OpenTTD.
This is a fork that modifies the real OpenTTD rendering pipeline — not a separate viewer or a mod. The camera looks at the map with a real perspective (vanishing point), and sprites shrink continuously with their distance from the camera. Gameplay logic is untouched.
Stage 3 orbit view: the ground is a real 3D heightfield mesh, and trees, roads and buildings are drawn as camera-facing billboards across the whole visible map.
Working on master:
- Perspective camera — the fixed isometric projection in the viewport renderer is replaced by a perspective projection (
src/core/projective.hpp) with a real vanishing point. - Camera pitch —
gui.three_d_pitch(0–100) tilts the camera from steep (0) to flat (100). The horizon moves, and the area above it is filled with a sky colour so the tilt is clearly visible. - Continuous depth scaling — sprites shrink smoothly with distance using the exact perspective factor
(focal + depth) / focal, normalised to the bottom viewport edge. On the 32bpp SSE blitters the RGBA mip-map of the current zoom is software-scaled to the exact size (nearest neighbour, no performance impact); other blitters fall back to discrete zoom steps. - Hotkey —
CTRL+Dtoggles 3D mode. - Settings (in-game console):
gui.three_d_mode— master switch (default off)gui.three_d_strength— 0–100, perspective strength (default 50)gui.three_d_pitch— 0–100, camera tilt (default 50)gui.three_d_scale— depth scaling on/off
| Stage | Goal | Status |
|---|---|---|
| 1 | Perspective camera: mode-7-style projection in the viewport renderer, scroll/picking corrected, CTRL+D hotkey | ✅ Done |
| 2 | Depth scaling: sprites shrink with distance — continuous perspective factor, pitch-dependent, sky above the horizon | ✅ Done |
| 3 | True 3D rendering: GL pipeline, real ground mesh (heightmap), free mouse-driven camera (orbit / zoom / pan / yaw), Z-buffer | 🚧 In progress — orbit camera, ground mesh, billboards, picking done (issue #3) |
- The full implementation plan (10 steps, milestones, risks) is tracked in issue #3.
- A yaw (rotation) is not possible with the current sprite system: houses and industry have 4 fixed views, vehicles 8, but trees, ground and signals exist in only one view. The stage-3 plan solves this with camera-facing billboards plus yaw-quantised view selection for multi-view sprites.
The fork is based on upstream OpenTTD 77ba2b2 (master). Build instructions are identical to upstream — see the original repository.
GPL-2.0 — see LICENSE (and COPYING.md for the full license text as used by upstream OpenTTD).
Only the rendering path is touched: viewport projection, sprite drawing and a few new settings (gui.three_d_*). Gameplay, networking and savegame code are unchanged.