A zero-dependency 2D Arcade Physics Engine for games, designed for massive simulation games like Dwarf Fortress or Rimworld needing many thousands of moving bodies at once. Built for speed, it prioritizes performance over realistic physics, enabling 50,000+ bodies at 60 FPS when running as a server. This screenshot is 30,000 static bodies (🟥), 15,000 dynamic bodies (9000 moving (🟩) and 6000 only moving if collided against (🟦))
SKALE Physics is made for certain genres of games requiring massive numbers of bodies without realism, namely massive simulation games and multiplayer games. It achieves this by removing features simulation games rarely need, and using arcade-style physics rather than realistic simulations.
On a 2014 CPU (i5 4690K), in browser, it handles:
- 40,000 static boxes 🟥
- 10,000 dynamic boxes (6,000 moving 🟩, 4,000 sleeping 🟦)
- 60 FPS in the browser, with even better performance on servers (rendering is the bottleneck).
SKALE Physics includes:
| Feature | Description |
|---|---|
| High Performance | Fastest JavaScript physics engine, outperforming Box2D WASM, Matter.js, and Phaser Arcade Physics. |
| Collision Detection | AABB/Circle collisions only for maximum speed (no SAT). |
| Layers | Define which bodies collide with each other using collision and layer masks. |
| Body Sleeping | Optimizes performance by putting non-moving bodies to sleep. |
| Triggers | Support for trigger bodies. |
| Optimized RBush | Optimized RBush implementation, 10% faster than RBush. |
| Broadphase Padding | Significant optimization for collision detection. |
| Physics Properties | Mass, bounce, damping, velocity, acceleration, impulse. |
| World Bounds | Bodies can't leave the defined world boundaries. |
| Wall Sliding | Smooth sliding along walls. |
| Data-Oriented Design | Optimized for speed with minimal overhead. |
| Multithreading | Each map can have its own "Physics World" on a separate thread for multiplayer games. |
| Body Interactions | Bodies can push or impart forces on each other. |
The library is in alpha and lacks three features for completion:
- Raycasting
- Circle Colliders
- Collision/Trigger Callbacks
It works great for games that don’t require these features, but it could use a more comprehensive API.
SKALE Physics is designed for:
- Massive simulation games needing many thousands of bodies (e.g., Dwarf Fortress, Rimworld).
- Multiplayer games requiring very high NPC/player counts across many maps (multithreaded physics worlds per map).
- Browser or server environments, with superior performance on servers due to browser rendering bottlenecks.
It sacrifices features like joints, constraints, stable stacking, and compound colliders (although I'm considering compound colliders) for speed, as these are rarely used in the type of massive simulation games this physics engine was made for.
In a way this library is as if you wanted 2D RPG movement in your game then later decided you want physics just in case.
| Environment | Static Bodies | Dynamic Bodies | FPS | Hardware |
|---|---|---|---|---|
| Server | 40,000 | 20,000 (12,000 moving, 8,000 sleeping) | 62 | i5 4690K (2014) |
| Browser | 20,000 | 10,000 (6,000 moving, 4,000 sleeping) | 60 | i5 4690K (2014) |