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Particle Effects: CPU-Simulated Programmable Particle System
The s&box particle system is CPU-simulated (multithreaded) and fully programmable via components. You can emit particles manually, iterate and modify them at runtime, write custom controllers, and react to collisions.
Architecture
A particle effect is built from multiple components on a GameObject:
| Component | Role |
|---|---|
| ParticleEffect | Base effect. Holds particle list, ticks simulation. Configure max particles, lifetime, force, collision. |
| Renderer (e.g. ParticleSpriteRenderer) | Renders particles. Sprite renderer draws camera-facing quads. |
| Emitter | Defines spawn rate (burst or over time), shape, and start velocity. Optional if calling ParticleEffect.Emit manually. |
| Controllers | Custom components that modify particles each frame (color over lifetime, size curves, etc.) |
Manual Emission
You can skip built-in emitters and emit particles directly in code:
CSHARP
var effect = Components.Get<ParticleEffect>();
effect.Emit( new ParticleEffect.EmitParams
{
Position = WorldPosition,
Velocity = Vector3.Up * 100f
} );Key Design Decisions
- CPU simulation — enables full programmability and iteration over particles in C#
- Multithreaded — performance scales with cores despite being CPU-based
- Component-based — mix and match emitters, renderers, and controllers for flexibility
- Collision support — particles can collide with the world (optional feature on ParticleEffect)
Custom Controllers
Write a component implementing particle controller logic to create custom behaviors (attract to point, follow spline, react to game state). See the Custom Particle Controller documentation for the interface details.
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