particles-lifecycle

Particle Lifecycle

Manage particle birth, life, death, and rebirth for continuous effects.

Quick Start

interface Particle {
  position: THREE.Vector3;
  velocity: THREE.Vector3;
  life: number;      // Current life (decrements)
  maxLife: number;   // Starting life
  alive: boolean;
}

// Update loop
for (const p of particles) {
  if (!p.alive) continue;
  
  p.life -= delta;
  if (p.life <= 0) {
    p.alive = false;
    continue;
  }
  
  // Age factor (0 at birth, 1 at death)
  const age = 1 - p.life / p.maxLife;
  
  // Update position, apply fade, etc.
}

Emission Patterns

Continuous Emission

class ContinuousEmitter {
  private accumulator = 0;
  
  emit(
    particles: Particle[],
    rate: number,      // Particles per second
    delta: number,
    spawnFn: () => Particle
  ) {
    this.accumulator += rate * delta;
    
    while (this.accumulator >= 1) {
      this.accumulator -= 1;
      
      // Find dead particle to reuse
      const dead = particles.find(p => !p.alive);
      if (dead) {
        Object.assign(dead, spawnFn());
        dead.alive = true;
      }
    }
  }
}

// Usage
const emitter = new ContinuousEmitter();

useFrame((_, delta) => {
  emitter.emit(particles, 100, delta, () => ({
    position: new THREE.Vector3(0, 0, 0),
    velocity: new THREE.Vector3(
      (Math.random() - 0.5) * 2,
      Math.random() * 5,
      (Math.random() - 0.5) * 2
    ),
    life: 2 + Math.random(),
    maxLife: 2 + Math.random(),
    alive: true
  }));
});

Burst Emission

function emitBurst(
  particles: Particle[],
  count: number,
  origin: THREE.Vector3,
  speed: number,
  lifeRange: [number, number]
) {
  let emitted = 0;
  
  for (const p of particles) {
    if (emitted >= count) break;
    if (p.alive) continue;
    
    // Random direction on sphere
    const theta = Math.random() * Math.PI * 2;
    const phi = Math.acos(2 * Math.random() - 1);
    
    const dir = new THREE.Vector3(
      Math.sin(phi) * Math.cos(theta),
      Math.sin(phi) * Math.sin(theta),
      Math.cos(phi)
    );
    
    p.position.copy(origin);
    p.velocity.copy(dir).multiplyScalar(speed * (0.5 + Math.random()));
    p.maxLife = lifeRange[0] + Math.random() * (lifeRange[1] - lifeRange[0]);
    p.life = p.maxLife;
    p.alive = true;
    
    emitted++;
  }
  
  return emitted;
}