Particles

Particle System

Creating and controlling particle effects in Phaser 4 -- ParticleEmitter creation and configuration, emitter ops (value formats), gravity wells, emission and death zones, flow vs burst modes, following game objects, and particle callbacks.

Key source paths: src/gameobjects/particles/ Related skills: ../sprites-and-images/SKILL.md, ../loading-assets/SKILL.md

Quick Start

// In a Scene's create() method:

// Basic continuous emitter (flow mode)
const emitter = this.add.particles(400, 300, 'flares', {
    frame: 'red',
    speed: 200,
    lifespan: 2000,
    scale: { start: 1, end: 0 },
    alpha: { start: 1, end: 0 },
    gravityY: 150
});

// One-shot burst (explode mode)
const burst = this.add.particles(400, 300, 'flares', {
    frame: 'blue',
    speed: { min: 100, max: 300 },
    lifespan: 1000,
    scale: { start: 0.5, end: 0 },
    emitting: false   // don't auto-start
});
burst.explode(20);    // emit 20 particles at once

Core Concepts

ParticleEmitter

ParticleEmitter extends GameObject and is added directly to the display list. It is both a game object (positionable, scalable, maskable) and the emitter itself. There is no separate manager -- this.add.particles() returns a ParticleEmitter instance.

Factory signature:

this.add.particles(x, y, texture, config);
// x, y: world position (both optional, default 0)
// texture: string key or Texture instance
// config: ParticleEmitterConfig object (optional, can call setConfig later)

Mixins: AlphaSingle, BlendMode, Depth, Lighting, Mask, RenderNodes, ScrollFactor, Texture, Transform, Visible. So you can call setPosition(), setScale(), setDepth(), setBlendMode(), setMask(), setScrollFactor(), etc.

Particle

A lightweight object owned by its emitter. Key properties: x, y, velocityX/Y, accelerationX/Y, scaleX/Y, alpha, angle, rotation, tint, life (total ms), lifeCurrent (remaining ms), lifeT (0-1 normalized), bounce, delayCurrent, holdCurrent. Particles are pooled internally -- you never create them manually.

EmitterOp Value Formats

Most config properties (speed, scale, alpha, angle, x, y, etc.) accept flexible value formats:

x: 400                                        // static value
x: [100, 200, 300, 400]                       // random pick from array
x: { min: 100, max: 700 }                     // random float in range
x: { min: 100, max: 700, int: true }          // random integer
x: { random: [100, 700] }                     // random integer shorthand
scale: { start: 0, end: 1 }                   // ease over lifetime (default linear)
scale: { start: 0, end: 1, ease: 'bounce.out' }  // custom ease
scale: { start: 4, end: 0.5, random: true }   // random start, ease to end
x: { values: [50, 500, 200, 800], interpolation: 'catmull' }  // interpolation
x: { steps: 32, start: 0, end: 576 }          // stepped sequential
x: { steps: 32, start: 0, end: 576, yoyo: true }  // stepped with yoyo
x: {                                           // custom callbacks
    onEmit: (particle, key, t, value) => value,
    onUpdate: (particle, key, t, value) => value
}
x: (particle, key, t, value) => value + 50    // emit-time callback shorthand

Emit-only (no onUpdate): angle, delay, hold, lifespan, quantity, speedX, speedY. Emit + Update (support start/end, onUpdate): accelerationX/Y, alpha, bounce, maxVelocityX/Y, moveToX/Y, rotate, scaleX/Y, tint, x, y.

Flow vs Explode (Burst)

Flow mode (frequency >= 0): emits quantity particles every frequency ms. Default is frequency: 0 (every frame) with emitting: true.

Explode mode (frequency = -1): emits a batch all at once, then stops.

emitter.flow(100, 5);           // 5 particles every 100ms
emitter.flow(100, 5, 50);       // auto-stop after 50 total
emitter.explode(30, 200, 400);  // burst 30 at position
emitter.explode(30);            // burst at emitter position

Common Patterns

Scale, Alpha, and Color Over Lifetime

// Scale and alpha with custom easing
this.add.particles(400, 300, 'spark', {
    lifespan: 2000,
    speed: 100,
    scale: { start: 1, end: 0, ease: 'power2' },
    alpha: { start: 1, end: 0, ease: 'cubic.in' }
});

Color Interpolation

The color property interpolates through an array of colors over particle lifetime (overrides tint):

this.add.particles(400, 300, 'spark', {
    lifespan: 2000, speed: 100, scale: { start: 0.5, end: 0 },
    color: [0xfacc22, 0xf89800, 0xf83600, 0x9f0404], colorEase: 'quad.out'
});

Tinting Particles

this.add.particles(400, 300, 'spark', { tint: 0xff0000 });                           // static
this.add.particles(400, 300, 'spark', { tint: { start: 0xffffff, end: 0xff0000 } }); // over lifetime

Gravity Wells

A GravityWell applies inverse-square gravitational force, pulling (or repelling with negative power) particles toward a point.

const emitter = this.add.particles(400, 300, 'spark', {
    speed: 100, lifespan: 4000, scale: { start: 0.4, end: 0 }, quantity: 2
});

const well = emitter.createGravityWell({
    x: 400, y: 300, power: 2, epsilon: 100, gravity: 50
});

// Update at runtime
well.x = 300;
well.power = -1;  // negative = repel

// Or create manually and add
const well2 = new Phaser.GameObjects.Particles.GravityWell(500, 200, 3, 100, 50);
emitter.addParticleProcessor(well2);
emitter.removeParticleProcessor(well2);

Emission Zones (Random)

A RandomZone spawns particles at random positions within a shape. The source must have a getRandomPoint(point) method -- all Phaser geometry classes (Circle, Ellipse, Rectangle, Triangle, Polygon, Line) support this, or provide a custom source:

// Using built-in geometry
this.add.particles(400, 300, 'spark', {
    speed: 50, lifespan: 2000,
    emitZone: { type: 'random', source: new Phaser.Geom.Circle(0, 0, 100) }
});

// Custom source object (any object with getRandomPoint)
emitter.addEmitZone({
    type: 'random',
    source: {
        getRandomPoint: (point) => {
            const a = Math.random() * Math.PI * 2;
            point.x = Math.cos(a) * 100;
            point.y = Math.sin(a) * 50;
            return point;
        }
    }
});

Emission Zones (Edge)

An EdgeZone places particles sequentially along shape edges. The source must have a getPoints(quantity, stepRate) method. Curves, Paths, and all geometry shapes support this:

this.add.particles(400, 300, 'spark', {
    lifespan: 1500, speed: 20,
    emitZone: {
        type: 'edge',
        source: new Phaser.Geom.Circle(0, 0, 150),
        quantity: 48,     // number of points on edge (use 0 with stepRate instead)
        yoyo: false,      // reverse direction at ends
        seamless: true    // remove duplicate endpoint
    }
});

// Or add post-creation with any source that has getPoints
emitter.addEmitZone({ type: 'edge', source: geom, quantity: 50, yoyo: false, seamless: true });

Multiple emission zones: Pass an array to emitZone or call addEmitZone() multiple times. Zones iterate in sequence. The total property controls how many particles emit before rotating to the next zone (-1 = never rotate).

this.add.particles(400, 300, 'spark', {
    emitZone: [
        { type: 'random', source: new Phaser.Geom.Circle(0, 0, 50) },
        { type: 'random', source: new Phaser.Geom.Circle(200, 0, 50) }
    ]
});

Death Zones

A DeathZone kills particles when they enter (or leave) a region. The source must have a contains(x, y) method.

// Kill particles entering a rectangle
this.add.particles(400, 100, 'spark', {
    speed: 200, lifespan: 5000, gravityY: 100,
    deathZone: { type: 'onEnter', source: new Phaser.Geom.Rectangle(300, 400, 200, 50) }
});

// Kill particles leaving a circle (confine to area)
this.add.particles(400, 300, 'spark', {
    speed: 100, lifespan: 5000,
    deathZone: { type: 'onLeave', source: new Phaser.Geom.Circle(400, 300, 150) }
});

// Custom death zone source (any object with contains)
emitter.addDeathZone({
    type: 'onEnter',
    source: { contains: (x, y) => x > 600 && y > 400 }
});

Following a Game Object

const player = this.add.sprite(100, 100, 'player');
const emitter = this.add.particles(0, 0, 'spark', {
    speed: 50, lifespan: 800, scale: { start: 0.5, end: 0 }
});

emitter.startFollow(player);                       // follow position
emitter.startFollow(player, 10, -20);              // with offset
emitter.startFollow(player, 0, 0, true);           // track visibility too
emitter.stopFollow();

// Or via config:
this.add.particles(0, 0, 'spark', { follow: player, followOffset: { x: 0, y: -20 } });

Particle Callbacks

// Via config
const emitter = this.add.particles(400, 300, 'spark', {
    speed: 100, lifespan: 2000,
    emitCallback: (particle, emitter) => { /* on emit */ },
    deathCallback: (particle) => { /* on death */ }
});

// Or set after creation
emitter.onParticleEmit((particle, emitter) => { /* ... */ });
emitter.onParticleDeath((particle) => { /* ... */ });

// Iterate alive/dead particles
emitter.forEachAlive((particle, emitter) => { /* particle.x, particle.lifeT */ });

Duration, StopAfter, and Advance

// Auto-stop after 3 seconds (alive particles continue until they expire)
this.add.particles(400, 300, 'spark', { speed: 100, duration: 3000 });

// Emit exactly 50 particles then stop
this.add.particles(400, 300, 'spark', { speed: 100, stopAfter: 50 });

// Pre-warm: fast-forward 2 seconds so particles visible on first frame
this.add.particles(400, 300, 'spark', { speed: 100, lifespan: 2000, advance: 2000 });
// Or manually: emitter.fastForward(2000, 50);

Particle Bounds (Bounce)

this.add.particles(400, 300, 'spark', {
    speed: 200, lifespan: 5000, bounce: 0.8,
    bounds: { x: 100, y: 100, width: 600, height: 400 },
    collideLeft: true, collideRight: true, collideTop: true, collideBottom: true
});
// Or: emitter.addParticleBounds(100, 100, 600, 400);

Texture Frames and Animations

// Random frame per particle
this.add.particles(400, 300, 'flares', { frame: ['red', 'green', 'blue'] });

// Sequential frames cycling through with quantity per frame
this.add.particles(400, 300, 'flares', {
    frame: { frames: ['red', 'green', 'blue'], cycle: true, quantity: 4 }
});

// Particle animation (plays anim over particle lifetime)
this.add.particles(400, 300, 'explosion', { anim: 'explode_anim', lifespan: 1000 });

// Multiple anims, randomly assigned
this.add.particles(400, 300, 'sheet', {
    anim: { anims: ['fire', 'smoke'], cycle: false, quantity: 1 }
});

Sorting Particles

this.add.particles(400, 300, 'spark', { sortProperty: 'y', sortOrderAsc: true });
// Or: sortCallback: (a, b) => a.y - b.y

Custom Particle Processor

Extend ParticleProcessor to apply custom per-particle logic each frame. Implement update(particle, delta, step, t):

class WindProcessor extends Phaser.GameObjects.Particles.ParticleProcessor {
    constructor (windX, windY) {
        super(0, 0);
        this.windX = windX;
        this.windY = windY;
    }

    update (particle, delta, step, t) {
        particle.velocityX += this.windX * step;
        particle.velocityY += this.windY * step;
    }
}

emitter.addParticleProcessor(new WindProcessor(0.5, 0));

Custom Particle Class

Extend Particle and override update for per-particle behavior. Set via particleClass in config:

class TrailParticle extends Phaser.GameObjects.Particles.Particle {
    update (delta, step, processors) {
        const result = super.update(delta, step, processors);
        this.alpha = this.lifeT;  // custom: alpha matches life progress
        return result;  // must return true if particle is still alive
    }
}

this.add.particles(400, 300, 'spark', {
    particleClass: TrailParticle,
    speed: 100, lifespan: 2000
});

Configuration Reference

ParticleEmitterConfig -- Simple Properties

ParticleEmitterConfig -- EmitterOp Properties

All accept the flexible value formats described above.

E = emit-only, E+U = emit + update (supports start/end, onUpdate)

Zone Config Properties

Events

All events are emitted on the ParticleEmitter instance itself.

emitter.on('stop', (emitter) => { /* stopped emitting */ });
emitter.on('complete', (emitter) => { /* all particles dead */ });
emitter.on('deathzone', (emitter, particle, zone) => { /* ... */ });

API Quick Reference

ParticleEmitter Key Methods

Lifecycle: start(advance?, duration?), stop(kill?), pause(), resume(), flow(frequency, count?, stopAfter?), explode(count?, x?, y?), emitParticleAt(x?, y?, count?), emitParticle(count?, x?, y?), fastForward(time, delta?).

Config: setConfig(config), updateConfig(config).

Following: startFollow(target, offX?, offY?, trackVisible?), stopFollow().

Zones: addEmitZone(config), removeEmitZone(zone), clearEmitZones(), addDeathZone(config), removeDeathZone(zone), clearDeathZones().

Processors: createGravityWell(config), addParticleProcessor(processor), removeParticleProcessor(processor), getProcessors().

Bounds: addParticleBounds(x, y, w, h, collideL?, collideR?, collideT?, collideB?).

Callbacks/Iteration: onParticleEmit(cb, ctx?), onParticleDeath(cb, ctx?), killAll(), forEachAlive(cb, ctx?), forEachDead(cb, ctx?).

Counts: getAliveParticleCount(), getDeadParticleCount(), getParticleCount(), atLimit(), reserve(count).

Property setters: setParticleSpeed(x, y?), setParticleScale(x, y?), setParticleGravity(x, y), setParticleAlpha(value), setParticleTint(value), setParticleLifespan(value), setEmitterAngle(value), setQuantity(qty), setFrequency(freq, qty?), setRadial(value), setEmitterFrame(frames, random?, qty?), setAnim(anims, random?, qty?).

Sorting: setSortProperty(property, ascending?), setSortCallback(callback), depthSort().

Utility: getBounds(padding?, advance?, delta?, output?), overlap(target).

GravityWell

Constructor: new GravityWell(x, y, power, epsilon, gravity) or new GravityWell(config) where config is { x, y, power, epsilon, gravity }.

Gotchas

• No ParticleEmitterManager: Removed in v3.60. this.add.particles() returns a ParticleEmitter directly.
• speed vs speedX/speedY: speed sets speedX and deactivates speedY (radial). speedX/speedY switches to point mode (radial: false).
• scale vs scaleX/scaleY: scale applies to scaleX and deactivates scaleY. Use both for non-uniform scaling.
• color overrides tint: They are mutually exclusive; color (array) takes priority.
• moveToX/moveToY: Both must be set to activate. Overrides angle and speed.
• emitting vs active: emitting: false = no new particles but alive ones update. active: false = entire emitter frozen.
• stop vs complete: 'stop' fires when emission stops. 'complete' fires when the last alive particle dies.
• frequency: 0: Means emit every frame (max rate), not "never." Use emitting: false to prevent emission.
• frequency: -1: Puts the emitter in explode mode -- it will not flow automatically. Use explode() to emit bursts.
• hold freezes particle: After lifespan expires, hold keeps the particle visible and frozen for the specified ms before it dies. Useful for trail/lingering effects.
• advance fast-forwards: Pre-warms the emitter by simulating the given ms on creation, so particles are already visible on the first frame.
• reserve(count) pre-allocates: Call reserve() or set reserve in config to pre-create particle objects upfront, avoiding GC spikes during gameplay from on-demand allocation.
• Zone source methods: RandomZone needs getRandomPoint(point). EdgeZone needs getPoints(quantity, stepRate). DeathZone needs contains(x, y).
• Particle pool: maxParticles limits total objects (not alive count). Use maxAliveParticles for visible limit.
• Texture required: The emitter needs a valid texture key. Use frame config for multi-frame textures.

Source Files

See references/REFERENCE.md for the full source file map. Key entry points: src/gameobjects/particles/ParticleEmitter.js (main class), src/gameobjects/particles/Particle.js (individual particle), src/gameobjects/particles/zones/ (zone classes).