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Particles

Introduction¶

Particle uses its own lightweight physics system, and can interact only with its Emitter's bounds and zones. Built-in game object of phaser.

Author: Richard Davey

Usage¶

Load texture¶

scene.load.image(key, url);

Reference: load image

Add particle¶

Create a particle manager

var particles = scene.add.particles(key);

Create particle manager and emitters

var particles = scene.add.particles(key, [
    emitterConfig0,
    emitterConfig1,
    // ...
]);

or

var particles = scene.make.particles({
    key: key,
    // origin: {x: 0.5, y: 0.5},
    add: true,
    emitters: [
        emitterConfig0,
        emitterConfig1,
        // ...
    ]
});

Create a particle emitter

var emitter = particles.createEmitter({
    // **basic properties of particles**
    // **initial position**
    // x: 0,             // { min, max }, or { min, max, steps }
    // y: 0,             // { min, max }, or { min, max, steps }
    // follow: null,
    // followOffset: {
    //    x: 0,
    //    y: 0
    // },
    // **emit zone**
    // emitZone: {
    //     type: 'random',    // 'random', or 'edge'
    //     source: geom,      // Geom like Circle, or a Path or Curve
    //     **type = edge**
    //     quantity: 1,
    //     stepRate: 0,
    //     yoyo: false,
    //     seamless: true
    // },

    // **target position**
    // moveToX:          // { min, max }, or { min, max, steps }
    // moveToY:          // { min, max }, or { min, max, steps }
    // **death zone**
    // deathZone: {
    //      type: 'onEnter',  // 'onEnter', or 'onLeave'
    //      source: geom      // Geom like Circle or Rect that supports a 'contains' function
    // }

    // **angle**
    // radial: true,
    // angle: { min: 0, max: 360 },  // { start, end, steps }

    // **scale**
    // scale: 1,             // { start, end },
    // scaleX: 1,
    // scaleY: 1,

    // **render**
    // frame:                // one or more texture frames, or a configuration object.
    // alpha: 1,             // { min, max }
    // visible: true,
    // tint: 0xffffffff,     // a number 0xfffffff, or an array [ 0xffff00, 0xff0000, 0x00ff00, 0x0000ff ]
    // blendMode: 'NORMAL',  // Phaser.BlendModes

    // delay: 0,
    // lifespan: 1000,       // { min, max }, or { min, max, steps }

    // **physics**
    // speed:                // { min, max }, or { min, max, steps }
    // speedX:               // { min, max }, or { min, max, steps }
    // speedY:               // { min, max }, or { min, max, steps }
    // gravityX:
    // gravityY:
    // accelerationX:
    // accelerationY:
    // maxVelocityX: 10000,
    // maxVelocityY: 10000,

    // **bounce**
    // bounce: 0,
    // bounds: nul,           // Phaser.Geom.Rectangle, or { x, y, width, height }
    // collideBottom: true,
    // collideTop: true,
    // collideLeft: true,
    // collideRight : true,

    // **callback**
    // emitCallback: null,
    // emitCallbackScope: null,
    // deathCallback: null,
    // deathCallbackScope: null,

    // **custom particle**
    // particleClass: Phaser.GameObjects.Particles.Particle

    // **emitter**
    // name: '',
    // on: true,          // set false to stop emitter
    // active: true,      // set false to pause emitter and particles
    // frequency: 0,      // -1 for exploding emitter
    // quantity: 1,       // { min, max }
    // maxParticles: 0,
    // reserve: 0,
    // rotate: 0,         // { start, end }, or { start, end, ease }
    // timeScale: 1,

});

Format of value
- {min, max} : Pick a random value between min and max
- {start, end} : Pick values incremented continuously across a range. (ease='Linear')
  - {start, end, ease}
  - {start, end, ease, easeParams}
- {start, end, steps} : Pick values incremented by steps across a range.
- {start, end, random}
  - random: true or false
- {random:[start, end]} : Pick a random number between start and and.
- {min, max, steps} : Pick values between min to max, with steps.
- {onEmit: function(particle, key, t, value) {return value}} : Get return value from a function invoking.
on : Controls if the emitter is currently emitting a particle flow (when frequency >= 0). Already alive particles will continue to update until they expire.
active : Whether this emitter updates itself and its particles.
frequency
- 0 : One particle flow cycle for each logic update (the maximum flow frequency).
- > 0 : The time interval between particle flow cycles in ms.
- -1 : Exploding emitter.
maxParticles
- 0 : Unlimited.
- > 0 : Hard limit the amount of particle objects.
frames : One or more texture frames, or a configuration object.
- String or number value
- Array of string or number value
- Configuration object :
```
{
    frames: [],
    cycle: false,
    quantity: 1
}
```

emitZone :

Emit zone

{
    type: 'random',
    source: geom,
}

Emit edge

{
    type: 'edge',
    source: curve,

    quantity: 1,
    stepRate: 0,
    yoyo: false,
    seamless: true
}

deathZone

{
    type: 'onEnter',
    source: geom
}

lifespan : The lifespan of emitted particles, in ms.
- Infinity : Immortal particle.
reserve : Creates specified number of inactive particles and adds them to this emitter's pool.
name : The name of this Particle Emitter.
- Get emitter by name
```
var emitter = particles.emitters.getByName(name);
```

Emit zone¶

emitter.setEmitZone({
    type: 'random',
    source: geom,
});

source : Geom like Circle, Ellipse, Rectangle,Triangle, Polygon, BitmapZone, or Path or Curve, which has getRandomPoint(point) method

Custom zone

{
    getRandomPoint: function(point) {
        // point.x = ...
        // point.y = ...
        return point;
    }
}

Zone source¶

Get
```
var source = emitter.emitZone.source;
```

Clear zone¶

emitter.setEmitZone();

Emit edge¶

emitter.setEmitZone({
    type: 'edge',
    source: curve,

    quantity: 1,
    stepRate: 0,
    yoyo: false,
    seamless: true
});

source : Geom like Circle, Ellipse, Rectangle,Triangle, Polygon, or Path or Curve, which has getPoints(quantity, stepRate) method

Custom edge

{
    getPoints: function(quantity, stepRate) {
        // output = [point0, point1, ...];  // point: Phaser.Math.Vector2, or {x, y}
        return output;
    }
}

quantity : The number of particles to place on the source edge. Set to 0 to use stepRate instead.
stepRate : The distance between each particle. When set, quantity is implied and should be set to 0.
yoyo : Whether particles are placed from start to end and then end to start. Default is false.
seamless : Whether one endpoint will be removed if it's identical to the other. Default is true.

quantity or stepRate

Any geometry like circle, ellipse, kine, polygon, rectangle, triangle source has quantity, or stepRate
Curve source has quantity, or stepRate
Path source only has quantity

Curve source¶

Get curve source
```
var source = emitter.emitZone.source;
```
Update points of curve source
```
emitter.emitZone.updateSource();
```
Set source to another curve, also update points
```
emitter.emitZone.changeSource(curve);
```

Clear edge zone¶

emitter.setEmitZone();

Death zone¶

emitter.setDeathZone({
     type: 'onEnter',
     source: geom
});

type : 'onEnter' or 'onLeave'

source : Geom like Circle, Ellipse, Rectangle,Triangle, Polygon

Custom source :

{
    contains: function (x, y) {
        // ...
        return bool;
    }
}

Zone source¶

Get
```
var source = emitter.deathZone.source;
```

Clear zone¶

emitter.setDeathZone();

Control¶

Start
```
emitter.start();  // set `on` to true
```
Stop
```
emitter.stop();   // set `on` to false
```

Pause

emitter.pause();  // set `active` to false

Resume

emitter.resume();  // set `active` to true

Explode
```
emitter.explode(count, x, y);
```

Emit

emitter.emitParticleAt(x, y, count);

or

emitter.emitParticle(count, x, y);

Kill all alive particles
```
emitter.killAll()
```

Properties¶

emitter.fromJSON(config);

Position¶

Emitter

Position
```
emitter.setPosition(x, y);
```

Follow

Start

emitter.startFollow(target);
// emitter.startFollow(target, offsetX, offsetY, trackVisible);

trackVisible : Whether the emitter's visible state will track the target's visible state.

Stop
```
emitter.stopFollow();
```

All emitters

particles.setPosition(x, y);

or

particles.x = x;
particles.y = y;

Rotation¶

Emitter

emitter.setRadial(bool);   // set true to emit particles in all directions between angle min and max
emitter.setAngle(value);

All emitters

particles.setAngle(angle); // angle in degrees
// particles.setRotation(angle); // angle in radians

or

particles.angle = angle;
// particles.rotation = angle;

Scale¶

Emitter

emitter.setScale(value);

or

emitter.setScaleX(value);
emitter.setScaleY(value);

All emitters

particles.setScale(value);
// particles.setScale(x, y);

or

particles.scaleX = scaleX;
particles.scaleY = scaleY;

Render¶

Frame
```
emitter.setFrame(frames);  // pickRandom = true, quantity = 1
emitter.setFrame(frames, pickRandom, quantity);
```
- frames : One or more texture frames, or a configuration object.
  - String or number value
  - Array of string or number value
  - Configuration object :
```
{
    frames: [],
    cycle: false,
    quantity: 1
}
```
- pickRandom : Whether frames should be assigned at random from frames.
- quantity : The number of consecutive particles that will receive each frame.

Alpha

emitter.setAlpha(value);   // value: 0 ~ 1

Visible

emitter.setVisible(visible);  // visible: true/false

Blend mode

emitter.setBlendMode(mode);  // Phaser.BlendModes

Physics¶

Speed

emitter.setSpeed(value);

or

emitter.setSpeedX(value);
emitter.setSpeedY(value);

Gravity

emitter.setGravity(x, y);

or

emitter.setGravityX(value);
emitter.setGravityY(value);

Bounds

emitter.setBounds(x, y, width, height);

or

emitter.setBounds(rect);

rect : Phaser.Geom.Rectangle, or { x, y, width, height }

Time¶

Lifespan

emitter.setLifespan(value);  // time in ms

Frequency
```
emitter.setFrequency(frequency, quantity);
```
- frequency : The time interval (>= 0) of each flow cycle, in ms; or -1 to put the emitter in explosion mode.
- quantity : The number of particles to release at each flow cycle or explosion.

Quantity¶

emitter.setQuantity(quantity);

Particles¶

Hard limit the amount of particle objects
```
var count = emitter.maxParticles;
```
- Whether this emitter is at its limit
```
var atLimit = emitter.atLimit();
```

Alive (active) particles

Amount of alive particles

var count = emitter.getAliveParticleCount();

Add callback for newly emitted particle

var callback = function(particle, emitter) { /* ... */ }
emitter.onParticleEmit(callback, context);

Clear callback
```
emitter.onParticleEmit();
```

For each alive particle

var callback = function(particle, emitter) { /* ... */ }
emitter.forEachAlive(callback, context);

Dead (inactive) particles

Amount of dead particles

var count = emitter.getDeadParticleCount();

Add callback for each particle death

var callback = function(particle, emitter) { /* ... */ }
emitter.onParticleDeath(callback, context);

Clear callback
```
emitter.onParticleDeath();
```

For each dead particle

var callback = function(particle, emitter) { /* ... */ }
emitter.forEachDead(callback, context);

Add dead particles into pool
```
emitter.reserve(count);
```

Total (alive + dead) number of particles

var count = emitter.getParticleCount();

Custom particle class

class MyParticle extends Phaser.GameObjects.Particles.Particle {
    constructor (emitter) {
        super(emitter);
        /* ... */
    }

    update (delta, step, processors) {
        super.update(delta, step, processors);
        /* ... */
    }
}

Properties¶

emitter
frame
x, y
angle (degree), rotation (radians)
alpha, tint, color
velocityX, velocityY
accelerationX, accelerationY
maxVelocityX, maxVelocityY
bounce
scaleX, scaleY
life, lifeCurrent, lifeT

Gravity well¶

Create a gravity well

var well = particles.createGravityWell(x, y);
//var well = particles.createGravityWell(x, y, power, epsilon, gravity);

or

var well = particles.createGravityWell({
    // x: 0,
    // y: 0,
    // power: 0,
    // epsilon: 100,
    // gravity: 50
});

Enable

Active
```
well.active = true;
```
Inactive
```
well.active = false;
```

Position
```
well.x = x;
well.y = y;
```
Gravity
```
well.gravity = value;
```
Power
```
well.power = value;
```

Custom gravity well

var well = {
    active: true,
    update: function(particle, delta) {
        // particle.velocityX = 
        // particle.velocityY =       
        // return dead;      
    }
}
particles.addGravityWell(well);

Return true to kill particle.

Particles manager¶

Fire all emitters¶

particles.emitParticleAt(x, y);
// particles.emitParticleAt(x, y, count);

Z index of emitters¶

Z index of emitters is the same as particles.emitters (an array).

Bring an emitter to top

particles.emitters.bringToTop(emitter);

Send an emitter to bottom

particles.emitters.sendToBack(emitter);

Move an emitter up
```
particles.emitters.moveUp(emitter);
```
Move an emitter down
```
particles.emitters.moveDown(emitter);
```

Move an emitter to index

particles.emitters.moveTo(emitter, index);

Reverse order
```
particles.emitters.reverse();
```
Shuffle order
```
particles.emitters.shuffle();
```

Swap 2 emitters

particles.emitters.swap(emitter0, emitter1);