mwg API
    Preparing search index...

    Class ParticleEmitter

    A pooled particle emitter: sparks off a sword hit, dust under a footstep, rain over a map.

    Pooled rather than allocating per particle, because this is the one primitive in the framework that can be asked to create and discard thousands of short-lived things per second, and a garbage collector pause is exactly the frame-time cost this project's own performance priority cares about. The pool is allocated once at max and reused forever after; asking for more particles than that while max are already alive drops the request rather than growing, so a runaway emitter degrades visibly instead of eating memory.

    Every random draw goes through mwg/core's seeded Random, so a replayed or seeded run produces the same spray, rather than particles being the one thing on screen that a deterministic replay cannot reproduce.

    import { ParticleEmitter, type Texture2D } from '@datamoc/mwg/two-d/render';

    declare const sparkTexture: Texture2D;

    const sparks = new ParticleEmitter({
    	texture: sparkTexture,
    	max: 64,
    	life: [0.2, 0.4],
    	speed: [80, 160],
    	gravity: { x: 0, y: 300 },
    	scale: [1, 0.2],
    	alpha: [1, 0],
    });
    sparks.x = 100;
    sparks.y = 60;

    sparks.burst(12); // a sword hit: 12 particles at once, fewer if the pool is nearly full
    sparks.update(1 / 60); // steps physics and, since a texture was given, the sprites too
    console.log(sparks.activeCount); // 12 - still alive right after the burst

    Hierarchy

    • Container
      • ParticleEmitter
    Index
    constructor
    activeCount attachedTo isEmitting particles
    attach burst clear detach start stop update

    • Follows target, repositioning on every update tick and every burst(), plus once right now so the position is fresh before the first tick. A second attach replaces the first; detach() stops following and keeps the last position. A destroyed Container target cannot move again, so it auto-detaches (thunk targets are read unconditionally - their liveness is the caller's).

      Parameters

      Returns void

      import { ParticleEmitter } from '@datamoc/mwg/two-d/render';

      const aura = new ParticleEmitter({ rate: 20 });
      const hero = { x: 100, y: 200 };
      aura.attach(() => hero, { offsetY: -10 });
      aura.start();
      aura.update(1 / 60);
      aura.detach();

    • Emits count particles at once - a hit spark, an explosion.

      Parameters

      • count: number
      • at: { tint?: number; x?: number; y?: number } = {}

        where this burst happens and what colour it is, in the emitter's parent space, instead of the emitter's own position and tint - one emitter can then throw sparks of a different colour from each broken part without being moved or duplicated.

      Returns number

      how many were actually emitted, which is fewer than asked when the pool is full

    Settings
    Member Visibility

    On This Page
    Constructors
    Accessors
    Methods