Method update

packages/melonjs/src/particles/emitter.ts:278–352

* @ignore

(dt: number)

	 * @ignore
	 */
	override update(dt: number): boolean {
		// frame-skip: only do the bookkeeping when actually configured.
		// Defaults to 0 (every frame), and that path is the hot one.
		if (this.settings.framesToSkip > 0) {
			if (++this._updateCount > this.settings.framesToSkip) {
				this._updateCount = 0;
			}
			if (this._updateCount > 0) {
				this._dt += dt;
				return this.isDirty;
			}
			dt += this._dt;
			this._dt = 0;
		}

		// Update particles. `super.update(dt)` walks every child
		// (each Particle) through Container.update — visibility check,
		// per-particle `update(dt)`, etc. CRITICAL: assign it to a
		// local first, then OR into `this.isDirty`. Writing this as
		// `this.isDirty = this.isDirty || super.update(dt)` would
		// short-circuit when `isDirty` is already true (very common),
		// silently skipping the whole child walk — particles would
		// keep `inViewport = false` and never draw.
		const childrenDirty = super.update(dt);
		this.isDirty = this.isDirty || childrenDirty;

		// Launch new particles, if emitter is Stream
		if (this._enabled && this._stream) {
			// Check if the emitter has duration set
			if (this._durationTimer !== Infinity) {
				this._durationTimer -= dt;

				if (this._durationTimer <= 0) {
					this.stopStream();
					return this.isDirty;
				}
			}

			// Increase the emitter launcher timer
			this._frequencyTimer += dt;

			// Check for new particles launch
			const particlesCount = this.getChildren().length;
			if (
				particlesCount < this.settings.totalParticles &&
				this._frequencyTimer >= this.settings.frequency
			) {
				this.addParticles(
					Math.min(
						this.settings.maxParticles,
						this.settings.totalParticles - particlesCount,
					),
				);
				this._frequencyTimer = 0;
				this.isDirty = true;
			}
		}