three.tdl.particle.system/src/js/trail.js

GPU based particle system for three.js. Heavily based on tdl library (https://github.com/greggman/tdl)

// source: https://github.com/greggman/tdl/blob/master/tdl/particles.js
// ported to three.js by fazeaction

import { ParticleEmitter } from './emitter.js'

class Trail extends ParticleEmitter {
	constructor( particleSystem, maxParticles, parameters, opt_texture, opt_perParticleParamSetter, opt_clock )	{
		super(particleSystem, opt_texture, opt_clock);

		this.allocateParticles_(maxParticles, parameters);
		this.validateParameters(parameters);

		this.parameters = parameters;
		this.perParticleParamSetter = opt_perParticleParamSetter;
		this.birthIndex_ = 0;
		this.maxParticles_ = maxParticles;
	}

	birthParticles ( position ) {

		var numParticles = this.parameters.numParticles;
		this.parameters.startTime = this.timeSource_();
		this.parameters.position = position;

		while ( this.birthIndex_ + numParticles >= this.maxParticles_ ) {

			var numParticlesToEnd = this.maxParticles_ - this.birthIndex_;

			this.createParticles_( this.birthIndex_, numParticlesToEnd,	this.parameters, this.perParticleParamSetter );
			numParticles -= numParticlesToEnd;

			this.birthIndex_ = 0;

		}

		this.createParticles_( this.birthIndex_, numParticles, this.parameters, this.perParticleParamSetter );

		if ( this.birthIndex_ === 0 ) {

			this.particleSystem.scene.add( this );

		}

		this.birthIndex_ += numParticles;


	}

}

export { Trail }