proton-engine/src/behaviour/RandomDrift.js

Proton is a simple and powerful javascript particle animation engine.

import Vector2D from "../math/Vector2D";
import MathUtil from "../math/MathUtil";
import Behaviour from "./Behaviour";

export default class RandomDrift extends Behaviour {
  /**
   * @memberof! Proton#
   * @augments Behaviour
   * @constructor
   * @alias RandomDrift
   *
   * @param {Number} driftX 				X value of the new Vector2D
   * @param {Number} driftY  				Y value of the new Vector2D
   * @param {Number} delay 				How much delay the drift should have
   * @param {Number} [life=Infinity] 		this behaviour's life
   * @param {String} [easing=easeLinear] 	this behaviour's easing
   *
   * @property {Number} time The time of the drift
   * @property {String} name The Behaviour name
   */
  constructor(driftX, driftY, delay, life, easing) {
    super(life, easing);

    this.reset(driftX, driftY, delay);
    this.time = 0;
    this.name = "RandomDrift";
  }

  /**
   * Reset this behaviour's parameters
   *
   * @method reset
   * @memberof Proton#RandomDrift
   * @instance
   *
   * @param {Number} driftX 				X value of the new Vector2D
   * @param {Number} driftY  				Y value of the new Vector2D
   * @param {Number} delay 				How much delay the drift should have
   * @param {Number} [life=Infinity] 		this behaviour's life
   * @param {String} [easing=easeLinear] 	this behaviour's easing
   */
  reset(driftX, driftY, delay, life, easing) {
    this.panFoce = new Vector2D(driftX, driftY);
    this.panFoce = this.normalizeForce(this.panFoce);
    this.delay = delay;

    life && super.reset(life, easing);
  }

  initialize(particle) {
    particle.data.time = 0;
  }

  /**
   * Apply this behaviour for all particles every time
   *
   * @method applyBehaviour
   * @memberof Proton#RandomDrift
   * @instance
   *
   * @param {Particle} particle
   * @param {Number} 			time the integrate time 1/ms
   * @param {Int} 			index the particle index
   */
  applyBehaviour(particle, time, index) {
    this.calculate(particle, time, index);
    particle.data.time += time;

    if (particle.data.time >= this.delay) {
      particle.a.addXY(
        MathUtil.randomAToB(-this.panFoce.x, this.panFoce.x),
        MathUtil.randomAToB(-this.panFoce.y, this.panFoce.y)
      );

      particle.data.time = 0;
    }
  }
}