fieldkit/lib/physics/particle.js

Basic building blocks for computational design projects. Written in CoffeeScript for browser and server environments.

// Generated by CoffeeScript 1.6.3
(function() {
  var Particle, Particle2, Particle3, State, Vec2, Vec3, vector,
    __hasProp = {}.hasOwnProperty,
    __extends = function(child, parent) { for (var key in parent) { if (__hasProp.call(parent, key)) child[key] = parent[key]; } function ctor() { this.constructor = child; } ctor.prototype = parent.prototype; child.prototype = new ctor(); child.__super__ = parent.prototype; return child; };

  vector = require('../math/vector');

  Vec2 = vector.Vec2;

  Vec3 = vector.Vec3;

  State = {
    ALIVE: 0,
    LOCKED: 1,
    IDLE: 2,
    DEAD: 3
  };

  /*
  
    VerLer Particle Baseclass
  
    FIELD flavoured particle integrator.
    Supports Verlet-style integration for 'strict' relationships e.g. Springs + Constraints
    and also Euler-style continous force integration for smooth/ flowing behaviour e.g. Flocking
  */


  Particle = (function() {
    Particle.prototype.id = 0;

    Particle.prototype.state = State.ALIVE;

    Particle.prototype.age = 0;

    Particle.prototype.lifetime = -1;

    Particle.prototype.position = null;

    Particle.prototype.drag = 0.03;

    Particle.prototype.prev = null;

    Particle.prototype.force = null;

    Particle.prototype.velocity = null;

    function Particle(id) {
      this.id = id;
      this.size = 1;
      this.isLocked = false;
    }

    Particle.prototype.clearVelocity = function() {
      return this.prev.set(this.position);
    };

    Particle.prototype.scaleVelocity = function(amount) {
      return this.prev.lerp(this.position, 1.0 - amount);
    };

    Particle.prototype.setPosition = function(v) {
      this.position.set(v);
      return this.prev.set(v);
    };

    Particle.prototype.lock = function() {
      return this.state = State.LOCKED;
    };

    Particle.prototype.unlock = function() {
      return this.state = State.ALIVE;
    };

    Particle.prototype.die = function() {
      return this.state = State.DEAD;
    };

    Particle.prototype.idle = function() {
      return this.state = State.IDLE;
    };

    Particle.prototype.toString = function() {
      return "Particle(" + this.position + ")";
    };

    return Particle;

  })();

  /*
  
    3D VerLer Particle
  */


  Particle3 = (function(_super) {
    var tmp;

    __extends(Particle3, _super);

    tmp = new Vec3();

    function Particle3(id) {
      this.id = id;
      this.position = new Vec3();
      this.prev = new Vec3();
      this.force = new Vec3();
      this.velocity = new Vec3();
    }

    Particle3.prototype.update = function() {
      this.age++;
      if (this.state > State.ALIVE) {
        return;
      }
      if (this.lifetime > 0 && this.age === this.lifetime) {
        this.state = State.DEAD;
      }
      tmp.set(this.position);
      this.position.x += (this.position.x - this.prev.x) + this.force.x;
      this.position.y += (this.position.y - this.prev.y) + this.force.y;
      this.position.z += (this.position.z - this.prev.z) + this.force.z;
      this.prev.set(tmp);
      this.prev.lerp(this.position, this.drag);
      return this.force.zero();
    };

    Particle3.prototype.setPosition3 = function(x, y, z) {
      this.position.set3(x, y, z);
      return this.prev.set3(x, y, z);
    };

    return Particle3;

  })(Particle);

  /*
  
    2D VerLer Particle
  */


  Particle2 = (function(_super) {
    var tmp;

    __extends(Particle2, _super);

    tmp = new Vec2();

    function Particle2(id) {
      this.id = id;
      this.position = new Vec2();
      this.prev = new Vec2();
      this.force = new Vec2();
      this.velocity = new Vec2();
    }

    Particle2.prototype.update = function() {
      this.age++;
      if (this.state > State.ALIVE) {
        return;
      }
      if (this.lifetime > 0 && this.age === this.lifetime) {
        this.state = State.DEAD;
      }
      tmp.set(this.position);
      this.position.x += (this.position.x - this.prev.x) + this.force.x;
      this.position.y += (this.position.y - this.prev.y) + this.force.y;
      this.prev.set(tmp);
      this.prev.lerp(this.position, this.drag);
      return this.force.zero();
    };

    Particle2.prototype.setPosition2 = function(x, y) {
      this.position.set2(x, y);
      return this.prev.set2(x, y);
    };

    return Particle2;

  })(Particle);

  module.exports = {
    Particle: Particle,
    Particle2: Particle2,
    Particle3: Particle3,
    State: State
  };

}).call(this);