shape-shifter/scripts/dot.js

S.Dot = function (x, y) {
  this.p = new S.Point({
    x: x,
    y: y,
    z: 5,
    a: 1,
    h: 0
  });

  this.e = 0.07;
  this.s = true;

  this.c = new S.Color(255, 255, 255, this.p.a);

  this.t = this.clone();
  this.q = [];
};

S.Dot.prototype = {
  clone: function () {
    return new S.Point({
      x: this.x,
      y: this.y,
      z: this.z,
      a: this.a,
      h: this.h
    });
  },

  _draw: function () {
    this.c.a = this.p.a;
    S.Drawing.drawCircle(this.p, this.c);
  },

  _moveTowards: function (n) {
    var details = this.distanceTo(n, true),
        dx = details[0],
        dy = details[1],
        d = details[2],
        e = this.e * d;

    if (this.p.h === -1) {
      this.p.x = n.x;
      this.p.y = n.y;
      return true;
    }

    if (d > 1) {
      this.p.x -= ((dx / d) * e);
      this.p.y -= ((dy / d) * e);
    } else {
      if (this.p.h > 0) {
        this.p.h--;
      } else {
        return true;
      }
    }

    return false;
  },

  _update: function () {
    var p,
        d;

    if (this._moveTowards(this.t)) {
      p = this.q.shift();

      if (p) {
        this.t.x = p.x || this.p.x;
        this.t.y = p.y || this.p.y;
        this.t.z = p.z || this.p.z;
        this.t.a = p.a || this.p.a;
        this.p.h = p.h || 0;
      } else {
        if (this.s) {
          this.p.x -= Math.sin(Math.random() * 3.142);
          this.p.y -= Math.sin(Math.random() * 3.142);
        } else {
          this.move(new S.Point({
            x: this.p.x + (Math.random() * 50) - 25,
            y: this.p.y + (Math.random() * 50) - 25,
          }));
        }
      }
    }

    d = this.p.a - this.t.a;
    this.p.a = Math.max(0.1, this.p.a - (d * 0.05));
    d = this.p.z - this.t.z;
    this.p.z = Math.max(1, this.p.z - (d * 0.05));
  },

  distanceTo: function (n, details) {
    var dx = this.p.x - n.x,
        dy = this.p.y - n.y,
        d = Math.sqrt(dx * dx + dy * dy);

    return details ? [dx, dy, d] : d;
  },

  move: function (p, avoidStatic) {
    if (!avoidStatic || (avoidStatic && this.distanceTo(p) > 1)) {
      this.q.push(p);
    }
  },

  render: function () {
    this._update();
    this._draw();
  }
};