liner_uniform_motion_eular.js

var vector = function(x, y){
  switch(arguments.length){
    case 0: x = 0;
    case 1: y = 0;
  }
  this.x = x;
  this.y = y;
};

var my_object = function(p, v){
  switch(arguments.length){
    case 0: p = new vector();
    case 1: v = new vector();
  }
  this.position = p;
  this.velocity = v;
};
my_object.prototype = {
  update: function(t){
    this.position.x += this.velocity.x * t;
    this.position.y += this.velocity.y * t;
  }
};

var world = function(){};
world.prototype = {
  time: 0,
  objects: [],
  append: function(o){
    this.objects.push(o);
  },
  update: function(t){
    var os = this.objects;
    for (k in os)
      os[k].update(t);
    this.time += t;
  },
  dump: function(){
    var r = '=== dump of world ===\n';
    r += 'time: ' + this.time + '[sec]\n';
    var os = this.objects;
    for (k in os){
      var o = os[k];
      r += 'os[' + k + 
        '] p(' + o.position.x + ', ' + o.position.y +
        ') v(' + o.velocity.x + ', ' + o.velocity.y +
        ')\n'
        ;
    }
    return r;
  },
};

var main = function(){
  var w;
  
  var initialize = function() {
    w = new world();
  
    var os = [
      new my_object(),
      new my_object(
        new vector(3,3)
      ),
      new my_object(
        new vector(0,0),
        new vector(1,2)
      ),
      new my_object(
        new vector(3.5,-4.0),
        new vector(1.1, 0.5)
      ),
      new my_object(
        new vector(-10.0      ,-10.0 ),
        new vector(  1.7320504,  1.41421356)
      ),
    ];
  
    for (k in os)
      w.append(os[k]);
  };
  
  var test = function() {
    console.log(w.dump());
    w.update(1.0);
    console.log(w.dump());
    w.update(2.0);
    console.log(w.dump());
    w.update(3.0);
    console.log(w.dump());
  };

  initialize();
  test();
};

main();

=== dump of world ===
time: 0[sec]
os[0] p(0, 0) v(0, 0)
os[1] p(3, 3) v(0, 0)
os[2] p(0, 0) v(1, 2)
os[3] p(3.5, -4) v(1.1, 0.5)
os[4] p(-10, -10) v(1.7320504, 1.41421356)

=== dump of world ===
time: 1[sec]
os[0] p(0, 0) v(0, 0)
os[1] p(3, 3) v(0, 0)
os[2] p(1, 2) v(1, 2)
os[3] p(4.6, -3.5) v(1.1, 0.5)
os[4] p(-8.2679496, -8.58578644) v(1.7320504, 1.41421356)

=== dump of world ===
time: 3[sec]
os[0] p(0, 0) v(0, 0)
os[1] p(3, 3) v(0, 0)
os[2] p(3, 6) v(1, 2)
os[3] p(6.8, -2.5) v(1.1, 0.5)
os[4] p(-4.803848799999999, -5.757359319999999) v(1.7320504, 1.41421356)

=== dump of world ===
time: 6[sec]
os[0] p(0, 0) v(0, 0)
os[1] p(3, 3) v(0, 0)
os[2] p(6, 12) v(1, 2)
os[3] p(10.1, -1) v(1.1, 0.5)
os[4] p(0.39230240000000105, -1.514718639999999) v(1.7320504, 1.41421356)