javascript programming
exa_10_physics3

function diff(v, w) {
  return {x:v.x-w.x, y:v.y-w.y};
}

function lenSq(v) {
  return v.x*v.x+v.y*v.y;
}

function distanceSq(v, w) {
  var delta = diff(v, w);
  return lenSq(delta);
}

function dot(v, w) {
  return v.x*w.x + v.y*w.y;
}

function mult(v, s) {
  return {x:v.x*s, y:v.y*s};
}

function Shell(pos,vel,radius) {
  this.pos = pos;
  this.vel = vel;
  this.radius = radius;
  this.mass = 1;
}

Shell.prototype = { updateAndDraw : updateAndDraw };

var g = -9.8;  // m/s^2
var shells = [];
var deg60 = Math.PI/3;
var muzVel = 50;
var gamma = 0.75;

function keyPressHandler(event) {
  if ( event.keyCode === " ".charCodeAt(0) ) {
    shells.push( new Shell({x:20,y:20}, {x:muzVel*Math.cos(deg60), y:muzVel*Math.sin(deg60)}, 10) );
  }
}

var canv, ctx;
var lastFrameTime;

function start() {
  canv = document.getElementById("canv");
  ctx = canv.getContext("2d");
  canv.addEventListener("keydown", keyPressHandler);
  requestAnimationFrame( update );
  lastFrameTime = new Date().getTime();
}

function update() {
  ctx.clearRect(0,0,canv.width,canv.height);
  var now = new Date().getTime();
  dt = (now - lastFrameTime)/1000;
  lastFrameTime = now;
  for (let shell of shells)
    shell.updateAndDraw(dt);
  requestAnimationFrame( update );
}
</script>
</head>
<body onload="start();">
<canvas id="canv" width="300" height="200" style="border:1px gray solid;" tabindex='1'></canvas>
</body>
</html>

Part 3

javascript programmingexa_10_physics3

javascript programming
exa_10_physics3