cannon ball

by jmcjc5u

HTML

<div id="info">CannonBall
  <br/>Press SPACE tp fire</div>
<script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/84/three.min.js"></script>
<script src="https://threejs.org/examples/js/controls/OrbitControls.js">


</script>
<script src="https://jyunming-chen.github.io/tutsplus/js/KeyboardState.js"></script>

CSS

#info {
  position: absolute;
  top: 0px;
  width: 100%;
  padding: 10px;
  text-align: center;
  color: #ffff00
}

body {
  overflow: hidden;
}

JavaScript

var camera, scene, renderer, controls;
var keyboard = new KeyboardState();
var ball;
var pos, vel, force;

init();
start();
animate();

function init() {

	scene = new THREE.Scene();

  camera = new THREE.PerspectiveCamera(50, window.innerWidth / window.innerHeight, 1, 1000);
  camera.position.z = 500;
  scene.add(camera);

  var gridXZ = new THREE.GridHelper(400, 20, 'red', 'white');
  scene.add(gridXZ);

  renderer = new THREE.WebGLRenderer();
  renderer.setSize(window.innerWidth, window.innerHeight);
  renderer.setClearColor(0x888888);

  controls = new THREE.OrbitControls(camera, renderer.domElement);

  document.body.appendChild(renderer.domElement);
  ////////////////////////////////////////////////////////////////////////

  var geometry = new THREE.SphereGeometry(10, 20, 20);
  ball = new THREE.Mesh(geometry, new THREE.MeshNormalMaterial());
  scene.add(ball);

	//////////////
  pos = new THREE.Vector3();
  vel = new THREE.Vector3();
  force = new THREE.Vector3(0,-10,0);
  
}

function start () {
  stopped = false;
	//pos.set (200*Math.random()-100, 0, 200*Math.random()-100);
  vel.set (Math.random()-0.5, 1, Math.random()-0.5).normalize().multiplyScalar(35);
}

function update(dt) {
	vel.add (force.clone().multiplyScalar(dt));
  pos.add (vel.clone().multiplyScalar(dt));
  
  if (pos.y < 0) {
  	pos.y = 0;
    stopped = true;
  }
}

function animate() {
  controls.update();

  ball.position.copy (pos)
	if (stopped) {
    keyboard.update();
  	if (keyboard.down("space")) start();
  } else {
  	update (0.1);
  }
  
  requestAnimationFrame(animate);
  render();
}

function render() {
  renderer.render(scene, camera);
}

// important to add this 
// in jsfiddle!
window.focus();