hw2p 222

threejs 2D template

by zx22516969

HTML

<div id="info">THREE.JS 2D Template
  <br/>Left & right click to draw line</div>
<script src="http://cdnjs.cloudflare.com/ajax/libs/three.js/r70/three.min.js"></script>

<!-- the following disable the regular right-button click -->
<script type="text/javascript">
  document.oncontextmenu = function() {
    return false;
  }

</script>

CSS

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

body {
  overflow: hidden;
}

JavaScript

var camera, scene, renderer;
var screenSize = 100;

var mouse = new THREE.Vector2();
var leftPt, rightPt; // Vector2

init();
animate();

function init() {

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

  document.body.appendChild(renderer.domElement);
  window.addEventListener('resize', onWindowResize, false);
  window.addEventListener('mousedown', onDocumentMouseDown, false);

  scene = new THREE.Scene();

  var halfSize = screenSize / 2;
  camera = new THREE.OrthographicCamera(-halfSize, halfSize, halfSize, -halfSize, -10, 10);
  camera.position.z = 10;

  // draw border
  var material = new THREE.LineBasicMaterial({
    color: 0x0000ff
  });

  var geometry = new THREE.Geometry();
  var borderSize = halfSize * 0.8;
  geometry.vertices.push(
    new THREE.Vector3(-borderSize, -borderSize, 0),
    new THREE.Vector3(borderSize, -borderSize, 0),
    new THREE.Vector3(borderSize, borderSize, 0),
    new THREE.Vector3(-borderSize, borderSize, 0),
    new THREE.Vector3(-borderSize, -borderSize, 0));

  var border = new THREE.Line(geometry, material);
  scene.add(border);
  
  leftPt = null;
  rightPt = null;
}

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

function onWindowResize() {
  camera.aspect = window.innerWidth / window.innerHeight;
  camera.updateProjectionMatrix();
  renderer.setSize(window.innerWidth, window.innerHeight);
}

function onDocumentMouseDown(event) {
  event.preventDefault();
  // Normalized Device Coordinate (NDC): [-1,1]x[-1,1]
  mouse.x = (event.clientX / window.innerWidth) * 2 - 1;
  mouse.y = -(event.clientY / window.innerHeight) * 2 + 1;

  console.log(mouse.x + ', ' + mouse.y);

  if (event.button === 0) { // left button
    leftPt = new THREE.Vector2(mouse.x * screenSize/2, mouse.y * screenSize/2);
    var mesh = new THREE.Mesh(new THREE.CircleGeometry(1, 10),
      new THREE.MeshBasicMaterial());
   ...