Hierarchy Study

2-link arm

by oKLo

HTML

<div id="info">Hierarchy Study
  <br><br>
  2-link arm
</div>
<script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/r70/three.min.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;
var angle = 0;
var sun, earth;

init();
animate();

function makeLink() {
	oneLink = new THREE.Object3D();
  var mesh = new THREE.Mesh (new THREE.PlaneGeometry(15,5), new THREE.MeshBasicMaterial({wireframe:true}));
  oneLink.add (mesh);
  mesh.position.set (7.5,0,0);
  return oneLink;
}

function init() {
  scene = new THREE.Scene();

  camera = new THREE.OrthographicCamera(-50, 50, 50, -50, -10, 10);
  camera.position.z = 10;
  scene.add(camera);

  var gridXZ = new THREE.GridHelper(50, 10);
  gridXZ.setColors(new THREE.Color(0xff00ff), new THREE.Color(0xffffff));
  gridXZ.rotation.x = Math.PI / 2;
  scene.add(gridXZ);

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

  document.body.appendChild(renderer.domElement);
  window.addEventListener('resize', onWindowResize, false);
	///////////////////////////////////////////////////////////////
	var oneLink = makeLink();
  link1 = oneLink.clone();
  link2 = oneLink.clone();
  
  scene.add (link1);
  link1.add (link2);
}

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


function animate() {
  this.sign = (this.sign === undefined) ? 1 : this.sign;
  angle += this.sign* 0.01;
	if (Math.abs(angle) > 0.5)
  	this.sign *= -1;
  
  var theta1 = angle;
  var theta2 = 2*angle;
  link1.rotation.z = theta1;
  link2.rotation.z = theta2;
  link2.position.set (15,0,0);
	  
  requestAnimationFrame(animate);
  renderer.render(scene, camera);
}