Threejs - Ray cast against Math Line

by black strings

HTML

<script src="https://rawgit.com/mrdoob/three.js/dev/build/three.js"></script>
<script src="https://rawgit.com/mrdoob/three.js/dev/examples/js/controls/OrbitControls.js"></script>

CSS

/* fix mouse click offset errors when doing drags */
body {
  margin: 0;
}

JavaScript

class Main {
	constructor(){
    this.objects = []; 
    this.scene = new THREE.Scene();
    
    var width = window.innerWidth;
    var height = window.innerHeight * .75;
    this.camera = new THREE.PerspectiveCamera( 
    	35, width/height, 0.1, 1000 
    );
    
    this.renderer = new THREE.WebGLRenderer();
    
    
    this.renderer.setSize( width, height );
    this.renderer.setClearColor( 0xcccccc, 1 ); 
    
    // controls should set 2nd param or mouse move will be all over the main dom element
    // null on 2nd param, threejs will use the parent as the mouse click and prevent default
    this.controls = new THREE.OrbitControls(this.camera, this.renderer.domElement);
    
    // will turn off zooming while panning with right mouse click, false by default
    this.controls.screenSpacePanning = true;
    
    document.body.appendChild( this.renderer.domElement );
    this.scene.add(this.camera);

    
    this.setToFullOrbit(this.controls);
    this.camera.position.copy(new THREE.Vector3(10,10,10));
    // fix first frame render issue going invisible
    this.camera.lookAt(new THREE.Vector3(0,0,0));

    var axisHelper = new THREE.AxisHelper();
    this.scene.add(axisHelper);
    
    var grid = new THREE.GridHelper();
    this.scene.add(grid);

		this.createScene();

  }
  
  createScene(){
  
  		// the line sgement
  	var v1 = new THREE.Vector3(0,1,0);
    var v2 = new THREE.Vector3(9,1,0);
    
    // line visual helper
    var lineGeo = new THREE.Geometry();
    lineGeo.vertices.push(v1, v2);
    var line = new THREE.Line(lineGeo);
    this.scene.add(line);
    
   	// the math ray
    var ray = new THREE.Ray();
    var origin = new THREE.Vector3(2,-3,0);
    var direction = new THREE.Vector3(1,1,0);
		direction.normalize(); // must normalize ray direction vector or won't get desired result
    ray.set(origin, direction);
    
    // visually see the ray (does not draw an infinite line, only up to a defined length)
    var rayHelper = new...