Added THREE.ArrowHelper

src/extras/helpers/ArrowHelper.js

@@ -0,0 +1,60 @@
+/**
+ * @author WestLangley / https://github.com/WestLangley
+ * @author zz85 / https://github.com/zz85
+ */
+ 
+THREE.ArrowHelper = function ( origin, dir, length, hex ) {
+
+    THREE.Object3D.call( this );
+
+    var lineGeometry = new THREE.Geometry();
+    lineGeometry.vertices.push( new THREE.Vertex() );
+    lineGeometry.vertices.push( new THREE.Vertex( new THREE.Vector3( 0, 1, 0 ) ) );
+    
+    line = new THREE.Line( lineGeometry, new THREE.LineBasicMaterial( { color : hex } ) );
+    this.add( line );
+    
+    var coneGeometry = new THREE.CylinderGeometry( 0, 0.05, 0.25, 5, 1 );
+    
+    cone = new THREE.Mesh( coneGeometry, new THREE.MeshBasicMaterial( { color : hex } ) );
+    cone.position.set( 0, 1, 0 );
+    this.add( cone );
+    
+    this.position = origin;
+    
+    this.setDirection( dir );
+    
+    this.setLength( length );
+
+};
+
+THREE.ArrowHelper.prototype = new THREE.Object3D();
+THREE.ArrowHelper.prototype.constructor = THREE.ArrowHelper;
+
+THREE.ArrowHelper.prototype.setDirection = function( dir ) {
+
+    var axis = new THREE.Vector3( 0, 1, 0 ).crossSelf( dir );
+    
+    var radians = Math.acos( new THREE.Vector3( 0, 1, 0 ).dot( dir.clone().normalize() ) );
+    
+    this.matrix = new THREE.Matrix4().setRotationAxis( axis.normalize(), radians );
+            
+    this.rotation.getRotationFromMatrix( this.matrix, this.scale );
+    
+};
+
+THREE.ArrowHelper.prototype.setLength = function( length ) {
+
+    this.scale.set( length, length, length );
+
+};
+
+THREE.ArrowHelper.prototype.setColor = function( hex ) {
+
+    this.children[0].material.color.setHex( hex );
+    this.children[1].material.color.setHex( hex );
+
+};
+
+
+