From f5b359ced315eaf234ed6a72c4f53b2d05ae60d0 Mon Sep 17 00:00:00 2001
From: "Mr.doob" <info@mrdoob.com>
Date: Tue, 28 Jan 2014 20:13:57 +0100
Subject: [PATCH] Implemented @WestLangley Vector3.reflect() from #4340.

---
 src/math/Vector3.js | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/src/math/Vector3.js b/src/math/Vector3.js
index c2f7f9e0ff..9d88594af2 100644
--- a/src/math/Vector3.js
+++ b/src/math/Vector3.js
@@ -689,13 +689,14 @@ THREE.extend( THREE.Vector3.prototype, {
 
 	reflect: function () {
 
-		var v1 = new THREE.Vector3();
+		// reflect incident vector off plane orthogonal to normal
+		// normal is assumed to have unit length
 
-		return function ( vector ) {
+		var v1 = new THREE.Vector3();
 
-		    v1.copy( this ).projectOnVector( vector ).multiplyScalar( 2 );
+		return function ( normal ) {
 
-		    return this.subVectors( v1, this );
+			return this.sub( v1.copy( normal ).multiplyScalar( 2 * this.dot( normal ) ) );
 
 		}
 
-- 
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