From e2d7d68a4056f82a17ba6ca53ed492bb7dd04d11 Mon Sep 17 00:00:00 2001
From: plouj <plouj@b8c14938-b733-429d-887c-d66ed1f8cd15>
Date: Tue, 15 Jan 2008 22:23:41 +0000
Subject: [PATCH] simplified vector_reflect_about_normal

git-svn-id: http://svn.plouj.com/repos/eraytracer@35 b8c14938-b733-429d-887c-d66ed1f8cd15
---
 raytracer.erl | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/raytracer.erl b/raytracer.erl
index 9fd68ae..7f72c8a 100644
--- a/raytracer.erl
+++ b/raytracer.erl
@@ -327,11 +327,11 @@ vector_neg(#vector{x=X, y=Y, z=Z}) ->
     #vector{x=-X, y=-Y, z=-Z}.
 
 vector_reflect_about_normal(Vector, Normal) ->
-    vector_sub(
+    vector_add(
       vector_scalar_mult(
 	Normal,
 	2*vector_dot_product(Normal, vector_neg(Vector))),
-      vector_neg(Vector)).
+      Vector).
 
 vector_rotate(V1, _V2) ->
     %TODO: implement using quaternions
-- 
2.11.4.GIT