From bdb648b84f5e0bbb442721ed899638de46f28e6d Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop+git@gmail.com>
Date: Fri, 23 Jan 2009 04:15:25 +0000
Subject: [PATCH] added transform_normal() to util/Transform

git-svn-id: svn://anubis/fart/trunk@34 7f9b0f55-74a9-4bce-be96-3c2cd072584d
---
 util/Transform.cc | 5 +++++
 util/Transform.h  | 1 +
 util/Vector.cc    | 3 ++-
 util/Vector.h     | 2 +-
 4 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/util/Transform.cc b/util/Transform.cc
index 962a52d..1ca90b3 100644
--- a/util/Transform.cc
+++ b/util/Transform.cc
@@ -64,6 +64,11 @@ Vector Transform::transform_direction(Transform & t, const Vector & v)
     return t.getMatrix() % v;
 }
 
+Vector Transform::transform_normal(Transform & t, const Vector & v)
+{
+    return (t.getMatrix() % v).normalize();
+}
+
 Ray Transform::transform_ray(Transform & t, const Ray & r)
 {
     Vector newPosition = t.getMatrix() * r.getOrigin();
diff --git a/util/Transform.h b/util/Transform.h
index 11af3be..d03e7d2 100644
--- a/util/Transform.h
+++ b/util/Transform.h
@@ -17,6 +17,7 @@ class Transform
         Matrix & getMatrix() { return m_matrix; }
         Vector transform_point(Transform & t, const Vector & v);
         Vector transform_direction(Transform & t, const Vector & v);
+        Vector transform_normal(Transform & t, const Vector & v);
         Ray transform_ray(Transform & t, const Ray & r);
 
     protected:
diff --git a/util/Vector.cc b/util/Vector.cc
index 2208d11..744214c 100644
--- a/util/Vector.cc
+++ b/util/Vector.cc
@@ -17,7 +17,7 @@ Vector::Vector(double x, double y, double z)
     m_array[2] = z;
 }
 
-void Vector::normalize()
+Vector & Vector::normalize()
 {
     double length = sqrt(m_array[0] * m_array[0]
                        + m_array[1] * m_array[1]
@@ -25,6 +25,7 @@ void Vector::normalize()
     m_array[0] /= length;
     m_array[1] /= length;
     m_array[2] /= length;
+    return *this;
 }
 
 std::ostream & operator<<(std::ostream & out, const Vector & v)
diff --git a/util/Vector.h b/util/Vector.h
index 0704d93..390e89c 100644
--- a/util/Vector.h
+++ b/util/Vector.h
@@ -11,7 +11,7 @@ class Vector
         Vector(double x, double y, double z);
         double & operator[](int idx) { return m_array[idx]; }
         double operator[](int idx) const { return m_array[idx]; }
-        void normalize();
+        Vector & normalize();
 
     private:
         double  m_array[3];