From 866f22a6371bbbeccf3723f3add475598f908902 Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop+git@gmail.com>
Date: Wed, 28 Jan 2009 23:47:46 +0000
Subject: [PATCH] added operator*(Vector,double) and operator/(Vector,double)
 to util/Vector; added lookAt() to util/Transform (needs testing)

git-svn-id: svn://anubis/fart/trunk@63 7f9b0f55-74a9-4bce-be96-3c2cd072584d
---
 util/Transform.cc | 23 +++++++++++++++++++++++
 util/Transform.h  |  3 +++
 util/Vector.cc    | 18 ++++++++++++++++++
 util/Vector.h     |  2 ++
 4 files changed, 46 insertions(+)

diff --git a/util/Transform.cc b/util/Transform.cc
index 20cdd49..514a4c7 100644
--- a/util/Transform.cc
+++ b/util/Transform.cc
@@ -13,6 +13,29 @@ Transform Transform::getInverse()
     return inv;
 }
 
+void Transform::lookAt(const Vector & eye,
+                       const Vector & focus,
+                       const Vector & up)
+{
+    Vector forward = focus - eye;
+    forward.normalize();
+    Vector up_projected_onto_forward = forward * (up % forward) / up.mag2();
+    Vector perpendicular_up = (up - up_projected_onto_forward).normalize();
+    Vector right = forward * perpendicular_up;
+    Matrix mult;
+    mult[0][0] = right[0];
+    mult[0][1] = right[1];
+    mult[0][2] = right[2];
+    mult[1][0] = forward[0];
+    mult[1][1] = forward[1];
+    mult[1][2] = forward[2];
+    mult[2][0] = perpendicular_up[0];
+    mult[2][1] = perpendicular_up[1];
+    mult[2][2] = perpendicular_up[2];
+    m_matrix *= mult;
+    translate(-eye[0], -eye[1], -eye[2]);
+}
+
 void Transform::translate(double x, double y, double z)
 {
     Matrix t = Matrix::identity();
diff --git a/util/Transform.h b/util/Transform.h
index fb1babc..39cdc23 100644
--- a/util/Transform.h
+++ b/util/Transform.h
@@ -12,6 +12,9 @@ class Transform
     public:
         Transform();
         Transform getInverse();
+        void lookAt(const Vector & eye,
+                    const Vector & focus,
+                    const Vector & up);
         void translate(double x, double y, double z);
         void rotate(double angle, double xv, double yv, double zv);
         void scale(double xs, double ys, double zs);
diff --git a/util/Vector.cc b/util/Vector.cc
index 6ed1a23..b2498a1 100644
--- a/util/Vector.cc
+++ b/util/Vector.cc
@@ -79,3 +79,21 @@ Vector operator-(const Vector & v1, const Vector & v2)
     result[2] = v1[2] - v2[2];
     return result;
 }
+
+Vector operator*(const Vector & v1, double scale)
+{
+    Vector result = v1;
+    result[0] *= scale;
+    result[1] *= scale;
+    result[2] *= scale;
+    return result;
+}
+
+Vector operator/(const Vector & v1, double scale)
+{
+    Vector result = v1;
+    result[0] /= scale;
+    result[1] /= scale;
+    result[2] /= scale;
+    return result;
+}
diff --git a/util/Vector.h b/util/Vector.h
index 3fb7009..1a5f0cc 100644
--- a/util/Vector.h
+++ b/util/Vector.h
@@ -24,5 +24,7 @@ double operator%(const Vector & v1, const Vector & v2);
 Vector operator*(const Vector & v1, const Vector & v2);
 Vector operator+(const Vector & v1, const Vector & v2);
 Vector operator-(const Vector & v1, const Vector & v2);
+Vector operator*(const Vector & v1, double scale);
+Vector operator/(const Vector & v1, double scale);
 
 #endif