From d4413d7f58ffae57b2486409d9836d6a20b873c0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Einar=20Johan=20T=2E=20S=C3=B8ma=CC=8Aen?=
 <einarjohants@gmail.com>
Date: Tue, 31 Jan 2012 16:59:09 +0100
Subject: [PATCH] MATH: Add in the inverse functions from Portalib3d

---
 math/matrix4.cpp | 27 +++++++++++++++++++++++++++
 math/matrix4.h   |  4 +++-
 2 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/math/matrix4.cpp b/math/matrix4.cpp
index ba2e21d887a..572580f54f7 100644
--- a/math/matrix4.cpp
+++ b/math/matrix4.cpp
@@ -66,5 +66,32 @@ void Matrix<4, 4>::translate(const Vector3d &vec) {
 	operator()(2, 3) += v.z();
 }
 
+// The following functions are adapted from Portalib3d, which no longer is 
+// available on the net, but was used in the iconoclast-project:
+// http://code.google.com/p/iconoclast/
+// Original copyright notice (license.txt was not supplied in iconoclast,
+// but should match our LGPL-license):
+// Author:	Brett Porter
+// Email: brettporter@yahoo.com
+// Website: http://rsn.gamedev.net/pl3d
+// Copyright (C)2000, 2001, Brett Porter. All Rights Reserved.
+// This source code is released under the LGPL. See license.txt for details.
+
+void Matrix<4, 4>::inverseTranslate(Vector3d *v) {
+	v->x() = v->x() - getValue(0, 3);
+	v->y() = v->y() - getValue(1, 3);
+	v->z() = v->z() - getValue(2, 3);
+}
+
+void Matrix<4, 4>::inverseRotate(Vector3d *v) {
+	Vector3d temp;
+	
+	temp.x() = v->x() * getValue(0, 0) + v->y() * getValue(1, 0) + v->z() * getValue(2, 0);
+	temp.y() = v->x() * getValue(0, 1) + v->y() * getValue(1, 1) + v->z() * getValue(2, 1);
+	temp.z() = v->x() * getValue(0, 2) + v->y() * getValue(1, 2) + v->z() * getValue(2, 2);
+	
+	*v = temp;
+}
+	
 } // end of namespace Math
 
diff --git a/math/matrix4.h b/math/matrix4.h
index 3dad7a5664b..e372facdadf 100644
--- a/math/matrix4.h
+++ b/math/matrix4.h
@@ -37,7 +37,9 @@ public:
 	Matrix(const MatrixBase<4, 4> &m);
 
 	void transform(Vector3d *v, bool translate) const;
-
+	void inverseTranslate(Vector3d *v);
+	void inverseRotate(Vector3d *v);
+	
 	Vector3d getPosition() const;
 	void setPosition(const Vector3d &v);