From afefc93fc6282a2a93714e12c6c363ba07789921 Mon Sep 17 00:00:00 2001
From: Robert Rouhani <robert.rouhani@gmail.com>
Date: Fri, 18 Jan 2013 15:13:36 -0800
Subject: [PATCH] Fixed bug in Matrix4.LookAt.

---
 Source/OpenTK/Math/Matrix4.cs | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/Source/OpenTK/Math/Matrix4.cs b/Source/OpenTK/Math/Matrix4.cs
index 78fd74a4..f27de106 100644
--- a/Source/OpenTK/Math/Matrix4.cs
+++ b/Source/OpenTK/Math/Matrix4.cs
@@ -806,13 +806,20 @@ namespace OpenTK
             float c = -(zFar + zNear) / (zFar - zNear);
             float d = -(2.0f * zFar * zNear) / (zFar - zNear);
 
-            result = Identity;
             result.Row0.X = x;
+            result.Row0.Y = 0;
+            result.Row0.Z = 0;
+            result.Row0.W = 0;
+            result.Row1.X = 0;
             result.Row1.Y = y;
+            result.Row1.Z = 0;
+            result.Row1.W = 0;
             result.Row2.X = a;
             result.Row2.Y = b;
             result.Row2.Z = c;
             result.Row2.W = -1;
+            result.Row3.X = 0;
+            result.Row3.Y = 0;
             result.Row3.Z = d;
             result.Row3.W = 0;
         }
@@ -1040,23 +1047,24 @@ namespace OpenTK
             Vector3 x = Vector3.Normalize(Vector3.Cross(up, z));
             Vector3 y = Vector3.Normalize(Vector3.Cross(z, x));
 
-            Matrix4 result = Identity;
+            Matrix4 result;
 
-            //rotation
             result.Row0.X = x.X;
             result.Row0.Y = y.X;
             result.Row0.Z = z.X;
+            result.Row0.W = 0;
             result.Row1.X = x.Y;
             result.Row1.Y = y.Y;
             result.Row1.Z = z.Y;
+            result.Row1.W = 0;
             result.Row2.X = x.Z;
             result.Row2.Y = y.Z;
             result.Row2.Z = z.Z;
-
-            //position
-            result.Row0.W = -eye.X;
-            result.Row1.W = -eye.Y;
-            result.Row2.W = -eye.Z;
+            result.Row2.W = 0;
+            result.Row3.X = -((x.X * eye.X) + (x.Y * eye.Y) + (x.Z * eye.Z));
+            result.Row3.Y = -((y.X * eye.X) + (y.Y * eye.Y) + (y.Z * eye.Z));
+            result.Row3.Z = -((z.X * eye.X) + (z.Y * eye.Y) + (z.Z * eye.Z));
+            result.Row3.W = 1;
 
             return result;
         }