From 7e4bdad41a973ba8e0cf439b545d91e4a3cbfd94 Mon Sep 17 00:00:00 2001
From: Latif Khalifa <latifer@streamgrid.net>
Date: Fri, 27 Jun 2014 11:15:54 +0200
Subject: [PATCH] Better hashcodes for Vectors and Vertices

---
 OpenMetaverse/Rendering/Rendering.cs | 32 +++++++++++++++++++++++++++-
 OpenMetaverseTypes/Vector2.cs        |  4 +++-
 OpenMetaverseTypes/Vector3.cs        |  5 ++++-
 3 files changed, 38 insertions(+), 3 deletions(-)

diff --git a/OpenMetaverse/Rendering/Rendering.cs b/OpenMetaverse/Rendering/Rendering.cs
index 06f09335..285ca561 100644
--- a/OpenMetaverse/Rendering/Rendering.cs
+++ b/OpenMetaverse/Rendering/Rendering.cs
@@ -80,7 +80,7 @@ namespace OpenMetaverse.Rendering
     #region Structs
 
     [StructLayout(LayoutKind.Explicit)]
-    public struct Vertex
+    public struct Vertex : IEquatable<Vertex>
     {
         [FieldOffset(0)]
         public Vector3 Position;
@@ -93,6 +93,36 @@ namespace OpenMetaverse.Rendering
         {
             return String.Format("P: {0} N: {1} T: {2}", Position, Normal, TexCoord);
         }
+
+        public override int GetHashCode()
+        {
+            int hash = Position.GetHashCode();
+            hash = hash * 31 + Normal.GetHashCode();
+            hash = hash * 31 + TexCoord.GetHashCode();
+            return hash;
+        }
+
+        public static bool operator ==(Vertex value1, Vertex value2)
+        {
+            return value1.Position == value2.Position
+                && value1.Normal == value2.Normal
+                && value1.TexCoord == value2.TexCoord;
+        }
+
+        public static bool operator !=(Vertex value1, Vertex value2)
+        {
+            return !(value1 == value2);
+        }
+
+        public override bool Equals(object obj)
+        {
+            return (obj is Vertex) ? this == (Vertex)obj : false;
+        }
+
+        public bool Equals(Vertex other)
+        {
+            return this == other;
+        }
     }
 
     public struct ProfileFace
diff --git a/OpenMetaverseTypes/Vector2.cs b/OpenMetaverseTypes/Vector2.cs
index 14a90012..f2330bf2 100644
--- a/OpenMetaverseTypes/Vector2.cs
+++ b/OpenMetaverseTypes/Vector2.cs
@@ -355,7 +355,9 @@ namespace OpenMetaverse
 
         public override int GetHashCode()
         {
-            return X.GetHashCode() ^ Y.GetHashCode();
+            int hash = X.GetHashCode();
+            hash = hash * 31 + Y.GetHashCode();
+            return hash;
         }
 
         /// <summary>
diff --git a/OpenMetaverseTypes/Vector3.cs b/OpenMetaverseTypes/Vector3.cs
index 834f9984..06285597 100644
--- a/OpenMetaverseTypes/Vector3.cs
+++ b/OpenMetaverseTypes/Vector3.cs
@@ -441,7 +441,10 @@ namespace OpenMetaverse
 
         public override int GetHashCode()
         {
-            return X.GetHashCode() ^ Y.GetHashCode() ^ Z.GetHashCode();
+            int hash = X.GetHashCode();
+            hash = hash * 31 + Y.GetHashCode();
+            hash = hash * 31 + Z.GetHashCode();
+            return hash;
         }
 
         /// <summary>