1 files changed, 63 insertions, 6 deletions

diff --git a/OpenSim/Region/Physics/Meshing/Meshmerizer.cs b/OpenSim/Region/Physics/Meshing/Meshmerizer.cs
index f469ad6..0873035 100644
--- a/OpenSim/Region/Physics/Meshing/Meshmerizer.cs
+++ b/OpenSim/Region/Physics/Meshing/Meshmerizer.cs
@@ -76,6 +76,7 @@ namespace OpenSim.Region.Physics.Meshing
 
         private float minSizeForComplexMesh = 0.2f; // prims with all dimensions smaller than this will have a bounding box mesh
 
+        private Dictionary<ulong, Mesh> m_uniqueMeshes = new Dictionary<ulong, Mesh>();
 
         /// <summary>
         /// creates a simple box mesh of the specified size. This mesh is of very low vertex count and may
@@ -170,9 +171,62 @@ namespace OpenSim.Region.Physics.Meshing
 
         }
 
-        public Mesh CreateMeshFromPrimMesher(string primName, PrimitiveBaseShape primShape, PhysicsVector size, float lod)
+        private ulong GetMeshKey( PrimitiveBaseShape pbs, PhysicsVector size, float lod )
+        {
+            ulong hash = 5381;
+
+            hash = djb2(hash, pbs.PathCurve);
+            hash = djb2(hash, (byte)((byte)pbs.HollowShape | (byte)pbs.ProfileShape));
+            hash = djb2(hash, pbs.PathBegin);
+            hash = djb2(hash, pbs.PathEnd);
+            hash = djb2(hash, pbs.PathScaleX);
+            hash = djb2(hash, pbs.PathScaleY);
+            hash = djb2(hash, pbs.PathShearX);
+            hash = djb2(hash, pbs.PathShearY);
+            hash = djb2(hash, (byte)pbs.PathTwist);
+            hash = djb2(hash, (byte)pbs.PathTwistBegin);
+            hash = djb2(hash, (byte)pbs.PathRadiusOffset);
+            hash = djb2(hash, (byte)pbs.PathTaperX);
+            hash = djb2(hash, (byte)pbs.PathTaperY);
+            hash = djb2(hash, pbs.PathRevolutions);
+            hash = djb2(hash, (byte)pbs.PathSkew);
+            hash = djb2(hash, pbs.ProfileBegin);
+            hash = djb2(hash, pbs.ProfileEnd);
+            hash = djb2(hash, pbs.ProfileHollow);
+
+            // TODO: Separate scale out from the primitive shape data (after
+            // scaling is supported at the physics engine level)
+            byte[] scaleBytes = size.GetBytes();
+            for (int i = 0; i < scaleBytes.Length; i++)
+                hash = djb2(hash, scaleBytes[i]);
+
+            // Include LOD in hash, accounting for endianness
+            byte[] lodBytes = new byte[4];
+            Buffer.BlockCopy(BitConverter.GetBytes(lod), 0, lodBytes, 0, 4);
+            if (!BitConverter.IsLittleEndian)
+            {
+                Array.Reverse(lodBytes, 0, 4);
+            }
+            for (int i = 0; i < lodBytes.Length; i++)
+                hash = djb2(hash, lodBytes[i]);
+
+            return hash;
+        }
+
+        private ulong djb2(ulong hash, byte c)
+        {
+            return ((hash << 5) + hash) + (ulong)c;
+        }
+
+        private ulong djb2(ulong hash, ushort c)
+        {
+            hash = ((hash << 5) + hash) + (ulong)((byte)c);
+            return ((hash << 5) + hash) + (ulong)(c >> 8);
+        }
+        
+
+        private Mesh CreateMeshFromPrimMesher(string primName, PrimitiveBaseShape primShape, PhysicsVector size, float lod)
         {
-            Mesh mesh = new Mesh();
             PrimMesh primMesh;
             PrimMesher.SculptMesh sculptMesh;
 
@@ -385,8 +439,6 @@ namespace OpenSim.Region.Physics.Meshing
 
                 coords = primMesh.coords;
                 faces = primMesh.faces;
-
-
             }
 
 
@@ -401,13 +453,13 @@ namespace OpenSim.Region.Physics.Meshing
                 vertices.Add(new Vertex(c.X, c.Y, c.Z));
             }
 
+            Mesh mesh = new Mesh();
             // Add the corresponding triangles to the mesh
             for (int i = 0; i < numFaces; i++)
             {
                 Face f = faces[i];
                 mesh.Add(new Triangle(vertices[f.v1], vertices[f.v2], vertices[f.v3]));
             }
-
             return mesh;
         }
 
@@ -418,7 +470,12 @@ namespace OpenSim.Region.Physics.Meshing
 
         public IMesh CreateMesh(String primName, PrimitiveBaseShape primShape, PhysicsVector size, float lod, bool isPhysical)
         {
+            // If this mesh has been created already, return it instead of creating another copy
+            // For large regions with 100k+ prims and hundreds of copies of each, this can save a GB or more of memory
+            ulong key = GetMeshKey(primShape, size, lod);
             Mesh mesh = null;
+            if (m_uniqueMeshes.TryGetValue(key, out mesh))
+                return mesh;
 
             if (size.X < 0.01f) size.X = 0.01f;
             if (size.Y < 0.01f) size.Y = 0.01f;
@@ -441,7 +498,7 @@ namespace OpenSim.Region.Physics.Meshing
                 // trim the vertex and triangle lists to free up memory
                 mesh.TrimExcess();
             }
-
+            m_uniqueMeshes.Add(key, mesh);
             return mesh;
         }
     }