Implemented a "FrontBack" prioritizer, using distance plus the plane equation to give double weight to prims/avatars in front of you

OpenSim/Region/Framework/Scenes/Scene.cs

@@ -61,6 +61,7 @@ namespace OpenSim.Region.Framework.Scenes
             Time = 0,
             Distance = 1,
             SimpleAngularDistance = 2,
+            FrontBack = 3,
         }
 
         public delegate void SynchronizeSceneHandler(Scene scene);
@@ -540,6 +541,9 @@ namespace OpenSim.Region.Framework.Scenes
                         case "simpleangulardistance":
                             m_update_prioritization_scheme = UpdatePrioritizationSchemes.SimpleAngularDistance;
                             break;
+                        case "frontback":
+                            m_update_prioritization_scheme = UpdatePrioritizationSchemes.FrontBack;
+                            break;
                         default:
                             m_log.Warn("[SCENE]: UpdatePrioritizationScheme was not recognized, setting to default settomg of Time");
                             m_update_prioritization_scheme = UpdatePrioritizationSchemes.Time;

OpenSim/Region/Framework/Scenes/SceneObjectGroup.cs

@@ -493,8 +493,8 @@ namespace OpenSim.Region.Framework.Scenes
 
         public Vector3 GroupScale()
         {
-            Vector3 minScale = new Vector3(Constants.RegionSize,Constants.RegionSize,Constants.RegionSize);
+            Vector3 minScale = new Vector3(Constants.RegionSize, Constants.RegionSize, Constants.RegionSize);
-            Vector3 maxScale = new Vector3(0f,0f,0f);
+            Vector3 maxScale = Vector3.Zero;
             Vector3 finalScale = new Vector3(0.5f, 0.5f, 0.5f);
 
             lock (m_parts)
@@ -577,7 +577,6 @@ namespace OpenSim.Region.Framework.Scenes
             {
                 foreach (SceneObjectPart part in m_parts.Values)
                 {
-
                     Vector3 worldPos = part.GetWorldPosition();
                     Vector3 offset = worldPos - AbsolutePosition;
                     Quaternion worldRot;
@@ -3366,6 +3365,8 @@ namespace OpenSim.Region.Framework.Scenes
                     return GetPriorityByDistance(client);
                 case Scene.UpdatePrioritizationSchemes.SimpleAngularDistance:
                     return GetPriorityBySimpleAngularDistance(client);
+                case Scenes.Scene.UpdatePrioritizationSchemes.FrontBack:
+                    return GetPriorityByFrontBack(client);
                 default:
                     throw new InvalidOperationException("UpdatePrioritizationScheme not defined");
             }
@@ -3398,6 +3399,16 @@ namespace OpenSim.Region.Framework.Scenes
             return double.NaN;
         }
 
+        private double GetPriorityByFrontBack(IClientAPI client)
+        {
+            ScenePresence presence = Scene.GetScenePresence(client.AgentId);
+            if (presence != null)
+            {
+                return GetPriorityByFrontBack(presence.CameraPosition, presence.CameraAtAxis);
+            }
+            return double.NaN;
+        }
+
         public double GetPriorityByDistance(Vector3 position)
         {
             return Vector3.Distance(AbsolutePosition, position);
@@ -3427,5 +3438,21 @@ namespace OpenSim.Region.Framework.Scenes
             else
                 return double.MinValue;
         }
+
+        public double GetPriorityByFrontBack(Vector3 camPosition, Vector3 camAtAxis)
+        {
+            // Distance
+            double priority = Vector3.Distance(camPosition, AbsolutePosition);
+
+            // Scale
+            //priority -= GroupScale().Length();
+
+            // Plane equation
+            float d = -Vector3.Dot(camPosition, camAtAxis);
+            float p = Vector3.Dot(camAtAxis, AbsolutePosition) + d;
+            if (p < 0.0f) priority *= 2.0f;
+
+            return priority;
+        }
     }
 }

OpenSim/Region/Framework/Scenes/ScenePresence.cs

@@ -297,6 +297,21 @@ namespace OpenSim.Region.Framework.Scenes
             get { return Util.Axes2Rot(m_CameraAtAxis, m_CameraLeftAxis, m_CameraUpAxis); }
         }
 
+        public Vector3 CameraAtAxis
+        {
+            get { return m_CameraAtAxis; }
+        }
+
+        public Vector3 CameraLeftAxis
+        {
+            get { return m_CameraLeftAxis; }
+        }
+
+        public Vector3 CameraUpAxis
+        {
+            get { return m_CameraUpAxis; }
+        }
+
         public Vector3 Lookat
         {
             get
@@ -3867,6 +3882,8 @@ namespace OpenSim.Region.Framework.Scenes
                     return GetPriorityByDistance(client);
                 case Scene.UpdatePrioritizationSchemes.SimpleAngularDistance:
                     return GetPriorityByDistance(client);
+                case Scenes.Scene.UpdatePrioritizationSchemes.FrontBack:
+                    return GetPriorityByFrontBack(client);
                 default:
                     throw new InvalidOperationException("UpdatePrioritizationScheme not defined.");
             }
@@ -3888,11 +3905,34 @@ namespace OpenSim.Region.Framework.Scenes
             return double.NaN;
         }
 
+        private double GetPriorityByFrontBack(IClientAPI client)
+        {
+            ScenePresence presence = Scene.GetScenePresence(client.AgentId);
+            if (presence != null)
+            {
+                return GetPriorityByFrontBack(presence.CameraPosition, presence.CameraAtAxis);
+            }
+            return double.NaN;
+        }
+
         private double GetPriorityByDistance(Vector3 position)
         {
             return Vector3.Distance(AbsolutePosition, position);
         }
 
+        private double GetPriorityByFrontBack(Vector3 camPosition, Vector3 camAtAxis)
+        {
+            // Distance
+            double priority = Vector3.Distance(camPosition, AbsolutePosition);
+
+            // Plane equation
+            float d = -Vector3.Dot(camPosition, camAtAxis);
+            float p = Vector3.Dot(camAtAxis, AbsolutePosition) + d;
+            if (p < 0.0f) priority *= 2.0f;
+
+            return priority;
+        }
+
         private double GetSOGUpdatePriority(SceneObjectGroup sog)
         {
             switch (Scene.UpdatePrioritizationScheme)
@@ -3903,6 +3943,8 @@ namespace OpenSim.Region.Framework.Scenes
                     return sog.GetPriorityByDistance((IsChildAgent) ? AbsolutePosition : CameraPosition);
                 case Scene.UpdatePrioritizationSchemes.SimpleAngularDistance:
                     return sog.GetPriorityBySimpleAngularDistance((IsChildAgent) ? AbsolutePosition : CameraPosition);
+                case Scenes.Scene.UpdatePrioritizationSchemes.FrontBack:
+                    return sog.GetPriorityByFrontBack(CameraPosition, CameraAtAxis);
                 default:
                     throw new InvalidOperationException("UpdatePrioritizationScheme not defined");
             }
@@ -3929,6 +3971,8 @@ namespace OpenSim.Region.Framework.Scenes
                     case Scene.UpdatePrioritizationSchemes.Distance:
                     case Scene.UpdatePrioritizationSchemes.SimpleAngularDistance:
                         return GetPriorityByDistance((IsChildAgent) ? AbsolutePosition : CameraPosition);
+                    case Scenes.Scene.UpdatePrioritizationSchemes.FrontBack:
+                        return GetPriorityByFrontBack(CameraPosition, CameraAtAxis);
                     default:
                         throw new InvalidOperationException("UpdatePrioritizationScheme not defined");
                 }

bin/OpenSim.ini.example

@@ -1397,8 +1397,8 @@
 
 [InterestManagement]
      ; This section controls how state updates are prioritized for each client
-     ; Valid values are Time, Distance, and SimpleAngularDistance
+     ; Valid values are Time, Distance, SimpleAngularDistance, and FrontBack
-     UpdatePrioritizationScheme = Distance;
+     UpdatePrioritizationScheme = FrontBack;
      ReprioritizationEnabled = true;
      ReprioritizationInterval = 2000.0;
      RootReprioritizationDistance = 10.0;