2 files changed, 48 insertions, 3 deletions

diff --git a/OpenSim/Region/Framework/Scenes/Scene.cs b/OpenSim/Region/Framework/Scenes/Scene.cs
index b876fc6..2a69ee1 100755
--- a/OpenSim/Region/Framework/Scenes/Scene.cs
+++ b/OpenSim/Region/Framework/Scenes/Scene.cs
@@ -423,6 +423,17 @@ namespace OpenSim.Region.Framework.Scenes
         private int landMS;
         private int spareMS;
 
+        // A temporary configuration flag to enable using FireAndForget to process
+        //   collisions from the physics engine. There is a problem with collisions
+        //   stopping sometimes and MB's suspicion is some race condition passing
+        //   collisions from the physics engine callback to the script engine.
+        //   This causes the collision events to be passed with a FireAndForget
+        //   call which should eliminate that linkage. Testers can turn this on
+        //   and see if collisions stop. If they don't, the problem is somewhere else.
+        //   This feature defaults to 'off' so, by default, the simulator operation
+        //   is not changed.
+        public bool ShouldUseFireAndForgetForCollisions = false;
+
         /// <summary>
         /// Tick at which the last frame was processed.
         /// </summary>
@@ -1075,8 +1086,14 @@ namespace OpenSim.Region.Framework.Scenes
                 m_update_presences        = startupConfig.GetInt("UpdateAgentsEveryNFrames",          m_update_presences);
                 m_update_terrain          = startupConfig.GetInt("UpdateTerrainEveryNFrames",         m_update_terrain);
                 m_update_temp_cleaning    = startupConfig.GetInt("UpdateTempCleaningEveryNSeconds",   m_update_temp_cleaning);
+
+                if (startupConfig.Contains("ShouldUseFireAndForgetForCollisions"))
+                {
+                    ShouldUseFireAndForgetForCollisions = startupConfig.GetBoolean("ShouldUseFireAndForgetForCollisions", false);
+                }
             }
 
+
             // FIXME: Ultimately this should be in a module.
             SendPeriodicAppearanceUpdates = false;
 
diff --git a/OpenSim/Region/Framework/Scenes/SceneObjectPart.cs b/OpenSim/Region/Framework/Scenes/SceneObjectPart.cs
index 781c20c..f52c9c8 100644
--- a/OpenSim/Region/Framework/Scenes/SceneObjectPart.cs
+++ b/OpenSim/Region/Framework/Scenes/SceneObjectPart.cs
@@ -126,6 +126,8 @@ namespace OpenSim.Region.Framework.Scenes
         
         private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
 
+        private bool shouldUseFireAndForgetForCollisions = true;
+
         /// <summary>
         /// Dynamic attributes can be created and deleted as required.
         /// </summary>
@@ -2392,7 +2394,7 @@ namespace OpenSim.Region.Framework.Scenes
                     CollidingMessage = CreateColliderArgs(this, colliders);
 
                     if (CollidingMessage.Colliders.Count > 0)
-                        notify(LocalId, CollidingMessage);
+                        DoNotify(notify, LocalId, CollidingMessage);
 
                     if (PassCollisions)
                         sendToRoot = true;
@@ -2406,7 +2408,7 @@ namespace OpenSim.Region.Framework.Scenes
                 {
                     CollidingMessage = CreateColliderArgs(ParentGroup.RootPart, colliders);
                     if (CollidingMessage.Colliders.Count > 0)
-                        notify(ParentGroup.RootPart.LocalId, CollidingMessage);
+                        DoNotify(notify, ParentGroup.RootPart.LocalId, CollidingMessage);
                 }
             }
         }
@@ -2421,7 +2423,33 @@ namespace OpenSim.Region.Framework.Scenes
                 colliding.Add(CreateDetObjectForGround());
                 LandCollidingMessage.Colliders = colliding;
 
-                notify(LocalId, LandCollidingMessage);
+                DoNotify(notify, LocalId, LandCollidingMessage);
+            }
+        }
+
+        private void DoNotify(ScriptCollidingNotification notify, uint id, ColliderArgs collargs)
+        {
+            if (m_parentGroup != null && ParentGroup.Scene != null && ParentGroup.Scene.ShouldUseFireAndForgetForCollisions)
+            {
+                // For those learning C#, FireAndForget takes a function, an object to pass
+                //    to that function and an ID string. The "oo => {}" construct is a lambda expression
+                //    for a function with one arguement ('oo'). The 'new Object[] {}" construct creates an Object
+                //    that is an object array and initializes it with three items (the parameters
+                //    being passed). The parameters passed are the function to call ('notify') and
+                //    its two arguements. Finally, once in the function (called later by the FireAndForget
+                //    thread scheduler), the passed object is cast to an object array and then each
+                //    of its items (aoo[0] to aoo[2]) are individually cast to what they are and
+                //    then used in a call of the passed ScriptCollidingNotification function.
+                Util.FireAndForget(oo =>
+                {
+                    Object[] aoo = (Object[])oo;
+                    ((ScriptCollidingNotification)aoo[0])((uint)aoo[1], (ColliderArgs)aoo[2]);
+
+                }, new Object[] { notify, id, collargs }, "SOP.Collision");
+            }
+            else
+            {
+                notify(id, collargs);
             }
         }