1 files changed, 64 insertions, 50 deletions

diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSLinkset.cs b/OpenSim/Region/Physics/BulletSPlugin/BSLinkset.cs
index 6f8430c..4a71612 100755
--- a/OpenSim/Region/Physics/BulletSPlugin/BSLinkset.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSLinkset.cs
@@ -40,6 +40,7 @@ public class BSLinkset
     public BSPrim Root { get { return m_linksetRoot; } }
 
     private BSScene m_scene;
+    public BSScene Scene { get { return m_scene; } }
 
     private List<BSPrim> m_children;
 
@@ -80,14 +81,14 @@ public class BSLinkset
 
     // Link to a linkset where the child knows the parent.
     // Parent changing should not happen so do some sanity checking.
-    // We return the parent's linkset so the child can track it's membership.
-    public BSLinkset AddMeToLinkset(BSPrim child, BSPrim parent)
+    // We return the parent's linkset so the child can track its membership.
+    public BSLinkset AddMeToLinkset(BSPrim child)
     {
         lock (m_linksetActivityLock)
         {
-            parent.Linkset.AddChildToLinkset(child);
+            AddChildToLinkset(child);
         }
-        return parent.Linkset;
+        return this;
     }
 
     public BSLinkset RemoveMeFromLinkset(BSPrim child)
@@ -101,7 +102,7 @@ public class BSLinkset
                 {
                     // Note that we don't do a foreach because the remove routine
                     //    takes it out of the list.
-                    RemoveChildFromLinkset(m_children[0]);
+                    RemoveChildFromOtherLinkset(m_children[0]);
                 }
                 m_children.Clear(); // just to make sure
             }
@@ -113,9 +114,10 @@ public class BSLinkset
         }
 
         // The child is down to a linkset of just itself
-        return new BSLinkset(m_scene, child);
+        return new BSLinkset(Scene, child);
     }
 
+    /* DEPRECATED: this is really bad in that it trys to unlink other prims.
     // An existing linkset had one of its members rebuilt or something.
     // Go through the linkset and rebuild the pointers to the bodies of the linkset members.
     public BSLinkset RefreshLinkset(BSPrim requestor)
@@ -124,6 +126,7 @@ public class BSLinkset
 
         lock (m_linksetActivityLock)
         {
+            // The body pointer is refetched in case anything has moved.
             System.IntPtr aPtr = BulletSimAPI.GetBodyHandle2(m_scene.World.Ptr, m_linksetRoot.LocalID);
             if (aPtr == System.IntPtr.Zero)
             {
@@ -155,13 +158,14 @@ public class BSLinkset
                 }
                 foreach (BSPrim bsp in toRemove)
                 {
-                    RemoveChildFromLinkset(bsp);
+                    RemoveChildFromOtherLinkset(bsp);
                 }
             }
         }
 
         return ret;
     }
+     */
 
 
     // Return 'true' if the passed object is the root object of this linkset
@@ -170,6 +174,8 @@ public class BSLinkset
         return (requestor.LocalID == m_linksetRoot.LocalID);
     }
 
+    public int NumberOfChildren { get { return m_children.Count; } }
+
     // Return 'true' if this linkset has any children (more than the root member)
     public bool HasAnyChildren { get { return (m_children.Count > 0); } }
 
@@ -208,7 +214,8 @@ public class BSLinkset
             com += bp.Position * bp.MassRaw;
             totalMass += bp.MassRaw;
         }
-        com /= totalMass;
+        if (totalMass != 0f)
+            com /= totalMass;
 
         return com;
     }
@@ -221,51 +228,54 @@ public class BSLinkset
         {
             com += bp.Position * bp.MassRaw;
         }
-        com /= m_children.Count + 1;
+        com /= (m_children.Count + 1);
 
         return com;
     }
 
     // I am the root of a linkset and a new child is being added
-    public void AddChildToLinkset(BSPrim pchild)
+    // Called while LinkActivity is locked.
+    public void AddChildToLinkset(BSPrim child)
     {
-        BSPrim child = pchild;
         if (!HasChild(child))
         {
             m_children.Add(child);
 
-            m_scene.TaintedObject(delegate()
+            BSPrim root = Root; // capture the root as of now
+            m_scene.TaintedObject("AddChildToLinkset", delegate()
             {
                 DebugLog("{0}: AddChildToLinkset: adding child {1} to {2}", LogHeader, child.LocalID, m_linksetRoot.LocalID);
-                DetailLog("{0},AddChildToLinkset,child={1}", m_linksetRoot.LocalID, pchild.LocalID);
-                PhysicallyLinkAChildToRoot(pchild);     // build the physical binding between me and the child
+                DetailLog("{0},AddChildToLinkset,taint,child={1}", m_linksetRoot.LocalID, child.LocalID);
+                PhysicallyLinkAChildToRoot(root, child);     // build the physical binding between me and the child
             });
         }
         return;
     }
 
+    // Forcefully removing a child from a linkset.
+    // This is not being called by the child so we have to make sure the child doesn't think
+    //    it's still connected to the linkset.
+    // Normal OpenSimulator operation will never do this because other SceneObjectPart information
+    //    has to be updated also (like pointer to prim's parent).
+    public void RemoveChildFromOtherLinkset(BSPrim pchild)
+    {
+        pchild.Linkset = new BSLinkset(m_scene, pchild);
+        RemoveChildFromLinkset(pchild);
+    }
+
     // I am the root of a linkset and one of my children is being removed.
     // Safe to call even if the child is not really in my linkset.
-    public void RemoveChildFromLinkset(BSPrim pchild)
+    public void RemoveChildFromLinkset(BSPrim child)
     {
-        BSPrim child = pchild;
-
         if (m_children.Remove(child))
         {
-            m_scene.TaintedObject(delegate()
+            BSPrim root = Root; // capture the root as of now
+            m_scene.TaintedObject("RemoveChildFromLinkset", delegate()
             {
                 DebugLog("{0}: RemoveChildFromLinkset: Removing constraint to {1}", LogHeader, child.LocalID);
-                DetailLog("{0},RemoveChildFromLinkset,child={1}", m_linksetRoot.LocalID, pchild.LocalID);
+                DetailLog("{0},RemoveChildFromLinkset,taint,child={1}", m_linksetRoot.LocalID, child.LocalID);
 
-                if (m_children.Count == 0)
-                {
-                    // if the linkset is empty, make sure all linkages have been removed
-                    PhysicallyUnlinkAllChildrenFromRoot();
-                }
-                else
-                {
-                    PhysicallyUnlinkAChildFromRoot(pchild);
-                }
+                PhysicallyUnlinkAChildFromRoot(root, child);
             });
         }
         else
@@ -278,14 +288,14 @@ public class BSLinkset
 
     // Create a constraint between me (root of linkset) and the passed prim (the child).
     // Called at taint time!
-    private void PhysicallyLinkAChildToRoot(BSPrim childPrim)
+    private void PhysicallyLinkAChildToRoot(BSPrim rootPrim, BSPrim childPrim)
     {
         // Zero motion for children so they don't interpolate
         childPrim.ZeroMotion();
 
         // relative position normalized to the root prim
-        OMV.Quaternion invThisOrientation = OMV.Quaternion.Inverse(m_linksetRoot.Orientation);
-        OMV.Vector3 childRelativePosition = (childPrim.Position - m_linksetRoot.Position) * invThisOrientation;
+        OMV.Quaternion invThisOrientation = OMV.Quaternion.Inverse(rootPrim.Orientation);
+        OMV.Vector3 childRelativePosition = (childPrim.Position - rootPrim.Position) * invThisOrientation;
 
         // relative rotation of the child to the parent
         OMV.Quaternion childRelativeRotation = invThisOrientation * childPrim.Orientation;
@@ -293,16 +303,17 @@ public class BSLinkset
         // create a constraint that allows no freedom of movement between the two objects
         // http://bulletphysics.org/Bullet/phpBB3/viewtopic.php?t=4818
         // DebugLog("{0}: CreateLinkset: Adding a constraint between root prim {1} and child prim {2}", LogHeader, LocalID, childPrim.LocalID);
-        DetailLog("{0},LinkAChildToMe,taint,root={1},child={2}", m_linksetRoot.LocalID, m_linksetRoot.LocalID, childPrim.LocalID);
-        BSConstraint constrain = m_scene.Constraints.CreateConstraint(
-                        m_scene.World, m_linksetRoot.Body, childPrim.Body,
-                        // childRelativePosition,
-                        // childRelativeRotation,
-                        OMV.Vector3.Zero,
-                        OMV.Quaternion.Identity,
+        DetailLog("{0},PhysicallyLinkAChildToRoot,taint,root={1},child={2}", rootPrim.LocalID, rootPrim.LocalID, childPrim.LocalID);
+        BS6DofConstraint constrain = new BS6DofConstraint(
+                        m_scene.World, rootPrim.Body, childPrim.Body,
+                        childRelativePosition,
+                        childRelativeRotation,
                         OMV.Vector3.Zero,
-                        OMV.Quaternion.Identity
+                        -childRelativeRotation
                         );
+        m_scene.Constraints.AddConstraint(constrain);
+
+        // zero linear and angular limits makes the objects unable to move in relation to each other
         constrain.SetLinearLimits(OMV.Vector3.Zero, OMV.Vector3.Zero);
         constrain.SetAngularLimits(OMV.Vector3.Zero, OMV.Vector3.Zero);
 
@@ -317,29 +328,32 @@ public class BSLinkset
 
     // Remove linkage between myself and a particular child
     // Called at taint time!
-    private void PhysicallyUnlinkAChildFromRoot(BSPrim childPrim)
+    private void PhysicallyUnlinkAChildFromRoot(BSPrim rootPrim, BSPrim childPrim)
     {
-        DebugLog("{0}: PhysicallyUnlinkAChildFromRoot: RemoveConstraint between root prim {1} and child prim {2}", 
-                    LogHeader, m_linksetRoot.LocalID, childPrim.LocalID);
-        DetailLog("{0},PhysicallyUnlinkAChildFromRoot,taint,root={1},child={2}", m_linksetRoot.LocalID, m_linksetRoot.LocalID, childPrim.LocalID);
-        // BulletSimAPI.RemoveConstraint(_scene.WorldID, LocalID, childPrim.LocalID);
-        m_scene.Constraints.RemoveAndDestroyConstraint(m_linksetRoot.Body, childPrim.Body);
+        // DebugLog("{0}: PhysicallyUnlinkAChildFromRoot: RemoveConstraint between root prim {1} and child prim {2}", 
+        //             LogHeader, rootPrim.LocalID, childPrim.LocalID);
+        DetailLog("{0},PhysicallyUnlinkAChildFromRoot,taint,root={1},child={2}", rootPrim.LocalID, rootPrim.LocalID, childPrim.LocalID);
+
+        m_scene.Constraints.RemoveAndDestroyConstraint(rootPrim.Body, childPrim.Body);
+        // Make the child refresh its location
+        BulletSimAPI.PushUpdate2(childPrim.Body.Ptr);
     }
 
     // Remove linkage between myself and any possible children I might have
     // Called at taint time!
-    private void PhysicallyUnlinkAllChildrenFromRoot()
+    private void PhysicallyUnlinkAllChildrenFromRoot(BSPrim rootPrim)
     {
         // DebugLog("{0}: PhysicallyUnlinkAllChildren:", LogHeader);
-        DetailLog("{0},PhysicallyUnlinkAllChildren,taint", m_linksetRoot.LocalID);
-        m_scene.Constraints.RemoveAndDestroyConstraint(m_linksetRoot.Body);
-        // BulletSimAPI.RemoveConstraintByID(_scene.WorldID, LocalID);
+        DetailLog("{0},PhysicallyUnlinkAllChildren,taint", rootPrim.LocalID);
+
+        m_scene.Constraints.RemoveAndDestroyConstraint(rootPrim.Body);
     }
 
     // Invoke the detailed logger and output something if it's enabled.
     private void DebugLog(string msg, params Object[] args)
     {
-        m_scene.Logger.DebugFormat(msg, args);
+        if (m_scene.ShouldDebugLog)
+            m_scene.Logger.DebugFormat(msg, args);
     }
 
     // Invoke the detailed logger and output something if it's enabled.