Stop llPushObject() from causing problems by adding force via a taint rather than directly.

This isn't a perfect solution since there can be a race between the taint processing and taint setting, as force needs to be reset after processing.
Needs careful locking in the future.

1 files changed, 25 insertions, 2 deletions

diff --git a/OpenSim/Region/Physics/OdePlugin/ODECharacter.cs b/OpenSim/Region/Physics/OdePlugin/ODECharacter.cs
index f93d7ba..19d87c2 100644
--- a/OpenSim/Region/Physics/OdePlugin/ODECharacter.cs
+++ b/OpenSim/Region/Physics/OdePlugin/ODECharacter.cs
@@ -100,7 +100,14 @@ namespace OpenSim.Region.Physics.OdePlugin
         private bool m_hackSentFall = false;
         private bool m_hackSentFly = false;
         private int m_requestedUpdateFrequency = 0;
-        private Vector3 m_taintPosition = Vector3.Zero;
+        private Vector3 m_taintPosition;
+
+        /// <summary>
+        /// Hold set forces so we can process them outside physics calculations.  This prevents race conditions if we set force
+        /// while calculatios are going on
+        /// </summary>
+        private Vector3 m_taintForce;
+
         internal uint m_localID = 0;
         // taints and their non-tainted counterparts
         private bool m_isPhysical = false; // the current physical status
@@ -832,7 +839,10 @@ namespace OpenSim.Region.Physics.OdePlugin
                 {
                     m_pidControllerActive = false;
                     force *= 100f;
-                    doForce(force);
+                    m_taintForce += force;
+                    _parent_scene.AddPhysicsActorTaint(this);
+
+                    //doForce(force);
                     // If uncommented, things get pushed off world
                     //
                     // m_log.Debug("Push!");
@@ -1250,6 +1260,19 @@ namespace OpenSim.Region.Physics.OdePlugin
                 }
             }
 
+            if (m_taintForce != Vector3.Zero)
+            {
+                if (Body != IntPtr.Zero)
+                {
+                    // FIXME: This is not a good solution since it's subject to a race condition if a force is another
+                    // thread sets a new force while we're in this loop (since it could be obliterated by
+                    // m_taintForce = Vector3.Zero.  Need to lock ProcessTaints() when we set a new tainted force.
+                    doForce(m_taintForce);
+                }
+                
+                m_taintForce = Vector3.Zero;
+            }
+
             if (m_taintTargetVelocity != _target_velocity)
                 _target_velocity = m_taintTargetVelocity;