From 3a458e2a36253f6514720213deaa19372b06cc52 Mon Sep 17 00:00:00 2001
From: Robert Adams <Robert.Adams@intel.com>
Date: Wed, 10 Oct 2012 13:56:16 -0700
Subject: [PATCH] BulletSim: Use full linkset mass when computing vehicle
 gravity force. Add taint-time specification to new AddForce().

---
 OpenSim/Region/Physics/BulletSPlugin/BSDynamics.cs |  6 +++---
 OpenSim/Region/Physics/BulletSPlugin/BSLinkset.cs  |  9 +++------
 OpenSim/Region/Physics/BulletSPlugin/BSPrim.cs     | 12 ++++++++++--
 3 files changed, 16 insertions(+), 11 deletions(-)

diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSDynamics.cs b/OpenSim/Region/Physics/BulletSPlugin/BSDynamics.cs
index 76230a19da..56342b88f8 100644
--- a/OpenSim/Region/Physics/BulletSPlugin/BSDynamics.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSDynamics.cs
@@ -462,7 +462,7 @@ namespace OpenSim.Region.Physics.BulletSPlugin
                 return;
 
             // Set the prim's inertia to zero. The vehicle code handles that and this
-            //    removes the torque action introduced by Bullet.
+            //    removes the motion and torque actions introduced by Bullet.
             Vector3 inertia = Vector3.Zero;
             BulletSimAPI.SetMassProps2(Prim.BSBody.ptr, Prim.MassRaw, inertia);
             BulletSimAPI.UpdateInertiaTensor2(Prim.BSBody.ptr);
@@ -540,7 +540,7 @@ namespace OpenSim.Region.Physics.BulletSPlugin
             // add Gravity and Buoyancy
             // There is some gravity, make a gravity force vector that is applied after object velocity.
             // m_VehicleBuoyancy: -1=2g; 0=1g; 1=0g;
-            Vector3 grav = Prim.PhysicsScene.DefaultGravity * (Prim.MassRaw * (1f - m_VehicleBuoyancy));
+            Vector3 grav = Prim.PhysicsScene.DefaultGravity * (Prim.Linkset.LinksetMass * (1f - m_VehicleBuoyancy));
 
             /*
              * RA: Not sure why one would do this
@@ -681,7 +681,7 @@ namespace OpenSim.Region.Physics.BulletSPlugin
             Prim.ForceVelocity = m_newVelocity;
             // apply gravity force
             // Why is this set here? The physics engine already does gravity.
-            Prim.AddForce(grav, false);
+            Prim.AddForce(grav, false, true);
 
             // Apply friction
             Vector3 keepFraction = Vector3.One - (Vector3.One / (m_linearFrictionTimescale / pTimestep));
diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSLinkset.cs b/OpenSim/Region/Physics/BulletSPlugin/BSLinkset.cs
index b84ccdccce..43b12623cc 100755
--- a/OpenSim/Region/Physics/BulletSPlugin/BSLinkset.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSLinkset.cs
@@ -165,13 +165,11 @@ public class BSLinkset
     // May be called at runtime or taint-time (just pass the appropriate flag).
     public void Refresh(BSPhysObject requestor, bool inTaintTime)
     {
-        // If there are no children, there can't be any constraints to recompute
-        if (!HasAnyChildren)
+        // If there are no children, not physical or not root, I am not the one that recomputes the constraints
+        // (For the moment, static linksets do create constraints so remove the test for physical.)
+        if (!HasAnyChildren || /*!requestor.IsPhysical ||*/ !IsRoot(requestor))
             return;
 
-        // Only the root does the recomputation
-        if (IsRoot(requestor))
-        {
         BSScene.TaintCallback refreshOperation = delegate()
             {
                 RecomputeLinksetConstraintVariables();
@@ -182,7 +180,6 @@ public class BSLinkset
             refreshOperation();
         else
             PhysicsScene.TaintedObject("BSLinkSet.Refresh", refreshOperation);
-        }
     }
 
     // The object is going dynamic (physical). Do any setup necessary
diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSPrim.cs b/OpenSim/Region/Physics/BulletSPlugin/BSPrim.cs
index b26f0491a1..692713de92 100644
--- a/OpenSim/Region/Physics/BulletSPlugin/BSPrim.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSPrim.cs
@@ -855,6 +855,9 @@ public sealed class BSPrim : BSPhysObject
 
     private List<OMV.Vector3> m_accumulatedForces = new List<OMV.Vector3>();
     public override void AddForce(OMV.Vector3 force, bool pushforce) {
+        AddForce(force, pushforce, false);
+    }
+    public void AddForce(OMV.Vector3 force, bool pushforce, bool inTaintTime) {
         // for an object, doesn't matter if force is a pushforce or not
         if (force.IsFinite())
         {
@@ -867,11 +870,12 @@ public sealed class BSPrim : BSPhysObject
             m_log.WarnFormat("{0}: Got a NaN force applied to a prim. LocalID={1}", LogHeader, LocalID);
             return;
         }
-        PhysicsScene.TaintedObject("BSPrim.AddForce", delegate()
+        BSScene.TaintCallback addForceOperation = delegate()
         {
             OMV.Vector3 fSum = OMV.Vector3.Zero;
             lock (m_accumulatedForces)
             {
+                // Sum the accumulated additional forces for one big force to apply once.
                 foreach (OMV.Vector3 v in m_accumulatedForces)
                 {
                     fSum += v;
@@ -881,7 +885,11 @@ public sealed class BSPrim : BSPhysObject
             // DetailLog("{0},BSPrim.AddObjectForce,taint,force={1}", LocalID, fSum);
             // For unknown reasons, "ApplyCentralForce" adds this force to the total force on the object.
             BulletSimAPI.ApplyCentralForce2(BSBody.ptr, fSum);
-        });
+        };
+        if (inTaintTime)
+            addForceOperation();
+        else
+            PhysicsScene.TaintedObject("BSPrim.AddForce", addForceOperation);
     }
 
     public override void AddAngularForce(OMV.Vector3 force, bool pushforce) {