BulletSim: increase vehicle stability by suppressing Bullet's update to angular velocity.

OpenSim/Region/Physics/BulletSPlugin/BSDynamics.cs

@@ -805,6 +805,7 @@ namespace OpenSim.Region.Physics.BulletSPlugin
             // m_angularFrictionTimescale      // body angular velocity  decay rate
             // m_lastAngularVelocity           // what was last applied to body
 
+            /*
             if (m_angularMotorDirection.LengthSquared() > 0.0001)
             {
                 Vector3 origVel = m_angularMotorVelocity;
@@ -823,6 +824,7 @@ namespace OpenSim.Region.Physics.BulletSPlugin
             {
                 m_angularMotorVelocity = Vector3.Zero;
             }
+            */
 
             Vector3 angularMotorContribution = m_angularMotor.Step(pTimestep);
 
@@ -842,15 +844,13 @@ namespace OpenSim.Region.Physics.BulletSPlugin
                 // verticalError.X and .Y are the World error amounts. They are 0 when there is no
                 //      error (Vehicle Body is 'vertical'), and .Z will be 1. As the body leans to its
                 //      side |.X| will increase to 1 and .Z fall to 0. As body inverts |.X| will fall
-                //      and .Z will go // negative. Similar for tilt and |.Y|. .X and .Y must be
+                //      and .Z will go negative. Similar for tilt and |.Y|. .X and .Y must be
                 //      modulated to prevent a stable inverted body.
 
                 // Error is 0 (no error) to +/- 2 (max error)
-                if (verticalError.Z < 0.0f)
+                verticalError.X = Math.Max(-2f, Math.Min(verticalError.X, 2f));
-                {
+                verticalError.Y = Math.Max(-2f, Math.Min(verticalError.Y, 2f));
-                    verticalError.X = 2.0f - verticalError.X;
+
-                    verticalError.Y = 2.0f - verticalError.Y;
-                }
                 // scale it by VAservo (timestep and timescale)
                 verticalError = verticalError * VAservo;
 
@@ -1013,10 +1013,15 @@ namespace OpenSim.Region.Physics.BulletSPlugin
                 // Also remove any motion that is on the object so added motion is only from vehicle.
                 Vector3 applyAngularForce = ((m_lastAngularVelocity * pTimestep) 
                                                 - Prim.ForceRotationalVelocity);
+                // Unscale the force by the angular factor so it overwhelmes the Bullet additions.
                 Prim.ForceRotationalVelocity = applyAngularForce;
 
-                VDetailLog("{0},MoveAngular,done,newRotVel={1},lastAngular={2}", 
+                VDetailLog("{0},MoveAngular,done,angMotor={1},vertAttr={2},bank={3},deflect={4},newAngForce={5},lastAngular={6}",
-                                    Prim.LocalID, applyAngularForce, m_lastAngularVelocity);
+                                    Prim.LocalID,
+                                    angularMotorContribution, verticalAttractionContribution,
+                                    bankingContribution, deflectionContribution,
+                                    applyAngularForce, m_lastAngularVelocity
+                                    );
             }
         }
 

OpenSim/Region/Physics/BulletSPlugin/BSPrim.cs

@@ -1380,54 +1380,16 @@ public sealed class BSPrim : BSPhysObject
 
     public override void UpdateProperties(EntityProperties entprop)
     {
-        /*
-        UpdatedProperties changed = 0;
-        // assign to the local variables so the normal set action does not happen
-        // if (_position != entprop.Position)
-        if (!_position.ApproxEquals(entprop.Position, POSITION_TOLERANCE))
-        {
-            _position = entprop.Position;
-            changed |= UpdatedProperties.Position;
-        }
-        // if (_orientation != entprop.Rotation)
-        if (!_orientation.ApproxEquals(entprop.Rotation, ROTATION_TOLERANCE))
-        {
-            _orientation = entprop.Rotation;
-            changed |= UpdatedProperties.Rotation;
-        }
-        // if (_velocity != entprop.Velocity)
-        if (!_velocity.ApproxEquals(entprop.Velocity, VELOCITY_TOLERANCE))
-        {
-            _velocity = entprop.Velocity;
-            changed |= UpdatedProperties.Velocity;
-        }
-        // if (_acceleration != entprop.Acceleration)
-        if (!_acceleration.ApproxEquals(entprop.Acceleration, ACCELERATION_TOLERANCE))
-        {
-            _acceleration = entprop.Acceleration;
-            changed |= UpdatedProperties.Acceleration;
-        }
-        // if (_rotationalVelocity != entprop.RotationalVelocity)
-        if (!_rotationalVelocity.ApproxEquals(entprop.RotationalVelocity, ROTATIONAL_VELOCITY_TOLERANCE))
-        {
-            _rotationalVelocity = entprop.RotationalVelocity;
-            changed |= UpdatedProperties.RotationalVel;
-        }
-        if (changed != 0)
-        {
-            // Only update the position of single objects and linkset roots
-            if (Linkset.IsRoot(this))
-            {
-                base.RequestPhysicsterseUpdate();
-            }
-        }
-        */
-
-        // Don't check for damping here -- it's done in BulletSim and SceneObjectPart.
-
         // Updates only for individual prims and for the root object of a linkset.
         if (Linkset.IsRoot(this))
         {
+            // A temporary kludge to suppress the rotational effects introduced on vehicles by Bullet
+            // TODO: handle physics introduced by Bullet with computed vehicle physics.
+            if (_vehicle.IsActive)
+            {
+                entprop.RotationalVelocity = OMV.Vector3.Zero;
+            }
+
             // Assign directly to the local variables so the normal set action does not happen
             _position = entprop.Position;
             _orientation = entprop.Rotation;

OpenSim/Region/Physics/BulletSPlugin/BSScene.cs

@@ -515,9 +515,9 @@ public sealed class BSScene : PhysicsScene, IPhysicsParameters
             collidersCount = 0;
         }
 
-        // Don't have to use the pointers passed back since we know it is the same pinned memory we passed in
+        // Don't have to use the pointers passed back since we know it is the same pinned memory we passed in.
 
-        // Get a value for 'now' so all the collision and update routines don't have to get their own
+        // Get a value for 'now' so all the collision and update routines don't have to get their own.
         SimulationNowTime = Util.EnvironmentTickCount();
 
         // If there were collisions, process them by sending the event to the prim.
@@ -563,6 +563,7 @@ public sealed class BSScene : PhysicsScene, IPhysicsParameters
                 ObjectsWithCollisions.Remove(po);
             ObjectsWithNoMoreCollisions.Clear();
         }
+        // Done with collisions.
 
         // If any of the objects had updated properties, tell the object it has been changed by the physics engine
         if (updatedEntityCount > 0)
@@ -586,9 +587,8 @@ public sealed class BSScene : PhysicsScene, IPhysicsParameters
 
         // The physics engine returns the number of milliseconds it simulated this call.
         // These are summed and normalized to one second and divided by 1000 to give the reported physics FPS.
-        // We multiply by 55 to give a recognizable running rate (55 or less).
+        // Multiply by 55 to give a nominal frame rate of 55.
-        return numSubSteps * m_fixedTimeStep * 1000 * 55;
+        return (float)numSubSteps * m_fixedTimeStep * 1000f * 55f;
-        // return timeStep * 1000 * 55;
     }
 
     // Something has collided
@@ -1172,7 +1172,7 @@ public sealed class BSScene : PhysicsScene, IPhysicsParameters
             (s) => { return s.m_params[0].avatarFriction; },
             (s,p,l,v) => { s.UpdateParameterObject(ref s.m_params[0].avatarFriction, p, l, v); } ),
         new ParameterDefn("AvatarStandingFriction", "Avatar friction when standing. Changed on avatar recreation.",
-            0.99f,
+            10.0f,
             (s,cf,p,v) => { s.m_params[0].avatarStandingFriction = cf.GetFloat(p, v); },
             (s) => { return s.m_params[0].avatarStandingFriction; },
             (s,p,l,v) => { s.m_params[0].avatarStandingFriction = v; } ),

OpenSim/Region/Physics/BulletSPlugin/BulletSimAPI.cs

@@ -357,7 +357,7 @@ public enum CollisionFlags : uint
     CF_CHARACTER_OBJECT              = 1 << 4,
     CF_DISABLE_VISUALIZE_OBJECT      = 1 << 5,
     CF_DISABLE_SPU_COLLISION_PROCESS = 1 << 6,
-    // Following used by BulletSim to control collisions
+    // Following used by BulletSim to control collisions and updates
     BS_SUBSCRIBE_COLLISION_EVENTS    = 1 << 10,
     BS_FLOATS_ON_WATER               = 1 << 11,
     BS_NONE                          = 0,