BulletSim: move collision processing for linksets from BSPrimLinkable

into the linkset implementation classes.
Add HasSomeCollision attribute that remembers of any component of
   a linkset has a collision.
Update vehicle code (BSDynamic) to use the HasSomeCollision in place of
   IsColliding to make constraint based linksets properly notice the ground.
Add linkset functions to change physical attributes of all the members
   of a linkset.

OpenSim/Region/Physics/BulletSPlugin/BSDynamics.cs

@@ -1001,7 +1001,7 @@ namespace OpenSim.Region.Physics.BulletSPlugin
             else if (newVelocityLengthSq < 0.001f)
                 VehicleVelocity = Vector3.Zero;
 
-            VDetailLog("{0},  MoveLinear,done,isColl={1},newVel={2}", ControllingPrim.LocalID, ControllingPrim.IsColliding, VehicleVelocity );
+            VDetailLog("{0},  MoveLinear,done,isColl={1},newVel={2}", ControllingPrim.LocalID, ControllingPrim.HasSomeCollision, VehicleVelocity );
 
         } // end MoveLinear()
 
@@ -1062,7 +1062,7 @@ namespace OpenSim.Region.Physics.BulletSPlugin
                 Vector3 linearDeflectionW = linearDeflectionV * VehicleOrientation;
 
                 // Optionally, if not colliding, don't effect world downward velocity. Let falling things fall.
-                if (BSParam.VehicleLinearDeflectionNotCollidingNoZ && !m_controllingPrim.IsColliding)
+                if (BSParam.VehicleLinearDeflectionNotCollidingNoZ && !m_controllingPrim.HasSomeCollision)
                 {
                     linearDeflectionW.Z = 0f;
                 }
@@ -1222,7 +1222,7 @@ namespace OpenSim.Region.Physics.BulletSPlugin
                 float targetHeight = Type == Vehicle.TYPE_BOAT ? GetWaterLevel(VehiclePosition) : GetTerrainHeight(VehiclePosition);
                 distanceAboveGround = VehiclePosition.Z - targetHeight;
                 // Not colliding if the vehicle is off the ground
-                if (!Prim.IsColliding)
+                if (!Prim.HasSomeCollision)
                 {
                     // downForce = new Vector3(0, 0, -distanceAboveGround / m_bankingTimescale);
                     VehicleVelocity += new Vector3(0, 0, -distanceAboveGround);
@@ -1233,12 +1233,12 @@ namespace OpenSim.Region.Physics.BulletSPlugin
                 //     be computed with a motor.
                 // TODO: add interaction with banking.
                 VDetailLog("{0},  MoveLinear,limitMotorUp,distAbove={1},colliding={2},ret={3}",
-                                Prim.LocalID, distanceAboveGround, Prim.IsColliding, ret);
+                                Prim.LocalID, distanceAboveGround, Prim.HasSomeCollision, ret);
                  */
 
                 // Another approach is to measure if we're going up. If going up and not colliding,
                 //     the vehicle is in the air.  Fix that by pushing down.
-                if (!ControllingPrim.IsColliding && VehicleVelocity.Z > 0.1)
+                if (!ControllingPrim.HasSomeCollision && VehicleVelocity.Z > 0.1)
                 {
                     // Get rid of any of the velocity vector that is pushing us up.
                     float upVelocity = VehicleVelocity.Z;
@@ -1260,7 +1260,7 @@ namespace OpenSim.Region.Physics.BulletSPlugin
                     }
                         */
                     VDetailLog("{0},  MoveLinear,limitMotorUp,collide={1},upVel={2},newVel={3}",
-                                    ControllingPrim.LocalID, ControllingPrim.IsColliding, upVelocity, VehicleVelocity);
+                                    ControllingPrim.LocalID, ControllingPrim.HasSomeCollision, upVelocity, VehicleVelocity);
                 }
             }
         }
@@ -1270,14 +1270,14 @@ namespace OpenSim.Region.Physics.BulletSPlugin
             Vector3 appliedGravity = m_VehicleGravity * m_vehicleMass;
 
             // Hack to reduce downward force if the vehicle is probably sitting on the ground
-            if (ControllingPrim.IsColliding && IsGroundVehicle)
+            if (ControllingPrim.HasSomeCollision && IsGroundVehicle)
                 appliedGravity *= BSParam.VehicleGroundGravityFudge;
 
             VehicleAddForce(appliedGravity);
 
             VDetailLog("{0},  MoveLinear,applyGravity,vehGrav={1},collid={2},fudge={3},mass={4},appliedForce={5}",
                             ControllingPrim.LocalID, m_VehicleGravity,
-                            ControllingPrim.IsColliding, BSParam.VehicleGroundGravityFudge, m_vehicleMass, appliedGravity);
+                            ControllingPrim.HasSomeCollision, BSParam.VehicleGroundGravityFudge, m_vehicleMass, appliedGravity);
         }
 
         // =======================================================================

OpenSim/Region/Physics/BulletSPlugin/BSLinkset.cs

@@ -203,6 +203,33 @@ public abstract class BSLinkset
         return ret;
     }
 
+    // Called after a simulation step to post a collision with this object.
+    // Return 'true' if linkset processed the collision. 'false' says the linkset didn't have
+    //     anything to add for the collision and it should be passed through normal processing.
+    // Default processing for a linkset.
+    public virtual bool HandleCollide(uint collidingWith, BSPhysObject collidee,
+                                OMV.Vector3 contactPoint, OMV.Vector3 contactNormal, float pentrationDepth)
+    {
+        bool ret = false;
+
+        // prims in the same linkset cannot collide with each other
+        BSPrimLinkable convCollidee = collidee as BSPrimLinkable;
+        if (convCollidee != null && (LinksetID == convCollidee.Linkset.LinksetID))
+        {
+            // By returning 'true', we tell the caller the collision has been 'handled' so it won't
+            //     do anything about this collision and thus, effectivily, ignoring the collision.
+            ret = true;
+        }
+        else
+        {
+            // Not a collision between members of the linkset. Must be a real collision.
+            // So the linkset root can know if there is a collision anywhere in the linkset.
+            LinksetRoot.SomeCollisionSimulationStep = m_physicsScene.SimulationStep;
+        }
+
+        return ret;
+    }
+
     // I am the root of a linkset and a new child is being added
     // Called while LinkActivity is locked.
     protected abstract void AddChildToLinkset(BSPrimLinkable child);
@@ -250,6 +277,53 @@ public abstract class BSLinkset
     // Called at taint-time!!
     public abstract bool RemoveDependencies(BSPrimLinkable child);
 
+    // ================================================================
+    // Some physical setting happen to all members of the linkset
+    public virtual void SetPhysicalFriction(float friction)
+    {
+        ForEachMember((member) =>
+            {
+                if (member.PhysBody.HasPhysicalBody)
+                    m_physicsScene.PE.SetFriction(member.PhysBody, friction);
+                return false;   // 'false' says to continue looping
+            }
+        );
+    }
+    public virtual void SetPhysicalRestitution(float restitution)
+    {
+        ForEachMember((member) =>
+            {
+                if (member.PhysBody.HasPhysicalBody)
+                    m_physicsScene.PE.SetRestitution(member.PhysBody, restitution);
+                return false;   // 'false' says to continue looping
+            }
+        );
+    }
+    public virtual void SetPhysicalGravity(OMV.Vector3 gravity)
+    {
+        ForEachMember((member) =>
+            {
+                if (member.PhysBody.HasPhysicalBody)
+                    m_physicsScene.PE.SetGravity(member.PhysBody, gravity);
+                return false;   // 'false' says to continue looping
+            }
+        );
+    }
+    public virtual void ComputeLocalInertia()
+    {
+        ForEachMember((member) =>
+            {
+                if (member.PhysBody.HasPhysicalBody)
+                {
+                    OMV.Vector3 inertia = m_physicsScene.PE.CalculateLocalInertia(member.PhysShape.physShapeInfo, member.Mass);
+                    member.Inertia = inertia * BSParam.VehicleInertiaFactor;
+                    m_physicsScene.PE.SetMassProps(member.PhysBody, member.Mass, member.Inertia);
+                    m_physicsScene.PE.UpdateInertiaTensor(member.PhysBody);
+                }
+                return false;   // 'false' says to continue looping
+            }
+        );
+    }
     // ================================================================
     protected virtual float ComputeLinksetMass()
     {
@@ -311,6 +385,5 @@ public abstract class BSLinkset
         if (m_physicsScene.PhysicsLogging.Enabled)
             m_physicsScene.DetailLog(msg, args);
     }
-
 }
 }

OpenSim/Region/Physics/BulletSPlugin/BSPhysObject.cs

@@ -353,6 +353,16 @@ public abstract class BSPhysObject : PhysicsActor
                 CollidingStep = BSScene.NotASimulationStep;
             }
     }
+    // Complex objects (like linksets) need to know if there is a collision on any part of
+    //    their shape. 'IsColliding' has an existing definition of reporting a collision on
+    //    only this specific prim or component of linksets.
+    // 'HasSomeCollision' is defined as reporting if there is a collision on any part of
+    //    the complex body that this prim is the root of.
+    public virtual bool HasSomeCollision
+    {
+        get { return IsColliding; }
+        set { IsColliding = value; }
+    }
     public override bool CollidingGround {
         get { return (CollidingGroundStep == PhysScene.SimulationStep); }
         set
@@ -386,6 +396,7 @@ public abstract class BSPhysObject : PhysicsActor
     // Return 'true' if a collision was processed and should be sent up.
     // Return 'false' if this object is not enabled/subscribed/appropriate for or has already seen this collision.
     // Called at taint time from within the Step() function
+    public delegate bool CollideCall(uint collidingWith, BSPhysObject collidee, OMV.Vector3 contactPoint, OMV.Vector3 contactNormal, float pentrationDepth);
     public virtual bool Collide(uint collidingWith, BSPhysObject collidee,
                     OMV.Vector3 contactPoint, OMV.Vector3 contactNormal, float pentrationDepth)
     {

OpenSim/Region/Physics/BulletSPlugin/BSPrim.cs

@@ -495,8 +495,8 @@ public class BSPrim : BSPhysObject
         }
     }
 
-        // Find and return a handle to the current vehicle actor.
+    // Find and return a handle to the current vehicle actor.
-        // Return 'null' if there is no vehicle actor.
+    // Return 'null' if there is no vehicle actor.
     public BSDynamics GetVehicleActor()
     {
         BSDynamics ret = null;
@@ -507,6 +507,7 @@ public class BSPrim : BSPhysObject
         }
         return ret;
     }
+
     public override int VehicleType {
         get {
             int ret = (int)Vehicle.TYPE_NONE;

OpenSim/Region/Physics/BulletSPlugin/BSPrimLinkable.cs

@@ -200,20 +200,38 @@ public class BSPrimLinkable : BSPrimDisplaced
     }
 
     // Called after a simulation step to post a collision with this object.
+    // This returns 'true' if the collision has been queued and the SendCollisions call must
+    //     be made at the end of the simulation step.
     public override bool Collide(uint collidingWith, BSPhysObject collidee,
                     OMV.Vector3 contactPoint, OMV.Vector3 contactNormal, float pentrationDepth)
     {
-        // prims in the same linkset cannot collide with each other
+        bool ret = false;
-        BSPrimLinkable convCollidee = collidee as BSPrimLinkable;
+        // Ask the linkset if it wants to handle the collision
-        if (convCollidee != null && (this.Linkset.LinksetID == convCollidee.Linkset.LinksetID))
+        if (!Linkset.HandleCollide(collidingWith, collidee, contactPoint, contactNormal, pentrationDepth))
         {
-            return false;
+            // The linkset didn't handle it so pass the collision through normal processing
+            ret = base.Collide(collidingWith, collidee, contactPoint, contactNormal, pentrationDepth);
         }
+        return ret;
+    }
 
-        // TODO: handle collisions of other objects with with children of linkset.
+    // A linkset reports any collision on any part of the linkset.
-        //    This is a problem for LinksetCompound since the children are packed into the root.
+    public long SomeCollisionSimulationStep = 0;
+    public override bool HasSomeCollision
+    {
+        get
+        {
+            return (SomeCollisionSimulationStep == PhysScene.SimulationStep) || base.IsColliding;
+        }
+        set
+        {
+            if (value)
+                SomeCollisionSimulationStep = PhysScene.SimulationStep;
+            else
+                SomeCollisionSimulationStep = 0;
 
-        return base.Collide(collidingWith, collidee, contactPoint, contactNormal, pentrationDepth);
+            base.HasSomeCollision = value;
+        }
     }
 }
 }