BulletSim: add function to push avatar up when hitting stairs.

It looks like BulletSim and ODE rely on penetration correction to cause
the avatar to move up and thus allowing walking up stairs. Object
penetration was minimized for walking and flying (so one doesn't go
through walls) and this stopped stairs from working. This commit
introduces avatar movement code to check for collisions at the
feet while walking and attempts to raise the avatar for the steps.
Not yet perfect but movement is better.

1 files changed, 27 insertions, 0 deletions

diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSPhysObject.cs b/OpenSim/Region/Physics/BulletSPlugin/BSPhysObject.cs
index 534f929..e8575f6 100755
--- a/OpenSim/Region/Physics/BulletSPlugin/BSPhysObject.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSPhysObject.cs
@@ -79,6 +79,7 @@ public abstract class BSPhysObject : PhysicsActor
         Material = MaterialAttributes.Material.Wood;
 
         CollisionCollection = new CollisionEventUpdate();
+        CollisionsLastTick = CollisionCollection;
         SubscribedEventsMs = 0;
         CollidingStep = 0;
         CollidingGroundStep = 0;
@@ -159,6 +160,7 @@ public abstract class BSPhysObject : PhysicsActor
     public abstract OMV.Quaternion ForceOrientation { get; set; }
 
     // The system is telling us the velocity it wants to move at.
+    // Velocity in world coordinates.
     // protected OMV.Vector3 m_targetVelocity;  // use the definition in PhysicsActor
     public override OMV.Vector3 TargetVelocity
     {
@@ -169,6 +171,15 @@ public abstract class BSPhysObject : PhysicsActor
             Velocity = value;
         }
     }
+    public virtual float TargetSpeed
+    {
+        get
+        {
+            OMV.Vector3 characterOrientedVelocity = TargetVelocity * OMV.Quaternion.Inverse(OMV.Quaternion.Normalize(RawOrientation));
+            return characterOrientedVelocity.X;
+        }
+    }
+    public abstract OMV.Vector3 RawVelocity { get; set; }
     public abstract OMV.Vector3 ForceVelocity { get; set; }
 
     public abstract OMV.Vector3 ForceRotationalVelocity { get; set; }
@@ -177,6 +188,15 @@ public abstract class BSPhysObject : PhysicsActor
 
     public virtual bool ForceBodyShapeRebuild(bool inTaintTime) { return false; }
 
+    public virtual float ForwardSpeed
+    {
+        get
+        {
+            OMV.Vector3 characterOrientedVelocity = RawVelocity * OMV.Quaternion.Inverse(OMV.Quaternion.Normalize(RawOrientation));
+            return characterOrientedVelocity.X;
+        }
+    }
+
     #region Collisions
 
     // Requested number of milliseconds between collision events. Zero means disabled.
@@ -223,9 +243,13 @@ public abstract class BSPhysObject : PhysicsActor
 
     // The collisions that have been collected this tick
     protected CollisionEventUpdate CollisionCollection;
+    // Remember collisions from last tick for fancy collision based actions
+    //     (like a BSCharacter walking up stairs).
+    protected CollisionEventUpdate CollisionsLastTick;
 
     // The simulation step is telling this object about a collision.
     // 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 virtual bool Collide(uint collidingWith, BSPhysObject collidee,
                     OMV.Vector3 contactPoint, OMV.Vector3 contactNormal, float pentrationDepth)
@@ -286,6 +310,9 @@ public abstract class BSPhysObject : PhysicsActor
             // DetailLog("{0},{1}.SendCollisionUpdate,call,numCollisions={2}", LocalID, TypeName, CollisionCollection.Count);
             base.SendCollisionUpdate(CollisionCollection);
 
+            // Remember the collisions from this tick for some collision specific processing.
+            CollisionsLastTick = CollisionCollection;
+
             // The CollisionCollection instance is passed around in the simulator.
             // Make sure we don't have a handle to that one and that a new one is used for next time.
             //    This fixes an interesting 'gotcha'. If we call CollisionCollection.Clear() here,