BulletSim: adjust avatar position when the avatar's size is changed.

This fixes the problem of avatars bouncing when logged in.
Added a little height to the avatar height fudges to eliminate a problem
of feet being in the ground a bit.

OpenSim/Region/Physics/BulletSPlugin/BSCharacter.cs

@@ -96,8 +96,8 @@ public sealed class BSCharacter : BSPhysObject
         m_moveActor = new BSActorAvatarMove(PhysScene, this, AvatarMoveActorName);
         PhysicalActors.Add(AvatarMoveActorName, m_moveActor);
 
-        DetailLog("{0},BSCharacter.create,call,size={1},scale={2},density={3},volume={4},mass={5}",
+        DetailLog("{0},BSCharacter.create,call,size={1},scale={2},density={3},volume={4},mass={5},pos={6}",
-                            LocalID, _size, Scale, Density, _avatarVolume, RawMass);
+                            LocalID, _size, Scale, Density, _avatarVolume, RawMass, pos);
 
         // do actual creation in taint time
         PhysScene.TaintedObject("BSCharacter.create", delegate()
@@ -190,6 +190,10 @@ public sealed class BSCharacter : BSPhysObject
         }
 
         set {
+            // This is how much the avatar size is changing. Positive means getting bigger.
+            // The avatar altitude must be adjusted for this change.
+            float heightChange = value.Z - _size.Z;
+
             _size = value;
             // Old versions of ScenePresence passed only the height. If width and/or depth are zero,
             //     replace with the default values.
@@ -207,6 +211,10 @@ public sealed class BSCharacter : BSPhysObject
                 {
                     PhysScene.PE.SetLocalScaling(PhysShape.physShapeInfo, Scale);
                     UpdatePhysicalMassProperties(RawMass, true);
+
+                    // Adjust the avatar's position to account for the increase/decrease in size
+                    ForcePosition = new OMV.Vector3(RawPosition.X, RawPosition.Y, RawPosition.Z + heightChange / 2f);
+
                     // Make sure this change appears as a property update event
                     PhysScene.PE.PushUpdate(PhysBody);
                 }

OpenSim/Region/Physics/BulletSPlugin/BSParam.cs

@@ -570,9 +570,9 @@ public static class BSParam
         new ParameterDefn<float>("AvatarHeightLowFudge", "A fudge factor to make small avatars stand on the ground",
             -0.2f ),
         new ParameterDefn<float>("AvatarHeightMidFudge", "A fudge distance to adjust average sized avatars to be standing on ground",
-            0.1f ),
+            0.2f ),
         new ParameterDefn<float>("AvatarHeightHighFudge", "A fudge factor to make tall avatars stand on the ground",
-            0.1f ),
+            0.2f ),
 	    new ParameterDefn<float>("AvatarContactProcessingThreshold", "Distance from capsule to check for collisions",
             0.1f ),
 	    new ParameterDefn<float>("AvatarBelowGroundUpCorrectionMeters", "Meters to move avatar up if it seems to be below ground",