From 3c7eacf39b3768e88b09f9a5a438df0be0dbe03e Mon Sep 17 00:00:00 2001
From: "Justin Clark-Casey (justincc)" <jjustincc@googlemail.com>
Date: Tue, 2 Sep 2014 23:35:03 +0100
Subject: [PATCH] Fix recent regression from 473c5594 where camera started to
 judder on moving vehicles.

Other parts of OpenSimulator are relying on SP.Velocity == 0 for vehicles.
So add and use SP.GetWorldVelocity() instead when we need vehicle velocity, along the same lines as existing SP.GetWorldRotation()
---
 .../Region/Framework/Scenes/ScenePresence.cs  | 40 ++++++++++++-------
 .../Shared/Api/Implementation/LSL_Api.cs      |  6 +--
 2 files changed, 28 insertions(+), 18 deletions(-)

diff --git a/OpenSim/Region/Framework/Scenes/ScenePresence.cs b/OpenSim/Region/Framework/Scenes/ScenePresence.cs
index e0b76407c7..f2a636afc2 100644
--- a/OpenSim/Region/Framework/Scenes/ScenePresence.cs
+++ b/OpenSim/Region/Framework/Scenes/ScenePresence.cs
@@ -608,8 +608,11 @@ namespace OpenSim.Region.Framework.Scenes
         }
 
         /// <summary>
-        /// Current velocity of the avatar.
+        /// Velocity of the avatar with respect to its local reference frame.
         /// </summary>
+        /// <remarks>
+        /// So when sat on a vehicle this will be 0.  To get velocity with respect to the world use GetWorldVelocity()
+        /// </remarks>
         public override Vector3 Velocity
         {
             get
@@ -622,10 +625,10 @@ namespace OpenSim.Region.Framework.Scenes
 //                        "[SCENE PRESENCE]: Set velocity {0} for {1} in {2} via getting Velocity!",
 //                        m_velocity, Name, Scene.RegionInfo.RegionName);
                 }
-                else if (ParentPart != null)
-                {
-                    return ParentPart.ParentGroup.Velocity;
-                }
+//                else if (ParentPart != null)
+//                {
+//                    return ParentPart.ParentGroup.Velocity;
+//                }
 
                 return m_velocity;
             }
@@ -749,25 +752,32 @@ namespace OpenSim.Region.Framework.Scenes
         }
 
         /// <summary>
-        /// Gets the world rotation of this presence.
+        /// Get rotation relative to the world.
         /// </summary>
-        /// <remarks>
-        /// Unlike Rotation, this returns the world rotation no matter whether the avatar is sitting on a prim or not.
-        /// </remarks>
         /// <returns></returns>
         public Quaternion GetWorldRotation()
         {
-            if (IsSatOnObject)
-            {
-                SceneObjectPart sitPart = ParentPart;
+            SceneObjectPart sitPart = ParentPart;
 
-                if (sitPart != null)
-                    return sitPart.GetWorldRotation() * Rotation;
-            }
+            if (sitPart != null)
+                return sitPart.GetWorldRotation() * Rotation;
 
             return Rotation;
         }
 
+        /// <summary>
+        /// Get velocity relative to the world.
+        /// </summary>
+        public Vector3 GetWorldVelocity()
+        {
+            SceneObjectPart sitPart = ParentPart;
+
+            if (sitPart != null)
+                return sitPart.ParentGroup.Velocity;
+
+            return Velocity;
+        }
+
         public void AdjustKnownSeeds()
         {
             Dictionary<ulong, string> seeds;
diff --git a/OpenSim/Region/ScriptEngine/Shared/Api/Implementation/LSL_Api.cs b/OpenSim/Region/ScriptEngine/Shared/Api/Implementation/LSL_Api.cs
index 5d7fc9db0d..7c384b268f 100644
--- a/OpenSim/Region/ScriptEngine/Shared/Api/Implementation/LSL_Api.cs
+++ b/OpenSim/Region/ScriptEngine/Shared/Api/Implementation/LSL_Api.cs
@@ -2560,7 +2560,7 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api
             if (m_host.ParentGroup.IsAttachment)
             {
                 ScenePresence avatar = m_host.ParentGroup.Scene.GetScenePresence(m_host.ParentGroup.AttachedAvatar);
-                vel = avatar.Velocity;
+                vel = avatar.GetWorldVelocity();
             }
             else
             {
@@ -11221,7 +11221,7 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api
                                 ret.Add(new LSL_Rotation(av.GetWorldRotation()));
                                 break;
                             case ScriptBaseClass.OBJECT_VELOCITY:
-                                ret.Add(new LSL_Vector(av.Velocity.X, av.Velocity.Y, av.Velocity.Z));
+                                ret.Add(new LSL_Vector(av.GetWorldVelocity()));
                                 break;
                             case ScriptBaseClass.OBJECT_OWNER:
                                 ret.Add(new LSL_String(id));
@@ -11342,7 +11342,7 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api
                                     ScenePresence sp = World.GetScenePresence(obj.ParentGroup.AttachedAvatar);
 
                                     if (sp != null)
-                                        vel = sp.Velocity;
+                                        vel = sp.GetWorldVelocity();
                                 }
                                 else
                                 {