From 412dd7dfc56a10f590a42d0e6d014da9f4551bbf Mon Sep 17 00:00:00 2001
From: "Justin Clark-Casey (justincc)" <jjustincc@googlemail.com>
Date: Thu, 26 Feb 2015 00:48:51 +0000
Subject: [PATCH] When an avatar is walking across a region border, force the
 first AgentUpdate received on the new root agent to update movement
 parameters.

This prevents the avatar from drifting in its last direction of travel if a movement key was released at certain moments in the cross.
Relates to http://opensimulator.org/mantis/view.php?id=7435
---
 .../Region/Framework/Scenes/ScenePresence.cs  | 23 +++++++++++++++----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/OpenSim/Region/Framework/Scenes/ScenePresence.cs b/OpenSim/Region/Framework/Scenes/ScenePresence.cs
index 0414f893c3..973f2cf1ce 100644
--- a/OpenSim/Region/Framework/Scenes/ScenePresence.cs
+++ b/OpenSim/Region/Framework/Scenes/ScenePresence.cs
@@ -378,6 +378,11 @@ namespace OpenSim.Region.Framework.Scenes
         /// </summary>
         public uint MovementFlag { get; private set; }
 
+        /// <summary>
+        /// Set this if we need to force a movement update on the next received AgentUpdate from the viewer.
+        /// </summary>
+        private const uint ForceUpdateMovementFlagValue = uint.MaxValue;
+
         /// <summary>
         /// Is the agent stop control flag currently active?
         /// </summary>
@@ -1267,7 +1272,7 @@ namespace OpenSim.Region.Framework.Scenes
             // If we don't reset the movement flag here, an avatar that crosses to a neighbouring sim and returns will
             // stall on the border crossing since the existing child agent will still have the last movement
             // recorded, which stops the input from being processed.
-            MovementFlag = 0;
+            MovementFlag = ForceUpdateMovementFlagValue;
 
             m_scene.EventManager.TriggerOnMakeRootAgent(this);
 
@@ -1925,13 +1930,13 @@ namespace OpenSim.Region.Framework.Scenes
         /// </summary>
         public void HandleAgentUpdate(IClientAPI remoteClient, AgentUpdateArgs agentData)
         {
-            //m_log.DebugFormat(
-            //    "[SCENE PRESENCE]: In {0} received agent update from {1}, flags {2}",
-            //    Scene.RegionInfo.RegionName, remoteClient.Name, (AgentManager.ControlFlags)agentData.ControlFlags);
+//            m_log.DebugFormat(
+//                "[SCENE PRESENCE]: In {0} received agent update from {1}, flags {2}",
+//                Scene.Name, remoteClient.Name, (AgentManager.ControlFlags)agentData.ControlFlags);
 
             if (IsChildAgent)
             {
-            //    // m_log.Debug("DEBUG: HandleAgentUpdate: child agent");
+//                m_log.DebugFormat("DEBUG: HandleAgentUpdate: child agent in {0}", Scene.Name);
                 return;
             }
 
@@ -2066,6 +2071,14 @@ namespace OpenSim.Region.Framework.Scenes
 
                 bool update_movementflag = false;
 
+                // If we were just made root agent then we must perform movement updates for the first AgentUpdate that
+                // we get
+                if (MovementFlag == ForceUpdateMovementFlagValue)
+                {
+                    MovementFlag = 0;
+                    update_movementflag = true;
+                }
+
                 if (agentData.UseClientAgentPosition)
                 {
                     MovingToTarget = (agentData.ClientAgentPosition - AbsolutePosition).Length() > 0.2f;