1 files changed, 15 insertions, 3 deletions

diff --git a/OpenSim/Region/Framework/Scenes/ScenePresence.cs b/OpenSim/Region/Framework/Scenes/ScenePresence.cs
index 1dc7e20..dae20a5 100644
--- a/OpenSim/Region/Framework/Scenes/ScenePresence.cs
+++ b/OpenSim/Region/Framework/Scenes/ScenePresence.cs
@@ -1648,12 +1648,24 @@ namespace OpenSim.Region.Framework.Scenes
 
             if (AllowMovement && !SitGround)
             {
-                Quaternion bodyRotation = agentData.BodyRotation;
+//                m_log.DebugFormat("[SCENE PRESENCE]: Initial body rotation {0} for {1}", agentData.BodyRotation, Name);
+
                 bool update_rotation = false;
 
-                if (bodyRotation != Rotation)
+                // Whilst not in mouselook, an avatar will transmit only the Z rotation as this is the only axis
+                // it rotates around.
+                // In mouselook, X and Y co-ordinate will also be sent but when used in Rotation, these cause unwanted
+                // excessive up and down movements of the camera when looking up and down.
+                // See http://opensimulator.org/mantis/view.php?id=3274
+                // This does not affect head movement, since this is controlled entirely by camera movement rather than
+                // body rotation.  It does not affect sitting avatar since it's the sitting part rotation that takes
+                // effect, not the avatar rotation.
+                // However, if we do need to store X and Y rotations in the future, another solution needs to be found
+                // for the mouselook bug.  Possibly, one could strip out X and Y rotations before sending the avatar
+                // update messages.
+                if (agentData.BodyRotation.Z != Rotation.Z || agentData.BodyRotation.W != Rotation.W)
                 {
-                    Rotation = bodyRotation;
+                    Rotation = new Quaternion(0, 0, agentData.BodyRotation.Z, agentData.BodyRotation.W);
                     update_rotation = true;
                 }