From 7c4e0ff03c5ba9331feb777247594e94fc0f7ac1 Mon Sep 17 00:00:00 2001
From: teravus <teravus@gmail.com>
Date: Wed, 30 Jan 2013 06:22:05 -0500
Subject: [PATCH] * Adds a satisfying angular roll when an avatar is flying and
 turning.  (General, not physics).  Makes flying not feel as stiff.

---
 .../ClientStack/Linden/UDP/LLClientView.cs    |  2 +-
 .../Region/Framework/Scenes/ScenePresence.cs  | 81 +++++++++++++++++++
 2 files changed, 82 insertions(+), 1 deletion(-)

diff --git a/OpenSim/Region/ClientStack/Linden/UDP/LLClientView.cs b/OpenSim/Region/ClientStack/Linden/UDP/LLClientView.cs
index 0ccd69a70b..88b64f5f66 100644
--- a/OpenSim/Region/ClientStack/Linden/UDP/LLClientView.cs
+++ b/OpenSim/Region/ClientStack/Linden/UDP/LLClientView.cs
@@ -4893,7 +4893,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
                 // may improve movement smoothness.
 //                acceleration = new Vector3(1, 0, 0);
                 
-                angularVelocity = Vector3.Zero;
+                angularVelocity = presence.AngularVelocity;
                 rotation = presence.Rotation;
 
                 if (sendTexture)
diff --git a/OpenSim/Region/Framework/Scenes/ScenePresence.cs b/OpenSim/Region/Framework/Scenes/ScenePresence.cs
index a90872e541..1d22560f3d 100644
--- a/OpenSim/Region/Framework/Scenes/ScenePresence.cs
+++ b/OpenSim/Region/Framework/Scenes/ScenePresence.cs
@@ -200,6 +200,11 @@ namespace OpenSim.Region.Framework.Scenes
 
         private const int LAND_VELOCITYMAG_MAX = 12;
 
+        private const float FLY_ROLL_MAX_RADIANS = 1.1f;
+
+        private const float FLY_ROLL_RADIANS_PER_SECOND = 0.06f;
+        private const float FLY_ROLL_RESET_RADIANS_PER_SECOND = 0.02f;
+
         private float m_health = 100f;
 
         protected ulong crossingFromRegion;
@@ -568,6 +573,14 @@ namespace OpenSim.Region.Framework.Scenes
             }
         }
 
+        // Used for limited viewer 'fake' user rotations.
+        private Vector3 m_AngularVelocity = Vector3.Zero;
+
+        public Vector3 AngularVelocity
+        {
+            get { return m_AngularVelocity; }
+        }
+
         public bool IsChildAgent { get; set; }
 
         /// <summary>
@@ -690,6 +703,8 @@ namespace OpenSim.Region.Framework.Scenes
 
         #endregion
 
+
+
         #region Constructor(s)
 
         public ScenePresence(
@@ -1033,6 +1048,49 @@ namespace OpenSim.Region.Framework.Scenes
             ControllingClient.StopFlying(this);
         }
 
+        /// <summary>
+        /// Applies a roll accumulator to the avatar's angular velocity for the avatar fly roll effect.
+        /// </summary>
+        /// <param name="amount">Postive or negative roll amount in radians</param>
+        private void ApplyFlyingRoll(float amount)
+        {
+            float noise = ((float)(Util.RandomClass.NextDouble()*0.2f)-0.1f);
+            float rollAmount = Util.Clamp(m_AngularVelocity.Z + amount, -FLY_ROLL_MAX_RADIANS, FLY_ROLL_MAX_RADIANS) + noise;
+            m_AngularVelocity.Z = rollAmount;
+        }
+
+        /// <summary>
+        /// incrementally sets roll amount to zero
+        /// </summary>
+        /// <param name="amount">Positive roll amount in radians</param>
+        /// <returns></returns>
+        private float CalculateFlyingRollResetToZero(float amount)
+        {
+            const float rollMinRadians = 0f;
+
+            if (m_AngularVelocity.Z > 0)
+            {
+                
+                float leftOverToMin = m_AngularVelocity.Z - rollMinRadians;
+                if (amount > leftOverToMin)
+                    return -leftOverToMin;
+                else
+                    return -amount;
+
+            }
+            else
+            {
+                
+                float leftOverToMin = -m_AngularVelocity.Z - rollMinRadians;
+                if (amount > leftOverToMin)
+                    return leftOverToMin;
+                else
+                    return amount;
+            }
+        }
+        
+
+
         // neighbouring regions we have enabled a child agent in
         // holds the seed cap for the child agent in that region
         private Dictionary<ulong, string> m_knownChildRegions = new Dictionary<ulong, string>();
@@ -1513,6 +1571,29 @@ namespace OpenSim.Region.Framework.Scenes
                     bool controlland = (((flags & AgentManager.ControlFlags.AGENT_CONTROL_UP_NEG) != 0) ||
                                         ((flags & AgentManager.ControlFlags.AGENT_CONTROL_NUDGE_UP_NEG) != 0));
 
+
+                   
+                    // Applies a satisfying roll effect to the avatar when flying.
+                    if (((flags & AgentManager.ControlFlags.AGENT_CONTROL_TURN_LEFT) != 0) && ((flags & AgentManager.ControlFlags.AGENT_CONTROL_YAW_POS) != 0))
+                    {
+                        ApplyFlyingRoll(FLY_ROLL_RADIANS_PER_SECOND);
+                        
+                    } 
+                    else if (((flags & AgentManager.ControlFlags.AGENT_CONTROL_TURN_RIGHT) != 0) &&
+                             ((flags & AgentManager.ControlFlags.AGENT_CONTROL_YAW_NEG) != 0))
+                    {
+                        ApplyFlyingRoll(-FLY_ROLL_RADIANS_PER_SECOND);
+
+                    }
+                    else
+                    {
+                        if (m_AngularVelocity.Z != 0)
+                            m_AngularVelocity.Z += CalculateFlyingRollResetToZero(FLY_ROLL_RESET_RADIANS_PER_SECOND);
+                        
+                    }
+                  
+
+
                     if (Flying && IsColliding && controlland)
                     {
                         // nesting this check because LengthSquared() is expensive and we don't