From 48134af6162249885740bad80a6b1bbb618bbc6e Mon Sep 17 00:00:00 2001
From: Kitto Flora
Date: Wed, 3 Feb 2010 16:20:13 -0500
Subject: Motor angular decay fix.

---
 OpenSim/Region/Physics/ChOdePlugin/ODEDynamics.cs | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

(limited to 'OpenSim/Region')

diff --git a/OpenSim/Region/Physics/ChOdePlugin/ODEDynamics.cs b/OpenSim/Region/Physics/ChOdePlugin/ODEDynamics.cs
index c03e381..4eb3313 100644
--- a/OpenSim/Region/Physics/ChOdePlugin/ODEDynamics.cs
+++ b/OpenSim/Region/Physics/ChOdePlugin/ODEDynamics.cs
@@ -646,12 +646,15 @@ namespace OpenSim.Region.Physics.OdePlugin
 //if(frcount == 0) Console.WriteLine("V0 = {0}", angObjectVel);        	
 //   	Vector3 FrAaccel = m_lastAngularVelocity - angObjectVel;
 //    Vector3 initavel =  angObjectVel;       	
-        	// Decay Angular Motor
+        	// Decay Angular Motor 1. In SL this also depends on attack rate! decay ~= 23/Attack.
+        	float atk_decayfactor = 23.0f  / (m_angularMotorTimescale * pTimestep); 
+        	m_angularMotorDVel -= m_angularMotorDVel / atk_decayfactor;
+        	// Decay Angular Motor 2.
         	if (m_angularMotorDecayTimescale < 300.0f)
         	{
-				float decayfactor = m_angularMotorDecayTimescale/pTimestep;
-	            Vector3 decayAmount = (m_angularMotorDVel/decayfactor);
-	            m_angularMotorDVel -= decayAmount;        	
+				float decayfactor = m_angularMotorDecayTimescale/pTimestep;			// df = Dec / pts
+	            Vector3 decayAmount = (m_angularMotorDVel/decayfactor);				// v-da = v-Dvel / df  = v-Dvel * pts / Dec
+	            m_angularMotorDVel -= decayAmount;        							// v-Dvel = v-Dvel - (v-Dvel / df  = v-Dvel * pts / Dec)
         	
 				if (m_angularMotorDVel.ApproxEquals(Vector3.Zero, 0.01f))
 				{
-- 
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