From 3b0df52d10c157cd2711d64ef9007d2afccbd468 Mon Sep 17 00:00:00 2001
From: Robert Adams
Date: Sun, 20 Jan 2013 09:33:13 -0800
Subject: BulletSim: modify motors to return correction rather than current
 value to better use them for incremental updates. Modify prim and character
 to use the new motors. Simplify the vehicle linear movement code to just
 update the velocity directly or the basic movement.

---
 OpenSim/Region/Physics/BulletSPlugin/BSDynamics.cs | 41 ++++++++--------------
 1 file changed, 14 insertions(+), 27 deletions(-)

(limited to 'OpenSim/Region/Physics/BulletSPlugin/BSDynamics.cs')

diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSDynamics.cs b/OpenSim/Region/Physics/BulletSPlugin/BSDynamics.cs
index f2c7cec..7c9b83b 100644
--- a/OpenSim/Region/Physics/BulletSPlugin/BSDynamics.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSDynamics.cs
@@ -957,39 +957,25 @@ namespace OpenSim.Region.Physics.BulletSPlugin
 
         public void ComputeLinearVelocity(float pTimestep)
         {
-            Vector3 linearMotorStep = m_linearMotor.Step(pTimestep);
+            // Step the motor from the current value. Get the correction needed this step.
+            Vector3 currentVel = VehicleVelocity * Quaternion.Inverse(VehicleOrientation);
+            Vector3 linearMotorCorrection = m_linearMotor.Step(pTimestep, currentVel);
 
-            // The movement computed in the linear motor is relative to the vehicle
-            //     coordinates. Rotate the movement to world coordinates.
-            Vector3 linearMotorVelocity = linearMotorStep * VehicleOrientation;
+            // Motor is vehicle coordinates. Rotate it to world coordinates
+            Vector3 linearMotorVelocity = linearMotorCorrection * VehicleOrientation;
 
-            // If we're a ground vehicle, don't loose any Z action (like gravity acceleration).
-            float mixFactor = 1f;   // 1 means use all linear motor Z value, 0 means use all existing Z
+            // If we're a ground vehicle, don't add any upward Z movement
             if ((m_flags & VehicleFlag.LIMIT_MOTOR_UP) != 0)
             {
-                if (!Prim.IsColliding)
-                {
-                    // If a ground vehicle and not on the ground, I want gravity effect
-                    mixFactor = 0.2f;
-                }
-            }
-            else
-            {
-                // I'm not a ground vehicle but don't totally loose the effect of the environment
-                mixFactor = 0.8f;
+                if (linearMotorVelocity.Z > 0f)
+                    linearMotorVelocity.Z = 0f;
             }
-            linearMotorVelocity.Z = mixFactor * linearMotorVelocity.Z + (1f - mixFactor) * VehicleVelocity.Z;
-
-            // What we want to contribute to the vehicle's existing velocity
-            Vector3 linearMotorForce = linearMotorVelocity - VehicleVelocity;
-
-            // Act against the inertia of the vehicle
-            linearMotorForce *= m_vehicleMass;
 
-            VehicleAddForceImpulse(linearMotorForce * pTimestep);
+            // Add this correction to the velocity to make it faster/slower.
+            VehicleVelocity += linearMotorVelocity;
 
-            VDetailLog("{0},  MoveLinear,velocity,vehVel={1},step={2},stepVel={3},mix={4},force={5}",
-                        Prim.LocalID, VehicleVelocity, linearMotorStep, linearMotorVelocity, mixFactor, linearMotorForce);
+            VDetailLog("{0},  MoveLinear,velocity,vehVel={1},correction={2},force={3}",
+                        Prim.LocalID, VehicleVelocity, linearMotorCorrection, linearMotorVelocity);
         }
 
         public void ComputeLinearTerrainHeightCorrection(float pTimestep)
@@ -1204,6 +1190,7 @@ namespace OpenSim.Region.Physics.BulletSPlugin
         {
             // The user wants this many radians per second angular change?
             Vector3 angularMotorContribution = m_angularMotor.Step(pTimestep);
+            angularMotorContribution = m_angularMotor.CurrentValue;
 
             // ==================================================================
             // From http://wiki.secondlife.com/wiki/LlSetVehicleFlags :
@@ -1234,7 +1221,7 @@ namespace OpenSim.Region.Physics.BulletSPlugin
                                     + deflectionContribution
                                     + bankingContribution;
 
-            // Add of the above computation are made relative to vehicle coordinates.
+            // All of the above computation are made relative to vehicle coordinates.
             // Convert to world coordinates.
             m_lastAngularVelocity *= VehicleOrientation;
 
-- 
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