BulletSim: Modify first and default vehicle vertical attractor to be feature complete with use of the Limit Roll Only Flag.

Signed-off-by: Robert Adams <misterblue@misterblue.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSDynamics.cs b/OpenSim/Region/Physics/BulletSPlugin/BSDynamics.cs
index 05374e8..2bf32e7 100644
--- a/OpenSim/Region/Physics/BulletSPlugin/BSDynamics.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSDynamics.cs
@@ -1438,6 +1438,12 @@ namespace OpenSim.Region.Physics.BulletSPlugin
                             // This is only half the distance to the target so it will take 2 seconds to complete the turn.
                             Vector3 torqueVector = Vector3.Cross(predictedUp, Vector3.UnitZ);
 
+                            if ((m_flags & VehicleFlag.LIMIT_ROLL_ONLY) != 0)
+                            {
+                                Vector3 vehicleForwardAxis = Vector3.UnitX * VehicleOrientation;
+                                torqueVector = ProjectVector(torqueVector, vehicleForwardAxis);
+                            }
+
                             // Scale vector by our timescale since it is an acceleration it is r/s^2 or radians a timescale squared
                             Vector3 vertContributionV = torqueVector * verticalAttractionSpeed * verticalAttractionSpeed;
 
@@ -1739,6 +1745,14 @@ namespace OpenSim.Region.Physics.BulletSPlugin
 
         }
 
+        //Given a Vector and a unit vector will return the amount of the vector is on the same axis as the unit.
+        private Vector3 ProjectVector(Vector3 vector, Vector3 onNormal)
+        {
+            float vectorDot = Vector3.Dot(vector, onNormal);
+            return onNormal * vectorDot;
+
+        }
+
         private float ClampInRange(float low, float val, float high)
         {
             return Math.Max(low, Math.Min(val, high));