1 files changed, 219 insertions, 0 deletions

diff --git a/OpenSim/Region/PhysicsModules/BulletS/BSActorLockAxis.cs b/OpenSim/Region/PhysicsModules/BulletS/BSActorLockAxis.cs
new file mode 100755
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--- /dev/null
+++ b/OpenSim/Region/PhysicsModules/BulletS/BSActorLockAxis.cs
@@ -0,0 +1,219 @@
+/*
+ * Copyright (c) Contributors, http://opensimulator.org/
+ * See CONTRIBUTORS.TXT for a full list of copyright holders.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyrightD
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the OpenSimulator Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+using OMV = OpenMetaverse;
+
+namespace OpenSim.Region.Physics.BulletSPlugin
+{
+public class BSActorLockAxis : BSActor
+{
+    private BSConstraint LockAxisConstraint = null;
+    private bool HaveRegisteredForBeforeStepCallback = false;
+
+    // The lock access flags (which axises were locked) when the contraint was built.
+    // Used to see if locking has changed since when the constraint was built.
+    OMV.Vector3 LockAxisLinearFlags;
+    OMV.Vector3 LockAxisAngularFlags;
+
+    public BSActorLockAxis(BSScene physicsScene, BSPhysObject pObj, string actorName)
+        : base(physicsScene, pObj, actorName)
+    {
+        m_physicsScene.DetailLog("{0},BSActorLockAxis,constructor", m_controllingPrim.LocalID);
+        LockAxisConstraint = null;
+        HaveRegisteredForBeforeStepCallback = false;
+    }
+
+    // BSActor.isActive
+    public override bool isActive
+    {
+        get { return Enabled && m_controllingPrim.IsPhysicallyActive; }
+    }
+
+    // Release any connections and resources used by the actor.
+    // BSActor.Dispose()
+    public override void Dispose()
+    {
+        Enabled = false;
+        UnRegisterForBeforeStepCallback();
+        RemoveAxisLockConstraint();
+    }
+
+    // Called when physical parameters (properties set in Bullet) need to be re-applied.
+    // Called at taint-time.
+    // BSActor.Refresh()
+    public override void Refresh()
+    {
+        // Since the axis logging is done with a constraint, Refresh() time is good for
+        //    changing parameters but this needs to wait until the prim/linkset is physically
+        //    constructed. Therefore, the constraint itself is placed at pre-step time.
+
+        // If all the axis are free, we don't need to exist
+        // Refresh() only turns off. Enabling is done by InitializeAxisActor()
+        //      whenever parameters are changed.
+        //      This leaves 'enable' free to turn off an actor when it is not wanted to run.
+        if (m_controllingPrim.LockedAngularAxis == m_controllingPrim.LockedAxisFree
+                && m_controllingPrim.LockedLinearAxis == m_controllingPrim.LockedAxisFree)
+        {
+            Enabled = false;
+        }
+
+        if (isActive)
+        {
+            RegisterForBeforeStepCallback();
+        }
+        else
+        {
+            RemoveDependencies();
+            UnRegisterForBeforeStepCallback();
+        }
+    }
+
+    // The object's physical representation is being rebuilt so pick up any physical dependencies (constraints, ...).
+    //     Register a prestep action to restore physical requirements before the next simulation step.
+    // Called at taint-time.
+    // BSActor.RemoveDependencies()
+    public override void RemoveDependencies()
+    {
+        RemoveAxisLockConstraint();
+    }
+
+    private void RegisterForBeforeStepCallback()
+    {
+        if (!HaveRegisteredForBeforeStepCallback)
+        {
+            m_physicsScene.BeforeStep += PhysicsScene_BeforeStep;
+            HaveRegisteredForBeforeStepCallback = true;
+        }
+    }
+
+    private void UnRegisterForBeforeStepCallback()
+    {
+        if (HaveRegisteredForBeforeStepCallback)
+        {
+            m_physicsScene.BeforeStep -= PhysicsScene_BeforeStep;
+            HaveRegisteredForBeforeStepCallback = false;
+        }
+    }
+
+    private void PhysicsScene_BeforeStep(float timestep)
+    {
+        // If all the axis are free, we don't need to exist
+        if (m_controllingPrim.LockedAngularAxis == m_controllingPrim.LockedAxisFree
+                && m_controllingPrim.LockedLinearAxis == m_controllingPrim.LockedAxisFree)
+        {
+            Enabled = false;
+        }
+
+        // If the object is physically active, add the axis locking constraint
+        if (isActive)
+        {
+            // Check to see if the locking parameters have changed
+            if (m_controllingPrim.LockedLinearAxis != this.LockAxisLinearFlags
+                || m_controllingPrim.LockedAngularAxis != this.LockAxisAngularFlags)
+            {
+                // The locking has changed. Remove the old constraint and build a new one
+                RemoveAxisLockConstraint();
+            }
+
+            AddAxisLockConstraint();
+        }
+        else
+        {
+            RemoveAxisLockConstraint();
+        }
+    }
+
+    // Note that this relies on being called at TaintTime
+    private void AddAxisLockConstraint()
+    {
+        if (LockAxisConstraint == null)
+        {
+            // Lock that axis by creating a 6DOF constraint that has one end in the world and
+            //    the other in the object.
+            // http://www.bulletphysics.org/Bullet/phpBB3/viewtopic.php?p=20817
+            // http://www.bulletphysics.org/Bullet/phpBB3/viewtopic.php?p=26380
+
+            // Remove any existing axis constraint (just to be sure)
+            RemoveAxisLockConstraint();
+
+            BSConstraint6Dof axisConstrainer = new BSConstraint6Dof(m_physicsScene.World, m_controllingPrim.PhysBody,
+                                OMV.Vector3.Zero, OMV.Quaternion.Identity,
+                                false /* useLinearReferenceFrameB */, true /* disableCollisionsBetweenLinkedBodies */);
+            LockAxisConstraint = axisConstrainer;
+            m_physicsScene.Constraints.AddConstraint(LockAxisConstraint);
+
+            // Remember the clocking being inforced so we can notice if they have changed
+            LockAxisLinearFlags = m_controllingPrim.LockedLinearAxis;
+            LockAxisAngularFlags = m_controllingPrim.LockedAngularAxis;
+
+            // The constraint is tied to the world and oriented to the prim.
+
+            if (!axisConstrainer.SetLinearLimits(m_controllingPrim.LockedLinearAxisLow, m_controllingPrim.LockedLinearAxisHigh))
+            {
+                m_physicsScene.DetailLog("{0},BSActorLockAxis.AddAxisLockConstraint,failedSetLinearLimits",
+                        m_controllingPrim.LocalID);
+            }
+
+            if (!axisConstrainer.SetAngularLimits(m_controllingPrim.LockedAngularAxisLow, m_controllingPrim.LockedAngularAxisHigh))
+            {
+                m_physicsScene.DetailLog("{0},BSActorLockAxis.AddAxisLockConstraint,failedSetAngularLimits",
+                        m_controllingPrim.LocalID);
+            }
+
+            m_physicsScene.DetailLog("{0},BSActorLockAxis.AddAxisLockConstraint,create,linLow={1},linHi={2},angLow={3},angHi={4}",
+                                        m_controllingPrim.LocalID,
+                                        m_controllingPrim.LockedLinearAxisLow,
+                                        m_controllingPrim.LockedLinearAxisHigh,
+                                        m_controllingPrim.LockedAngularAxisLow,
+                                        m_controllingPrim.LockedAngularAxisHigh);
+
+            // Constants from one of the posts mentioned above and used in Bullet's ConstraintDemo.
+            axisConstrainer.TranslationalLimitMotor(true /* enable */, 5.0f, 0.1f);
+
+            axisConstrainer.RecomputeConstraintVariables(m_controllingPrim.RawMass);
+
+            RegisterForBeforeStepCallback();
+        }
+    }
+
+    private void RemoveAxisLockConstraint()
+    {
+        UnRegisterForBeforeStepCallback();
+        if (LockAxisConstraint != null)
+        {
+            m_physicsScene.Constraints.RemoveAndDestroyConstraint(LockAxisConstraint);
+            LockAxisConstraint = null;
+            m_physicsScene.DetailLog("{0},BSActorLockAxis.RemoveAxisLockConstraint,destroyingConstraint", m_controllingPrim.LocalID);
+        }
+    }
+}
+}