1 files changed, 174 insertions, 0 deletions

diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSActorHover.cs b/OpenSim/Region/Physics/BulletSPlugin/BSActorHover.cs
new file mode 100755
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--- /dev/null
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSActorHover.cs
@@ -0,0 +1,174 @@
+/*
+ * 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 OpenSim.Region.Physics.Manager;
+
+using OMV = OpenMetaverse;
+
+namespace OpenSim.Region.Physics.BulletSPlugin
+{
+public class BSActorHover : BSActor
+{
+    private BSFMotor m_hoverMotor;
+
+    public BSActorHover(BSScene physicsScene, BSPhysObject pObj, string actorName)
+        : base(physicsScene, pObj, actorName)
+    {
+        m_hoverMotor = null;
+        m_physicsScene.DetailLog("{0},BSActorHover,constructor", m_controllingPrim.LocalID);
+    }
+
+    // BSActor.isActive
+    public override bool isActive
+    {
+        get { return Enabled; }
+    }
+
+    // Release any connections and resources used by the actor.
+    // BSActor.Dispose()
+    public override void Dispose()
+    {
+        Enabled = false;
+    }
+
+    // Called when physical parameters (properties set in Bullet) need to be re-applied.
+    // Called at taint-time.
+    // BSActor.Refresh()
+    public override void Refresh()
+    {
+        m_physicsScene.DetailLog("{0},BSActorHover,refresh", m_controllingPrim.LocalID);
+
+        // If not active any more, turn me off
+        if (!m_controllingPrim.HoverActive)
+        {
+            SetEnabled(false);
+        }
+
+        // If the object is physically active, add the hoverer prestep action
+        if (isActive)
+        {
+            ActivateHover();
+        }
+        else
+        {
+            DeactivateHover();
+        }
+    }
+
+    // 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.RemoveBodyDependencies()
+    public override void RemoveBodyDependencies()
+    {
+        // Nothing to do for the hoverer since it is all software at pre-step action time.
+    }
+
+    // If a hover motor has not been created, create one and start the hovering.
+    private void ActivateHover()
+    {
+        if (m_hoverMotor == null)
+        {
+            // Turning the target on
+            m_hoverMotor = new BSFMotor("BSActorHover",
+                                        m_controllingPrim.HoverTau,               // timeScale
+                                        BSMotor.Infinite,           // decay time scale
+                                        BSMotor.Infinite,           // friction timescale
+                                        1f                          // efficiency
+            );
+            m_hoverMotor.SetTarget(ComputeCurrentHoverHeight());
+            m_hoverMotor.SetCurrent(m_controllingPrim.RawPosition.Z);
+            m_hoverMotor.PhysicsScene = m_physicsScene; // DEBUG DEBUG so motor will output detail log messages.
+
+            m_physicsScene.BeforeStep += Hoverer;
+        }
+    }
+
+    private void DeactivateHover()
+    {
+        if (m_hoverMotor != null)
+        {
+            m_physicsScene.BeforeStep -= Hoverer;
+            m_hoverMotor = null;
+        }
+    }
+
+    // Called just before the simulation step. Update the vertical position for hoverness.
+    private void Hoverer(float timeStep)
+    {
+        // Don't do hovering while the object is selected.
+        if (!isActive)
+            return;
+
+        m_hoverMotor.SetCurrent(m_controllingPrim.RawPosition.Z);
+        m_hoverMotor.SetTarget(ComputeCurrentHoverHeight());
+        float targetHeight = m_hoverMotor.Step(timeStep);
+
+        // 'targetHeight' is where we'd like the Z of the prim to be at this moment.
+        // Compute the amount of force to push us there.
+        float moveForce = (targetHeight - m_controllingPrim.RawPosition.Z) * m_controllingPrim.RawMass;
+        // Undo anything the object thinks it's doing at the moment
+        moveForce = -m_controllingPrim.RawVelocity.Z * m_controllingPrim.Mass;
+
+        m_physicsScene.PE.ApplyCentralImpulse(m_controllingPrim.PhysBody, new OMV.Vector3(0f, 0f, moveForce));
+        m_physicsScene.DetailLog("{0},BSPrim.Hover,move,targHt={1},moveForce={2},mass={3}",
+                        m_controllingPrim.LocalID, targetHeight, moveForce, m_controllingPrim.RawMass);
+    }
+
+    // Based on current position, determine what we should be hovering at now.
+    // Must recompute often. What if we walked offa cliff>
+    private float ComputeCurrentHoverHeight()
+    {
+        float ret = m_controllingPrim.HoverHeight;
+        float groundHeight = m_physicsScene.TerrainManager.GetTerrainHeightAtXYZ(m_controllingPrim.RawPosition);
+
+        switch (m_controllingPrim.HoverType)
+        {
+            case PIDHoverType.Ground:
+                ret = groundHeight + m_controllingPrim.HoverHeight;
+                break;
+            case PIDHoverType.GroundAndWater:
+                float waterHeight = m_physicsScene.TerrainManager.GetWaterLevelAtXYZ(m_controllingPrim.RawPosition);
+                if (groundHeight > waterHeight)
+                {
+                    ret = groundHeight + m_controllingPrim.HoverHeight;
+                }
+                else
+                {
+                    ret = waterHeight + m_controllingPrim.HoverHeight;
+                }
+                break;
+        }
+        return ret;
+    }
+}
+}