/*
 * Copyright (c) Contributors, http://opensimulator.org/
 * See CONTRIBUTORS.TXT for a full list of copyright holders.
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 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
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 *       documentation and/or other materials provided with the distribution.
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 *       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
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 *
 * The quotations from http://wiki.secondlife.com/wiki/Linden_Vehicle_Tutorial
 * are Copyright (c) 2009 Linden Research, Inc and are used under their license
 * of Creative Commons Attribution-Share Alike 3.0
 * (http://creativecommons.org/licenses/by-sa/3.0/).
 */

using System;
using System.Collections.Generic;
using System.Reflection;
using System.Runtime.InteropServices;
using OpenMetaverse;
using OpenSim.Framework;
using OpenSim.Region.Physics.Manager;

using OMV = OpenMetaverse;

namespace OpenSim.Region.Physics.BulletSPlugin
{
public class BSPrimDisplaced : BSPrim
{
    // The purpose of this subclass is to do any mapping between what the simulator thinks
    //    the prim position and orientation is and what the physical position/orientation.
    //    This difference happens because Bullet assumes the center-of-mass is the <0,0,0>
    //    of the prim/linkset. The simulator, on the other hand, tracks the location of
    //    the prim/linkset by the location of the root prim. So, if center-of-mass is anywhere
    //    but the origin of the root prim, the physical origin is displaced from the simulator origin.
    //
    // This routine works by capturing ForcePosition and
    //    adjusting the simulator values (being set) into the physical values.
    //    The conversion is also done in the opposite direction (physical origin -> simulator origin).
    //
    // The updateParameter call is also captured and the values from the physics engine
    //    are converted into simulator origin values before being passed to the base
    //    class.

    public virtual OMV.Vector3 PositionDisplacement { get; set; }

    public BSPrimDisplaced(uint localID, String primName, BSScene parent_scene, OMV.Vector3 pos, OMV.Vector3 size,
                       OMV.Quaternion rotation, PrimitiveBaseShape pbs, bool pisPhysical)
        : base(localID, primName, parent_scene, pos, size, rotation, pbs, pisPhysical)
    {
        ClearDisplacement();
    }

    // Clears any center-of-mass displacement introduced by linksets, etc.
    // Does not clear the displacement set by the user.
    public void ClearDisplacement()
    {
        SetEffectiveCenterOfMassDisplacement(OMV.Vector3.Zero);
    }

    // Set this sets and computes the displacement from the passed prim to the center-of-mass.
    // A user set value for center-of-mass overrides whatever might be passed in here.
    // The displacement is in local coordinates (relative to root prim in linkset oriented coordinates).
    // Called at taint time.
    public virtual void SetEffectiveCenterOfMassDisplacement(Vector3 centerOfMassDisplacement)
    {
        Vector3 comDisp;
        if (UserSetCenterOfMassDisplacement.HasValue)
            comDisp = (OMV.Vector3)UserSetCenterOfMassDisplacement;
        else
            comDisp = centerOfMassDisplacement;

        if (comDisp.ApproxEquals(Vector3.Zero, 0.01f) )
            comDisp = Vector3.Zero;

        DetailLog("{0},BSPrimDisplaced.SetEffectiveCenterOfMassDisplacement,userSet={1},comDisp={2}",
                                    LocalID, UserSetCenterOfMassDisplacement.HasValue, comDisp);
        if ( comDisp != PositionDisplacement )
        {
            // Displacement setting is changing.
            // The relationship between the physical object and simulated object must be aligned.
            PositionDisplacement = comDisp;
            this.ForcePosition = RawPosition;
        }
    }

    public override Vector3 ForcePosition
    {
        get { return base.ForcePosition; }
        set
        {
            if (PositionDisplacement != OMV.Vector3.Zero)
            {
                // The displacement is always relative to the vehicle so, when setting position,
                //    the caller means to set the position of the root prim.
                // This offsets the setting value to the center-of-mass and sends that to the
                //    physics engine.
                OMV.Vector3 displacedPos = value - (PositionDisplacement * RawOrientation);
                DetailLog("{0},BSPrimDisplaced.ForcePosition,val={1},disp={2},newPos={3}", LocalID, value, PositionDisplacement, displacedPos);
                base.ForcePosition = displacedPos;
            }
            else
            {
                base.ForcePosition = value;
            }
        }
    }

    // These are also overridden by BSPrimLinkable if the prim can be part of a linkset
    public override OMV.Vector3 CenterOfMass
    {
        get { return RawPosition; }
    }

    public override OMV.Vector3 GeometricCenter
    {
        get { return RawPosition; }
    }

    public override void UpdateProperties(EntityProperties entprop)
    {
        // Undo any center-of-mass displacement that might have been done.
        if (PositionDisplacement != OMV.Vector3.Zero)
        {
            // The origional shape was offset from 'zero' by PositionDisplacement.
            // These physical location must be back converted to be centered around the displaced
            //     root shape.

            // The root position is the reported position displaced by the rotated displacement.
            OMV.Vector3 displacedPos = entprop.Position + (PositionDisplacement * entprop.Rotation);
            DetailLog("{0},BSPrimDisplaced.UpdateProperties,physPos={1},disp={2},newPos={3}",
                                    LocalID, entprop.Position, PositionDisplacement, displacedPos);
            entprop.Position = displacedPos;
        }

        base.UpdateProperties(entprop);
    }
}
}