AttractorMotor.cpp

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/*************************************************************************
 *                                                                       *
 * Open Physics Abstraction Layer                                        *
 * Copyright (C) 2004-2005                                               *
 * Alan Fischer  alan.fischer@gmail.com                                  *
 * Andres Reinot  andres@reinot.com                                      *
 * Tyler Streeter  tylerstreeter@gmail.com                               *
 * All rights reserved.                                                  *
 * Web: opal.sourceforge.net                                             *
 *                                                                       *
 * This library is free software; you can redistribute it and/or         *
 * modify it under the terms of EITHER:                                  *
 *   (1) The GNU Lesser General Public License as published by the Free  *
 *       Software Foundation; either version 2.1 of the License, or (at  *
 *       your option) any later version. The text of the GNU Lesser      *
 *       General Public License is included with this library in the     *
 *       file license-LGPL.txt.                                          *
 *   (2) The BSD-style license that is included with this library in     *
 *       the file license-BSD.txt.                                       *
 *                                                                       *
 * This library is distributed in the hope that it will be useful,       *
 * but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the files    *
 * license-LGPL.txt and license-BSD.txt for more details.                *
 *                                                                       *
 *************************************************************************/

#include "AttractorMotor.h"
#include "Solid.h"

namespace opal
{
        AttractorMotor::AttractorMotor()
        : Motor()
        {
                // "mData" will be initialized in its own constructor.
                mSolid0Mass = 0;
                mSolid1Mass = 0;
                mMassConstant = 0;
        }

        AttractorMotor::~AttractorMotor()
        {
        }

        //void AttractorMotor::init(Solid* solid0, Solid* solid1)
        //{
        //      Motor::init();
        //      mSolid0 = solid0;
        //      mSolid1 = solid1;
        //      mSolid0Mass = solid0->getMass();
        //      mSolid1Mass = solid1->getMass();

        //      // Update this constant since the masses changed.
        //      mMassConstant = mStrength * mSolid0Mass * mSolid1Mass;
        //}

        void AttractorMotor::init(const AttractorMotorData& data)
        {
                Motor::init();
                mData = data;

                if (data.solid0 && data.solid1)
                {
                        mSolid0Mass = data.solid0->getMass();
                        mSolid1Mass = data.solid1->getMass();

                        // Update this constant since the masses changed.
                        mMassConstant = data.strength * mSolid0Mass * mSolid1Mass;
                }
        }

        const AttractorMotorData& AttractorMotor::getData()const
        {
                return mData;
        }

        MotorType AttractorMotor::getType()const
        {
                return mData.getType();
        }

        void AttractorMotor::setName(const std::string& name)
        {
                mData.name = name;
        }

        const std::string& AttractorMotor::getName()const
        {
                return mData.name;
        }

        bool AttractorMotor::isEnabled()const
        {
                return mData.enabled;
        }

        void AttractorMotor::setEnabled(bool e)
        {
                //if (!mInitCalled)
                //{
                //      return;
                //}

                mData.enabled = e;
        }

        void AttractorMotor::internal_update()
        {
                if (mData.enabled && mData.solid0 && mData.solid1)
                {
                        Point3r pos1 = mData.solid0->getPosition();
                        Point3r pos2 = mData.solid1->getPosition();

                        // Create a unit vector pointing from mSolid1 to mSolid0.
                        Vec3r direction = pos1 - pos2;
                        real distanceSquared = direction.lengthSquared();
                        if (0 != distanceSquared)
                        {
                                direction.normalize();
                        }

                        Force f;
                        f.singleStep = true;
                        f.type = GLOBAL_FORCE;
                        f.vec = direction;

                        // Use force magnitude = (strength * m0 * m1) / distance^exponent.
                        if ((real)2.0 == mData.exponent)
                        {
                                // If we know the exponent is 2, this can speed things up.
                                f.vec *= (mMassConstant / distanceSquared);
                        }
                        else
                        {
                                f.vec *= (mMassConstant / (pow(direction.length(), 
                                        mData.exponent)));
                        }

                        mData.solid1->addForce(f);
                        f.vec *= (real)-1.0;
                        mData.solid0->addForce(f);
                }
        }

        void AttractorMotor::setStrength(real s)
        {
                mData.strength = s;

                // Update this constant since the strength changed.
                mMassConstant = mData.strength * mSolid0Mass * mSolid1Mass;
        }

        real AttractorMotor::getStrength()const
        {
                return mData.strength;
        }

        void AttractorMotor::setExponent(real e)
        {
                mData.exponent = e;
        }

        real AttractorMotor::getExponent()const
        {
                return mData.exponent;
        }

        bool AttractorMotor::internal_dependsOnSolid(Solid* s)
        {
                if (s == mData.solid0 || s == mData.solid1)
                {
                        return true;
                }
                else
                {
                        return false;
                }
        }
}

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