FloorConstraint.cpp

/***************************************************************************
 *   This file is part of OpenCAL: Open Computer Animation Library         *
 *   I created OpenCAL as my master's thesis Computer Science (multimedia) *
 *   at the tUL university in Diepenbeek, Belgium                          *
 *                                                                         *
 *   Copyright (C) 2003-2004 by Jeroen Dierckx                             *
 *   jeroen.dierckx@student.luc.ac.be                                      *
 *                                                                         *
 ***************************************************************************/

// Includes
#include "FloorConstraint.h"
#include <OpenCAL/Plane.h>
#include <OpenCAL/PhysicsSystem.h>
#include <OpenCAL/PhysicalObject.h>
#include <OpenCAL/ObjectIterator.h>
using namespace OpenCAL;

#include <OpenCAL/Vector3.h>
using namespace Utils;

using namespace std;


/******************************
* Constructors and destructor *
******************************/

FloorConstraint::FloorConstraint(PhysicsSystem *parent)
: Constraint(parent), m_height(0.0f), m_plane(new Plane(parent)),
  //m_repulsion(10.0f), m_friction(0.6f), m_absorption(0.5f)
  m_restitution(0.0f), m_friction(0.3f)
{
}

FloorConstraint::FloorConstraint(PhysicsSystem *parent, Plane *floorPlane)
: Constraint(parent), m_height(0.0f), m_plane(floorPlane),
  //m_repulsion(10.0f), m_friction(0.6f), m_absorption(0.5f)
  m_restitution(0.0f), m_friction(0.3f)
{
}

FloorConstraint::~FloorConstraint()
{
}


/******************
* Other functions *
******************/

void OpenCAL::FloorConstraint::satisfy( )
{
    //if(!m_enabled) return;
    Constraint::satisfy();

    Vector3 point = m_plane->getPosition();
    Vector3 normal = m_plane->getNormal();

    ObjectIterator it(m_parent);
    while(*it)
//  for(unsigned int i = 0; i < m_parent->numObjects(); ++i)
    {
        PhysicalObject *object = (PhysicalObject *) *it;
//      PhysicalObject *object = (PhysicalObject *) m_parent->getObject(i);

/*
        float test = (object->getPosition() - point).dotProduct(normal);
        Vector3 vn = normal.dotProduct(object->getVelocity()) * object->getVelocity();
        Vector3 vt = object->getVelocity() - vn;

        if(test <= EPSILON && test >= -EPSILON) // Contact
        {
            float force = normal.dotProduct(object->getForce());
            if(force < 0.0f)
                object->addForce(-force * object->getForce());

            object->addForce(-m_friction * (-object->getForce()).dotProduct(normal) * object->getVelocity());
        }
        else if(test < 0.0f) // Collision
        {
            vn *= -m_restitution;
            object->setVelocity(vn + vt);
        }
*/

        float y = object->getPosition().getY();
        Vector3 vel;

        if(y <= (m_height + Math::verySmall) && y >= (m_height -Math::verySmall)) // Contact
        {
            Vector3 vel = object->getVelocity();

/*
            if(object->getForce().getY() < 0.0f)
                object->getForceP()->setY(-object->getForce().getY());
*/
            vel.setY(0.0f);
            object->addForce(-m_friction * vel);
        }
        else if(y < m_height) // Collision
        {
            object->getVelocityP()->setY(-object->getVelocityP()->getY() * m_restitution);
            object->getPositionP()->setY(m_height);

/*
            // Apply ground friction
            vel = object->getVelocity();
            vel.setY(0.0f); // No vertical velocity in friction
            object->addForce(-vel * m_friction);

            // Apply ground absorption
            vel = object->getVelocity();
            vel.setX(0.0f);
            vel.setZ(0.0f); // Only vertical velocity in absorption
            if(vel.getY() < 0.0f) // Only if moving towards ground
                object->addForce(-vel * m_absorption);

            // Apply ground repulsion
            object->addForce(Vector3(0, m_repulsion, 0) * (m_height - y));

            object->getPositionP()->setY(m_height);
*/
        }

        ++it;
    }
}

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