K3dIntrLinePlane.cpp

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/***************************************************************************
 *   Copyright (C) 2007 by Jan Koci   *
 *   honza.koci@email.cz   *
 *   http://kengine.sourceforge.net/tutorial/
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program 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         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/

#include "K3dIntrLinePlane.h"

K3dIntrLinePlane::K3dIntrLinePlane(K3dGameData *_pGameData):
        K3dDistance(_pGameData)
{
        m_pGameData = _pGameData;
}

K3dIntrLinePlane::~K3dIntrLinePlane()
{
}

bool K3dIntrLinePlane::LinePlane(const K3dRay &_rkLine, const K3dPlane &_rkPlane)
{
        m_kIntrPoint.Reset();
        // Calculate distance plane and line origin point
        m_fDistanceOrigin = PointPlane(_rkPlane, *_rkLine.GetOrigin());
        // Calculate distance plane and line direction point
        m_fDistanceDirection = PointPlane(_rkPlane, *_rkLine.GetDirection());
        // If sign of origin and direction is equal then return false
        int iSignOrigin = K3dMath::Sign(m_fDistanceOrigin);
        int iSignDistance = K3dMath::Sign(m_fDistanceDirection);
        if(iSignOrigin == iSignDistance)
        {
                switch (iSignOrigin)
                {
                        case -1:
                                m_eLinePos = K3D_BACK_LINE;
                                break;
                        case 0:
                                m_eLinePos = K3D_ON_PLANE_LINE;
                                break;
                        case 1:
                                m_eLinePos = K3D_FRONT_LINE;
                                break;
                        default: 
                                break;
                }
                return false;
        }
        // Calculate origin
        float fOrigin = m_pGameData->GetVector3Work()->Dot( *_rkPlane.GetNormal(), *_rkLine.GetOrigin());
        fOrigin -= _rkPlane.GetDistance();
        // Calculate direction
        K3dVector3Obj kLineDirection = *_rkLine.GetDirection() - *_rkLine.GetOrigin();
        float fDirection = m_pGameData->GetVector3Work()->Dot( *_rkPlane.GetNormal(), kLineDirection );
        // If direction is not zero then the line intersect the plane
        if(fDirection!=(float)0)
        {
                // Calculate t value
                float fValue = 1/fDirection;
                fValue = -fOrigin * fValue;
                // Calculate result point
                m_kIntrPoint = *_rkLine.GetOrigin() + (kLineDirection * fValue);
                // Set line position oposit the plane
                m_eLinePos = K3D_LINE_INTR_PLANE;
                return true;
        }
        // Set line position oposit the plane
        if(iSignOrigin == -1)
        {
                m_eLinePos = K3D_BACK_LINE;
        }
        else
        {
                m_eLinePos = K3D_FRONT_LINE;
        }
        return false;
}       

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