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/* Copyright (C) 2009 Wildfire Games.
* This file is part of 0 A.D.
*
* 0 A.D. 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.
*
* 0 A.D. 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 0 A.D. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* A Plane in R3 and several utility methods.
*/
// Note that the format used for the plane equation is
// Ax + By + Cz + D = 0, where <A,B,C> is the normal vector.
#ifndef INCLUDED_PLANE
#define INCLUDED_PLANE
#include "Vector3D.h"
#include "Vector4D.h"
enum PLANESIDE
{
PS_FRONT,
PS_BACK,
PS_ON
};
class CPlane
{
public:
CPlane();
CPlane(const CVector4D& coeffs) : m_Norm(coeffs.X, coeffs.Y, coeffs.Z), m_Dist(coeffs.W) { }
//sets the plane equation from 3 points on that plane
void Set(const CVector3D& p1, const CVector3D& p2, const CVector3D& p3);
//sets the plane equation from a normal and a point on
//that plane
void Set(const CVector3D& norm, const CVector3D& point);
//normalizes the plane equation
void Normalize();
//returns the side of the plane on which this point lies
PLANESIDE ClassifyPoint(const CVector3D& point) const;
//returns true if this point is on the back side
inline bool IsPointOnBackSide(const CVector3D& point) const;
//solves the plane equation for a particular point
inline float DistanceToPlane(const CVector3D& point) const;
//calculates the intersection point of a line with this
//plane. Returns false if there is no intersection
bool FindLineSegIntersection(const CVector3D& start, const CVector3D& end, CVector3D* intsect) const;
bool FindRayIntersection(const CVector3D& start, const CVector3D& direction, CVector3D* intsect) const;
public:
CVector3D m_Norm; //normal vector of the plane
float m_Dist; //Plane distance (ie D in the plane eq.)
static const float m_EPS;
};
float CPlane::DistanceToPlane(const CVector3D& point) const
{
return m_Norm.X * point.X + m_Norm.Y * point.Y + m_Norm.Z * point.Z + m_Dist;
}
bool CPlane::IsPointOnBackSide(const CVector3D& point) const
{
return DistanceToPlane(point) < -m_EPS;
}
#endif
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