Line data    Source code

       1             : /* Copyright (C) 2009 Wildfire Games.
       2             :  * This file is part of 0 A.D.
       3             :  *
       4             :  * 0 A.D. is free software: you can redistribute it and/or modify
       5             :  * it under the terms of the GNU General Public License as published by
       6             :  * the Free Software Foundation, either version 2 of the License, or
       7             :  * (at your option) any later version.
       8             :  *
       9             :  * 0 A.D. is distributed in the hope that it will be useful,
      10             :  * but WITHOUT ANY WARRANTY; without even the implied warranty of
      11             :  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      12             :  * GNU General Public License for more details.
      13             :  *
      14             :  * You should have received a copy of the GNU General Public License
      15             :  * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
      16             :  */
      17             : 
      18             : /*
      19             :  * A Plane in R3 and several utility methods.
      20             :  */
      21             : 
      22             : // Note that the format used for the plane equation is
      23             : // Ax + By + Cz + D = 0, where <A,B,C> is the normal vector.
      24             : 
      25             : #ifndef INCLUDED_PLANE
      26             : #define INCLUDED_PLANE
      27             : 
      28             : #include "Vector3D.h"
      29             : #include "Vector4D.h"
      30             : 
      31             : enum PLANESIDE
      32             : {
      33             :     PS_FRONT,
      34             :     PS_BACK,
      35             :     PS_ON
      36             : };
      37             : 
      38             : class CPlane
      39             : {
      40             :     public:
      41             :         CPlane();
      42          16 :         CPlane(const CVector4D& coeffs) : m_Norm(coeffs.X, coeffs.Y, coeffs.Z), m_Dist(coeffs.W) { }
      43             : 
      44             :         //sets the plane equation from 3 points on that plane
      45             :         void Set(const CVector3D& p1, const CVector3D& p2, const CVector3D& p3);
      46             : 
      47             :         //sets the plane equation from a normal and a point on
      48             :         //that plane
      49             :         void Set(const CVector3D& norm, const CVector3D& point);
      50             : 
      51             :         //normalizes the plane equation
      52             :         void Normalize();
      53             : 
      54             :         //returns the side of the plane on which this point lies
      55             :         PLANESIDE ClassifyPoint(const CVector3D& point) const;
      56             :         //returns true if this point is on the back side
      57             :         inline bool IsPointOnBackSide(const CVector3D& point) const;
      58             : 
      59             :         //solves the plane equation for a particular point
      60             :         inline float DistanceToPlane(const CVector3D& point) const;
      61             : 
      62             :         //calculates the intersection point of a line with this
      63             :         //plane. Returns false if there is no intersection
      64             :         bool FindLineSegIntersection(const CVector3D& start, const CVector3D& end, CVector3D* intsect) const;
      65             :         bool FindRayIntersection(const CVector3D& start, const CVector3D& direction, CVector3D* intsect) const;
      66             : 
      67             :     public:
      68             :         CVector3D m_Norm;   //normal vector of the plane
      69             :         float m_Dist;       //Plane distance (ie D in the plane eq.)
      70             :         static const float m_EPS;
      71             : };
      72             : 
      73          48 : float CPlane::DistanceToPlane(const CVector3D& point) const
      74             : {
      75          48 :     return m_Norm.X * point.X + m_Norm.Y * point.Y + m_Norm.Z * point.Z + m_Dist;
      76             : }
      77             : 
      78           0 : bool CPlane::IsPointOnBackSide(const CVector3D& point) const
      79             : {
      80           0 :     return DistanceToPlane(point) < -m_EPS;
      81             : }
      82             : 
      83             : #endif