Pyrogenesis  trunk
Plane.h
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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
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
32 {
36 };
37
38 class CPlane
39 {
40  public:
41  CPlane();
42  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 float CPlane::DistanceToPlane(const CVector3D& point) const
74 {
75  return m_Norm.X * point.X + m_Norm.Y * point.Y + m_Norm.Z * point.Z + m_Dist;
76 }
77
78 bool CPlane::IsPointOnBackSide(const CVector3D& point) const
79 {
80  return DistanceToPlane(point) < -m_EPS;
81 }
82
83 #endif
Definition: Decompose.h:22
PLANESIDE
Definition: Plane.h:31
bool FindRayIntersection(const CVector3D &start, const CVector3D &direction, CVector3D *intsect) const
Definition: Plane.cpp:105
Definition: Vector3D.h:30
Definition: Decompose.h:22
void Set(const CVector3D &p1, const CVector3D &p2, const CVector3D &p3)
Definition: Plane.cpp:38
Definition: Vector4D.h:30
Definition: Plane.h:35
void Normalize()
Definition: Plane.cpp:65
CPlane(const CVector4D &coeffs)
Definition: Plane.h:42
CPlane()
Definition: Plane.cpp:32
float X
Definition: Vector3D.h:33
float Y
Definition: Vector3D.h:33
float DistanceToPlane(const CVector3D &point) const
Definition: Plane.h:73
Definition: Plane.h:33
bool FindLineSegIntersection(const CVector3D &start, const CVector3D &end, CVector3D *intsect) const
Definition: Plane.cpp:91
bool IsPointOnBackSide(const CVector3D &point) const
Definition: Plane.h:78
static const float m_EPS
Definition: Plane.h:70
PLANESIDE ClassifyPoint(const CVector3D &point) const
Definition: Plane.cpp:77
#define X(id)
Definition: CStrIntern.cpp:90
Definition: Decompose.h:22
CVector3D m_Norm
Definition: Plane.h:68
float Z
Definition: Vector3D.h:33
Definition: Plane.h:38
Definition: Plane.h:34
float m_Dist
Definition: Plane.h:69