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
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