Celestia/src/celmath/plane.h at master · httpsgithu/Celestia · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
// plane.h
//
// Copyright (C) 2000-2008, Chris Laurel <claurel@shatters.net>
//
// 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.

#ifndef _CELMATH_PLANE_H_
#define _CELMATH_PLANE_H_

#include <celmath/mathlib.h>
#include <celmath/vecmath.h>


template<class T> class Plane
{
 public:
    inline Plane();
    inline Plane(const Plane<T>&);
    inline Plane(const Vector3<T>&, T);
    inline Plane(const Vector3<T>&, const Point3<T>&);

    T distanceTo(const Point3<T>&) const;
    T distanceToSegment(const Point3<T>&, const Vector3<T>&) const;

    static Point3<T> intersection(const Plane<T>&,
                                  const Plane<T>&,
                                  const Plane<T>&);

 public:
    Vector3<T> normal;
    T d;
};


typedef Plane<float> Planef;
typedef Plane<double> Planed;


template<class T> Plane<T>::Plane() : normal(0, 0, 1), d(0)
{
}

template<class T> Plane<T>::Plane(const Plane<T>& p) :
    normal(p.normal), d(p.d)
{
}

template<class T> Plane<T>::Plane(const Vector3<T>& _normal, T _d) :
    normal(_normal), d(_d)
{
}

template<class T> Plane<T>::Plane(const Vector3<T>& _normal, const Point3<T>& _point) :
    normal(_normal)
{
    d = _normal.x * _point.x + _normal.y * _point.y + _normal.z * _point.z;
}

template<class T> T Plane<T>::distanceTo(const Point3<T>& p) const
{
    return normal.x * p.x + normal.y * p.y + normal.z * p.z + d;
}

// Distance between a plane and a segment defined by orig+dir*t, t <= 0 <= 1
template<class T> T Plane<T>::distanceToSegment(const Point3<T>& origin,
                                                const Vector3<T>& direction) const
{
    T u = (direction * normal);
    T dist;

    // Avoid divide by zero; near-zero values shouldn't cause problems
    if (u == 0)
    {
        // All points equidistant; we can just compute distance to origin
        dist = distanceTo(origin);
    }
    else
    {
        T t = -(d + Vector3<T>(origin.x, origin.y, origin.z) * normal) / u;
        if (t < 0)
        {
            dist = distanceTo(origin);
        }
        else if (t > 1)
        {
            dist = distanceTo(origin + direction);
        }
        else
        {
            // Segment intersects plane
            dist = 0.0;
        }
    }

    return dist;
}


template<class T> Plane<T> operator*(const Matrix3<T>& m, const Plane<T>& p)
{
    Vector3<T> v = m * p.normal;
    return Plane<T>(v, p.d);
}

template<class T> Plane<T> operator*(const Plane<T>& p, const Matrix3<T>& m)
{
    Vector3<T> v = p.normal * m;
    return Plane<T>(v, p.d);
}

template<class T> Plane<T> operator*(const Matrix4<T>& m, const Plane<T>& p)
{
    Vector4<T> v = m * Vector4<T>(p.normal.x, p.normal.y, p.normal.z, p.d);
    return Plane<T>(Vector3<T>(v.x, v.y, v.z), v.w);
}

template<class T> Plane<T> operator*(const Plane<T>& p, const Matrix4<T>& m)
{
    Vector4<T> v = Vector4<T>(p.normal.x, p.normal.y, p.normal.z, p.d) * m;
    return Plane<T>(Vector3<T>(v.x, v.y, v.z), v.w);
}

template<class T> Point3<T> Plane<T>::intersection(const Plane<T>& p0,
                                                   const Plane<T>& p1,
                                                   const Plane<T>& p2)
{
    T d = Matrix3<T>(p0.normal, p1.normal, p2.normal).determinant();

    Vector3<T> v = (p0.d * cross(p1.normal, p2.normal) +
                    p1.d * cross(p2.normal, p0.normal) +
                    p2.d * cross(p0.normal, p1.normal)) * (1.0f / d);
    return Point3<T>(v.x, v.y, v.z);
}

#endif // _CELMATH_PLANE_H_