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1 /*
2    Copyright (C) 2001-2006, William Joseph.
3    All Rights Reserved.
4
5    This file is part of GtkRadiant.
6
7    GtkRadiant is free software; you can redistribute it and/or modify
8    it under the terms of the GNU General Public License as published by
9    the Free Software Foundation; either version 2 of the License, or
10    (at your option) any later version.
11
12    GtkRadiant is distributed in the hope that it will be useful,
13    but WITHOUT ANY WARRANTY; without even the implied warranty of
14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15    GNU General Public License for more details.
16
17    You should have received a copy of the GNU General Public License
18    along with GtkRadiant; if not, write to the Free Software
19    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
20  */
21
22 #if !defined( INCLUDED_MATH_PLANE_H )
23 #define INCLUDED_MATH_PLANE_H
24
25 /// \file
26 /// \brief Plane data types and related operations.
27
28 #include "math/matrix.h"
29
30 /// \brief A plane equation stored in double-precision floating-point.
31 class Plane3
32 {
33 public:
34 double a, b, c, d;
35
36 Plane3(){
37 }
38 Plane3( double _a, double _b, double _c, double _d )
39         : a( _a ), b( _b ), c( _c ), d( _d ){
40 }
41 template<typename Element>
42 Plane3( const BasicVector3<Element>& normal, double dist )
43         : a( normal.x() ), b( normal.y() ), c( normal.z() ), d( dist ){
44 }
45
46 BasicVector3<double>& normal(){
47         return reinterpret_cast<BasicVector3<double>&>( *this );
48 }
49 const BasicVector3<double>& normal() const {
50         return reinterpret_cast<const BasicVector3<double>&>( *this );
51 }
52 double& dist(){
53         return d;
54 }
55 const double& dist() const {
56         return d;
57 }
58 };
59
60 inline Plane3 plane3_normalised( const Plane3& plane ){
61         double rmagnitude = 1.0 / sqrt( plane.a * plane.a + plane.b * plane.b + plane.c * plane.c );
62         return Plane3(
63                            plane.a * rmagnitude,
64                            plane.b * rmagnitude,
65                            plane.c * rmagnitude,
66                            plane.d * rmagnitude
67                            );
68 }
69
70 inline Plane3 plane3_translated( const Plane3& plane, const Vector3& translation ){
71         Plane3 transformed;
72         transformed.a = plane.a;
73         transformed.b = plane.b;
74         transformed.c = plane.c;
75         transformed.d = -( ( -plane.d * transformed.a + translation.x() ) * transformed.a +
76                                            ( -plane.d * transformed.b + translation.y() ) * transformed.b +
77                                            ( -plane.d * transformed.c + translation.z() ) * transformed.c );
78         return transformed;
79 }
80
81 inline Plane3 plane3_transformed( const Plane3& plane, const Matrix4& transform ){
82         Plane3 transformed;
83         transformed.a = transform[0] * plane.a + transform[4] * plane.b + transform[8] * plane.c;
84         transformed.b = transform[1] * plane.a + transform[5] * plane.b + transform[9] * plane.c;
85         transformed.c = transform[2] * plane.a + transform[6] * plane.b + transform[10] * plane.c;
86         transformed.d = -( ( -plane.d * transformed.a + transform[12] ) * transformed.a +
87                                            ( -plane.d * transformed.b + transform[13] ) * transformed.b +
88                                            ( -plane.d * transformed.c + transform[14] ) * transformed.c );
89         return transformed;
90 }
91
92 inline Plane3 plane3_inverse_transformed( const Plane3& plane, const Matrix4& transform ){
93         return Plane3
94                    (
95                            transform[ 0] * plane.a + transform[ 1] * plane.b + transform[ 2] * plane.c + transform[ 3] * plane.d,
96                            transform[ 4] * plane.a + transform[ 5] * plane.b + transform[ 6] * plane.c + transform[ 7] * plane.d,
97                            transform[ 8] * plane.a + transform[ 9] * plane.b + transform[10] * plane.c + transform[11] * plane.d,
98                            transform[12] * plane.a + transform[13] * plane.b + transform[14] * plane.c + transform[15] * plane.d
99                    );
100 }
101
102 inline Plane3 plane3_flipped( const Plane3& plane ){
103         return Plane3( vector3_negated( plane.normal() ), -plane.dist() );
104 }
105
106 const double c_PLANE_NORMAL_EPSILON = 0.0001f;
107 const double c_PLANE_DIST_EPSILON = 0.02;
108
109 inline bool plane3_equal( const Plane3& self, const Plane3& other ){
110         return vector3_equal_epsilon( self.normal(), other.normal(), c_PLANE_NORMAL_EPSILON )
111                    && float_equal_epsilon( self.dist(), other.dist(), c_PLANE_DIST_EPSILON );
112 }
113
114 inline bool plane3_opposing( const Plane3& self, const Plane3& other ){
115         return plane3_equal( self, plane3_flipped( other ) );
116 }
117
118 inline bool plane3_valid( const Plane3& self ){
119         return float_equal_epsilon( vector3_dot( self.normal(), self.normal() ), 1.0, 0.01 );
120 }
121
122 template<typename Element>
123 inline Plane3 plane3_for_points( const BasicVector3<Element>& p0, const BasicVector3<Element>& p1, const BasicVector3<Element>& p2 ){
124         Plane3 self;
125         self.normal() = vector3_normalised( vector3_cross( vector3_subtracted( p1, p0 ), vector3_subtracted( p2, p0 ) ) );
126         self.dist() = vector3_dot( p0, self.normal() );
127         return self;
128 }
129
130 template<typename Element>
131 inline Plane3 plane3_for_points( const BasicVector3<Element> planepts[3] ){
132         return plane3_for_points( planepts[2], planepts[1], planepts[0] );
133 }
134
135
136 #endif