1 /*
2  * This file is a part of Poly2Tri-C
3  * (c) Barak Itkin <lightningismyname@gmail.com>
4  * http://code.google.com/p/poly2tri-c/
5  *
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without modification,
9  * are permitted provided that the following conditions are met:
10  *
11  * * Redistributions of source code must retain the above copyright notice,
12  *   this list of conditions and the following disclaimer.
13  * * Redistributions in binary form must reproduce the above copyright notice,
14  *   this list of conditions and the following disclaimer in the documentation
15  *   and/or other materials provided with the distribution.
16  * * Neither the name of Poly2Tri nor the names of its contributors may be
17  *   used to endorse or promote products derived from this software without specific
18  *   prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
23  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
24  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
25  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
26  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
27  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
28  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
29  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
30  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31  */
32 
33 #ifndef __P2TC_REFINE_MATH_H__
34 #define __P2TC_REFINE_MATH_H__
35 
36 #include <glib.h>
37 #include "vector2.h"
38 #include "circle.h"
39 
40 gdouble   p2tr_math_length_sq  (gdouble x1,
41                                 gdouble y1,
42                                 gdouble x2,
43                                 gdouble y2);
44 
45 gdouble   p2tr_math_length_sq2 (const P2trVector2 *pt1,
46                                 const P2trVector2 *pt2);
47 
48 
49 /**
50  * Find the circumscribing circle of a triangle defined by the given
51  * points.
52  * @param[in] A The first vertex of the triangle
53  * @param[in] B The second vertex of the triangle
54  * @param[in] C The third vertex of the triangle
55  * @param[out] circle The circumscribing circle of the triangle
56  */
57 void      p2tr_math_triangle_circumcircle (const P2trVector2 *A,
58                                            const P2trVector2 *B,
59                                            const P2trVector2 *C,
60                                            P2trCircle    *circle);
61 
62 typedef enum
63 {
64   P2TR_INTRIANGLE_OUT = -1,
65   P2TR_INTRIANGLE_ON = 0,
66   P2TR_INTRIANGLE_IN = 1
67 } P2trInTriangle;
68 
69 /**
70  * Return the barycentric coordinates of a point inside a triangle. This
71  * means that the computation returns @ref u and @ref v so that the
72  * following equation is satisfied:
73  * {{{ AP = u * AB + v * AC }}}
74  *
75  * @param[in] A The first point of the triangle
76  * @param[in] B The second point of the triangle
77  * @param[in] C The third point of the triangle
78  * @param[in] P The point whose barycentric coordinates should be
79  *              computed
80  * @param[out] u The first barycentric coordinate
81  * @param[out] v The second barycentric coordinate
82  */
83 void p2tr_math_triangle_barcycentric (const P2trVector2 *A,
84                                       const P2trVector2 *B,
85                                       const P2trVector2 *C,
86                                       const P2trVector2 *P,
87                                       gdouble           *u,
88                                       gdouble           *v);
89 
90 P2trInTriangle p2tr_math_intriangle (const P2trVector2 *A,
91                                      const P2trVector2 *B,
92                                      const P2trVector2 *C,
93                                      const P2trVector2 *P);
94 
95 P2trInTriangle p2tr_math_intriangle2 (const P2trVector2 *A,
96                                       const P2trVector2 *B,
97                                       const P2trVector2 *C,
98                                       const P2trVector2 *P,
99                                       gdouble           *u,
100                                       gdouble           *v);
101 
102 typedef enum
103 {
104   P2TR_ORIENTATION_CW = -1,
105   P2TR_ORIENTATION_LINEAR = 0,
106   P2TR_ORIENTATION_CCW = 1
107 } P2trOrientation;
108 
109 P2trOrientation p2tr_math_orient2d (const P2trVector2 *A,
110                                     const P2trVector2 *B,
111                                     const P2trVector2 *C);
112 
113 typedef enum
114 {
115   P2TR_INCIRCLE_IN,
116   P2TR_INCIRCLE_ON,
117   P2TR_INCIRCLE_OUT
118 } P2trInCircle;
119 
120 P2trInCircle p2tr_math_incircle (const P2trVector2 *A,
121                                  const P2trVector2 *B,
122                                  const P2trVector2 *C,
123                                  const P2trVector2 *D);
124 
125 gboolean  p2tr_math_diametral_circle_contains (const P2trVector2 *X,
126                                                const P2trVector2 *Y,
127                                                const P2trVector2 *W);
128 
129 gboolean  p2tr_math_diametral_lens_contains   (const P2trVector2 *X,
130                                                const P2trVector2 *Y,
131                                                const P2trVector2 *W);
132 #endif
133