BRL-CAD
bot_mirror.c
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1 /* B O T _ M I R R O R . C
2  * BRL-CAD
3  *
4  * Copyright (c) 2009-2014 United States Government as represented by
5  * the U.S. Army Research Laboratory.
6  *
7  * This library is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public License
9  * version 2.1 as published by the Free Software Foundation.
10  *
11  * This library is distributed in the hope that it will be useful, but
12  * WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with this file; see the file named COPYING for more
18  * information.
19  */
20 /** @file primitives/bot/bot_mirror.c
21  *
22  * mirror support
23  *
24  */
25 
26 #include "common.h"
27 
28 #include "raytrace.h"
29 #include "rtgeom.h"
30 
31 
32 /**
33  * Given a pointer to an internal GED database object, mirror the
34  * object's values about the given transformation matrix.
35  */
36 int
37 rt_bot_mirror(struct rt_db_internal *ip, register const plane_t plane)
38 {
39  struct rt_bot_internal *bot;
40 
41  mat_t mirmat;
42  mat_t rmat;
43  mat_t temp;
44  vect_t nvec;
45  vect_t xvec;
46  vect_t mirror_dir;
47  point_t mirror_pt;
48  fastf_t ang;
49 
50  size_t i;
51 
52  static point_t origin = {0.0, 0.0, 0.0};
53 
55 
56  bot = (struct rt_bot_internal *)ip->idb_ptr;
57  RT_BOT_CK_MAGIC(bot);
58 
59  MAT_IDN(mirmat);
60 
61  VMOVE(mirror_dir, plane);
62  VSCALE(mirror_pt, plane, plane[W]);
63 
64  /* Build mirror transform matrix, for those who need it. */
65  /* First, perform a mirror down the X axis */
66  mirmat[0] = -1.0;
67 
68  /* Create the rotation matrix */
69  VSET(xvec, 1, 0, 0);
70  VCROSS(nvec, xvec, mirror_dir);
71  VUNITIZE(nvec);
72  ang = -acos(VDOT(xvec, mirror_dir));
73  bn_mat_arb_rot(rmat, origin, nvec, ang*2.0);
74 
75  /* Add the rotation to mirmat */
76  MAT_COPY(temp, mirmat);
77  bn_mat_mul(mirmat, temp, rmat);
78 
79  /* Add the translation to mirmat */
80  mirmat[3 + X*4] += mirror_pt[X] * mirror_dir[X];
81  mirmat[3 + Y*4] += mirror_pt[Y] * mirror_dir[Y];
82  mirmat[3 + Z*4] += mirror_pt[Z] * mirror_dir[Z];
83 
84  /* mirror each vertex */
85  for (i=0; i<bot->num_vertices; i++) {
86  point_t pt;
87 
88  VMOVE(pt, &bot->vertices[i*3]);
89  MAT4X3PNT(&bot->vertices[i*3], mirmat, pt);
90  }
91 
92  /* Reverse each faces' order */
93  for (i=0; i<bot->num_faces; i++) {
94  int save_face = bot->faces[i*3];
95 
96  bot->faces[i*3] = bot->faces[i*3 + Z];
97  bot->faces[i*3 + Z] = save_face;
98  }
99 
100  /* fix normals */
101  for (i=0; i<bot->num_normals; i++) {
102  vectp_t np = &bot->normals[i*3];
103  vect_t n1;
104  vect_t n2;
105  mat_t mat;
106 
107  VMOVE(n1, np);
108  VCROSS(n2, mirror_dir, n1);
109  VUNITIZE(n2);
110  ang = M_PI_2 - acos(VDOT(n1, mirror_dir));
111  bn_mat_arb_rot(mat, origin, n2, ang*2);
112  MAT4X3VEC(np, mat, n1);
113  }
114 
115  return 0;
116 }
117 
118 
119 /*
120  * Local Variables:
121  * tab-width: 8
122  * mode: C
123  * indent-tabs-mode: t
124  * c-file-style: "stroustrup"
125  * End:
126  * ex: shiftwidth=4 tabstop=8
127  */
#define VSET(a, b, c, d)
Definition: color.c:53
Header file for the BRL-CAD common definitions.
Definition: color.c:49
#define RT_CK_DB_INTERNAL(_p)
Definition: raytrace.h:207
void bn_mat_mul(mat_t o, const mat_t a, const mat_t b)
void * idb_ptr
Definition: raytrace.h:195
Definition: color.c:51
int rt_bot_mirror(struct rt_db_internal *ip, register const plane_t plane)
Definition: bot_mirror.c:37
double fastf_t
Definition: defines.h:300
void bn_mat_arb_rot(mat_t m, const point_t pt, const vect_t dir, const fastf_t ang)
Definition: mat.c:987
Definition: color.c:50