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
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
|
/*************************************************************************
* Copyright (C) 2010 Tavian Barnes <tavianator@gmail.com> *
* *
* This file is part of The Dimension Library. *
* *
* The Dimension Library is free software; you can redistribute it and/ *
* or modify it under the terms of the GNU Lesser General Public License *
* as published by the Free Software Foundation; either version 3 of the *
* License, or (at your option) any later version. *
* *
* The Dimension Library is distributed in the hope that it will be *
* useful, but WITHOUT ANY WARRANTY; without even the implied warranty *
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU *
* Lesser General Public License for more details. *
* *
* You should have received a copy of the GNU Lesser General Public *
* License along with this program. If not, see *
* <http://www.gnu.org/licenses/>. *
*************************************************************************/
#include "dimension.h"
#include <math.h>
/*
* Cube
*/
/* Cube callbacks */
static bool dmnsn_cube_intersection_fn(const dmnsn_object *cube,
dmnsn_line line,
dmnsn_intersection *intersection);
static bool dmnsn_cube_inside_fn(const dmnsn_object *cube,
dmnsn_vector point);
/* Allocate a new cube object */
dmnsn_object *
dmnsn_new_cube()
{
dmnsn_object *cube = dmnsn_new_object();
cube->intersection_fn = &dmnsn_cube_intersection_fn;
cube->inside_fn = &dmnsn_cube_inside_fn;
cube->bounding_box.min = dmnsn_new_vector(-1.0, -1.0, -1.0);
cube->bounding_box.max = dmnsn_new_vector(1.0, 1.0, 1.0);
return cube;
}
/* Intersections callback for a cube */
static bool
dmnsn_cube_intersection_fn(const dmnsn_object *cube, dmnsn_line line,
dmnsn_intersection *intersection)
{
/* Clip the given line against the X, Y, and Z slabs */
dmnsn_line line_trans = dmnsn_transform_line(cube->trans_inv, line);
dmnsn_vector nmin, nmax;
double tmin = -INFINITY, tmax = INFINITY;
if (line_trans.n.x != 0.0) {
double tx1 = (-1.0 - line_trans.x0.x)/line_trans.n.x;
double tx2 = (+1.0 - line_trans.x0.x)/line_trans.n.x;
if (tx1 < tx2) {
if (tx1 > tmin) {
tmin = tx1;
nmin = dmnsn_new_vector(-1.0, 0.0, 0.0);
}
if (tx2 < tmax) {
tmax = tx2;
nmax = dmnsn_new_vector(+1.0, 0.0, 0.0);
}
} else {
if (tx2 > tmin) {
tmin = tx2;
nmin = dmnsn_new_vector(+1.0, 0.0, 0.0);
}
if (tx1 < tmax) {
tmax = tx1;
nmax = dmnsn_new_vector(-1.0, 0.0, 0.0);
}
}
if (tmin > tmax)
return false;
}
if (line_trans.n.y != 0.0) {
double ty1 = (-1.0 - line_trans.x0.y)/line_trans.n.y;
double ty2 = (+1.0 - line_trans.x0.y)/line_trans.n.y;
if (ty1 < ty2) {
if (ty1 > tmin) {
tmin = ty1;
nmin = dmnsn_new_vector(0.0, -1.0, 0.0);
}
if (ty2 < tmax) {
tmax = ty2;
nmax = dmnsn_new_vector(0.0, +1.0, 0.0);
}
} else {
if (ty2 > tmin) {
tmin = ty2;
nmin = dmnsn_new_vector(0.0, +1.0, 0.0);
}
if (ty1 < tmax) {
tmax = ty1;
nmax = dmnsn_new_vector(0.0, -1.0, 0.0);
}
}
if (tmin > tmax)
return false;
}
if (line_trans.n.z != 0.0) {
double tz1 = (-1.0 - line_trans.x0.z)/line_trans.n.z;
double tz2 = (+1.0 - line_trans.x0.z)/line_trans.n.z;
if (tz1 < tz2) {
if (tz1 > tmin) {
tmin = tz1;
nmin = dmnsn_new_vector(0.0, 0.0, -1.0);
}
if (tz2 < tmax) {
tmax = tz2;
nmax = dmnsn_new_vector(0.0, 0.0, +1.0);
}
} else {
if (tz2 > tmin) {
tmin = tz2;
nmin = dmnsn_new_vector(0.0, 0.0, +1.0);
}
if (tz1 < tmax) {
tmax = tz1;
nmax = dmnsn_new_vector(0.0, 0.0, -1.0);
}
}
if (tmin > tmax)
return false;
}
if (tmin < 0.0) {
tmin = tmax;
nmin = nmax;
}
if (tmin >= 0.0) {
intersection->ray = line;
intersection->t = tmin;
intersection->normal = dmnsn_transform_normal(cube->trans, nmin);
intersection->texture = cube->texture;
intersection->interior = cube->interior;
return true;
} else {
return false;
}
}
/* Inside callback for a cube */
static bool
dmnsn_cube_inside_fn(const dmnsn_object *cube, dmnsn_vector point)
{
point = dmnsn_transform_vector(cube->trans_inv, point);
return point.x > -1.0 && point.x < 1.0
&& point.y > -1.0 && point.y < 1.0
&& point.z > -1.0 && point.z < 1.0;
}
|
