1 /*
2 Copyright (c) 2005-2021 Intel Corporation
3
4 Licensed under the Apache License, Version 2.0 (the "License");
5 you may not use this file except in compliance with the License.
6 You may obtain a copy of the License at
7
8 http://www.apache.org/licenses/LICENSE-2.0
9
10 Unless required by applicable law or agreed to in writing, software
11 distributed under the License is distributed on an "AS IS" BASIS,
12 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 See the License for the specific language governing permissions and
14 limitations under the License.
15 */
16
17 /*
18 The original source for this example is
19 Copyright (c) 1994-2008 John E. Stone
20 All rights reserved.
21
22 Redistribution and use in source and binary forms, with or without
23 modification, are permitted provided that the following conditions
24 are met:
25 1. Redistributions of source code must retain the above copyright
26 notice, this list of conditions and the following disclaimer.
27 2. Redistributions in binary form must reproduce the above copyright
28 notice, this list of conditions and the following disclaimer in the
29 documentation and/or other materials provided with the distribution.
30 3. The name of the author may not be used to endorse or promote products
31 derived from this software without specific prior written permission.
32
33 THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
34 OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
35 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
36 ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
37 DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
38 DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
39 OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
40 HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
41 LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
42 OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
43 SUCH DAMAGE.
44 */
45
46 /*
47 * box.cpp - This file contains the functions for dealing with boxes.
48 */
49
50 #include "machine.hpp"
51 #include "types.hpp"
52 #include "macros.hpp"
53 #include "box.hpp"
54 #include "vector.hpp"
55 #include "intersect.hpp"
56 #include "util.hpp"
57
box_bbox(void * obj,vector * min,vector * max)58 int box_bbox(void *obj, vector *min, vector *max) {
59 box *b = (box *)obj;
60
61 *min = b->min;
62 *max = b->max;
63
64 return 1;
65 }
66
67 static object_methods box_methods = { (void (*)(void *, void *))(box_intersect),
68 (void (*)(void *, void *, void *, void *))(box_normal),
69 box_bbox,
70 free };
71
newbox(void * tex,vector min,vector max)72 box *newbox(void *tex, vector min, vector max) {
73 box *b;
74
75 b = (box *)rt_getmem(sizeof(box));
76 memset(b, 0, sizeof(box));
77 b->methods = &box_methods;
78 b->tex = (texture *)tex;
79 b->min = min;
80 b->max = max;
81
82 return b;
83 }
84
box_intersect(box * bx,ray * ry)85 void box_intersect(box *bx, ray *ry) {
86 flt a, tx1, tx2, ty1, ty2, tz1, tz2;
87 flt tnear, tfar;
88
89 tnear = -FHUGE;
90 tfar = FHUGE;
91
92 if (ry->d.x == 0.0) {
93 if ((ry->o.x < bx->min.x) || (ry->o.x > bx->max.x))
94 return;
95 }
96 else {
97 tx1 = (bx->min.x - ry->o.x) / ry->d.x;
98 tx2 = (bx->max.x - ry->o.x) / ry->d.x;
99 if (tx1 > tx2) {
100 a = tx1;
101 tx1 = tx2;
102 tx2 = a;
103 }
104 if (tx1 > tnear)
105 tnear = tx1;
106 if (tx2 < tfar)
107 tfar = tx2;
108 }
109 if (tnear > tfar)
110 return;
111 if (tfar < 0.0)
112 return;
113
114 if (ry->d.y == 0.0) {
115 if ((ry->o.y < bx->min.y) || (ry->o.y > bx->max.y))
116 return;
117 }
118 else {
119 ty1 = (bx->min.y - ry->o.y) / ry->d.y;
120 ty2 = (bx->max.y - ry->o.y) / ry->d.y;
121 if (ty1 > ty2) {
122 a = ty1;
123 ty1 = ty2;
124 ty2 = a;
125 }
126 if (ty1 > tnear)
127 tnear = ty1;
128 if (ty2 < tfar)
129 tfar = ty2;
130 }
131 if (tnear > tfar)
132 return;
133 if (tfar < 0.0)
134 return;
135
136 if (ry->d.z == 0.0) {
137 if ((ry->o.z < bx->min.z) || (ry->o.z > bx->max.z))
138 return;
139 }
140 else {
141 tz1 = (bx->min.z - ry->o.z) / ry->d.z;
142 tz2 = (bx->max.z - ry->o.z) / ry->d.z;
143 if (tz1 > tz2) {
144 a = tz1;
145 tz1 = tz2;
146 tz2 = a;
147 }
148 if (tz1 > tnear)
149 tnear = tz1;
150 if (tz2 < tfar)
151 tfar = tz2;
152 }
153 if (tnear > tfar)
154 return;
155 if (tfar < 0.0)
156 return;
157
158 add_intersection(tnear, (object *)bx, ry);
159 add_intersection(tfar, (object *)bx, ry);
160 }
161
box_normal(box * bx,vector * pnt,ray * incident,vector * N)162 void box_normal(box *bx, vector *pnt, ray *incident, vector *N) {
163 vector a, b, c;
164 flt t;
165
166 c.x = (bx->max.x + bx->min.x) / 2.0;
167 c.y = (bx->max.y + bx->min.y) / 2.0;
168 c.z = (bx->max.z + bx->min.z) / 2.0;
169
170 VSub((vector *)pnt, &c, N);
171 b = (*N);
172
173 a.x = fabs(N->x);
174 a.y = fabs(N->y);
175 a.z = fabs(N->z);
176
177 N->x = 0.0;
178 N->y = 0.0;
179 N->z = 0.0;
180
181 t = MYMAX(a.x, MYMAX(a.y, a.z));
182
183 if (t == a.x)
184 N->x = b.x;
185
186 if (t == a.y)
187 N->y = b.y;
188
189 if (t == a.z)
190 N->z = b.z;
191
192 VNorm(N);
193 }
194