1 |
greg |
1.1 |
#ifndef lint |
2 |
greg |
2.2 |
static const char RCSid[] = "$Id$"; |
3 |
greg |
1.1 |
#endif |
4 |
|
|
/* |
5 |
|
|
* o_face.c - compute ray intersection with faces. |
6 |
greg |
2.2 |
*/ |
7 |
|
|
|
8 |
|
|
/* ==================================================================== |
9 |
|
|
* The Radiance Software License, Version 1.0 |
10 |
|
|
* |
11 |
|
|
* Copyright (c) 1990 - 2002 The Regents of the University of California, |
12 |
|
|
* through Lawrence Berkeley National Laboratory. All rights reserved. |
13 |
|
|
* |
14 |
|
|
* Redistribution and use in source and binary forms, with or without |
15 |
|
|
* modification, are permitted provided that the following conditions |
16 |
|
|
* are met: |
17 |
|
|
* |
18 |
|
|
* 1. Redistributions of source code must retain the above copyright |
19 |
|
|
* notice, this list of conditions and the following disclaimer. |
20 |
|
|
* |
21 |
|
|
* 2. Redistributions in binary form must reproduce the above copyright |
22 |
|
|
* notice, this list of conditions and the following disclaimer in |
23 |
|
|
* the documentation and/or other materials provided with the |
24 |
|
|
* distribution. |
25 |
|
|
* |
26 |
|
|
* 3. The end-user documentation included with the redistribution, |
27 |
|
|
* if any, must include the following acknowledgment: |
28 |
|
|
* "This product includes Radiance software |
29 |
|
|
* (http://radsite.lbl.gov/) |
30 |
|
|
* developed by the Lawrence Berkeley National Laboratory |
31 |
|
|
* (http://www.lbl.gov/)." |
32 |
|
|
* Alternately, this acknowledgment may appear in the software itself, |
33 |
|
|
* if and wherever such third-party acknowledgments normally appear. |
34 |
|
|
* |
35 |
|
|
* 4. The names "Radiance," "Lawrence Berkeley National Laboratory" |
36 |
|
|
* and "The Regents of the University of California" must |
37 |
|
|
* not be used to endorse or promote products derived from this |
38 |
|
|
* software without prior written permission. For written |
39 |
|
|
* permission, please contact [email protected]. |
40 |
|
|
* |
41 |
|
|
* 5. Products derived from this software may not be called "Radiance", |
42 |
|
|
* nor may "Radiance" appear in their name, without prior written |
43 |
|
|
* permission of Lawrence Berkeley National Laboratory. |
44 |
|
|
* |
45 |
|
|
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED |
46 |
|
|
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
47 |
|
|
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
48 |
|
|
* DISCLAIMED. IN NO EVENT SHALL Lawrence Berkeley National Laboratory OR |
49 |
|
|
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
50 |
|
|
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
51 |
|
|
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF |
52 |
|
|
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
53 |
|
|
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
54 |
|
|
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT |
55 |
|
|
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
56 |
|
|
* SUCH DAMAGE. |
57 |
|
|
* ==================================================================== |
58 |
greg |
1.1 |
* |
59 |
greg |
2.2 |
* This software consists of voluntary contributions made by many |
60 |
|
|
* individuals on behalf of Lawrence Berkeley National Laboratory. For more |
61 |
|
|
* information on Lawrence Berkeley National Laboratory, please see |
62 |
|
|
* <http://www.lbl.gov/>. |
63 |
greg |
1.1 |
*/ |
64 |
|
|
|
65 |
|
|
#include "ray.h" |
66 |
|
|
|
67 |
|
|
#include "face.h" |
68 |
|
|
|
69 |
|
|
|
70 |
|
|
o_face(o, r) /* compute intersection with polygonal face */ |
71 |
|
|
OBJREC *o; |
72 |
|
|
register RAY *r; |
73 |
|
|
{ |
74 |
|
|
double rdot; /* direction . normal */ |
75 |
|
|
double t; /* distance to intersection */ |
76 |
|
|
FVECT pisect; /* intersection point */ |
77 |
|
|
register FACE *f; /* face record */ |
78 |
|
|
register int i; |
79 |
|
|
|
80 |
|
|
f = getface(o); |
81 |
|
|
|
82 |
|
|
/* |
83 |
|
|
* First, we find the distance to the plane containing the |
84 |
|
|
* face. If this distance is less than zero or greater |
85 |
|
|
* than a previous intersection, we return. Otherwise, |
86 |
|
|
* we determine whether in fact the ray intersects the |
87 |
|
|
* face. The ray intersects the face if the |
88 |
|
|
* point of intersection with the plane of the face |
89 |
|
|
* is inside the face. |
90 |
|
|
*/ |
91 |
|
|
/* compute dist. to plane */ |
92 |
|
|
rdot = -DOT(r->rdir, f->norm); |
93 |
|
|
if (rdot <= FTINY && rdot >= -FTINY) /* ray parallels plane */ |
94 |
|
|
t = FHUGE; |
95 |
|
|
else |
96 |
greg |
1.2 |
t = (DOT(r->rorg, f->norm) - f->offset) / rdot; |
97 |
greg |
1.1 |
|
98 |
|
|
if (t <= FTINY || t >= r->rot) /* not good enough */ |
99 |
|
|
return(0); |
100 |
|
|
/* compute intersection */ |
101 |
|
|
for (i = 0; i < 3; i++) |
102 |
|
|
pisect[i] = r->rorg[i] + r->rdir[i]*t; |
103 |
|
|
|
104 |
greg |
1.3 |
if (!inface(pisect, f)) /* ray intersects face? */ |
105 |
|
|
return(0); |
106 |
greg |
1.1 |
|
107 |
greg |
1.3 |
r->ro = o; |
108 |
|
|
r->rot = t; |
109 |
|
|
VCOPY(r->rop, pisect); |
110 |
|
|
VCOPY(r->ron, f->norm); |
111 |
|
|
r->rod = rdot; |
112 |
greg |
1.4 |
r->rox = NULL; |
113 |
greg |
1.3 |
|
114 |
greg |
1.1 |
return(1); /* hit */ |
115 |
|
|
} |