src/rt/o_face.c

#ifndef lint
static const char       RCSid[] = "$Id$";
#endif
/*
 *  o_face.c - compute ray intersection with faces.
 */

/* ====================================================================
 * The Radiance Software License, Version 1.0
 *
 * Copyright (c) 1990 - 2002 The Regents of the University of California,
 * through Lawrence Berkeley National Laboratory.   All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *         notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in
 *       the documentation and/or other materials provided with the
 *       distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *           if any, must include the following acknowledgment:
 *             "This product includes Radiance software
 *                 (http://radsite.lbl.gov/)
 *                 developed by the Lawrence Berkeley National Laboratory
 *               (http://www.lbl.gov/)."
 *       Alternately, this acknowledgment may appear in the software itself,
 *       if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Radiance," "Lawrence Berkeley National Laboratory"
 *       and "The Regents of the University of California" must
 *       not be used to endorse or promote products derived from this
 *       software without prior written permission. For written
 *       permission, please contact [email protected].
 *
 * 5. Products derived from this software may not be called "Radiance",
 *       nor may "Radiance" appear in their name, without prior written
 *       permission of Lawrence Berkeley National Laboratory.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.   IN NO EVENT SHALL Lawrence Berkeley National Laboratory OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of Lawrence Berkeley National Laboratory.   For more
 * information on Lawrence Berkeley National Laboratory, please see
 * <http://www.lbl.gov/>.
 */

#include  "ray.h"

#include  "face.h"


o_face(o, r)            /* compute intersection with polygonal face */
OBJREC  *o;
register RAY  *r;
{
        double  rdot;           /* direction . normal */
        double  t;              /* distance to intersection */
        FVECT  pisect;          /* intersection point */
        register FACE  *f;      /* face record */
        register int  i;

        f = getface(o);
                
        /*
         *  First, we find the distance to the plane containing the
         *  face.  If this distance is less than zero or greater
         *  than a previous intersection, we return.  Otherwise,
         *  we determine whether in fact the ray intersects the
         *  face.  The ray intersects the face if the
         *  point of intersection with the plane of the face
         *  is inside the face.
         */
                                                /* compute dist. to plane */
        rdot = -DOT(r->rdir, f->norm);
        if (rdot <= FTINY && rdot >= -FTINY)    /* ray parallels plane */
                t = FHUGE;
        else
                t = (DOT(r->rorg, f->norm) - f->offset) / rdot;
        
        if (t <= FTINY || t >= r->rot)          /* not good enough */
                return(0);
                                                /* compute intersection */
        for (i = 0; i < 3; i++)
                pisect[i] = r->rorg[i] + r->rdir[i]*t;

        if (!inface(pisect, f))                 /* ray intersects face? */
                return(0);

        r->ro = o;
        r->rot = t;
        VCOPY(r->rop, pisect);
        VCOPY(r->ron, f->norm);
        r->rod = rdot;
        r->rox = NULL;

        return(1);                              /* hit */
}
Revision:	2.2
Committed:	Sat Feb 22 02:07:29 2003 UTC (22 years, 10 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.1:	+57 -5 lines
Log Message:	Changes and check-in for 3.5 release Includes new source files and modifications not recorded for many years See ray/doc/notes/ReleaseNotes for notes between 3.1 and 3.5 release
#	Content
1	#ifndef lint
2	static const char RCSid[] = "$Id$";
3	#endif
4	/*
5	* o_face.c - compute ray intersection with faces.
6	*/
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	*
59	* 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	*/
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	t = (DOT(r->rorg, f->norm) - f->offset) / rdot;
97
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	if (!inface(pisect, f)) /* ray intersects face? */
105	return(0);
106
107	r->ro = o;
108	r->rot = t;
109	VCOPY(r->rop, pisect);
110	VCOPY(r->ron, f->norm);
111	r->rod = rdot;
112	r->rox = NULL;
113
114	return(1); /* hit */
115	}