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 (21 years, 2 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
#	User	Rev	Content
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			}