src/rt/o_cone.c

#ifndef lint
static const char       RCSid[] = "$Id$";
#endif
/*
 *  o_cone.c - routine to determine ray intersection with cones.
 */

/* ====================================================================
 * 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  "otypes.h"

#include  "cone.h"


o_cone(o, r)                    /* intersect ray with cone */
OBJREC  *o;
register RAY  *r;
{
        FVECT  rox, rdx;
        double  a, b, c;
        double  root[2];
        int  nroots, rn;
        register CONE  *co;
        register int  i;

                                                /* get cone structure */
        co = getcone(o, 1);

        /*
         *     To intersect a ray with a cone, we transform the
         *  ray into the cone's normalized space.  This greatly
         *  simplifies the computation.
         *     For a cone or cup, normalization results in the
         *  equation:
         *
         *              x*x + y*y - z*z == 0
         *
         *     For a cylinder or tube, the normalized equation is:
         *
         *              x*x + y*y - r*r == 0
         *
         *     A normalized ring obeys the following set of equations:
         *
         *              z == 0                  &&
         *              x*x + y*y >= r0*r0      &&
         *              x*x + y*y <= r1*r1
         */

                                        /* transform ray */
        multp3(rox, r->rorg, co->tm);
        multv3(rdx, r->rdir, co->tm);
                                        /* compute intersection */

        if (o->otype == OBJ_CONE || o->otype == OBJ_CUP) {

                a = rdx[0]*rdx[0] + rdx[1]*rdx[1] - rdx[2]*rdx[2];
                b = 2.0*(rdx[0]*rox[0] + rdx[1]*rox[1] - rdx[2]*rox[2]);
                c = rox[0]*rox[0] + rox[1]*rox[1] - rox[2]*rox[2];

        } else if (o->otype == OBJ_CYLINDER || o->otype == OBJ_TUBE) {

                a = rdx[0]*rdx[0] + rdx[1]*rdx[1];
                b = 2.0*(rdx[0]*rox[0] + rdx[1]*rox[1]);
                c = rox[0]*rox[0] + rox[1]*rox[1] - CO_R0(co)*CO_R0(co);

        } else { /* OBJ_RING */

                if (rdx[2] <= FTINY && rdx[2] >= -FTINY)
                        return(0);                      /* parallel */
                root[0] = -rox[2]/rdx[2];
                if (root[0] <= FTINY || root[0] >= r->rot)
                        return(0);                      /* distance check */
                b = root[0]*rdx[0] + rox[0];
                c = root[0]*rdx[1] + rox[1];
                a = b*b + c*c;
                if (a < CO_R0(co)*CO_R0(co) || a > CO_R1(co)*CO_R1(co))
                        return(0);                      /* outside radii */
                r->ro = o;
                r->rot = root[0];
                for (i = 0; i < 3; i++)
                        r->rop[i] = r->rorg[i] + r->rdir[i]*r->rot;
                VCOPY(r->ron, co->ad);
                r->rod = -rdx[2];
                r->rox = NULL;
                return(1);                              /* good */
        }
                                        /* roots for cone, cup, cyl., tube */
        nroots = quadratic(root, a, b, c);

        for (rn = 0; rn < nroots; rn++) {       /* check real roots */
                if (root[rn] <= FTINY)
                        continue;               /* too small */
                if (root[rn] >= r->rot)
                        break;                  /* too big */
                                                /* check endpoints */
                for (i = 0; i < 3; i++) {
                        rox[i] = r->rorg[i] + root[rn]*r->rdir[i];
                        rdx[i] = rox[i] - CO_P0(co)[i];
                }
                b = DOT(rdx, co->ad); 
                if (b < 0.0)
                        continue;               /* before p0 */
                if (b > co->al)
                        continue;               /* after p1 */
                r->ro = o;
                r->rot = root[rn];
                VCOPY(r->rop, rox);
                                                /* get normal */
                if (o->otype == OBJ_CYLINDER)
                        a = CO_R0(co);
                else if (o->otype == OBJ_TUBE)
                        a = -CO_R0(co);
                else { /* OBJ_CONE || OBJ_CUP */
                        c = CO_R1(co) - CO_R0(co);
                        a = CO_R0(co) + b*c/co->al;
                        if (o->otype == OBJ_CUP) {
                                c = -c;
                                a = -a;
                        }
                }
                for (i = 0; i < 3; i++)
                        r->ron[i] = (rdx[i] - b*co->ad[i])/a;
                if (o->otype == OBJ_CONE || o->otype == OBJ_CUP)
                        for (i = 0; i < 3; i++)
                                r->ron[i] = (co->al*r->ron[i] - c*co->ad[i])
                                                /co->sl;
                r->rod = -DOT(r->rdir, r->ron);
                r->rox = NULL;
                return(1);                      /* good */
        }
        return(0);
}
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
#	Content
1	#ifndef lint
2	static const char RCSid[] = "$Id$";
3	#endif
4	/*
5	* o_cone.c - routine to determine ray intersection with cones.
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 "otypes.h"
68
69	#include "cone.h"
70
71
72	o_cone(o, r) /* intersect ray with cone */
73	OBJREC *o;
74	register RAY *r;
75	{
76	FVECT rox, rdx;
77	double a, b, c;
78	double root[2];
79	int nroots, rn;
80	register CONE *co;
81	register int i;
82
83	/* get cone structure */
84	co = getcone(o, 1);
85
86	/*
87	* To intersect a ray with a cone, we transform the
88	* ray into the cone's normalized space. This greatly
89	* simplifies the computation.
90	* For a cone or cup, normalization results in the
91	* equation:
92	*
93	* xx + yy - z*z == 0
94	*
95	* For a cylinder or tube, the normalized equation is:
96	*
97	* xx + yy - r*r == 0
98	*
99	* A normalized ring obeys the following set of equations:
100	*
101	* z == 0 &&
102	* xx + yy >= r0*r0 &&
103	* xx + yy <= r1*r1
104	*/
105
106	/* transform ray */
107	multp3(rox, r->rorg, co->tm);
108	multv3(rdx, r->rdir, co->tm);
109	/* compute intersection */
110
111	if (o->otype == OBJ_CONE \|\| o->otype == OBJ_CUP) {
112
113	a = rdx[0]rdx[0] + rdx[1]rdx[1] - rdx[2]*rdx[2];
114	b = 2.0(rdx[0]rox[0] + rdx[1]rox[1] - rdx[2]rox[2]);
115	c = rox[0]rox[0] + rox[1]rox[1] - rox[2]*rox[2];
116
117	} else if (o->otype == OBJ_CYLINDER \|\| o->otype == OBJ_TUBE) {
118
119	a = rdx[0]rdx[0] + rdx[1]rdx[1];
120	b = 2.0(rdx[0]rox[0] + rdx[1]*rox[1]);
121	c = rox[0]rox[0] + rox[1]rox[1] - CO_R0(co)*CO_R0(co);
122
123	} else { /* OBJ_RING */
124
125	if (rdx[2] <= FTINY && rdx[2] >= -FTINY)
126	return(0); /* parallel */
127	root[0] = -rox[2]/rdx[2];
128	if (root[0] <= FTINY \|\| root[0] >= r->rot)
129	return(0); /* distance check */
130	b = root[0]*rdx[0] + rox[0];
131	c = root[0]*rdx[1] + rox[1];
132	a = bb + cc;
133	if (a < CO_R0(co)CO_R0(co) \|\| a > CO_R1(co)CO_R1(co))
134	return(0); /* outside radii */
135	r->ro = o;
136	r->rot = root[0];
137	for (i = 0; i < 3; i++)
138	r->rop[i] = r->rorg[i] + r->rdir[i]*r->rot;
139	VCOPY(r->ron, co->ad);
140	r->rod = -rdx[2];
141	r->rox = NULL;
142	return(1); /* good */
143	}
144	/* roots for cone, cup, cyl., tube */
145	nroots = quadratic(root, a, b, c);
146
147	for (rn = 0; rn < nroots; rn++) { /* check real roots */
148	if (root[rn] <= FTINY)
149	continue; /* too small */
150	if (root[rn] >= r->rot)
151	break; /* too big */
152	/* check endpoints */
153	for (i = 0; i < 3; i++) {
154	rox[i] = r->rorg[i] + root[rn]*r->rdir[i];
155	rdx[i] = rox[i] - CO_P0(co)[i];
156	}
157	b = DOT(rdx, co->ad);
158	if (b < 0.0)
159	continue; /* before p0 */
160	if (b > co->al)
161	continue; /* after p1 */
162	r->ro = o;
163	r->rot = root[rn];
164	VCOPY(r->rop, rox);
165	/* get normal */
166	if (o->otype == OBJ_CYLINDER)
167	a = CO_R0(co);
168	else if (o->otype == OBJ_TUBE)
169	a = -CO_R0(co);
170	else { /* OBJ_CONE \|\| OBJ_CUP */
171	c = CO_R1(co) - CO_R0(co);
172	a = CO_R0(co) + b*c/co->al;
173	if (o->otype == OBJ_CUP) {
174	c = -c;
175	a = -a;
176	}
177	}
178	for (i = 0; i < 3; i++)
179	r->ron[i] = (rdx[i] - b*co->ad[i])/a;
180	if (o->otype == OBJ_CONE \|\| o->otype == OBJ_CUP)
181	for (i = 0; i < 3; i++)
182	r->ron[i] = (co->alr->ron[i] - cco->ad[i])
183	/co->sl;
184	r->rod = -DOT(r->rdir, r->ron);
185	r->rox = NULL;
186	return(1); /* good */
187	}
188	return(0);
189	}