src/common/cone.c

/* Copyright (c) 1991 Regents of the University of California */

#ifndef lint
static char SCCSid[] = "$SunId$ LBL";
#endif

/*
 *  cone.c - routines for making cones
 *
 *     2/12/86
 */

#include  "standard.h"

#include  "object.h"

#include  "otypes.h"

#include  "cone.h"

/*
 *     In general, a cone may be any one of a cone, a cylinder, a ring,
 *  a cup (inverted cone), or a tube (inverted cylinder).
 *     Most cones are specified with a starting point and radius and
 *  an ending point and radius.  In the cases of a cylinder or tube,
 *  only one radius is needed.  In the case of a ring, a normal direction
 *  is specified instead of a second endpoint.
 *
 *      mtype (cone|cup) name
 *      0
 *      0
 *      8 P0x P0y P0z P1x P1y P1z R0 R1
 *
 *      mtype (cylinder|tube) name
 *      0
 *      0
 *      7 P0x P0y P0z P1x P1y P1z R
 *
 *      mtype ring name
 *      0
 *      0
 *      8 Px Py Pz Nx Ny Nz R0 R1
 */


CONE *
getcone(o, getxf)                       /* get cone structure */
register OBJREC  *o;
int  getxf;
{
        double  fabs(), sqrt();
        register CONE  *co;

        if ((co = (CONE *)o->os) == NULL) {

                co = (CONE *)malloc(sizeof(CONE));
                if (co == NULL)
                        error(SYSTEM, "out of memory in makecone");

                co->ca = o->oargs.farg;
                                                /* get radii */
                if (o->otype == OBJ_CYLINDER || o->otype == OBJ_TUBE) {
                        if (o->oargs.nfargs != 7)
                                goto argcerr;
                        if (co->ca[6] <= FTINY)
                                goto raderr;
                        co->r0 = co->r1 = 6;
                } else {
                        if (o->oargs.nfargs != 8)
                                goto argcerr;
                        if (co->ca[6] < -FTINY || co->ca[7] < -FTINY)
                                goto raderr;
                        if (co->ca[6] < 0.0) co->ca[6] = 0.0;
                        if (co->ca[7] < 0.0) co->ca[7] = 0.0;
                        if (fabs(co->ca[7] - co->ca[6]) <= FTINY)
                                goto raderr;
                        co->r0 = 6;
                        co->r1 = 7;
                }
                                                /* get axis orientation */
                co->p0 = 0;
                if (o->otype == OBJ_RING) {
                        if (co->ca[6] > co->ca[7]) {    /* make r0 smaller */
                                co->r0 = 7;
                                co->r1 = 6;
                        }
                        co->p1 = 0;
                        VCOPY(co->ad, o->oargs.farg+3);
                } else {
                        co->p1 = 3;
                        co->ad[0] = co->ca[3] - co->ca[0];
                        co->ad[1] = co->ca[4] - co->ca[1];
                        co->ad[2] = co->ca[5] - co->ca[2];
                }
                co->al = normalize(co->ad);
                if (co->al == 0.0)
                        objerror(o, USER, "zero orientation");
                                        /* compute axis and side lengths */
                if (o->otype == OBJ_RING) {
                        co->al = 0.0;
                        co->sl = co->ca[co->r1] - co->ca[co->r0];
                } else if (o->otype == OBJ_CONE || o->otype == OBJ_CUP) {
                        co->sl = co->ca[7] - co->ca[6];
                        co->sl = sqrt(co->sl*co->sl + co->al*co->al);
                } else { /* OBJ_CYLINDER || OBJ_TUBE */
                        co->sl = co->al;
                }
                co->tm = NULL;
                o->os = (char *)co;
        }
        if (getxf && co->tm == NULL)
                conexform(co);
        return(co);

argcerr:
        objerror(o, USER, "bad # arguments");
raderr:
        objerror(o, USER, "illegal radii");
}


freecone(o)                     /* free memory associated with cone */
OBJREC  *o;
{
        register CONE  *co = (CONE *)o->os;

        if (co->tm != NULL)
                free((char *)co->tm);
        free(o->os);
        o->os = NULL;
}


conexform(co)                   /* get cone transformation matrix */
register CONE  *co;
{
        double  sqrt(), fabs();
        double  m4[4][4];
        register double  d;
        register int  i;

        co->tm = (double (*)[4])malloc(sizeof(m4));
        if (co->tm == NULL)
                error(SYSTEM, "out of memory in conexform");

                                /* translate to origin */
        setident4(co->tm);
        if (co->r0 == co->r1)
                d = 0.0;
        else
                d = co->ca[co->r0] / (co->ca[co->r1] - co->ca[co->r0]);
        for (i = 0; i < 3; i++)
                co->tm[3][i] = d*(co->ca[co->p1+i] - co->ca[co->p0+i])
                                - co->ca[co->p0+i];
        
                                /* rotate to positive z-axis */
        setident4(m4);
        d = co->ad[1]*co->ad[1] + co->ad[2]*co->ad[2];
        if (d <= FTINY*FTINY) {
                m4[0][0] = 0.0;
                m4[0][2] = co->ad[0];
                m4[2][0] = -co->ad[0];
                m4[2][2] = 0.0;
        } else {
                d = sqrt(d);
                m4[0][0] = d;
                m4[1][0] = -co->ad[0]*co->ad[1]/d;
                m4[2][0] = -co->ad[0]*co->ad[2]/d;
                m4[1][1] = co->ad[2]/d;
                m4[2][1] = -co->ad[1]/d;
                m4[0][2] = co->ad[0];
                m4[1][2] = co->ad[1];
                m4[2][2] = co->ad[2];
        }
        multmat4(co->tm, co->tm, m4);

                                /* scale z-axis */
        setident4(m4);
        if (co->p0 != co->p1 && co->r0 != co->r1) {
                d = fabs(co->ca[co->r1] - co->ca[co->r0]);
                m4[2][2] = d/co->al;
        }
        multmat4(co->tm, co->tm, m4);
}
Revision:	1.3
Committed:	Sat Jan 19 13:43:28 1991 UTC (33 years, 3 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 1.2:	+4 -2 lines
Log Message:	changed error checking to allow for slightly negative radii
#	User	Rev	Content
1	greg	1.3	/* Copyright (c) 1991 Regents of the University of California */
2	greg	1.1
3			#ifndef lint
4			static char SCCSid[] = "$SunId$ LBL";
5			#endif
6
7			/*
8			* cone.c - routines for making cones
9			*
10			* 2/12/86
11			*/
12
13			#include "standard.h"
14
15			#include "object.h"
16
17			#include "otypes.h"
18
19			#include "cone.h"
20
21			/*
22			* In general, a cone may be any one of a cone, a cylinder, a ring,
23			* a cup (inverted cone), or a tube (inverted cylinder).
24			* Most cones are specified with a starting point and radius and
25			* an ending point and radius. In the cases of a cylinder or tube,
26			* only one radius is needed. In the case of a ring, a normal direction
27			* is specified instead of a second endpoint.
28			*
29			* mtype (cone\|cup) name
30			* 0
31			* 0
32			* 8 P0x P0y P0z P1x P1y P1z R0 R1
33			*
34			* mtype (cylinder\|tube) name
35			* 0
36			* 0
37			* 7 P0x P0y P0z P1x P1y P1z R
38			*
39			* mtype ring name
40			* 0
41			* 0
42			* 8 Px Py Pz Nx Ny Nz R0 R1
43			*/
44
45
46			CONE *
47			getcone(o, getxf) /* get cone structure */
48			register OBJREC *o;
49			int getxf;
50			{
51			double fabs(), sqrt();
52			register CONE *co;
53
54			if ((co = (CONE *)o->os) == NULL) {
55
56			co = (CONE *)malloc(sizeof(CONE));
57			if (co == NULL)
58			error(SYSTEM, "out of memory in makecone");
59
60			co->ca = o->oargs.farg;
61			/* get radii */
62			if (o->otype == OBJ_CYLINDER \|\| o->otype == OBJ_TUBE) {
63			if (o->oargs.nfargs != 7)
64			goto argcerr;
65			if (co->ca[6] <= FTINY)
66			goto raderr;
67			co->r0 = co->r1 = 6;
68			} else {
69			if (o->oargs.nfargs != 8)
70			goto argcerr;
71	greg	1.3	if (co->ca[6] < -FTINY \|\| co->ca[7] < -FTINY)
72	greg	1.1	goto raderr;
73	greg	1.3	if (co->ca[6] < 0.0) co->ca[6] = 0.0;
74			if (co->ca[7] < 0.0) co->ca[7] = 0.0;
75	greg	1.1	if (fabs(co->ca[7] - co->ca[6]) <= FTINY)
76			goto raderr;
77			co->r0 = 6;
78			co->r1 = 7;
79			}
80			/* get axis orientation */
81			co->p0 = 0;
82			if (o->otype == OBJ_RING) {
83			if (co->ca[6] > co->ca[7]) { /* make r0 smaller */
84			co->r0 = 7;
85			co->r1 = 6;
86			}
87			co->p1 = 0;
88			VCOPY(co->ad, o->oargs.farg+3);
89			} else {
90			co->p1 = 3;
91			co->ad[0] = co->ca[3] - co->ca[0];
92			co->ad[1] = co->ca[4] - co->ca[1];
93			co->ad[2] = co->ca[5] - co->ca[2];
94			}
95			co->al = normalize(co->ad);
96			if (co->al == 0.0)
97			objerror(o, USER, "zero orientation");
98			/* compute axis and side lengths */
99			if (o->otype == OBJ_RING) {
100			co->al = 0.0;
101			co->sl = co->ca[co->r1] - co->ca[co->r0];
102			} else if (o->otype == OBJ_CONE \|\| o->otype == OBJ_CUP) {
103			co->sl = co->ca[7] - co->ca[6];
104			co->sl = sqrt(co->slco->sl + co->alco->al);
105			} else { /* OBJ_CYLINDER \|\| OBJ_TUBE */
106			co->sl = co->al;
107			}
108			co->tm = NULL;
109	greg	1.2	o->os = (char *)co;
110	greg	1.1	}
111			if (getxf && co->tm == NULL)
112			conexform(co);
113			return(co);
114
115			argcerr:
116			objerror(o, USER, "bad # arguments");
117			raderr:
118			objerror(o, USER, "illegal radii");
119			}
120
121
122			freecone(o) /* free memory associated with cone */
123			OBJREC *o;
124			{
125			register CONE co = (CONE )o->os;
126
127			if (co->tm != NULL)
128			free((char *)co->tm);
129			free(o->os);
130			o->os = NULL;
131			}
132
133
134			conexform(co) /* get cone transformation matrix */
135			register CONE *co;
136			{
137			double sqrt(), fabs();
138			double m4[4][4];
139			register double d;
140			register int i;
141
142			co->tm = (double (*)[4])malloc(sizeof(m4));
143			if (co->tm == NULL)
144			error(SYSTEM, "out of memory in conexform");
145
146			/* translate to origin */
147			setident4(co->tm);
148			if (co->r0 == co->r1)
149			d = 0.0;
150			else
151			d = co->ca[co->r0] / (co->ca[co->r1] - co->ca[co->r0]);
152			for (i = 0; i < 3; i++)
153			co->tm[3][i] = d*(co->ca[co->p1+i] - co->ca[co->p0+i])
154			- co->ca[co->p0+i];
155
156			/* rotate to positive z-axis */
157			setident4(m4);
158			d = co->ad[1]co->ad[1] + co->ad[2]co->ad[2];
159			if (d <= FTINY*FTINY) {
160			m4[0][0] = 0.0;
161			m4[0][2] = co->ad[0];
162			m4[2][0] = -co->ad[0];
163			m4[2][2] = 0.0;
164			} else {
165			d = sqrt(d);
166			m4[0][0] = d;
167			m4[1][0] = -co->ad[0]*co->ad[1]/d;
168			m4[2][0] = -co->ad[0]*co->ad[2]/d;
169			m4[1][1] = co->ad[2]/d;
170			m4[2][1] = -co->ad[1]/d;
171			m4[0][2] = co->ad[0];
172			m4[1][2] = co->ad[1];
173			m4[2][2] = co->ad[2];
174			}
175			multmat4(co->tm, co->tm, m4);
176
177			/* scale z-axis */
178			setident4(m4);
179			if (co->p0 != co->p1 && co->r0 != co->r1) {
180			d = fabs(co->ca[co->r1] - co->ca[co->r0]);
181			m4[2][2] = d/co->al;
182			}
183			multmat4(co->tm, co->tm, m4);
184			}