src/gen/mkillum2.c

#ifndef lint
static const char       RCSid[] = "$Id: mkillum2.c,v 2.10 2003/06/26 00:58:09 schorsch Exp $";
#endif
/*
 * Routines to do the actual calculation for mkillum
 */

#include <string.h>

#include  "mkillum.h"
#include  "face.h"
#include  "cone.h"
#include  "random.h"


o_default(ob, il, rt, nm)       /* default illum action */
OBJREC  *ob;
struct illum_args  *il;
struct rtproc  *rt;
char  *nm;
{
        sprintf(errmsg, "(%s): cannot make illum for %s \"%s\"",
                        nm, ofun[ob->otype].funame, ob->oname);
        error(WARNING, errmsg);
        printobj(il->altmat, ob);
}


o_face(ob, il, rt, nm)          /* make an illum face */
OBJREC  *ob;
struct illum_args  *il;
struct rtproc  *rt;
char  *nm;
{
#define MAXMISS         (5*n*il->nsamps)
        int  dim[3];
        int  n, nalt, nazi, h;
        float  *distarr;
        double  sp[2], r1, r2;
        FVECT  dn, org, dir;
        FVECT  u, v;
        double  ur[2], vr[2];
        int  nmisses;
        register FACE  *fa;
        register int  i, j;
                                /* get/check arguments */
        fa = getface(ob);
        if (fa->area == 0.0) {
                freeface(ob);
                o_default(ob, il, rt, nm);
                return;
        }
                                /* set up sampling */
        if (il->sampdens <= 0)
                nalt = nazi = 1;
        else {
                n = PI * il->sampdens;
                nalt = sqrt(n/PI) + .5;
                nazi = PI*nalt + .5;
        }
        n = nalt*nazi;
        distarr = (float *)calloc(n, 3*sizeof(float));
        if (distarr == NULL)
                error(SYSTEM, "out of memory in o_face");
                                /* take first edge longer than sqrt(area) */
        for (j = fa->nv-1, i = 0; i < fa->nv; j = i++) {
                u[0] = VERTEX(fa,i)[0] - VERTEX(fa,j)[0];
                u[1] = VERTEX(fa,i)[1] - VERTEX(fa,j)[1];
                u[2] = VERTEX(fa,i)[2] - VERTEX(fa,j)[2];
                if ((r1 = DOT(u,u)) >= fa->area-FTINY)
                        break;
        }
        if (i < fa->nv) {       /* got one! -- let's align our axes */
                r2 = 1.0/sqrt(r1);
                u[0] *= r2; u[1] *= r2; u[2] *= r2;
                fcross(v, fa->norm, u);
        } else                  /* oh well, we'll just have to wing it */
                mkaxes(u, v, fa->norm);
                                /* now, find limits in (u,v) coordinates */
        ur[0] = vr[0] = FHUGE;
        ur[1] = vr[1] = -FHUGE;
        for (i = 0; i < fa->nv; i++) {
                r1 = DOT(VERTEX(fa,i),u);
                if (r1 < ur[0]) ur[0] = r1;
                if (r1 > ur[1]) ur[1] = r1;
                r2 = DOT(VERTEX(fa,i),v);
                if (r2 < vr[0]) vr[0] = r2;
                if (r2 > vr[1]) vr[1] = r2;
        }
        dim[0] = random();
                                /* sample polygon */
        nmisses = 0;
        for (dim[1] = 0; dim[1] < nalt; dim[1]++)
            for (dim[2] = 0; dim[2] < nazi; dim[2]++)
                for (i = 0; i < il->nsamps; i++) {
                                        /* random direction */
                    h = ilhash(dim, 3) + i;
                    multisamp(sp, 2, urand(h));
                    r1 = (dim[1] + sp[0])/nalt;
                    r2 = (dim[2] + sp[1] - .5)/nazi;
                    flatdir(dn, r1, r2);
                    for (j = 0; j < 3; j++)
                        dir[j] = -dn[0]*u[j] - dn[1]*v[j] - dn[2]*fa->norm[j];
                                        /* random location */
                    do {
                        multisamp(sp, 2, urand(h+4862+nmisses));
                        r1 = ur[0] + (ur[1]-ur[0]) * sp[0];
                        r2 = vr[0] + (vr[1]-vr[0]) * sp[1];
                        for (j = 0; j < 3; j++)
                            org[j] = r1*u[j] + r2*v[j]
                                        + fa->offset*fa->norm[j];
                    } while (!inface(org, fa) && nmisses++ < MAXMISS);
                    if (nmisses > MAXMISS) {
                        objerror(ob, WARNING, "bad aspect");
                        rt->nrays = 0;
                        freeface(ob);
                        free((void *)distarr);
                        o_default(ob, il, rt, nm);
                        return;
                    }
                    for (j = 0; j < 3; j++)
                        org[j] += .001*fa->norm[j];
                                        /* send sample */
                    raysamp(distarr+3*(dim[1]*nazi+dim[2]), org, dir, rt);
                }
        rayflush(rt);
                                /* write out the face and its distribution */
        if (average(il, distarr, nalt*nazi)) {
                if (il->sampdens > 0)
                        flatout(il, distarr, nalt, nazi, u, v, fa->norm);
                illumout(il, ob);
        } else
                printobj(il->altmat, ob);
                                /* clean up */
        freeface(ob);
        free((void *)distarr);
#undef MAXMISS
}


o_sphere(ob, il, rt, nm)        /* make an illum sphere */
register OBJREC  *ob;
struct illum_args  *il;
struct rtproc  *rt;
char  *nm;
{
        int  dim[3];
        int  n, nalt, nazi;
        float  *distarr;
        double  sp[4], r1, r2, r3;
        FVECT  org, dir;
        FVECT  u, v;
        register int  i, j;
                                /* check arguments */
        if (ob->oargs.nfargs != 4)
                objerror(ob, USER, "bad # of arguments");
                                /* set up sampling */
        if (il->sampdens <= 0)
                nalt = nazi = 1;
        else {
                n = 4.*PI * il->sampdens;
                nalt = sqrt(2./PI*n) + .5;
                nazi = PI/2.*nalt + .5;
        }
        n = nalt*nazi;
        distarr = (float *)calloc(n, 3*sizeof(float));
        if (distarr == NULL)
                error(SYSTEM, "out of memory in o_sphere");
        dim[0] = random();
                                /* sample sphere */
        for (dim[1] = 0; dim[1] < nalt; dim[1]++)
            for (dim[2] = 0; dim[2] < nazi; dim[2]++)
                for (i = 0; i < il->nsamps; i++) {
                                        /* next sample point */
                    multisamp(sp, 4, urand(ilhash(dim,3)+i));
                                        /* random direction */
                    r1 = (dim[1] + sp[0])/nalt;
                    r2 = (dim[2] + sp[1] - .5)/nazi;
                    rounddir(dir, r1, r2);
                                        /* random location */
                    mkaxes(u, v, dir);          /* yuck! */
                    r3 = sqrt(sp[2]);
                    r2 = 2.*PI*sp[3];
                    r1 = r3*ob->oargs.farg[3]*cos(r2);
                    r2 = r3*ob->oargs.farg[3]*sin(r2);
                    r3 = ob->oargs.farg[3]*sqrt(1.01-r3*r3);
                    for (j = 0; j < 3; j++) {
                        org[j] = ob->oargs.farg[j] + r1*u[j] + r2*v[j] +
                                        r3*dir[j];
                        dir[j] = -dir[j];
                    }
                                        /* send sample */
                    raysamp(distarr+3*(dim[1]*nazi+dim[2]), org, dir, rt);
                }
        rayflush(rt);
                                /* write out the sphere and its distribution */
        if (average(il, distarr, nalt*nazi)) {
                if (il->sampdens > 0)
                        roundout(il, distarr, nalt, nazi);
                else
                        objerror(ob, WARNING, "diffuse distribution");
                illumout(il, ob);
        } else
                printobj(il->altmat, ob);
                                /* clean up */
        free((void *)distarr);
}


o_ring(ob, il, rt, nm)          /* make an illum ring */
OBJREC  *ob;
struct illum_args  *il;
struct rtproc  *rt;
char  *nm;
{
        int  dim[3];
        int  n, nalt, nazi;
        float  *distarr;
        double  sp[4], r1, r2, r3;
        FVECT  dn, org, dir;
        FVECT  u, v;
        register CONE  *co;
        register int  i, j;
                                /* get/check arguments */
        co = getcone(ob, 0);
                                /* set up sampling */
        if (il->sampdens <= 0)
                nalt = nazi = 1;
        else {
                n = PI * il->sampdens;
                nalt = sqrt(n/PI) + .5;
                nazi = PI*nalt + .5;
        }
        n = nalt*nazi;
        distarr = (float *)calloc(n, 3*sizeof(float));
        if (distarr == NULL)
                error(SYSTEM, "out of memory in o_ring");
        mkaxes(u, v, co->ad);
        dim[0] = random();
                                /* sample disk */
        for (dim[1] = 0; dim[1] < nalt; dim[1]++)
            for (dim[2] = 0; dim[2] < nazi; dim[2]++)
                for (i = 0; i < il->nsamps; i++) {
                                        /* next sample point */
                    multisamp(sp, 4, urand(ilhash(dim,3)+i));
                                        /* random direction */
                    r1 = (dim[1] + sp[0])/nalt;
                    r2 = (dim[2] + sp[1] - .5)/nazi;
                    flatdir(dn, r1, r2);
                    for (j = 0; j < 3; j++)
                        dir[j] = -dn[0]*u[j] - dn[1]*v[j] - dn[2]*co->ad[j];
                                        /* random location */
                    r3 = sqrt(CO_R0(co)*CO_R0(co) +
                            sp[2]*(CO_R1(co)*CO_R1(co) - CO_R0(co)*CO_R0(co)));
                    r2 = 2.*PI*sp[3];
                    r1 = r3*cos(r2);
                    r2 = r3*sin(r2);
                    for (j = 0; j < 3; j++)
                        org[j] = CO_P0(co)[j] + r1*u[j] + r2*v[j] +
                                        .001*co->ad[j];

                                        /* send sample */
                    raysamp(distarr+3*(dim[1]*nazi+dim[2]), org, dir, rt);
                }
        rayflush(rt);
                                /* write out the ring and its distribution */
        if (average(il, distarr, nalt*nazi)) {
                if (il->sampdens > 0)
                        flatout(il, distarr, nalt, nazi, u, v, co->ad);
                illumout(il, ob);
        } else
                printobj(il->altmat, ob);
                                /* clean up */
        freecone(ob);
        free((void *)distarr);
}


raysamp(res, org, dir, rt)      /* compute a ray sample */
float  res[3];
FVECT  org, dir;
register struct rtproc  *rt;
{
        register float  *fp;

        if (rt->nrays == rt->bsiz)
                rayflush(rt);
        rt->dest[rt->nrays] = res;
        fp = rt->buf + 6*rt->nrays++;
        *fp++ = org[0]; *fp++ = org[1]; *fp++ = org[2];
        *fp++ = dir[0]; *fp++ = dir[1]; *fp = dir[2];
}


rayflush(rt)                    /* flush buffered rays */
register struct rtproc  *rt;
{
        register int  i;

        if (rt->nrays <= 0)
                return;
        memset(rt->buf+6*rt->nrays, '\0', 6*sizeof(float));
        errno = 0;
        if ( process(&(rt->pd), (char *)rt->buf, (char *)rt->buf,
                        3*sizeof(float)*(rt->nrays+1),
                        6*sizeof(float)*(rt->nrays+1)) <
                        3*sizeof(float)*(rt->nrays+1) )
                error(SYSTEM, "error reading from rtrace process");
        i = rt->nrays;
        while (i--) {
                rt->dest[i][0] += rt->buf[3*i];
                rt->dest[i][1] += rt->buf[3*i+1];
                rt->dest[i][2] += rt->buf[3*i+2];
        }
        rt->nrays = 0;
}


mkaxes(u, v, n)                 /* compute u and v to go with n */
FVECT  u, v, n;
{
        register int  i;

        v[0] = v[1] = v[2] = 0.0;
        for (i = 0; i < 3; i++)
                if (n[i] < 0.6 && n[i] > -0.6)
                        break;
        v[i] = 1.0;
        fcross(u, v, n);
        normalize(u);
        fcross(v, n, u);
}


rounddir(dv, alt, azi)          /* compute uniform spherical direction */
register FVECT  dv;
double  alt, azi;
{
        double  d1, d2;

        dv[2] = 1. - 2.*alt;
        d1 = sqrt(1. - dv[2]*dv[2]);
        d2 = 2.*PI * azi;
        dv[0] = d1*cos(d2);
        dv[1] = d1*sin(d2);
}


flatdir(dv, alt, azi)           /* compute uniform hemispherical direction */
register FVECT  dv;
double  alt, azi;
{
        double  d1, d2;

        d1 = sqrt(alt);
        d2 = 2.*PI * azi;
        dv[0] = d1*cos(d2);
        dv[1] = d1*sin(d2);
        dv[2] = sqrt(1. - alt);
}
Revision:	2.11
Committed:	Mon Jun 30 14:59:11 2003 UTC (20 years, 9 months ago) by schorsch
Content type:	text/plain
Branch:	MAIN
Changes since 2.10:	+4 -2 lines
Log Message:	Replaced most outdated BSD function calls with their posix equivalents, and cleaned up a few other platform dependencies.
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	schorsch	2.11	static const char RCSid[] = "$Id: mkillum2.c,v 2.10 2003/06/26 00:58:09 schorsch Exp $";
3	greg	1.1	#endif
4			/*
5	greg	1.4	* Routines to do the actual calculation for mkillum
6	greg	1.1	*/
7
8	schorsch	2.11	#include <string.h>
9
10	greg	1.1	#include "mkillum.h"
11			#include "face.h"
12			#include "cone.h"
13	greg	1.2	#include "random.h"
14	greg	1.1
15	greg	1.2
16			o_default(ob, il, rt, nm) /* default illum action */
17	greg	1.1	OBJREC *ob;
18			struct illum_args *il;
19			struct rtproc *rt;
20	greg	1.2	char *nm;
21	greg	1.1	{
22	greg	1.2	sprintf(errmsg, "(%s): cannot make illum for %s \"%s\"",
23			nm, ofun[ob->otype].funame, ob->oname);
24			error(WARNING, errmsg);
25	greg	2.2	printobj(il->altmat, ob);
26	greg	1.2	}
27
28
29			o_face(ob, il, rt, nm) /* make an illum face */
30			OBJREC *ob;
31			struct illum_args *il;
32			struct rtproc *rt;
33			char *nm;
34			{
35	greg	1.3	#define MAXMISS (5nil->nsamps)
36	greg	1.10	int dim[3];
37			int n, nalt, nazi, h;
38	greg	1.3	float *distarr;
39	greg	1.10	double sp[2], r1, r2;
40	greg	1.4	FVECT dn, org, dir;
41	greg	1.3	FVECT u, v;
42			double ur[2], vr[2];
43			int nmisses;
44			register FACE *fa;
45			register int i, j;
46			/* get/check arguments */
47			fa = getface(ob);
48			if (fa->area == 0.0) {
49			freeface(ob);
50			o_default(ob, il, rt, nm);
51			return;
52			}
53			/* set up sampling */
54	greg	1.11	if (il->sampdens <= 0)
55			nalt = nazi = 1;
56			else {
57			n = PI * il->sampdens;
58			nalt = sqrt(n/PI) + .5;
59			nazi = PI*nalt + .5;
60			}
61	greg	1.3	n = nalt*nazi;
62			distarr = (float )calloc(n, 3sizeof(float));
63			if (distarr == NULL)
64			error(SYSTEM, "out of memory in o_face");
65	greg	2.3	/* take first edge longer than sqrt(area) */
66	greg	2.4	for (j = fa->nv-1, i = 0; i < fa->nv; j = i++) {
67			u[0] = VERTEX(fa,i)[0] - VERTEX(fa,j)[0];
68			u[1] = VERTEX(fa,i)[1] - VERTEX(fa,j)[1];
69			u[2] = VERTEX(fa,i)[2] - VERTEX(fa,j)[2];
70	greg	2.5	if ((r1 = DOT(u,u)) >= fa->area-FTINY)
71	greg	2.3	break;
72			}
73			if (i < fa->nv) { /* got one! -- let's align our axes */
74	greg	2.5	r2 = 1.0/sqrt(r1);
75			u[0] = r2; u[1] = r2; u[2] *= r2;
76	greg	2.3	fcross(v, fa->norm, u);
77			} else /* oh well, we'll just have to wing it */
78			mkaxes(u, v, fa->norm);
79			/* now, find limits in (u,v) coordinates */
80	greg	1.3	ur[0] = vr[0] = FHUGE;
81			ur[1] = vr[1] = -FHUGE;
82			for (i = 0; i < fa->nv; i++) {
83			r1 = DOT(VERTEX(fa,i),u);
84			if (r1 < ur[0]) ur[0] = r1;
85			if (r1 > ur[1]) ur[1] = r1;
86			r2 = DOT(VERTEX(fa,i),v);
87			if (r2 < vr[0]) vr[0] = r2;
88			if (r2 > vr[1]) vr[1] = r2;
89			}
90			dim[0] = random();
91			/* sample polygon */
92			nmisses = 0;
93			for (dim[1] = 0; dim[1] < nalt; dim[1]++)
94			for (dim[2] = 0; dim[2] < nazi; dim[2]++)
95			for (i = 0; i < il->nsamps; i++) {
96			/* random direction */
97	greg	1.10	h = ilhash(dim, 3) + i;
98	greg	1.11	multisamp(sp, 2, urand(h));
99	greg	1.10	r1 = (dim[1] + sp[0])/nalt;
100	greg	1.13	r2 = (dim[2] + sp[1] - .5)/nazi;
101	greg	1.3	flatdir(dn, r1, r2);
102			for (j = 0; j < 3; j++)
103	greg	1.5	dir[j] = -dn[0]u[j] - dn[1]v[j] - dn[2]*fa->norm[j];
104	greg	1.3	/* random location */
105			do {
106	greg	1.11	multisamp(sp, 2, urand(h+4862+nmisses));
107	greg	1.10	r1 = ur[0] + (ur[1]-ur[0]) * sp[0];
108			r2 = vr[0] + (vr[1]-vr[0]) * sp[1];
109	greg	1.3	for (j = 0; j < 3; j++)
110			org[j] = r1u[j] + r2v[j]
111			+ fa->offset*fa->norm[j];
112			} while (!inface(org, fa) && nmisses++ < MAXMISS);
113			if (nmisses > MAXMISS) {
114			objerror(ob, WARNING, "bad aspect");
115			rt->nrays = 0;
116			freeface(ob);
117	greg	2.9	free((void *)distarr);
118	greg	1.3	o_default(ob, il, rt, nm);
119			return;
120			}
121			for (j = 0; j < 3; j++)
122			org[j] += .001*fa->norm[j];
123			/* send sample */
124	greg	1.7	raysamp(distarr+3(dim[1]nazi+dim[2]), org, dir, rt);
125	greg	1.3	}
126			rayflush(rt);
127	greg	1.11	/* write out the face and its distribution */
128	greg	1.12	if (average(il, distarr, nalt*nazi)) {
129			if (il->sampdens > 0)
130			flatout(il, distarr, nalt, nazi, u, v, fa->norm);
131			illumout(il, ob);
132	greg	2.2	} else
133	greg	1.12	printobj(il->altmat, ob);
134	greg	1.3	/* clean up */
135			freeface(ob);
136	greg	2.9	free((void *)distarr);
137	greg	1.3	#undef MAXMISS
138	greg	1.2	}
139
140
141			o_sphere(ob, il, rt, nm) /* make an illum sphere */
142	greg	1.3	register OBJREC *ob;
143	greg	1.2	struct illum_args *il;
144			struct rtproc *rt;
145			char *nm;
146			{
147	greg	1.10	int dim[3];
148	greg	1.2	int n, nalt, nazi;
149			float *distarr;
150	greg	1.10	double sp[4], r1, r2, r3;
151	greg	1.4	FVECT org, dir;
152	greg	1.2	FVECT u, v;
153			register int i, j;
154			/* check arguments */
155			if (ob->oargs.nfargs != 4)
156			objerror(ob, USER, "bad # of arguments");
157			/* set up sampling */
158	greg	1.11	if (il->sampdens <= 0)
159			nalt = nazi = 1;
160			else {
161			n = 4.PI il->sampdens;
162	greg	2.7	nalt = sqrt(2./PI*n) + .5;
163			nazi = PI/2.*nalt + .5;
164	greg	1.11	}
165	greg	1.2	n = nalt*nazi;
166			distarr = (float )calloc(n, 3sizeof(float));
167			if (distarr == NULL)
168			error(SYSTEM, "out of memory in o_sphere");
169			dim[0] = random();
170			/* sample sphere */
171			for (dim[1] = 0; dim[1] < nalt; dim[1]++)
172	greg	1.8	for (dim[2] = 0; dim[2] < nazi; dim[2]++)
173	greg	1.2	for (i = 0; i < il->nsamps; i++) {
174	greg	1.10	/* next sample point */
175	greg	1.11	multisamp(sp, 4, urand(ilhash(dim,3)+i));
176	greg	1.2	/* random direction */
177	greg	1.10	r1 = (dim[1] + sp[0])/nalt;
178	greg	1.13	r2 = (dim[2] + sp[1] - .5)/nazi;
179	greg	1.2	rounddir(dir, r1, r2);
180			/* random location */
181	greg	1.8	mkaxes(u, v, dir); /* yuck! */
182	greg	1.10	r3 = sqrt(sp[2]);
183			r2 = 2.PIsp[3];
184	greg	1.5	r1 = r3ob->oargs.farg[3]cos(r2);
185			r2 = r3ob->oargs.farg[3]sin(r2);
186			r3 = ob->oargs.farg[3]sqrt(1.01-r3r3);
187			for (j = 0; j < 3; j++) {
188			org[j] = ob->oargs.farg[j] + r1u[j] + r2v[j] +
189			r3*dir[j];
190			dir[j] = -dir[j];
191			}
192	greg	1.2	/* send sample */
193	greg	1.7	raysamp(distarr+3(dim[1]nazi+dim[2]), org, dir, rt);
194	greg	1.2	}
195			rayflush(rt);
196	greg	1.11	/* write out the sphere and its distribution */
197	greg	1.12	if (average(il, distarr, nalt*nazi)) {
198			if (il->sampdens > 0)
199			roundout(il, distarr, nalt, nazi);
200			else
201			objerror(ob, WARNING, "diffuse distribution");
202			illumout(il, ob);
203	greg	2.2	} else
204	greg	1.12	printobj(il->altmat, ob);
205	greg	1.2	/* clean up */
206	greg	2.9	free((void *)distarr);
207	greg	1.2	}
208
209
210			o_ring(ob, il, rt, nm) /* make an illum ring */
211			OBJREC *ob;
212			struct illum_args *il;
213			struct rtproc *rt;
214			char *nm;
215			{
216	greg	1.10	int dim[3];
217	greg	1.3	int n, nalt, nazi;
218			float *distarr;
219	greg	1.10	double sp[4], r1, r2, r3;
220	greg	1.4	FVECT dn, org, dir;
221	greg	1.3	FVECT u, v;
222			register CONE *co;
223			register int i, j;
224			/* get/check arguments */
225			co = getcone(ob, 0);
226			/* set up sampling */
227	greg	1.11	if (il->sampdens <= 0)
228			nalt = nazi = 1;
229			else {
230			n = PI * il->sampdens;
231			nalt = sqrt(n/PI) + .5;
232			nazi = PI*nalt + .5;
233			}
234	greg	1.3	n = nalt*nazi;
235			distarr = (float )calloc(n, 3sizeof(float));
236			if (distarr == NULL)
237			error(SYSTEM, "out of memory in o_ring");
238			mkaxes(u, v, co->ad);
239			dim[0] = random();
240			/* sample disk */
241			for (dim[1] = 0; dim[1] < nalt; dim[1]++)
242			for (dim[2] = 0; dim[2] < nazi; dim[2]++)
243			for (i = 0; i < il->nsamps; i++) {
244	greg	1.10	/* next sample point */
245	greg	1.11	multisamp(sp, 4, urand(ilhash(dim,3)+i));
246	greg	1.3	/* random direction */
247	greg	1.10	r1 = (dim[1] + sp[0])/nalt;
248	greg	1.13	r2 = (dim[2] + sp[1] - .5)/nazi;
249	greg	1.3	flatdir(dn, r1, r2);
250			for (j = 0; j < 3; j++)
251	greg	1.5	dir[j] = -dn[0]u[j] - dn[1]v[j] - dn[2]*co->ad[j];
252	greg	1.3	/* random location */
253	greg	1.5	r3 = sqrt(CO_R0(co)*CO_R0(co) +
254	greg	1.10	sp[2](CO_R1(co)CO_R1(co) - CO_R0(co)*CO_R0(co)));
255			r2 = 2.PIsp[3];
256	greg	1.5	r1 = r3*cos(r2);
257			r2 = r3*sin(r2);
258	greg	1.3	for (j = 0; j < 3; j++)
259	greg	2.6	org[j] = CO_P0(co)[j] + r1u[j] + r2v[j] +
260	greg	1.5	.001*co->ad[j];
261	greg	1.3
262			/* send sample */
263	greg	1.7	raysamp(distarr+3(dim[1]nazi+dim[2]), org, dir, rt);
264	greg	1.3	}
265			rayflush(rt);
266	greg	1.11	/* write out the ring and its distribution */
267	greg	1.12	if (average(il, distarr, nalt*nazi)) {
268			if (il->sampdens > 0)
269			flatout(il, distarr, nalt, nazi, u, v, co->ad);
270			illumout(il, ob);
271	greg	2.2	} else
272	greg	1.12	printobj(il->altmat, ob);
273	greg	1.3	/* clean up */
274			freecone(ob);
275	greg	2.9	free((void *)distarr);
276	greg	1.2	}
277
278
279			raysamp(res, org, dir, rt) /* compute a ray sample */
280			float res[3];
281			FVECT org, dir;
282			register struct rtproc *rt;
283			{
284			register float *fp;
285
286			if (rt->nrays == rt->bsiz)
287			rayflush(rt);
288			rt->dest[rt->nrays] = res;
289			fp = rt->buf + 6*rt->nrays++;
290			fp++ = org[0]; fp++ = org[1]; *fp++ = org[2];
291			fp++ = dir[0]; fp++ = dir[1]; *fp = dir[2];
292			}
293
294
295			rayflush(rt) /* flush buffered rays */
296			register struct rtproc *rt;
297			{
298			register int i;
299
300			if (rt->nrays <= 0)
301			return;
302	schorsch	2.11	memset(rt->buf+6rt->nrays, '\0', 6sizeof(float));
303	greg	1.14	errno = 0;
304	schorsch	2.10	if ( process(&(rt->pd), (char )rt->buf, (char )rt->buf,
305	gregl	2.8	3sizeof(float)(rt->nrays+1),
306	greg	1.2	6sizeof(float)(rt->nrays+1)) <
307	gregl	2.8	3sizeof(float)(rt->nrays+1) )
308	greg	1.2	error(SYSTEM, "error reading from rtrace process");
309			i = rt->nrays;
310			while (i--) {
311			rt->dest[i][0] += rt->buf[3*i];
312			rt->dest[i][1] += rt->buf[3*i+1];
313			rt->dest[i][2] += rt->buf[3*i+2];
314			}
315			rt->nrays = 0;
316	greg	1.4	}
317
318
319			mkaxes(u, v, n) /* compute u and v to go with n */
320			FVECT u, v, n;
321			{
322			register int i;
323
324			v[0] = v[1] = v[2] = 0.0;
325			for (i = 0; i < 3; i++)
326			if (n[i] < 0.6 && n[i] > -0.6)
327			break;
328			v[i] = 1.0;
329			fcross(u, v, n);
330			normalize(u);
331			fcross(v, n, u);
332			}
333
334
335			rounddir(dv, alt, azi) /* compute uniform spherical direction */
336			register FVECT dv;
337			double alt, azi;
338			{
339			double d1, d2;
340
341			dv[2] = 1. - 2.*alt;
342			d1 = sqrt(1. - dv[2]*dv[2]);
343			d2 = 2.PI azi;
344			dv[0] = d1*cos(d2);
345			dv[1] = d1*sin(d2);
346			}
347
348
349			flatdir(dv, alt, azi) /* compute uniform hemispherical direction */
350			register FVECT dv;
351			double alt, azi;
352			{
353			double d1, d2;
354
355			d1 = sqrt(alt);
356			d2 = 2.PI azi;
357			dv[0] = d1*cos(d2);
358			dv[1] = d1*sin(d2);
359	greg	1.6	dv[2] = sqrt(1. - alt);
360	greg	1.1	}