src/gen/mkillum2.c

#ifndef lint
static const char       RCSid[] = "$Id: mkillum2.c,v 2.16 2004/09/17 21:43:50 greg 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"
#include  "selcall.h"


static void mkaxes(FVECT u, FVECT v, FVECT n);
static void rounddir(FVECT dv, double alt, double azi);
static void flatdir(FVECT dv, double alt, double azi);


static void
rayclean(                       /* finish all pending rays */
        struct rtproc *rt0
)
{
        rayflush(rt0, 1);
        while (raywait(rt0) != NULL)
                ;
}


int /* XXX type conflict with otypes.h */
o_default(      /* default illum action */
        OBJREC  *ob,
        struct illum_args  *il,
        struct rtproc  *rt0,
        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);
        return(1);
}


int
o_face(         /* make an illum face */
        OBJREC  *ob,
        struct illum_args  *il,
        struct rtproc  *rt0,
        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);
                return(o_default(ob, il, rt0, nm));
        }
                                /* 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");
                        rayclean(rt0);
                        freeface(ob);
                        free((void *)distarr);
                        return(o_default(ob, il, rt0, nm));
                    }
                    for (j = 0; j < 3; j++)
                        org[j] += .001*fa->norm[j];
                                        /* send sample */
                    raysamp(distarr+3*(dim[1]*nazi+dim[2]), org, dir, rt0);
                }
        rayclean(rt0);
                                /* 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);
        return(0);
#undef MAXMISS
}


int
o_sphere(       /* make an illum sphere */
        register OBJREC  *ob,
        struct illum_args  *il,
        struct rtproc  *rt0,
        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, rt0);
                }
        rayclean(rt0);
                                /* 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);
        return(1);
}


int
o_ring(         /* make an illum ring */
        OBJREC  *ob,
        struct illum_args  *il,
        struct rtproc  *rt0,
        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, rt0);
                }
        rayclean(rt0);
                                /* 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);
        return(1);
}


void
raysamp(        /* queue a ray sample */
        float  res[3],
        FVECT  org,
        FVECT  dir,
        struct rtproc *rt0
)
{
        register struct rtproc  *rt;
        register float  *fp;

        for (rt = rt0; rt != NULL; rt = rt->next)
                if (rt->nrays < rt->bsiz && rt->dest[rt->nrays] == NULL)
                        break;
        if (rt == NULL)         /* need to free up buffer? */
                rt = raywait(rt0);
        if (rt == NULL)
                error(SYSTEM, "raywait() returned NULL in raysamp()");
        fp = rt->buf + 6*rt->nrays;
        *fp++ = org[0]; *fp++ = org[1]; *fp++ = org[2];
        *fp++ = dir[0]; *fp++ = dir[1]; *fp = dir[2];
        rt->dest[rt->nrays++] = res;
        if (rt->nrays == rt->bsiz)
                rayflush(rt, 0);
}


void
rayflush(                       /* flush queued rays to rtrace */
        register struct rtproc  *rt,
        int  doall
)
{
        int     nw;

        do {
                if (rt->nrays <= 0)
                        continue;
                memset(rt->buf+6*rt->nrays, 0, 6*sizeof(float));
                nw = 6*sizeof(float)*(rt->nrays+1);
                errno = 0;
                if (writebuf(rt->pd.w, (char *)rt->buf, nw) < nw)
                        error(SYSTEM, "error writing to rtrace process");
                rt->nrays = 0;          /* flag buffer as flushed */
        } while (doall && (rt = rt->next) != NULL);
}


struct rtproc *
raywait(                        /* retrieve rtrace results */
        struct rtproc *rt0
)
{
        fd_set  readset, errset;
        int     nr;
        struct rtproc   *rtfree;
        register struct rtproc  *rt;
        register int    n;
                                /* prepare select call */
        FD_ZERO(&readset); FD_ZERO(&errset); n = 0;
        nr = 0;
        for (rt = rt0; rt != NULL; rt = rt->next) {
                if (rt->nrays == 0 && rt->dest[0] != NULL) {
                        FD_SET(rt->pd.r, &readset);
                        ++nr;
                }
                FD_SET(rt->pd.r, &errset);
                if (rt->pd.r >= n)
                        n = rt->pd.r + 1;
        }
        if (!nr)                /* no rays pending */
                return(NULL);
        if (nr > 1) {           /* call select for multiple processes */
                errno = 0;
                if (select(n, &readset, NULL, &errset, NULL) < 0)
                        error(SYSTEM, "select call error in raywait()");
        } else
                FD_ZERO(&errset);
        rtfree = NULL;          /* read from ready process(es) */
        for (rt = rt0; rt != NULL; rt = rt->next) {
                if (!FD_ISSET(rt->pd.r, &readset) &&
                                !FD_ISSET(rt->pd.r, &errset))
                        continue;
                for (n = 0; n < rt->bsiz && rt->dest[n] != NULL; n++)
                        ;
                nr = 3*sizeof(float)*(n+1);
                if (readbuf(rt->pd.r, (char *)rt->buf, nr) < nr)
                        error(USER, "rtrace process died");
                while (n-- > 0) {
                        rt->dest[n][0] += rt->buf[3*n];
                        rt->dest[n][1] += rt->buf[3*n+1];
                        rt->dest[n][2] += rt->buf[3*n+2];
                        rt->dest[n] = NULL;
                }
                rtfree = rt;
        }
        return(rtfree);
}


static void
mkaxes(                 /* compute u and v to go with n */
        FVECT  u,
        FVECT  v,
        FVECT  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);
}


static void
rounddir(               /* compute uniform spherical direction */
        register FVECT  dv,
        double  alt,
        double  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);
}


static void
flatdir(                /* compute uniform hemispherical direction */
        register FVECT  dv,
        double  alt,
        double  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:	2.17
Committed:	Sun Sep 19 08:42:22 2004 UTC (19 years, 7 months ago) by greg
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rad3R7P2, rad3R7P1, rad3R6, rad3R6P1, rad3R8
Changes since 2.16:	+11 -20 lines
Log Message:	Fixed deadlock upon termination of mkillum with -n option
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	greg	2.17	static const char RCSid[] = "$Id: mkillum2.c,v 2.16 2004/09/17 21:43:50 greg 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	2.16	#include "selcall.h"
15	greg	1.1
16	greg	2.13
17	greg	2.16	static void mkaxes(FVECT u, FVECT v, FVECT n);
18			static void rounddir(FVECT dv, double alt, double azi);
19			static void flatdir(FVECT dv, double alt, double azi);
20
21
22			static void
23			rayclean( /* finish all pending rays */
24			struct rtproc *rt0
25			)
26			{
27			rayflush(rt0, 1);
28			while (raywait(rt0) != NULL)
29			;
30			}
31	schorsch	2.12
32
33			int /* XXX type conflict with otypes.h */
34			o_default( /* default illum action */
35			OBJREC *ob,
36			struct illum_args *il,
37	greg	2.16	struct rtproc *rt0,
38	schorsch	2.12	char *nm
39			)
40	greg	1.1	{
41	greg	1.2	sprintf(errmsg, "(%s): cannot make illum for %s \"%s\"",
42			nm, ofun[ob->otype].funame, ob->oname);
43			error(WARNING, errmsg);
44	greg	2.2	printobj(il->altmat, ob);
45	greg	2.13	return(1);
46	greg	1.2	}
47
48
49	greg	2.13	int
50	schorsch	2.12	o_face( /* make an illum face */
51			OBJREC *ob,
52			struct illum_args *il,
53	greg	2.16	struct rtproc *rt0,
54	schorsch	2.12	char *nm
55			)
56	greg	1.2	{
57	greg	1.3	#define MAXMISS (5nil->nsamps)
58	greg	1.10	int dim[3];
59			int n, nalt, nazi, h;
60	greg	1.3	float *distarr;
61	greg	1.10	double sp[2], r1, r2;
62	greg	1.4	FVECT dn, org, dir;
63	greg	1.3	FVECT u, v;
64			double ur[2], vr[2];
65			int nmisses;
66			register FACE *fa;
67			register int i, j;
68			/* get/check arguments */
69			fa = getface(ob);
70			if (fa->area == 0.0) {
71			freeface(ob);
72	greg	2.16	return(o_default(ob, il, rt0, nm));
73	greg	1.3	}
74			/* set up sampling */
75	greg	1.11	if (il->sampdens <= 0)
76			nalt = nazi = 1;
77			else {
78			n = PI * il->sampdens;
79			nalt = sqrt(n/PI) + .5;
80			nazi = PI*nalt + .5;
81			}
82	greg	1.3	n = nalt*nazi;
83			distarr = (float )calloc(n, 3sizeof(float));
84			if (distarr == NULL)
85			error(SYSTEM, "out of memory in o_face");
86	greg	2.3	/* take first edge longer than sqrt(area) */
87	greg	2.4	for (j = fa->nv-1, i = 0; i < fa->nv; j = i++) {
88			u[0] = VERTEX(fa,i)[0] - VERTEX(fa,j)[0];
89			u[1] = VERTEX(fa,i)[1] - VERTEX(fa,j)[1];
90			u[2] = VERTEX(fa,i)[2] - VERTEX(fa,j)[2];
91	greg	2.5	if ((r1 = DOT(u,u)) >= fa->area-FTINY)
92	greg	2.3	break;
93			}
94			if (i < fa->nv) { /* got one! -- let's align our axes */
95	greg	2.5	r2 = 1.0/sqrt(r1);
96			u[0] = r2; u[1] = r2; u[2] *= r2;
97	greg	2.3	fcross(v, fa->norm, u);
98			} else /* oh well, we'll just have to wing it */
99			mkaxes(u, v, fa->norm);
100			/* now, find limits in (u,v) coordinates */
101	greg	1.3	ur[0] = vr[0] = FHUGE;
102			ur[1] = vr[1] = -FHUGE;
103			for (i = 0; i < fa->nv; i++) {
104			r1 = DOT(VERTEX(fa,i),u);
105			if (r1 < ur[0]) ur[0] = r1;
106			if (r1 > ur[1]) ur[1] = r1;
107			r2 = DOT(VERTEX(fa,i),v);
108			if (r2 < vr[0]) vr[0] = r2;
109			if (r2 > vr[1]) vr[1] = r2;
110			}
111			dim[0] = random();
112			/* sample polygon */
113			nmisses = 0;
114			for (dim[1] = 0; dim[1] < nalt; dim[1]++)
115			for (dim[2] = 0; dim[2] < nazi; dim[2]++)
116			for (i = 0; i < il->nsamps; i++) {
117			/* random direction */
118	greg	1.10	h = ilhash(dim, 3) + i;
119	greg	1.11	multisamp(sp, 2, urand(h));
120	greg	1.10	r1 = (dim[1] + sp[0])/nalt;
121	greg	1.13	r2 = (dim[2] + sp[1] - .5)/nazi;
122	greg	1.3	flatdir(dn, r1, r2);
123			for (j = 0; j < 3; j++)
124	greg	1.5	dir[j] = -dn[0]u[j] - dn[1]v[j] - dn[2]*fa->norm[j];
125	greg	1.3	/* random location */
126			do {
127	greg	1.11	multisamp(sp, 2, urand(h+4862+nmisses));
128	greg	1.10	r1 = ur[0] + (ur[1]-ur[0]) * sp[0];
129			r2 = vr[0] + (vr[1]-vr[0]) * sp[1];
130	greg	1.3	for (j = 0; j < 3; j++)
131			org[j] = r1u[j] + r2v[j]
132			+ fa->offset*fa->norm[j];
133			} while (!inface(org, fa) && nmisses++ < MAXMISS);
134			if (nmisses > MAXMISS) {
135			objerror(ob, WARNING, "bad aspect");
136	greg	2.16	rayclean(rt0);
137	greg	1.3	freeface(ob);
138	greg	2.9	free((void *)distarr);
139	greg	2.16	return(o_default(ob, il, rt0, nm));
140	greg	1.3	}
141			for (j = 0; j < 3; j++)
142			org[j] += .001*fa->norm[j];
143			/* send sample */
144	greg	2.16	raysamp(distarr+3(dim[1]nazi+dim[2]), org, dir, rt0);
145	greg	1.3	}
146	greg	2.16	rayclean(rt0);
147	greg	1.11	/* write out the face and its distribution */
148	greg	1.12	if (average(il, distarr, nalt*nazi)) {
149			if (il->sampdens > 0)
150			flatout(il, distarr, nalt, nazi, u, v, fa->norm);
151			illumout(il, ob);
152	greg	2.2	} else
153	greg	1.12	printobj(il->altmat, ob);
154	greg	1.3	/* clean up */
155			freeface(ob);
156	greg	2.9	free((void *)distarr);
157	greg	2.15	return(0);
158	greg	1.3	#undef MAXMISS
159	greg	1.2	}
160
161
162	greg	2.13	int
163	schorsch	2.12	o_sphere( /* make an illum sphere */
164			register OBJREC *ob,
165			struct illum_args *il,
166	greg	2.16	struct rtproc *rt0,
167	schorsch	2.12	char *nm
168			)
169	greg	1.2	{
170	greg	1.10	int dim[3];
171	greg	1.2	int n, nalt, nazi;
172			float *distarr;
173	greg	1.10	double sp[4], r1, r2, r3;
174	greg	1.4	FVECT org, dir;
175	greg	1.2	FVECT u, v;
176			register int i, j;
177			/* check arguments */
178			if (ob->oargs.nfargs != 4)
179			objerror(ob, USER, "bad # of arguments");
180			/* set up sampling */
181	greg	1.11	if (il->sampdens <= 0)
182			nalt = nazi = 1;
183			else {
184			n = 4.PI il->sampdens;
185	greg	2.7	nalt = sqrt(2./PI*n) + .5;
186			nazi = PI/2.*nalt + .5;
187	greg	1.11	}
188	greg	1.2	n = nalt*nazi;
189			distarr = (float )calloc(n, 3sizeof(float));
190			if (distarr == NULL)
191			error(SYSTEM, "out of memory in o_sphere");
192			dim[0] = random();
193			/* sample sphere */
194			for (dim[1] = 0; dim[1] < nalt; dim[1]++)
195	greg	1.8	for (dim[2] = 0; dim[2] < nazi; dim[2]++)
196	greg	1.2	for (i = 0; i < il->nsamps; i++) {
197	greg	1.10	/* next sample point */
198	greg	1.11	multisamp(sp, 4, urand(ilhash(dim,3)+i));
199	greg	1.2	/* random direction */
200	greg	1.10	r1 = (dim[1] + sp[0])/nalt;
201	greg	1.13	r2 = (dim[2] + sp[1] - .5)/nazi;
202	greg	1.2	rounddir(dir, r1, r2);
203			/* random location */
204	greg	1.8	mkaxes(u, v, dir); /* yuck! */
205	greg	1.10	r3 = sqrt(sp[2]);
206			r2 = 2.PIsp[3];
207	greg	1.5	r1 = r3ob->oargs.farg[3]cos(r2);
208			r2 = r3ob->oargs.farg[3]sin(r2);
209			r3 = ob->oargs.farg[3]sqrt(1.01-r3r3);
210			for (j = 0; j < 3; j++) {
211			org[j] = ob->oargs.farg[j] + r1u[j] + r2v[j] +
212			r3*dir[j];
213			dir[j] = -dir[j];
214			}
215	greg	1.2	/* send sample */
216	greg	2.16	raysamp(distarr+3(dim[1]nazi+dim[2]), org, dir, rt0);
217	greg	1.2	}
218	greg	2.16	rayclean(rt0);
219	greg	1.11	/* write out the sphere and its distribution */
220	greg	1.12	if (average(il, distarr, nalt*nazi)) {
221			if (il->sampdens > 0)
222			roundout(il, distarr, nalt, nazi);
223			else
224			objerror(ob, WARNING, "diffuse distribution");
225			illumout(il, ob);
226	greg	2.2	} else
227	greg	1.12	printobj(il->altmat, ob);
228	greg	1.2	/* clean up */
229	greg	2.9	free((void *)distarr);
230	greg	2.13	return(1);
231	greg	1.2	}
232
233
234	greg	2.13	int
235	schorsch	2.12	o_ring( /* make an illum ring */
236			OBJREC *ob,
237			struct illum_args *il,
238	greg	2.16	struct rtproc *rt0,
239	schorsch	2.12	char *nm
240			)
241	greg	1.2	{
242	greg	1.10	int dim[3];
243	greg	1.3	int n, nalt, nazi;
244			float *distarr;
245	greg	1.10	double sp[4], r1, r2, r3;
246	greg	1.4	FVECT dn, org, dir;
247	greg	1.3	FVECT u, v;
248			register CONE *co;
249			register int i, j;
250			/* get/check arguments */
251			co = getcone(ob, 0);
252			/* set up sampling */
253	greg	1.11	if (il->sampdens <= 0)
254			nalt = nazi = 1;
255			else {
256			n = PI * il->sampdens;
257			nalt = sqrt(n/PI) + .5;
258			nazi = PI*nalt + .5;
259			}
260	greg	1.3	n = nalt*nazi;
261			distarr = (float )calloc(n, 3sizeof(float));
262			if (distarr == NULL)
263			error(SYSTEM, "out of memory in o_ring");
264			mkaxes(u, v, co->ad);
265			dim[0] = random();
266			/* sample disk */
267			for (dim[1] = 0; dim[1] < nalt; dim[1]++)
268			for (dim[2] = 0; dim[2] < nazi; dim[2]++)
269			for (i = 0; i < il->nsamps; i++) {
270	greg	1.10	/* next sample point */
271	greg	1.11	multisamp(sp, 4, urand(ilhash(dim,3)+i));
272	greg	1.3	/* random direction */
273	greg	1.10	r1 = (dim[1] + sp[0])/nalt;
274	greg	1.13	r2 = (dim[2] + sp[1] - .5)/nazi;
275	greg	1.3	flatdir(dn, r1, r2);
276			for (j = 0; j < 3; j++)
277	greg	1.5	dir[j] = -dn[0]u[j] - dn[1]v[j] - dn[2]*co->ad[j];
278	greg	1.3	/* random location */
279	greg	1.5	r3 = sqrt(CO_R0(co)*CO_R0(co) +
280	greg	1.10	sp[2](CO_R1(co)CO_R1(co) - CO_R0(co)*CO_R0(co)));
281			r2 = 2.PIsp[3];
282	greg	1.5	r1 = r3*cos(r2);
283			r2 = r3*sin(r2);
284	greg	1.3	for (j = 0; j < 3; j++)
285	greg	2.6	org[j] = CO_P0(co)[j] + r1u[j] + r2v[j] +
286	greg	1.5	.001*co->ad[j];
287	greg	1.3
288			/* send sample */
289	greg	2.16	raysamp(distarr+3(dim[1]nazi+dim[2]), org, dir, rt0);
290	greg	1.3	}
291	greg	2.16	rayclean(rt0);
292	greg	1.11	/* write out the ring and its distribution */
293	greg	1.12	if (average(il, distarr, nalt*nazi)) {
294			if (il->sampdens > 0)
295			flatout(il, distarr, nalt, nazi, u, v, co->ad);
296			illumout(il, ob);
297	greg	2.2	} else
298	greg	1.12	printobj(il->altmat, ob);
299	greg	1.3	/* clean up */
300			freecone(ob);
301	greg	2.9	free((void *)distarr);
302	greg	2.13	return(1);
303	greg	1.2	}
304
305
306	schorsch	2.12	void
307	greg	2.16	raysamp( /* queue a ray sample */
308	schorsch	2.12	float res[3],
309			FVECT org,
310			FVECT dir,
311	greg	2.16	struct rtproc *rt0
312	schorsch	2.12	)
313	greg	1.2	{
314	greg	2.16	register struct rtproc *rt;
315	greg	1.2	register float *fp;
316
317	greg	2.16	for (rt = rt0; rt != NULL; rt = rt->next)
318			if (rt->nrays < rt->bsiz && rt->dest[rt->nrays] == NULL)
319			break;
320			if (rt == NULL) /* need to free up buffer? */
321			rt = raywait(rt0);
322			if (rt == NULL)
323	greg	2.17	error(SYSTEM, "raywait() returned NULL in raysamp()");
324	greg	2.16	fp = rt->buf + 6*rt->nrays;
325	greg	1.2	fp++ = org[0]; fp++ = org[1]; *fp++ = org[2];
326			fp++ = dir[0]; fp++ = dir[1]; *fp = dir[2];
327	greg	2.16	rt->dest[rt->nrays++] = res;
328			if (rt->nrays == rt->bsiz)
329			rayflush(rt, 0);
330	greg	1.2	}
331
332
333	schorsch	2.12	void
334	greg	2.16	rayflush( /* flush queued rays to rtrace */
335			register struct rtproc *rt,
336			int doall
337	schorsch	2.12	)
338	greg	1.2	{
339	greg	2.16	int nw;
340
341			do {
342			if (rt->nrays <= 0)
343			continue;
344			memset(rt->buf+6rt->nrays, 0, 6sizeof(float));
345			nw = 6sizeof(float)(rt->nrays+1);
346			errno = 0;
347			if (writebuf(rt->pd.w, (char *)rt->buf, nw) < nw)
348			error(SYSTEM, "error writing to rtrace process");
349			rt->nrays = 0; /* flag buffer as flushed */
350			} while (doall && (rt = rt->next) != NULL);
351			}
352
353	greg	1.2
354	greg	2.16	struct rtproc *
355			raywait( /* retrieve rtrace results */
356			struct rtproc *rt0
357			)
358			{
359			fd_set readset, errset;
360			int nr;
361	greg	2.17	struct rtproc *rtfree;
362			register struct rtproc *rt;
363	greg	2.16	register int n;
364			/* prepare select call */
365			FD_ZERO(&readset); FD_ZERO(&errset); n = 0;
366			nr = 0;
367			for (rt = rt0; rt != NULL; rt = rt->next) {
368			if (rt->nrays == 0 && rt->dest[0] != NULL) {
369			FD_SET(rt->pd.r, &readset);
370			++nr;
371			}
372			FD_SET(rt->pd.r, &errset);
373			if (rt->pd.r >= n)
374			n = rt->pd.r + 1;
375			}
376			if (!nr) /* no rays pending */
377			return(NULL);
378	greg	2.17	if (nr > 1) { /* call select for multiple processes */
379			errno = 0;
380			if (select(n, &readset, NULL, &errset, NULL) < 0)
381			error(SYSTEM, "select call error in raywait()");
382			} else
383	greg	2.16	FD_ZERO(&errset);
384			rtfree = NULL; /* read from ready process(es) */
385			for (rt = rt0; rt != NULL; rt = rt->next) {
386			if (!FD_ISSET(rt->pd.r, &readset) &&
387			!FD_ISSET(rt->pd.r, &errset))
388			continue;
389			for (n = 0; n < rt->bsiz && rt->dest[n] != NULL; n++)
390			;
391	greg	2.17	nr = 3sizeof(float)(n+1);
392			if (readbuf(rt->pd.r, (char *)rt->buf, nr) < nr)
393	greg	2.16	error(USER, "rtrace process died");
394			while (n-- > 0) {
395			rt->dest[n][0] += rt->buf[3*n];
396			rt->dest[n][1] += rt->buf[3*n+1];
397			rt->dest[n][2] += rt->buf[3*n+2];
398			rt->dest[n] = NULL;
399			}
400			rtfree = rt;
401	greg	1.2	}
402	greg	2.16	return(rtfree);
403	greg	1.4	}
404
405
406	greg	2.16	static void
407	schorsch	2.12	mkaxes( /* compute u and v to go with n */
408			FVECT u,
409			FVECT v,
410			FVECT n
411			)
412	greg	1.4	{
413			register int i;
414
415			v[0] = v[1] = v[2] = 0.0;
416			for (i = 0; i < 3; i++)
417			if (n[i] < 0.6 && n[i] > -0.6)
418			break;
419			v[i] = 1.0;
420			fcross(u, v, n);
421			normalize(u);
422			fcross(v, n, u);
423			}
424
425
426	greg	2.16	static void
427	schorsch	2.12	rounddir( /* compute uniform spherical direction */
428			register FVECT dv,
429			double alt,
430			double azi
431			)
432	greg	1.4	{
433			double d1, d2;
434
435			dv[2] = 1. - 2.*alt;
436			d1 = sqrt(1. - dv[2]*dv[2]);
437			d2 = 2.PI azi;
438			dv[0] = d1*cos(d2);
439			dv[1] = d1*sin(d2);
440			}
441
442
443	greg	2.16	static void
444	schorsch	2.12	flatdir( /* compute uniform hemispherical direction */
445			register FVECT dv,
446			double alt,
447			double azi
448			)
449	greg	1.4	{
450			double d1, d2;
451
452			d1 = sqrt(alt);
453			d2 = 2.PI azi;
454			dv[0] = d1*cos(d2);
455			dv[1] = d1*sin(d2);
456	greg	1.6	dv[2] = sqrt(1. - alt);
457	greg	1.1	}