src/rt/func.c

#ifndef lint
static const char       RCSid[] = "$Id: func.c,v 2.29 2015/05/20 12:58:30 greg Exp $";
#endif
/*
 *  func.c - interface to calcomp functions.
 */

#include "copyright.h"

#include  "ray.h"
#include  "paths.h"
#include  "otypes.h"
#include  "func.h"
#include <ctype.h>


#define  INITFILE       "rayinit.cal"
#define  CALSUF         ".cal"
#define  LCALSUF        4
char  REFVNAME[] = "`FILE_REFCNT";

XF  unitxf = {                  /* identity transform */
        {{1.0, 0.0, 0.0, 0.0},
        {0.0, 1.0, 0.0, 0.0},
        {0.0, 0.0, 1.0, 0.0},
        {0.0, 0.0, 0.0, 1.0}},
        1.0
};

XF  funcxf;                     /* current transformation */
static OBJREC  *fobj = NULL;    /* current function object */
static RAY  *fray = NULL;       /* current function ray */

static char  rayinitcal[] = INITFILE;

static double  l_erf(char *), l_erfc(char *), l_arg(char *);


void
initfunc()      /* initialize function evaluation */
{
        if (!rayinitcal[0])     /* already done? */
                return;
        esupport |= E_VARIABLE|E_FUNCTION|E_INCHAN|E_RCONST|E_REDEFW;
        esupport &= ~(E_OUTCHAN);
        setcontext("");
        scompile("Dx=$1;Dy=$2;Dz=$3;", NULL, 0);
        scompile("Nx=$4;Ny=$5;Nz=$6;", NULL, 0);
        scompile("Px=$7;Py=$8;Pz=$9;", NULL, 0);
        scompile("T=$10;Ts=$25;Rdot=$11;", NULL, 0);
        scompile("S=$12;Tx=$13;Ty=$14;Tz=$15;", NULL, 0);
        scompile("Ix=$16;Iy=$17;Iz=$18;", NULL, 0);
        scompile("Jx=$19;Jy=$20;Jz=$21;", NULL, 0);
        scompile("Kx=$22;Ky=$23;Kz=$24;", NULL, 0);
        scompile("Lu=$26;Lv=$27;", NULL, 0);
        funset("arg", 1, '=', l_arg);
        funset("erf", 1, ':', l_erf);
        funset("erfc", 1, ':', l_erfc);
        setnoisefuncs();
        setprismfuncs();
        loadfunc(rayinitcal);
        rayinitcal[0] = '\0';
}


/* Set parameters for current evaluation */
void
set_eparams(char *prms)
{
        static char     *last_params = NULL;
        char            vname[RMAXWORD];
        double          value;
        char            *cpd;
                                        /* check if already set */
        if ((prms == NULL) | (prms == last_params))
                return;
        if (last_params != NULL && !strcmp(prms, last_params))
                return;
        last_params = prms;             /* assign each variable */
        while (*prms) {
                if (isspace(*prms)) {
                        ++prms; continue;
                }
                if (!isalpha(*prms))
                        goto bad_params;
                cpd = vname;
                while (*prms && (*prms != '=') & !isspace(*prms)) {
                        if (!isid(*prms))
                                goto bad_params;
                        *cpd++ = *prms++;
                }
                if (cpd == vname)
                        goto bad_params;
                *cpd = '\0';
                while (isspace(*prms)) prms++;
                if (*prms++ != '=')
                        goto bad_params;
                value = atof(prms);
                if ((prms = fskip(prms)) == NULL)
                        goto bad_params;
                while (isspace(*prms)) prms++;
                prms += (*prms == ',') | (*prms == ';');
                varset(vname, '=', value);
        }
        return;
bad_params:
        sprintf(errmsg, "bad parameter list '%s'", last_params);
        error(USER, errmsg);
}


MFUNC *
getfunc(        /* get function for this modifier */
        OBJREC  *m,
        int  ff,
        unsigned int  ef,
        int  dofwd
)
{
        char  sbuf[MAXSTR];
        char  **arg;
        MFUNC  *f;
        int  ne, na;
        int  i;
                                        /* check to see if done already */
        if ((f = (MFUNC *)m->os) != NULL)
                return(f);
        fobj = NULL; fray = NULL;
        if (rayinitcal[0])              /* initialize on first call */
                initfunc();
        if ((na = m->oargs.nsargs) <= ff)
                goto toofew;
        arg = m->oargs.sarg;
        if ((f = (MFUNC *)calloc(1, sizeof(MFUNC))) == NULL)
                goto memerr;
        i = strlen(arg[ff]);                    /* set up context */
        if (i == 1 && arg[ff][0] == '.') {
                setcontext(f->ctx = "");        /* "." means no file */
        } else {
                strcpy(sbuf,arg[ff]);           /* file name is context */
                if (i > LCALSUF && !strcmp(sbuf+i-LCALSUF, CALSUF))
                        sbuf[i-LCALSUF] = '\0'; /* remove suffix */
                setcontext(f->ctx = savestr(sbuf));
                if (!vardefined(REFVNAME)) {    /* file loaded? */
                        loadfunc(arg[ff]);
                        varset(REFVNAME, '=', 1.0);
                } else                          /* reference_count++ */
                        varset(REFVNAME, '=', varvalue(REFVNAME)+1.0);
        }
        curfunc = NULL;                 /* parse expressions */
        sprintf(sbuf, "%s \"%s\"", ofun[m->otype].funame, m->oname);
        for (i=0, ne=0; ef && i < na; i++, ef>>=1)
                if (ef & 1) {                   /* flagged as an expression? */
                        if (ne >= MAXEXPR)
                                objerror(m, INTERNAL, "too many expressions");
                        initstr(arg[i], sbuf, 0);
                        f->ep[ne++] = getE1();
                        if (nextc != EOF)
                                syntax("unexpected character");
                }
        if (ef)
                goto toofew;
        if (i <= ff)                    /* find transform args */
                i = ff+1;
        while (i < na && arg[i][0] != '-')
                i++;
        if (i == na) {                  /* no transform */
                f->fxp = f->bxp = &unitxf;
        } else {                        /* get transform */
                if ((f->bxp = (XF *)malloc(sizeof(XF))) == NULL)
                        goto memerr;
                if (invxf(f->bxp, na-i, arg+i) != na-i)
                        objerror(m, USER, "bad transform");
                if (f->bxp->sca < 0.0)
                        f->bxp->sca = -f->bxp->sca;
                if (dofwd) {                    /* do both transforms */
                        if ((f->fxp = (XF *)malloc(sizeof(XF))) == NULL)
                                goto memerr;
                        xf(f->fxp, na-i, arg+i);
                        if (f->fxp->sca < 0.0)
                                f->fxp->sca = -f->fxp->sca;
                }
        }
        m->os = (char *)f;
        return(f);
toofew:
        objerror(m, USER, "too few string arguments");
memerr:
        error(SYSTEM, "out of memory in getfunc");
        return NULL; /* pro forma return */
}


void
freefunc(                       /* free memory associated with modifier */
        OBJREC  *m
)
{
        MFUNC  *f;
        int  i;

        if ((f = (MFUNC *)m->os) == NULL)
                return;
        for (i = 0; f->ep[i] != NULL; i++)
                epfree(f->ep[i]);
        if (f->ctx[0]) {                        /* done with definitions */
                setcontext(f->ctx);
                i = varvalue(REFVNAME)-.5;      /* reference_count-- */
                if (i > 0)
                        varset(REFVNAME, '=', (double)i);
                else
                        dcleanup(2);            /* remove definitions */
                freestr(f->ctx);
        }
        if (f->bxp != &unitxf)
                free((void *)f->bxp);
        if ((f->fxp != NULL) & (f->fxp != &unitxf))
                free((void *)f->fxp);
        free((void *)f);
        m->os = NULL;
}


int
setfunc(                        /* set channels for function call */
        OBJREC  *m,
        RAY     *r
)
{
        static RNUMBER  lastrno = ~0;
        MFUNC           *f;
                                        /* get function if any */
        if ((f = (MFUNC *)m->os) == NULL)
                objerror(m, CONSISTENCY, "setfunc called before getfunc");
                
        setcontext(f->ctx);             /* set evaluator context */
                                        /* check to see if matrix set */
        if ((m == fobj) & (r->rno == lastrno))
                return(0);
        fobj = m;
        fray = r;
        if (r->rox != NULL) {
                if (f->bxp != &unitxf) {
                        funcxf.sca = r->rox->b.sca * f->bxp->sca;
                        multmat4(funcxf.xfm, r->rox->b.xfm, f->bxp->xfm);
                } else
                        funcxf = r->rox->b;
        } else
                funcxf = *f->bxp;
        lastrno = r->rno;
        eclock++;               /* notify expression evaluator */
        return(1);
}


int
worldfunc(                      /* special function context sans object */
        char    *ctx,
        RAY     *r
)
{
        static RNUMBER  lastrno = ~0;

        if (rayinitcal[0])              /* initialize on first call */
                initfunc();
                                        /* set evaluator context */
        setcontext(ctx);
                                        /* check if ray already set */
        if ((fobj == NULL) & (r->rno == lastrno))
                return(0);
        fobj = NULL;
        fray = r;
        funcxf = unitxf;
        lastrno = r->rno;
        eclock++;               /* notify expression evaluator */
        return(1);
}


void
loadfunc(                       /* load definition file */
        char  *fname
)
{
        char  *ffname;

        if ((ffname = getpath(fname, getrlibpath(), R_OK)) == NULL) {
                sprintf(errmsg, "cannot find function file \"%s\"", fname);
                error(USER, errmsg);
        }
        fcompile(ffname);
}


static double
l_arg(char *nm)                 /* return nth real argument */
{
        int  n;

        if (fobj == NULL)
                error(USER, "arg(n) called without a context");

        n = argument(1) + .5;           /* round to integer */

        if (n < 1)
                return(fobj->oargs.nfargs);

        if (n > fobj->oargs.nfargs) {
                sprintf(errmsg, "missing real argument %d", n);
                objerror(fobj, USER, errmsg);
        }
        return(fobj->oargs.farg[n-1]);
}


static double
l_erf(char *nm)                 /* error function */
{
        return(erf(argument(1)));
}


static double
l_erfc(char *nm)                /* cumulative error function */
{
        return(erfc(argument(1)));
}


double
chanvalue(                      /* return channel n to calcomp */
        int  n
)
{
        if (fray == NULL)
                syntax("ray parameter used in constant expression");

        if (--n < 0)
                goto badchan;

        if (n <= 2)                     /* ray direction */

                return( (       fray->rdir[0]*funcxf.xfm[0][n] +
                                fray->rdir[1]*funcxf.xfm[1][n] +
                                fray->rdir[2]*funcxf.xfm[2][n]  )
                         / funcxf.sca );

        if (n <= 5)                     /* surface normal */

                return( (       fray->ron[0]*funcxf.xfm[0][n-3] +
                                fray->ron[1]*funcxf.xfm[1][n-3] +
                                fray->ron[2]*funcxf.xfm[2][n-3] )
                         / funcxf.sca );

        if (n <= 8) {                   /* intersection point */
                if (fray->rot >= FHUGE)
                        return(0.0);    /* XXX should be runtime error? */

                return( fray->rop[0]*funcxf.xfm[0][n-6] +
                                fray->rop[1]*funcxf.xfm[1][n-6] +
                                fray->rop[2]*funcxf.xfm[2][n-6] +
                                             funcxf.xfm[3][n-6] );
        }

        if (n == 9)                     /* total distance */
                return(raydist(fray,PRIMARY) * funcxf.sca);

        if (n == 10)                    /* dot product (range [-1,1]) */
                return( fray->rod <= -1.0 ? -1.0 :
                        fray->rod >= 1.0 ? 1.0 :
                        fray->rod );

        if (n == 11)                    /* scale */
                return(funcxf.sca);

        if (n <= 14)                    /* origin */
                return(funcxf.xfm[3][n-12]);

        if (n <= 17)                    /* i unit vector */
                return(funcxf.xfm[0][n-15] / funcxf.sca);

        if (n <= 20)                    /* j unit vector */
                return(funcxf.xfm[1][n-18] / funcxf.sca);

        if (n <= 23)                    /* k unit vector */
                return(funcxf.xfm[2][n-21] / funcxf.sca);

        if (n == 24)                    /* single ray (shadow) distance */
                return((fray->rot+raydist(fray->parent,SHADOW)) * funcxf.sca);

        if (n <= 26)                    /* local (u,v) coordinates */
                return(fray->uv[n-25]);
badchan:
        error(USER, "illegal channel number");
        return(0.0);
}
Revision:	2.30
Committed:	Wed May 20 13:16:20 2015 UTC (8 years, 11 months ago) by greg
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rad5R0
Changes since 2.29:	+2 -1 lines
Log Message:	Fixed include dependency
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	greg	2.30	static const char RCSid[] = "$Id: func.c,v 2.29 2015/05/20 12:58:30 greg Exp $";
3	greg	1.1	#endif
4			/*
5			* func.c - interface to calcomp functions.
6	greg	2.14	*/
7
8	greg	2.15	#include "copyright.h"
9	greg	1.1
10			#include "ray.h"
11	greg	2.21	#include "paths.h"
12	greg	1.1	#include "otypes.h"
13	greg	2.2	#include "func.h"
14	greg	2.30	#include <ctype.h>
15	greg	1.1
16	greg	2.2
17	greg	1.21	#define INITFILE "rayinit.cal"
18	greg	2.2	#define CALSUF ".cal"
19			#define LCALSUF 4
20	greg	2.10	char REFVNAME[] = "`FILE_REFCNT";
21	greg	1.21
22	greg	1.13	XF unitxf = { /* identity transform */
23	greg	2.8	{{1.0, 0.0, 0.0, 0.0},
24			{0.0, 1.0, 0.0, 0.0},
25			{0.0, 0.0, 1.0, 0.0},
26			{0.0, 0.0, 0.0, 1.0}},
27	greg	1.13	1.0
28			};
29
30	greg	1.12	XF funcxf; /* current transformation */
31			static OBJREC fobj = NULL; / current function object */
32			static RAY fray = NULL; / current function ray */
33	greg	1.1
34	greg	2.26	static char rayinitcal[] = INITFILE;
35
36	greg	2.20	static double l_erf(char ), l_erfc(char ), l_arg(char *);
37	greg	1.1
38	greg	2.2
39	greg	2.26	void
40			initfunc() /* initialize function evaluation */
41			{
42			if (!rayinitcal[0]) /* already done? */
43			return;
44			esupport \|= E_VARIABLE\|E_FUNCTION\|E_INCHAN\|E_RCONST\|E_REDEFW;
45			esupport &= ~(E_OUTCHAN);
46			setcontext("");
47			scompile("Dx=$1;Dy=$2;Dz=$3;", NULL, 0);
48			scompile("Nx=$4;Ny=$5;Nz=$6;", NULL, 0);
49			scompile("Px=$7;Py=$8;Pz=$9;", NULL, 0);
50			scompile("T=$10;Ts=$25;Rdot=$11;", NULL, 0);
51			scompile("S=$12;Tx=$13;Ty=$14;Tz=$15;", NULL, 0);
52			scompile("Ix=$16;Iy=$17;Iz=$18;", NULL, 0);
53			scompile("Jx=$19;Jy=$20;Jz=$21;", NULL, 0);
54			scompile("Kx=$22;Ky=$23;Kz=$24;", NULL, 0);
55			scompile("Lu=$26;Lv=$27;", NULL, 0);
56			funset("arg", 1, '=', l_arg);
57			funset("erf", 1, ':', l_erf);
58			funset("erfc", 1, ':', l_erfc);
59			setnoisefuncs();
60			setprismfuncs();
61			loadfunc(rayinitcal);
62			rayinitcal[0] = '\0';
63			}
64
65
66	greg	2.29	/* Set parameters for current evaluation */
67			void
68			set_eparams(char *prms)
69			{
70			static char *last_params = NULL;
71			char vname[RMAXWORD];
72			double value;
73			char *cpd;
74			/* check if already set */
75			if ((prms == NULL) \| (prms == last_params))
76			return;
77			if (last_params != NULL && !strcmp(prms, last_params))
78			return;
79			last_params = prms; /* assign each variable */
80			while (*prms) {
81			if (isspace(*prms)) {
82			++prms; continue;
83			}
84			if (!isalpha(*prms))
85			goto bad_params;
86			cpd = vname;
87			while (prms && (prms != '=') & !isspace(*prms)) {
88			if (!isid(*prms))
89			goto bad_params;
90			cpd++ = prms++;
91			}
92			if (cpd == vname)
93			goto bad_params;
94			*cpd = '\0';
95			while (isspace(*prms)) prms++;
96			if (*prms++ != '=')
97			goto bad_params;
98			value = atof(prms);
99			if ((prms = fskip(prms)) == NULL)
100			goto bad_params;
101			while (isspace(*prms)) prms++;
102			prms += (prms == ',') \| (prms == ';');
103			varset(vname, '=', value);
104			}
105			return;
106			bad_params:
107			sprintf(errmsg, "bad parameter list '%s'", last_params);
108			error(USER, errmsg);
109			}
110
111
112	greg	2.25	MFUNC *
113	schorsch	2.22	getfunc( /* get function for this modifier */
114			OBJREC *m,
115			int ff,
116			unsigned int ef,
117			int dofwd
118			)
119	greg	2.2	{
120			char sbuf[MAXSTR];
121	greg	2.25	char **arg;
122			MFUNC *f;
123	greg	2.2	int ne, na;
124	greg	2.25	int i;
125	greg	2.2	/* check to see if done already */
126			if ((f = (MFUNC *)m->os) != NULL)
127			return(f);
128	greg	2.7	fobj = NULL; fray = NULL;
129	greg	2.26	if (rayinitcal[0]) /* initialize on first call */
130			initfunc();
131	greg	2.2	if ((na = m->oargs.nsargs) <= ff)
132			goto toofew;
133			arg = m->oargs.sarg;
134			if ((f = (MFUNC *)calloc(1, sizeof(MFUNC))) == NULL)
135			goto memerr;
136			i = strlen(arg[ff]); /* set up context */
137	greg	2.26	if (i == 1 && arg[ff][0] == '.') {
138	greg	2.2	setcontext(f->ctx = ""); /* "." means no file */
139	greg	2.26	} else {
140	greg	2.14	strcpy(sbuf,arg[ff]); /* file name is context */
141	greg	2.2	if (i > LCALSUF && !strcmp(sbuf+i-LCALSUF, CALSUF))
142			sbuf[i-LCALSUF] = '\0'; /* remove suffix */
143			setcontext(f->ctx = savestr(sbuf));
144			if (!vardefined(REFVNAME)) { /* file loaded? */
145	greg	2.5	loadfunc(arg[ff]);
146	greg	2.2	varset(REFVNAME, '=', 1.0);
147			} else /* reference_count++ */
148			varset(REFVNAME, '=', varvalue(REFVNAME)+1.0);
149			}
150			curfunc = NULL; /* parse expressions */
151			sprintf(sbuf, "%s \"%s\"", ofun[m->otype].funame, m->oname);
152			for (i=0, ne=0; ef && i < na; i++, ef>>=1)
153			if (ef & 1) { /* flagged as an expression? */
154			if (ne >= MAXEXPR)
155			objerror(m, INTERNAL, "too many expressions");
156			initstr(arg[i], sbuf, 0);
157			f->ep[ne++] = getE1();
158			if (nextc != EOF)
159			syntax("unexpected character");
160			}
161			if (ef)
162			goto toofew;
163			if (i <= ff) /* find transform args */
164			i = ff+1;
165			while (i < na && arg[i][0] != '-')
166			i++;
167	greg	2.26	if (i == na) { /* no transform */
168			f->fxp = f->bxp = &unitxf;
169			} else { /* get transform */
170			if ((f->bxp = (XF *)malloc(sizeof(XF))) == NULL)
171	greg	2.3	goto memerr;
172	greg	2.26	if (invxf(f->bxp, na-i, arg+i) != na-i)
173	greg	2.2	objerror(m, USER, "bad transform");
174	greg	2.26	if (f->bxp->sca < 0.0)
175			f->bxp->sca = -f->bxp->sca;
176	greg	2.2	if (dofwd) { /* do both transforms */
177	greg	2.26	if ((f->fxp = (XF *)malloc(sizeof(XF))) == NULL)
178	greg	2.3	goto memerr;
179	greg	2.26	xf(f->fxp, na-i, arg+i);
180			if (f->fxp->sca < 0.0)
181			f->fxp->sca = -f->fxp->sca;
182	greg	2.2	}
183			}
184			m->os = (char *)f;
185			return(f);
186			toofew:
187	greg	2.4	objerror(m, USER, "too few string arguments");
188	greg	2.2	memerr:
189			error(SYSTEM, "out of memory in getfunc");
190	schorsch	2.22	return NULL; /* pro forma return */
191	greg	2.2	}
192
193
194	greg	2.25	void
195	schorsch	2.22	freefunc( /* free memory associated with modifier */
196			OBJREC *m
197			)
198	greg	2.2	{
199	greg	2.25	MFUNC *f;
200			int i;
201	greg	2.2
202			if ((f = (MFUNC *)m->os) == NULL)
203			return;
204			for (i = 0; f->ep[i] != NULL; i++)
205			epfree(f->ep[i]);
206			if (f->ctx[0]) { /* done with definitions */
207			setcontext(f->ctx);
208			i = varvalue(REFVNAME)-.5; /* reference_count-- */
209			if (i > 0)
210			varset(REFVNAME, '=', (double)i);
211			else
212			dcleanup(2); /* remove definitions */
213			freestr(f->ctx);
214			}
215	greg	2.26	if (f->bxp != &unitxf)
216			free((void *)f->bxp);
217			if ((f->fxp != NULL) & (f->fxp != &unitxf))
218			free((void *)f->fxp);
219	greg	2.14	free((void *)f);
220	greg	2.2	m->os = NULL;
221			}
222
223
224	greg	2.25	int
225	schorsch	2.22	setfunc( /* set channels for function call */
226	greg	2.26	OBJREC *m,
227			RAY *r
228	schorsch	2.22	)
229	greg	1.1	{
230	greg	2.26	static RNUMBER lastrno = ~0;
231			MFUNC *f;
232	greg	2.25	/* get function if any */
233	greg	2.26	if ((f = (MFUNC *)m->os) == NULL)
234			objerror(m, CONSISTENCY, "setfunc called before getfunc");
235
236			setcontext(f->ctx); /* set evaluator context */
237	greg	2.2	/* check to see if matrix set */
238	greg	2.25	if ((m == fobj) & (r->rno == lastrno))
239	greg	1.17	return(0);
240	greg	1.1	fobj = m;
241			fray = r;
242	greg	2.26	if (r->rox != NULL) {
243			if (f->bxp != &unitxf) {
244			funcxf.sca = r->rox->b.sca * f->bxp->sca;
245			multmat4(funcxf.xfm, r->rox->b.xfm, f->bxp->xfm);
246	greg	1.13	} else
247	schorsch	2.19	funcxf = r->rox->b;
248	greg	2.26	} else
249			funcxf = *f->bxp;
250			lastrno = r->rno;
251			eclock++; /* notify expression evaluator */
252			return(1);
253			}
254
255
256			int
257			worldfunc( /* special function context sans object */
258			char *ctx,
259			RAY *r
260			)
261			{
262			static RNUMBER lastrno = ~0;
263	greg	2.27
264			if (rayinitcal[0]) /* initialize on first call */
265			initfunc();
266	greg	2.26	/* set evaluator context */
267			setcontext(ctx);
268			/* check if ray already set */
269			if ((fobj == NULL) & (r->rno == lastrno))
270			return(0);
271			fobj = NULL;
272			fray = r;
273			funcxf = unitxf;
274	greg	1.16	lastrno = r->rno;
275	greg	1.1	eclock++; /* notify expression evaluator */
276	greg	1.17	return(1);
277	greg	1.1	}
278
279
280	greg	2.25	void
281	schorsch	2.22	loadfunc( /* load definition file */
282			char *fname
283			)
284	greg	1.1	{
285			char *ffname;
286
287	greg	2.18	if ((ffname = getpath(fname, getrlibpath(), R_OK)) == NULL) {
288	greg	1.1	sprintf(errmsg, "cannot find function file \"%s\"", fname);
289			error(USER, errmsg);
290			}
291			fcompile(ffname);
292			}
293
294
295	greg	2.2	static double
296	greg	2.20	l_arg(char nm) / return nth real argument */
297	greg	1.1	{
298	greg	2.25	int n;
299	greg	1.1
300	greg	2.7	if (fobj == NULL)
301	greg	2.25	error(USER, "arg(n) called without a context");
302	greg	2.7
303	greg	1.1	n = argument(1) + .5; /* round to integer */
304
305			if (n < 1)
306			return(fobj->oargs.nfargs);
307
308			if (n > fobj->oargs.nfargs) {
309			sprintf(errmsg, "missing real argument %d", n);
310			objerror(fobj, USER, errmsg);
311			}
312			return(fobj->oargs.farg[n-1]);
313	greg	1.19	}
314
315
316	greg	2.2	static double
317	greg	2.20	l_erf(char nm) / error function */
318	greg	1.19	{
319			return(erf(argument(1)));
320			}
321
322
323	greg	2.2	static double
324	greg	2.20	l_erfc(char nm) / cumulative error function */
325	greg	1.19	{
326			return(erfc(argument(1)));
327	greg	1.1	}
328
329
330	greg	2.25	double
331	schorsch	2.22	chanvalue( /* return channel n to calcomp */
332	greg	2.25	int n
333	schorsch	2.22	)
334	greg	1.1	{
335	greg	2.7	if (fray == NULL)
336			syntax("ray parameter used in constant expression");
337	greg	1.1
338	greg	1.10	if (--n < 0)
339			goto badchan;
340	greg	1.1
341	greg	2.17	if (n <= 2) /* ray direction */
342	greg	1.1
343	greg	1.12	return( ( fray->rdir[0]*funcxf.xfm[0][n] +
344			fray->rdir[1]*funcxf.xfm[1][n] +
345			fray->rdir[2]*funcxf.xfm[2][n] )
346			/ funcxf.sca );
347	greg	1.1
348	greg	2.17	if (n <= 5) /* surface normal */
349	greg	1.8
350	greg	1.12	return( ( fray->ron[0]*funcxf.xfm[0][n-3] +
351			fray->ron[1]*funcxf.xfm[1][n-3] +
352			fray->ron[2]*funcxf.xfm[2][n-3] )
353			/ funcxf.sca );
354	greg	1.8
355	greg	2.28	if (n <= 8) { /* intersection point */
356			if (fray->rot >= FHUGE)
357			return(0.0); /* XXX should be runtime error? */
358	greg	1.8
359	greg	1.12	return( fray->rop[0]*funcxf.xfm[0][n-6] +
360			fray->rop[1]*funcxf.xfm[1][n-6] +
361			fray->rop[2]*funcxf.xfm[2][n-6] +
362			funcxf.xfm[3][n-6] );
363	greg	2.28	}
364	greg	1.8
365	greg	2.13	if (n == 9) /* total distance */
366			return(raydist(fray,PRIMARY) * funcxf.sca);
367	greg	1.10
368	greg	1.18	if (n == 10) /* dot product (range [-1,1]) */
369			return( fray->rod <= -1.0 ? -1.0 :
370			fray->rod >= 1.0 ? 1.0 :
371			fray->rod );
372	greg	1.10
373	greg	1.8	if (n == 11) /* scale */
374	greg	1.12	return(funcxf.sca);
375	greg	1.8
376	greg	2.17	if (n <= 14) /* origin */
377	greg	1.12	return(funcxf.xfm[3][n-12]);
378	greg	1.8
379	greg	2.17	if (n <= 17) /* i unit vector */
380	greg	1.12	return(funcxf.xfm[0][n-15] / funcxf.sca);
381	greg	1.8
382	greg	2.17	if (n <= 20) /* j unit vector */
383			return(funcxf.xfm[1][n-18] / funcxf.sca);
384	greg	1.8
385	greg	2.17	if (n <= 23) /* k unit vector */
386	greg	1.12	return(funcxf.xfm[2][n-21] / funcxf.sca);
387	greg	2.6
388	greg	2.17	if (n == 24) /* single ray (shadow) distance */
389	greg	2.13	return((fray->rot+raydist(fray->parent,SHADOW)) * funcxf.sca);
390	greg	2.16
391	greg	2.17	if (n <= 26) /* local (u,v) coordinates */
392			return(fray->uv[n-25]);
393	greg	1.10	badchan:
394			error(USER, "illegal channel number");
395	greg	2.16	return(0.0);
396	greg	1.1	}