src/rt/func.c

#ifndef lint
static const char       RCSid[] = "$Id: func.c,v 2.28 2015/05/19 11:49:05 greg Exp $";
#endif
/*
 *  func.c - interface to calcomp functions.
 */

#include "copyright.h"

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