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#ifndef lint
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static const char RCSid[] = "$Id$";
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#endif
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/*
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* mx_func.c - routine for mixture functions.
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*/
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#include "copyright.h"
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#include "ray.h"
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#include "func.h"
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/*
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* A mixture function is specified:
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*
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* modifier mixfunc name
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* 4+ foremod backmod varname vfname xf
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* 0
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* n A1 A2 ..
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*
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* Vfname is the name of the file where the variable definition
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* can be found. The list of real arguments can be accessed by
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* definitions in the file. The xf is a transformation
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* to get from the original coordinates to the current coordinates.
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*/
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mx_func(m, r) /* compute mixture function */
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register OBJREC *m;
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RAY *r;
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{
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OBJECT obj;
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register int i;
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double coef;
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OBJECT mod[2];
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register MFUNC *mf;
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if (m->oargs.nsargs < 4)
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objerror(m, USER, "bad # arguments");
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obj = objndx(m);
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for (i = 0; i < 2; i++)
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if (!strcmp(m->oargs.sarg[i], VOIDID))
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mod[i] = OVOID;
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else if ((mod[i] = lastmod(obj, m->oargs.sarg[i])) == OVOID) {
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sprintf(errmsg, "undefined modifier \"%s\"",
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m->oargs.sarg[i]);
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objerror(m, USER, errmsg);
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}
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mf = getfunc(m, 3, 0x4, 0);
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setfunc(m, r);
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errno = 0;
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coef = evalue(mf->ep[0]);
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if (errno) {
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objerror(m, WARNING, "compute error");
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return(0);
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}
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if (raymixture(r, mod[0], mod[1], coef)) {
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if (m->omod != OVOID)
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objerror(m, USER, "inappropriate modifier");
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return(1);
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}
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return(0);
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}
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