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#ifndef lint
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static const char RCSid[] = "$Id: t_data.c,v 2.7 2003/03/05 16:16:53 greg Exp $";
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#endif
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/*
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* t_data.c - routine for stored textures
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*/
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#include "copyright.h"
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#include "ray.h"
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#include "data.h"
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#include "func.h"
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#include "rtotypes.h"
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/*
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* A stored texture is specified as follows:
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*
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* modifier texdata name
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* 8+ xfunc yfunc zfunc xdfname ydfname zdfname vfname v0 v1 .. xf
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* 0
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* n A1 A2 .. An
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*
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* Vfname is the name of the file where the variable definitions
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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 dfnames are the data file
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* names. The dimensions of the data files and the number
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* of variables must match. The funcs take three arguments to produce
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* interpolated values from 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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extern int
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t_data( /* interpolate texture data */
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register OBJREC *m,
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RAY *r
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)
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{
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int nv;
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FVECT disp;
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double dval[3], pt[MAXDIM];
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double d;
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DATARRAY *dp;
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register MFUNC *mf;
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register int i;
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if (m->oargs.nsargs < 8)
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objerror(m, USER, "bad # arguments");
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dp = getdata(m->oargs.sarg[3]);
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i = (1 << (nv = dp->nd)) - 1;
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mf = getfunc(m, 6, i<<7, 1);
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setfunc(m, r);
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errno = 0;
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for (i = 0; i < nv; i++)
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pt[i] = evalue(mf->ep[i]);
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if (errno == EDOM || errno == ERANGE)
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goto computerr;
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dval[0] = datavalue(dp, pt);
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for (i = 1; i < 3; i++) {
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dp = getdata(m->oargs.sarg[i+3]);
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if (dp->nd != nv)
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objerror(m, USER, "dimension error");
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dval[i] = datavalue(dp, pt);
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}
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errno = 0;
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for (i = 0; i < 3; i++)
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disp[i] = funvalue(m->oargs.sarg[i], 3, dval);
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if (errno == EDOM || errno == ERANGE)
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goto computerr;
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if (mf->f != &unitxf)
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multv3(disp, disp, mf->f->xfm);
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if (r->rox != NULL) {
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multv3(disp, disp, r->rox->f.xfm);
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d = 1.0 / (mf->f->sca * r->rox->f.sca);
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} else
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d = 1.0 / mf->f->sca;
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for (i = 0; i < 3; i++)
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r->pert[i] += disp[i] * d;
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return(0);
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computerr:
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objerror(m, WARNING, "compute error");
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return(0);
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}
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