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t_data.c
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Sat, Jun 29, 20:37

t_data.c
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#ifndef lint
static const char RCSid[] = "$Id: t_data.c,v 2.11 2014/07/08 18:25:00 greg Exp $";
#endif
/*
* t_data.c - routine for stored textures
*/
#include "copyright.h"
#include "ray.h"
#include "data.h"
#include "func.h"
#include "rtotypes.h"
/*
* A stored texture is specified as follows:
*
* modifier texdata name
* 8+ xfunc yfunc zfunc xdfname ydfname zdfname vfname v0 v1 .. xf
* 0
* n A1 A2 .. An
*
* Vfname is the name of the file where the variable definitions
* can be found. The list of real arguments can be accessed by
* definitions in the file. The dfnames are the data file
* names. The dimensions of the data files and the number
* of variables must match. The funcs take three arguments to produce
* interpolated values from the file. The xf is a transformation
* to get from the original coordinates to the current coordinates.
*/
int
t_data( /* interpolate texture data */
OBJREC *m,
RAY *r
)
{
int nv;
FVECT disp;
double dval[3], pt[MAXDIM];
double d;
DATARRAY *dp;
MFUNC *mf;
int i;
if (m->oargs.nsargs < 8)
objerror(m, USER, "bad # arguments");
dp = getdata(m->oargs.sarg[3]);
i = (1 << (nv = dp->nd)) - 1;
mf = getfunc(m, 6, i<<7, 1);
setfunc(m, r);
errno = 0;
for (i = 0; i < nv; i++)
pt[i] = evalue(mf->ep[i]);
if (errno == EDOM || errno == ERANGE)
goto computerr;
dval[0] = datavalue(dp, pt);
for (i = 1; i < 3; i++) {
dp = getdata(m->oargs.sarg[i+3]);
if (dp->nd != nv)
objerror(m, USER, "dimension error");
dval[i] = datavalue(dp, pt);
}
errno = 0;
for (i = 0; i < 3; i++)
disp[i] = funvalue(m->oargs.sarg[i], 3, dval);
if (errno == EDOM || errno == ERANGE)
goto computerr;
if (mf->fxp != &unitxf)
multv3(disp, disp, mf->fxp->xfm);
if (r->rox != NULL) {
multv3(disp, disp, r->rox->f.xfm);
d = 1.0 / (mf->fxp->sca * r->rox->f.sca);
} else
d = 1.0 / mf->fxp->sca;
VSUM(r->pert, r->pert, disp, d);
return(0);
computerr:
objerror(m, WARNING, "compute error");
return(0);
}

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