| 515 |
|
c_toSharpRGB(&cxy, yval, rgb); |
| 516 |
|
} |
| 517 |
|
|
| 518 |
+ |
static double |
| 519 |
+ |
pfrac(double x) |
| 520 |
+ |
{ |
| 521 |
+ |
return( x - (int)x ); |
| 522 |
+ |
} |
| 523 |
+ |
|
| 524 |
|
/* Query BSDF value and sample hypercube for the given vectors */ |
| 525 |
|
static int |
| 526 |
|
SDqueryTre(const SDTre *sdt, float *coef, |
| 527 |
|
const FVECT inVec, const FVECT outVec, double *hc) |
| 528 |
|
{ |
| 529 |
|
const RREAL *vtmp; |
| 530 |
+ |
double hcube[SD_MAXDIM+1]; |
| 531 |
|
float yval; |
| 532 |
|
FVECT rOutVec; |
| 533 |
|
RREAL gridPos[4]; |
| 534 |
+ |
double d; |
| 535 |
+ |
int i; |
| 536 |
|
|
| 537 |
|
if (sdt->stc[tt_Y] == NULL) /* paranoia, I hope */ |
| 538 |
|
return 0; |
| 576 |
|
disk2square(gridPos+2, outVec[0], outVec[1]); |
| 577 |
|
} else |
| 578 |
|
return 0; /* should be internal error */ |
| 579 |
< |
/* get BSDF value */ |
| 579 |
> |
|
| 580 |
> |
if (hc == NULL) hc = hcube; /* get BSDF value */ |
| 581 |
|
yval = SDlookupTre(sdt->stc[tt_Y], gridPos, hc); |
| 582 |
|
if (coef == NULL) /* just getting hypercube? */ |
| 583 |
|
return 1; |
| 584 |
+ |
d = 0; /* position-specific perturbation */ |
| 585 |
+ |
for (i = sdt->stc[tt_Y]->ndim; i--; ) |
| 586 |
+ |
d += pfrac((2<<i)/(hc[i]+.01687)) - .5; |
| 587 |
+ |
yval *= 1. + 1e-4*d; /* assumes tolerance is > 0.04% */ |
| 588 |
|
if (sdt->stc[tt_u] == NULL || sdt->stc[tt_v] == NULL) { |
| 589 |
|
*coef = yval; |
| 590 |
|
return 1; /* no color */ |
