| 607 |
|
SDgetTreCDist(const FVECT inVec, SDComponent *sdc) |
| 608 |
|
{ |
| 609 |
|
const SDTre *sdt; |
| 610 |
< |
double inCoord[2]; |
| 610 |
> |
double inCoord[2], quantum; |
| 611 |
|
int i; |
| 612 |
|
SDTreCDst *cd, *cdlast; |
| 613 |
|
/* check arguments */ |
| 614 |
|
if ((inVec == NULL) | (sdc == NULL) || |
| 615 |
|
(sdt = (SDTre *)sdc->dist) == NULL) |
| 616 |
|
return NULL; |
| 617 |
< |
if (sdt->st->ndim == 3) /* isotropic BSDF? */ |
| 617 |
> |
if (sdt->st->ndim == 3) { /* isotropic BSDF? */ |
| 618 |
|
inCoord[0] = .5 - .5*sqrt(inVec[0]*inVec[0] + inVec[1]*inVec[1]); |
| 619 |
< |
else if (sdt->st->ndim == 4) |
| 619 |
> |
} else if (sdt->st->ndim == 4) { |
| 620 |
|
SDdisk2square(inCoord, -inVec[0], -inVec[1]); |
| 621 |
< |
else |
| 621 |
> |
} else |
| 622 |
|
return NULL; /* should be internal error */ |
| 623 |
+ |
/* quantize to avoid f.p. errors */ |
| 624 |
+ |
quantum = SDsmallestLeaf(sdt->st); |
| 625 |
+ |
for (i = sdt->st->ndim - 2; i--; ) |
| 626 |
+ |
inCoord[i] = floor(inCoord[i]/quantum)*quantum + .5*quantum; |
| 627 |
|
cdlast = NULL; /* check for direction in cache list */ |
| 628 |
|
for (cd = (SDTreCDst *)sdc->cdList; cd != NULL; |
| 629 |
< |
cdlast = cd, cd = (SDTreCDst *)cd->next) { |
| 629 |
> |
cdlast = cd, cd = cd->next) { |
| 630 |
|
for (i = sdt->st->ndim - 2; i--; ) |
| 631 |
|
if ((cd->clim[i][0] > inCoord[i]) | |
| 632 |
|
(inCoord[i] >= cd->clim[i][1])) |
| 638 |
|
cdlast = cd = make_cdist(sdt, inCoord); |
| 639 |
|
if (cdlast != NULL) { /* move entry to head of cache list */ |
| 640 |
|
cdlast->next = cd->next; |
| 641 |
< |
cd->next = sdc->cdList; |
| 641 |
> |
cd->next = (SDTreCDst *)sdc->cdList; |
| 642 |
|
sdc->cdList = (SDCDst *)cd; |
| 643 |
|
} |
| 644 |
|
return (SDCDst *)cd; /* ready to go */ |
