| 23 |
|
* (opposite the surface normal) to bypass any intervening geometry. |
| 24 |
|
* Translation only affects scattered, non-source-directed samples. |
| 25 |
|
* A non-zero thickness has the further side-effect that an unscattered |
| 26 |
< |
* (view) ray will pass right through our material if it has any |
| 27 |
< |
* non-diffuse transmission, making the BSDF surface invisible. This |
| 28 |
< |
* shows the proxied geometry instead. Thickness has the further |
| 29 |
< |
* effect of turning off reflection on the hidden side so that rays |
| 30 |
< |
* heading in the opposite direction pass unimpeded through the BSDF |
| 26 |
> |
* (view) ray will pass right through our material, making the BSDF |
| 27 |
> |
* surface invisible and showing the proxied geometry instead. Thickness |
| 28 |
> |
* has the further effect of turning off reflection on the reverse side so |
| 29 |
> |
* rays heading in the opposite direction pass unimpeded through the BSDF |
| 30 |
|
* surface. A paired surface may be placed on the opposide side of |
| 31 |
|
* the detail geometry, less than this thickness away, if a two-way |
| 32 |
|
* proxy is desired. Note that the sign of the thickness is important. |
| 35 |
|
* hides geometry in front of the surface when rays hit from behind, |
| 36 |
|
* and applies only the transmission and backside reflectance properties. |
| 37 |
|
* Reflection is ignored on the hidden side, as those rays pass through. |
| 38 |
+ |
* When thickness is set to zero, shadow rays will be blocked unless |
| 39 |
+ |
* a BTDF has a strong "through" component in the source direction. |
| 40 |
+ |
* A separate test prevents over-counting by dropping specular & ambient |
| 41 |
+ |
* samples that are too close to this "through" direction. The same |
| 42 |
+ |
* restriction applies for the proxy case (thickness != 0). |
| 43 |
|
* The "up" vector for the BSDF is given by three variables, defined |
| 44 |
|
* (along with the thickness) by the named function file, or '.' if none. |
| 45 |
|
* Together with the surface normal, this defines the local coordinate |
| 47 |
|
* We do not reorient the surface, so if the BSDF has no back-side |
| 48 |
|
* reflectance and none is given in the real arguments, a BSDF surface |
| 49 |
|
* with zero thickness will appear black when viewed from behind |
| 50 |
< |
* unless backface visibility is off. |
| 50 |
> |
* unless backface visibility is on, when it becomes invisible. |
| 51 |
|
* The diffuse arguments are added to components in the BSDF file, |
| 52 |
|
* not multiplied. However, patterns affect this material as a multiplier |
| 53 |
|
* on everything except non-diffuse reflection. |
| 63 |
|
/* |
| 64 |
|
* Note that our reverse ray-tracing process means that the positions |
| 65 |
|
* of incoming and outgoing vectors may be reversed in our calls |
| 66 |
< |
* to the BSDF library. This is fine, since the bidirectional nature |
| 66 |
> |
* to the BSDF library. This is usually fine, since the bidirectional nature |
| 67 |
|
* of the BSDF (that's what the 'B' stands for) means it all works out. |
| 68 |
|
*/ |
| 69 |
|
|
| 76 |
|
RREAL toloc[3][3]; /* world to local BSDF coords */ |
| 77 |
|
RREAL fromloc[3][3]; /* local BSDF coords to world */ |
| 78 |
|
double thick; /* surface thickness */ |
| 79 |
+ |
COLOR cthru; /* "through" component multiplier */ |
| 80 |
|
SDData *sd; /* loaded BSDF data */ |
| 81 |
|
COLOR rdiff; /* diffuse reflection */ |
| 82 |
|
COLOR tdiff; /* diffuse transmission */ |
| 84 |
|
|
| 85 |
|
#define cvt_sdcolor(cv, svp) ccy2rgb(&(svp)->spec, (svp)->cieY, cv) |
| 86 |
|
|
| 87 |
+ |
/* Compute "through" component color */ |
| 88 |
+ |
static void |
| 89 |
+ |
compute_through(BSDFDAT *ndp) |
| 90 |
+ |
{ |
| 91 |
+ |
#define NDIR2CHECK 13 |
| 92 |
+ |
static const float dir2check[NDIR2CHECK][2] = { |
| 93 |
+ |
{0, 0}, |
| 94 |
+ |
{-0.8, 0}, |
| 95 |
+ |
{0, 0.8}, |
| 96 |
+ |
{0, -0.8}, |
| 97 |
+ |
{0.8, 0}, |
| 98 |
+ |
{-0.8, 0.8}, |
| 99 |
+ |
{-0.8, -0.8}, |
| 100 |
+ |
{0.8, 0.8}, |
| 101 |
+ |
{0.8, -0.8}, |
| 102 |
+ |
{-1.6, 0}, |
| 103 |
+ |
{0, 1.6}, |
| 104 |
+ |
{0, -1.6}, |
| 105 |
+ |
{1.6, 0}, |
| 106 |
+ |
}; |
| 107 |
+ |
const double peak_over = 2.0; |
| 108 |
+ |
SDSpectralDF *dfp; |
| 109 |
+ |
FVECT pdir; |
| 110 |
+ |
double tomega, srchrad; |
| 111 |
+ |
COLOR vpeak, vsum; |
| 112 |
+ |
int nsum, i; |
| 113 |
+ |
SDError ec; |
| 114 |
+ |
|
| 115 |
+ |
setcolor(ndp->cthru, .0, .0, .0); /* starting assumption */ |
| 116 |
+ |
|
| 117 |
+ |
if (ndp->pr->rod > 0) |
| 118 |
+ |
dfp = (ndp->sd->tf != NULL) ? ndp->sd->tf : ndp->sd->tb; |
| 119 |
+ |
else |
| 120 |
+ |
dfp = (ndp->sd->tb != NULL) ? ndp->sd->tb : ndp->sd->tf; |
| 121 |
+ |
|
| 122 |
+ |
if (dfp == NULL) |
| 123 |
+ |
return; /* no specular transmission */ |
| 124 |
+ |
if (bright(ndp->pr->pcol) <= FTINY) |
| 125 |
+ |
return; /* pattern is black, here */ |
| 126 |
+ |
srchrad = sqrt(dfp->minProjSA); /* else search for peak */ |
| 127 |
+ |
setcolor(vpeak, .0, .0, .0); |
| 128 |
+ |
setcolor(vsum, .0, .0, .0); |
| 129 |
+ |
nsum = 0; |
| 130 |
+ |
for (i = 0; i < NDIR2CHECK; i++) { |
| 131 |
+ |
FVECT tdir; |
| 132 |
+ |
SDValue sv; |
| 133 |
+ |
COLOR vcol; |
| 134 |
+ |
tdir[0] = -ndp->vray[0] + dir2check[i][0]*srchrad; |
| 135 |
+ |
tdir[1] = -ndp->vray[1] + dir2check[i][1]*srchrad; |
| 136 |
+ |
tdir[2] = -ndp->vray[2]; |
| 137 |
+ |
normalize(tdir); |
| 138 |
+ |
ec = SDevalBSDF(&sv, tdir, ndp->vray, ndp->sd); |
| 139 |
+ |
if (ec) |
| 140 |
+ |
goto baderror; |
| 141 |
+ |
cvt_sdcolor(vcol, &sv); |
| 142 |
+ |
addcolor(vsum, vcol); |
| 143 |
+ |
++nsum; |
| 144 |
+ |
if (bright(vcol) > bright(vpeak)) { |
| 145 |
+ |
copycolor(vpeak, vcol); |
| 146 |
+ |
VCOPY(pdir, tdir); |
| 147 |
+ |
} |
| 148 |
+ |
} |
| 149 |
+ |
ec = SDsizeBSDF(&tomega, pdir, ndp->vray, SDqueryMin, ndp->sd); |
| 150 |
+ |
if (ec) |
| 151 |
+ |
goto baderror; |
| 152 |
+ |
if (tomega > 1.5*dfp->minProjSA) |
| 153 |
+ |
return; /* not really a peak? */ |
| 154 |
+ |
if ((bright(vpeak) - ndp->sd->tLamb.cieY*(1./PI))*tomega <= .007) |
| 155 |
+ |
return; /* < 0.7% transmission */ |
| 156 |
+ |
for (i = 3; i--; ) /* remove peak from average */ |
| 157 |
+ |
colval(vsum,i) -= colval(vpeak,i); |
| 158 |
+ |
--nsum; |
| 159 |
+ |
if (peak_over*bright(vsum) >= nsum*bright(vpeak)) |
| 160 |
+ |
return; /* not peaky enough */ |
| 161 |
+ |
copycolor(ndp->cthru, vpeak); /* else use it */ |
| 162 |
+ |
scalecolor(ndp->cthru, tomega); |
| 163 |
+ |
multcolor(ndp->cthru, ndp->pr->pcol); /* modify by pattern */ |
| 164 |
+ |
return; |
| 165 |
+ |
baderror: |
| 166 |
+ |
objerror(ndp->mp, USER, transSDError(ec)); |
| 167 |
+ |
#undef NDIR2CHECK |
| 168 |
+ |
} |
| 169 |
+ |
|
| 170 |
|
/* Jitter ray sample according to projected solid angle and specjitter */ |
| 171 |
|
static void |
| 172 |
|
bsdf_jitter(FVECT vres, BSDFDAT *ndp, double sr_psa) |
| 187 |
|
{ |
| 188 |
|
int nsamp, ok = 0; |
| 189 |
|
FVECT vsrc, vsmp, vjit; |
| 190 |
< |
double tomega; |
| 190 |
> |
double tomega, tomega2; |
| 191 |
|
double sf, tsr, sd[2]; |
| 192 |
|
COLOR csmp, cdiff; |
| 193 |
|
double diffY; |
| 227 |
|
if (ec) |
| 228 |
|
goto baderror; |
| 229 |
|
/* check indirect over-counting */ |
| 230 |
< |
if (ndp->thick != 0 && ndp->pr->crtype & (SPECULAR|AMBIENT) |
| 230 |
> |
if ((ndp->thick != 0 || bright(ndp->cthru) > FTINY) |
| 231 |
> |
&& ndp->pr->crtype & (SPECULAR|AMBIENT) |
| 232 |
|
&& (vsrc[2] > 0) ^ (ndp->vray[2] > 0)) { |
| 233 |
|
double dx = vsrc[0] + ndp->vray[0]; |
| 234 |
|
double dy = vsrc[1] + ndp->vray[1]; |
| 252 |
|
multisamp(sd, 2, (i + frandom())/(double)nsamp); |
| 253 |
|
vsmp[0] += (sd[0] - .5)*sf; |
| 254 |
|
vsmp[1] += (sd[1] - .5)*sf; |
| 255 |
< |
if (normalize(vsmp) == 0) { |
| 167 |
< |
--nsamp; |
| 168 |
< |
continue; |
| 169 |
< |
} |
| 255 |
> |
normalize(vsmp); |
| 256 |
|
} |
| 257 |
|
bsdf_jitter(vjit, ndp, tsr); |
| 258 |
< |
/* compute BSDF */ |
| 258 |
> |
/* check for variable resolution */ |
| 259 |
> |
ec = SDsizeBSDF(&tomega2, vjit, vsmp, SDqueryMin, ndp->sd); |
| 260 |
> |
if (ec) |
| 261 |
> |
goto baderror; |
| 262 |
> |
if (tomega2 < .12*tomega) |
| 263 |
> |
continue; /* not safe to include */ |
| 264 |
> |
/* else compute BSDF */ |
| 265 |
|
ec = SDevalBSDF(&sv, vjit, vsmp, ndp->sd); |
| 266 |
|
if (ec) |
| 267 |
|
goto baderror; |
| 268 |
< |
if (sv.cieY - diffY <= FTINY) { |
| 177 |
< |
addcolor(cval, cdiff); |
| 268 |
> |
if (sv.cieY - diffY <= FTINY) |
| 269 |
|
continue; /* no specular part */ |
| 179 |
– |
} |
| 270 |
|
cvt_sdcolor(csmp, &sv); |
| 271 |
|
addcolor(cval, csmp); /* else average it in */ |
| 272 |
|
++ok; |
| 275 |
|
setcolor(cval, .0, .0, .0); |
| 276 |
|
return(0); /* no valid specular samples */ |
| 277 |
|
} |
| 278 |
< |
sf = 1./(double)nsamp; |
| 278 |
> |
sf = 1./(double)ok; |
| 279 |
|
scalecolor(cval, sf); |
| 280 |
|
/* subtract diffuse contribution */ |
| 281 |
|
for (i = 3*(diffY > FTINY); i--; ) |
| 557 |
|
nd.thick = evalue(mf->ep[0]); |
| 558 |
|
if ((-FTINY <= nd.thick) & (nd.thick <= FTINY)) |
| 559 |
|
nd.thick = .0; |
| 470 |
– |
/* check shadow */ |
| 471 |
– |
if (r->crtype & SHADOW) { |
| 472 |
– |
if (nd.thick != 0) |
| 473 |
– |
raytrans(r); /* pass-through */ |
| 474 |
– |
return(1); /* or shadow */ |
| 475 |
– |
} |
| 560 |
|
/* check backface visibility */ |
| 561 |
|
if (!hitfront & !backvis) { |
| 562 |
|
raytrans(r); |
| 563 |
|
return(1); |
| 564 |
|
} |
| 565 |
|
/* check other rays to pass */ |
| 566 |
< |
if (nd.thick != 0 && (!(r->crtype & (SPECULAR|AMBIENT)) || |
| 566 |
> |
if (nd.thick != 0 && (r->crtype & SHADOW || |
| 567 |
> |
!(r->crtype & (SPECULAR|AMBIENT)) || |
| 568 |
|
(nd.thick > 0) ^ hitfront)) { |
| 569 |
|
raytrans(r); /* hide our proxy */ |
| 570 |
|
return(1); |
| 573 |
|
nd.pr = r; |
| 574 |
|
/* get BSDF data */ |
| 575 |
|
nd.sd = loadBSDF(m->oargs.sarg[1]); |
| 576 |
+ |
/* early shadow check */ |
| 577 |
+ |
if (r->crtype & SHADOW && (nd.sd->tf == NULL) & (nd.sd->tb == NULL)) |
| 578 |
+ |
return(1); |
| 579 |
|
/* diffuse reflectance */ |
| 580 |
|
if (hitfront) { |
| 581 |
|
cvt_sdcolor(nd.rdiff, &nd.sd->rLambFront); |
| 629 |
|
nd.vray[2] = -r->rdir[2]; |
| 630 |
|
ec = SDmapDir(nd.vray, nd.toloc, nd.vray); |
| 631 |
|
} |
| 544 |
– |
if (!ec) |
| 545 |
– |
ec = SDinvXform(nd.fromloc, nd.toloc); |
| 632 |
|
if (ec) { |
| 633 |
|
objerror(m, WARNING, "Illegal orientation vector"); |
| 634 |
|
return(1); |
| 635 |
|
} |
| 636 |
< |
/* determine BSDF resolution */ |
| 637 |
< |
ec = SDsizeBSDF(nd.sr_vpsa, nd.vray, NULL, SDqueryMin+SDqueryMax, nd.sd); |
| 636 |
> |
compute_through(&nd); /* compute through component */ |
| 637 |
> |
if (r->crtype & SHADOW) { |
| 638 |
> |
RAY tr; /* attempt to pass shadow ray */ |
| 639 |
> |
if (rayorigin(&tr, TRANS, r, nd.cthru) < 0) |
| 640 |
> |
return(1); /* blocked */ |
| 641 |
> |
VCOPY(tr.rdir, r->rdir); |
| 642 |
> |
rayvalue(&tr); /* transmit with scaling */ |
| 643 |
> |
multcolor(tr.rcol, tr.rcoef); |
| 644 |
> |
copycolor(r->rcol, tr.rcol); |
| 645 |
> |
return(1); /* we're done */ |
| 646 |
> |
} |
| 647 |
> |
ec = SDinvXform(nd.fromloc, nd.toloc); |
| 648 |
> |
if (!ec) /* determine BSDF resolution */ |
| 649 |
> |
ec = SDsizeBSDF(nd.sr_vpsa, nd.vray, NULL, |
| 650 |
> |
SDqueryMin+SDqueryMax, nd.sd); |
| 651 |
|
if (ec) |
| 652 |
|
objerror(m, USER, transSDError(ec)); |
| 653 |
|
|
