| 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 */ |
| 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 */ |
| 87 |
> |
/* Compute "through" component color */ |
| 88 |
|
static void |
| 89 |
|
compute_through(BSDFDAT *ndp) |
| 90 |
|
{ |
| 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 |
< |
if (normalize(tdir) == 0) |
| 134 |
< |
continue; |
| 137 |
> |
normalize(tdir); |
| 138 |
|
ec = SDevalBSDF(&sv, tdir, ndp->vray, ndp->sd); |
| 139 |
|
if (ec) |
| 140 |
|
goto baderror; |
| 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 <= .001) |
| 155 |
< |
return; /* < 0.1% transmission */ |
| 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; |
| 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; |
| 194 |
|
SDValue sv; |
| 195 |
|
SDError ec; |
| 196 |
|
int i; |
| 197 |
+ |
/* in case we fail */ |
| 198 |
+ |
setcolor(cval, .0, .0, .0); |
| 199 |
|
/* transform source direction */ |
| 200 |
|
if (SDmapDir(vsrc, ndp->toloc, ldir) != SDEnone) |
| 201 |
|
return(0); |
| 224 |
|
diffY = .0; |
| 225 |
|
setcolor(cdiff, .0, .0, .0); |
| 226 |
|
} |
| 227 |
< |
/* assign number of samples */ |
| 227 |
> |
/* need projected solid angles */ |
| 228 |
> |
omega *= fabs(vsrc[2]); |
| 229 |
|
ec = SDsizeBSDF(&tomega, ndp->vray, vsrc, SDqueryMin, ndp->sd); |
| 230 |
|
if (ec) |
| 231 |
|
goto baderror; |
| 235 |
|
&& (vsrc[2] > 0) ^ (ndp->vray[2] > 0)) { |
| 236 |
|
double dx = vsrc[0] + ndp->vray[0]; |
| 237 |
|
double dy = vsrc[1] + ndp->vray[1]; |
| 238 |
< |
if (dx*dx + dy*dy <= omega+tomega) |
| 238 |
> |
if (dx*dx + dy*dy <= (4./PI)*(omega + tomega + |
| 239 |
> |
2.*sqrt(omega*tomega))) |
| 240 |
|
return(0); |
| 241 |
|
} |
| 242 |
+ |
/* assign number of samples */ |
| 243 |
|
sf = specjitter * ndp->pr->rweight; |
| 244 |
|
if (tomega <= .0) |
| 245 |
|
nsamp = 1; |
| 248 |
|
else |
| 249 |
|
nsamp = 4.*sf*omega/tomega + .5; |
| 250 |
|
nsamp += !nsamp; |
| 251 |
< |
setcolor(cval, .0, .0, .0); /* sample our source area */ |
| 244 |
< |
sf = sqrt(omega); |
| 251 |
> |
sf = sqrt(omega); /* sample our source area */ |
| 252 |
|
tsr = sqrt(tomega); |
| 253 |
|
for (i = nsamp; i--; ) { |
| 254 |
|
VCOPY(vsmp, vsrc); /* jitter query directions */ |
| 256 |
|
multisamp(sd, 2, (i + frandom())/(double)nsamp); |
| 257 |
|
vsmp[0] += (sd[0] - .5)*sf; |
| 258 |
|
vsmp[1] += (sd[1] - .5)*sf; |
| 259 |
< |
if (normalize(vsmp) == 0) { |
| 253 |
< |
--nsamp; |
| 254 |
< |
continue; |
| 255 |
< |
} |
| 259 |
> |
normalize(vsmp); |
| 260 |
|
} |
| 261 |
|
bsdf_jitter(vjit, ndp, tsr); |
| 262 |
|
/* compute BSDF */ |
| 263 |
|
ec = SDevalBSDF(&sv, vjit, vsmp, ndp->sd); |
| 264 |
|
if (ec) |
| 265 |
|
goto baderror; |
| 266 |
< |
if (sv.cieY - diffY <= FTINY) { |
| 263 |
< |
addcolor(cval, cdiff); |
| 266 |
> |
if (sv.cieY - diffY <= FTINY) |
| 267 |
|
continue; /* no specular part */ |
| 268 |
< |
} |
| 268 |
> |
/* check for variable resolution */ |
| 269 |
> |
ec = SDsizeBSDF(&tomega2, vjit, vsmp, SDqueryMin, ndp->sd); |
| 270 |
> |
if (ec) |
| 271 |
> |
goto baderror; |
| 272 |
> |
if (tomega2 < .12*tomega) |
| 273 |
> |
continue; /* not safe to include */ |
| 274 |
|
cvt_sdcolor(csmp, &sv); |
| 275 |
|
addcolor(cval, csmp); /* else average it in */ |
| 276 |
|
++ok; |
| 277 |
|
} |
| 278 |
< |
if (!ok) { |
| 279 |
< |
setcolor(cval, .0, .0, .0); |
| 280 |
< |
return(0); /* no valid specular samples */ |
| 281 |
< |
} |
| 274 |
< |
sf = 1./(double)nsamp; |
| 278 |
> |
if (!ok) /* no valid specular samples? */ |
| 279 |
> |
return(0); |
| 280 |
> |
|
| 281 |
> |
sf = 1./(double)ok; /* compute average BSDF */ |
| 282 |
|
scalecolor(cval, sf); |
| 283 |
|
/* subtract diffuse contribution */ |
| 284 |
|
for (i = 3*(diffY > FTINY); i--; ) |
