| 19 |
|
extern double specthresh; /* specular sampling threshold */ |
| 20 |
|
extern double specjitter; /* specular sampling jitter */ |
| 21 |
|
|
| 22 |
+ |
extern int backvis; /* back faces visible? */ |
| 23 |
+ |
|
| 24 |
+ |
static agaussamp(), getacoords(); |
| 25 |
+ |
|
| 26 |
|
/* |
| 27 |
|
* This routine implements the anisotropic Gaussian |
| 28 |
|
* model described by Ward in Siggraph `92 article. |
| 38 |
|
* 8 red grn blu rspec u-rough v-rough trans tspec |
| 39 |
|
*/ |
| 40 |
|
|
| 37 |
– |
#define BSPEC(m) (6.0) /* specularity parameter b */ |
| 38 |
– |
|
| 41 |
|
/* specularity flags */ |
| 42 |
|
#define SP_REFL 01 /* has reflected specular component */ |
| 43 |
|
#define SP_TRAN 02 /* has transmitted specular */ |
| 183 |
|
register RAY *r; |
| 184 |
|
{ |
| 185 |
|
ANISODAT nd; |
| 184 |
– |
double dtmp; |
| 186 |
|
COLOR ctmp; |
| 187 |
|
register int i; |
| 188 |
|
/* easy shadow test */ |
| 189 |
|
if (r->crtype & SHADOW) |
| 190 |
< |
return; |
| 190 |
> |
return(1); |
| 191 |
|
|
| 192 |
|
if (m->oargs.nfargs != (m->otype == MAT_TRANS2 ? 8 : 6)) |
| 193 |
|
objerror(m, USER, "bad number of real arguments"); |
| 203 |
|
nd.v_alpha = m->oargs.farg[5]; |
| 204 |
|
if (nd.u_alpha < FTINY || nd.v_alpha <= FTINY) |
| 205 |
|
objerror(m, USER, "roughness too small"); |
| 206 |
< |
/* reorient if necessary */ |
| 207 |
< |
if (r->rod < 0.0) |
| 208 |
< |
flipsurface(r); |
| 206 |
> |
/* check for back side */ |
| 207 |
> |
if (r->rod < 0.0) { |
| 208 |
> |
if (!backvis && m->otype != MAT_TRANS2) { |
| 209 |
> |
raytrans(r); |
| 210 |
> |
return(1); |
| 211 |
> |
} |
| 212 |
> |
flipsurface(r); /* reorient if backvis */ |
| 213 |
> |
} |
| 214 |
|
/* get modifiers */ |
| 215 |
|
raytexture(r, m->omod); |
| 216 |
|
nd.pdot = raynormal(nd.pnorm, r); /* perturb normal */ |
| 226 |
|
else |
| 227 |
|
setcolor(nd.scolor, 1.0, 1.0, 1.0); |
| 228 |
|
scalecolor(nd.scolor, nd.rspec); |
| 223 |
– |
/* improved model */ |
| 224 |
– |
dtmp = exp(-BSPEC(m)*nd.pdot); |
| 225 |
– |
for (i = 0; i < 3; i++) |
| 226 |
– |
colval(nd.scolor,i) += (1.0-colval(nd.scolor,i))*dtmp; |
| 227 |
– |
nd.rspec += (1.0-nd.rspec)*dtmp; |
| 229 |
|
/* check threshold */ |
| 230 |
< |
if (specthresh > FTINY && |
| 230 |
< |
(specthresh >= 1.-FTINY || |
| 231 |
< |
specthresh + .05 - .1*frandom() > nd.rspec)) |
| 230 |
> |
if (specthresh >= nd.rspec-FTINY) |
| 231 |
|
nd.specfl |= SP_RBLT; |
| 232 |
|
/* compute refl. direction */ |
| 233 |
|
for (i = 0; i < 3; i++) |
| 244 |
|
if (nd.tspec > FTINY) { |
| 245 |
|
nd.specfl |= SP_TRAN; |
| 246 |
|
/* check threshold */ |
| 247 |
< |
if (specthresh > FTINY && |
| 249 |
< |
(specthresh >= 1.-FTINY || |
| 250 |
< |
specthresh + .05 - .1*frandom() > nd.tspec)) |
| 247 |
> |
if (specthresh >= nd.tspec-FTINY) |
| 248 |
|
nd.specfl |= SP_TBLT; |
| 249 |
|
if (DOT(r->pert,r->pert) <= FTINY*FTINY) { |
| 250 |
|
VCOPY(nd.prdir, r->rdir); |
| 263 |
|
/* diffuse reflection */ |
| 264 |
|
nd.rdiff = 1.0 - nd.trans - nd.rspec; |
| 265 |
|
|
| 266 |
< |
if (r->ro != NULL && (r->ro->otype == OBJ_FACE || |
| 270 |
< |
r->ro->otype == OBJ_RING)) |
| 266 |
> |
if (r->ro != NULL && isflat(r->ro->otype)) |
| 267 |
|
nd.specfl |= SP_FLAT; |
| 268 |
|
|
| 269 |
|
getacoords(r, &nd); /* set up coordinates */ |
| 272 |
|
agaussamp(r, &nd); |
| 273 |
|
|
| 274 |
|
if (nd.rdiff > FTINY) { /* ambient from this side */ |
| 275 |
< |
ambient(ctmp, r); |
| 275 |
> |
ambient(ctmp, r, nd.pnorm); |
| 276 |
|
if (nd.specfl & SP_RBLT) |
| 277 |
|
scalecolor(ctmp, 1.0-nd.trans); |
| 278 |
|
else |
| 281 |
|
addcolor(r->rcol, ctmp); /* add to returned color */ |
| 282 |
|
} |
| 283 |
|
if (nd.tdiff > FTINY) { /* ambient from other side */ |
| 284 |
+ |
FVECT bnorm; |
| 285 |
+ |
|
| 286 |
|
flipsurface(r); |
| 287 |
< |
ambient(ctmp, r); |
| 287 |
> |
bnorm[0] = -nd.pnorm[0]; |
| 288 |
> |
bnorm[1] = -nd.pnorm[1]; |
| 289 |
> |
bnorm[2] = -nd.pnorm[2]; |
| 290 |
> |
ambient(ctmp, r, bnorm); |
| 291 |
|
if (nd.specfl & SP_TBLT) |
| 292 |
|
scalecolor(ctmp, nd.trans); |
| 293 |
|
else |
| 298 |
|
} |
| 299 |
|
/* add direct component */ |
| 300 |
|
direct(r, diraniso, &nd); |
| 301 |
+ |
|
| 302 |
+ |
return(1); |
| 303 |
|
} |
| 304 |
|
|
| 305 |
|
|
