| 23 |
|
extern double specthresh; /* specular sampling threshold */ |
| 24 |
|
extern double specjitter; /* specular sampling jitter */ |
| 25 |
|
|
| 26 |
+ |
static gaussamp(); |
| 27 |
+ |
|
| 28 |
|
/* |
| 29 |
< |
* This routine uses portions of the reflection |
| 30 |
< |
* model described by Cook and Torrance. |
| 29 |
< |
* The computation of specular components has been simplified by |
| 30 |
< |
* numerous approximations and ommisions to improve speed. |
| 29 |
> |
* This routine implements the isotropic Gaussian |
| 30 |
> |
* model described by Ward in Siggraph `92 article. |
| 31 |
|
* We orient the surface towards the incoming ray, so a single |
| 32 |
|
* surface can be used to represent an infinitely thin object. |
| 33 |
|
* |
| 38 |
|
* red grn blu rspec rough trans tspec |
| 39 |
|
*/ |
| 40 |
|
|
| 41 |
– |
#define BSPEC(m) (6.0) /* specularity parameter b */ |
| 42 |
– |
|
| 41 |
|
/* specularity flags */ |
| 42 |
|
#define SP_REFL 01 /* has reflected specular component */ |
| 43 |
|
#define SP_TRAN 02 /* has transmitted specular */ |
| 102 |
|
/* + source if flat */ |
| 103 |
|
if (np->specfl & SP_FLAT) |
| 104 |
|
dtmp += omega/(4.0*PI); |
| 105 |
< |
/* delta */ |
| 105 |
> |
/* half vector */ |
| 106 |
|
vtmp[0] = ldir[0] - np->rp->rdir[0]; |
| 107 |
|
vtmp[1] = ldir[1] - np->rp->rdir[1]; |
| 108 |
|
vtmp[2] = ldir[2] - np->rp->rdir[2]; |
| 109 |
|
d2 = DOT(vtmp, np->pnorm); |
| 110 |
< |
d2 = 2.0 - 2.0*d2/sqrt(DOT(vtmp,vtmp)); |
| 110 |
> |
d2 *= d2; |
| 111 |
> |
d2 = (DOT(vtmp,vtmp) - d2) / d2; |
| 112 |
|
/* gaussian */ |
| 113 |
|
dtmp = exp(-d2/dtmp)/(4.*PI*dtmp); |
| 114 |
|
/* worth using? */ |
| 154 |
|
{ |
| 155 |
|
NORMDAT nd; |
| 156 |
|
double transtest, transdist; |
| 158 |
– |
double dtmp; |
| 157 |
|
COLOR ctmp; |
| 158 |
|
register int i; |
| 159 |
|
/* easy shadow test */ |
| 183 |
|
nd.pdot = .001; /* non-zero for dirnorm() */ |
| 184 |
|
multcolor(nd.mcolor, r->pcol); /* modify material color */ |
| 185 |
|
transtest = 0; |
| 186 |
+ |
transdist = r->rot; |
| 187 |
|
/* get specular component */ |
| 188 |
|
if ((nd.rspec = m->oargs.farg[3]) > FTINY) { |
| 189 |
|
nd.specfl |= SP_REFL; |
| 193 |
|
else |
| 194 |
|
setcolor(nd.scolor, 1.0, 1.0, 1.0); |
| 195 |
|
scalecolor(nd.scolor, nd.rspec); |
| 197 |
– |
/* improved model */ |
| 198 |
– |
dtmp = exp(-BSPEC(m)*nd.pdot); |
| 199 |
– |
for (i = 0; i < 3; i++) |
| 200 |
– |
colval(nd.scolor,i) += (1.0-colval(nd.scolor,i))*dtmp; |
| 201 |
– |
nd.rspec += (1.0-nd.rspec)*dtmp; |
| 196 |
|
/* check threshold */ |
| 197 |
< |
if (!(nd.specfl & SP_PURE) && |
| 204 |
< |
specthresh > FTINY && |
| 205 |
< |
(specthresh >= 1.-FTINY || |
| 206 |
< |
specthresh + .05 - .1*frandom() > nd.rspec)) |
| 197 |
> |
if (!(nd.specfl & SP_PURE) && specthresh >= nd.rspec-FTINY) |
| 198 |
|
nd.specfl |= SP_RBLT; |
| 199 |
|
/* compute reflected ray */ |
| 200 |
|
for (i = 0; i < 3; i++) |
| 221 |
|
if (nd.tspec > FTINY) { |
| 222 |
|
nd.specfl |= SP_TRAN; |
| 223 |
|
/* check threshold */ |
| 224 |
< |
if (!(nd.specfl & SP_PURE) && specthresh > FTINY && |
| 225 |
< |
(specthresh >= 1.-FTINY || |
| 235 |
< |
specthresh + .05 - .1*frandom() > nd.tspec)) |
| 224 |
> |
if (!(nd.specfl & SP_PURE) && |
| 225 |
> |
specthresh >= nd.tspec-FTINY) |
| 226 |
|
nd.specfl |= SP_TBLT; |
| 227 |
|
if (r->crtype & SHADOW || |
| 228 |
|
DOT(r->pert,r->pert) <= FTINY*FTINY) { |
