| 19 |
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extern double specthresh; /* specular sampling threshold */ |
| 20 |
|
extern double specjitter; /* specular sampling jitter */ |
| 21 |
|
|
| 22 |
+ |
static agaussamp(), getacoords(); |
| 23 |
+ |
|
| 24 |
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/* |
| 25 |
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* This routine implements the anisotropic Gaussian |
| 26 |
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* model described by Ward in Siggraph `92 article. |
| 36 |
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* 8 red grn blu rspec u-rough v-rough trans tspec |
| 37 |
|
*/ |
| 38 |
|
|
| 37 |
– |
#define BSPEC(m) (6.0) /* specularity parameter b */ |
| 38 |
– |
|
| 39 |
|
/* specularity flags */ |
| 40 |
|
#define SP_REFL 01 /* has reflected specular component */ |
| 41 |
|
#define SP_TRAN 02 /* has transmitted specular */ |
| 181 |
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register RAY *r; |
| 182 |
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{ |
| 183 |
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ANISODAT nd; |
| 184 |
– |
double dtmp; |
| 184 |
|
COLOR ctmp; |
| 185 |
|
register int i; |
| 186 |
|
/* easy shadow test */ |
| 219 |
|
else |
| 220 |
|
setcolor(nd.scolor, 1.0, 1.0, 1.0); |
| 221 |
|
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; |
| 222 |
|
/* check threshold */ |
| 223 |
< |
if (specthresh > FTINY && |
| 230 |
< |
(specthresh >= 1.-FTINY || |
| 231 |
< |
specthresh + .05 - .1*frandom() > nd.rspec)) |
| 223 |
> |
if (specthresh >= nd.rspec-FTINY) |
| 224 |
|
nd.specfl |= SP_RBLT; |
| 225 |
|
/* compute refl. direction */ |
| 226 |
|
for (i = 0; i < 3; i++) |
| 237 |
|
if (nd.tspec > FTINY) { |
| 238 |
|
nd.specfl |= SP_TRAN; |
| 239 |
|
/* check threshold */ |
| 240 |
< |
if (specthresh > FTINY && |
| 249 |
< |
(specthresh >= 1.-FTINY || |
| 250 |
< |
specthresh + .05 - .1*frandom() > nd.tspec)) |
| 240 |
> |
if (specthresh >= nd.tspec-FTINY) |
| 241 |
|
nd.specfl |= SP_TBLT; |
| 242 |
|
if (DOT(r->pert,r->pert) <= FTINY*FTINY) { |
| 243 |
|
VCOPY(nd.prdir, r->rdir); |
