1 |
greg |
1.1 |
#ifndef lint |
2 |
greg |
2.48 |
static const char RCSid[] = "$Id: normal.c,v 2.47 2004/03/30 16:13:01 schorsch Exp $"; |
3 |
greg |
1.1 |
#endif |
4 |
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/* |
5 |
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* normal.c - shading function for normal materials. |
6 |
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* |
7 |
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* 8/19/85 |
8 |
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* 12/19/85 - added stuff for metals. |
9 |
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* 6/26/87 - improved specular model. |
10 |
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* 9/28/87 - added model for translucent materials. |
11 |
greg |
2.2 |
* Later changes described in delta comments. |
12 |
greg |
1.1 |
*/ |
13 |
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14 |
greg |
2.39 |
#include "copyright.h" |
15 |
greg |
2.38 |
|
16 |
greg |
1.1 |
#include "ray.h" |
17 |
greg |
2.46 |
#include "ambient.h" |
18 |
schorsch |
2.47 |
#include "source.h" |
19 |
greg |
1.1 |
#include "otypes.h" |
20 |
schorsch |
2.47 |
#include "rtotypes.h" |
21 |
greg |
2.2 |
#include "random.h" |
22 |
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23 |
greg |
2.34 |
#ifndef MAXITER |
24 |
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#define MAXITER 10 /* maximum # specular ray attempts */ |
25 |
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#endif |
26 |
greg |
2.38 |
/* estimate of Fresnel function */ |
27 |
greg |
2.44 |
#define FRESNE(ci) (exp(-5.85*(ci)) - 0.00287989916) |
28 |
greg |
2.34 |
|
29 |
greg |
2.24 |
|
30 |
greg |
1.1 |
/* |
31 |
greg |
2.22 |
* This routine implements the isotropic Gaussian |
32 |
|
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* model described by Ward in Siggraph `92 article. |
33 |
greg |
1.1 |
* We orient the surface towards the incoming ray, so a single |
34 |
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* surface can be used to represent an infinitely thin object. |
35 |
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* |
36 |
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* Arguments for MAT_PLASTIC and MAT_METAL are: |
37 |
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* red grn blu specular-frac. facet-slope |
38 |
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* |
39 |
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* Arguments for MAT_TRANS are: |
40 |
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* red grn blu rspec rough trans tspec |
41 |
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*/ |
42 |
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43 |
greg |
2.2 |
/* specularity flags */ |
44 |
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#define SP_REFL 01 /* has reflected specular component */ |
45 |
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#define SP_TRAN 02 /* has transmitted specular */ |
46 |
greg |
2.11 |
#define SP_PURE 04 /* purely specular (zero roughness) */ |
47 |
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#define SP_FLAT 010 /* flat reflecting surface */ |
48 |
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#define SP_RBLT 020 /* reflection below sample threshold */ |
49 |
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#define SP_TBLT 040 /* transmission below threshold */ |
50 |
greg |
1.1 |
|
51 |
greg |
1.3 |
typedef struct { |
52 |
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OBJREC *mp; /* material pointer */ |
53 |
greg |
2.16 |
RAY *rp; /* ray pointer */ |
54 |
greg |
2.2 |
short specfl; /* specularity flags, defined above */ |
55 |
greg |
1.1 |
COLOR mcolor; /* color of this material */ |
56 |
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COLOR scolor; /* color of specular component */ |
57 |
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FVECT vrefl; /* vector in direction of reflected ray */ |
58 |
greg |
1.14 |
FVECT prdir; /* vector in transmitted direction */ |
59 |
greg |
2.2 |
double alpha2; /* roughness squared */ |
60 |
greg |
1.1 |
double rdiff, rspec; /* reflected specular, diffuse */ |
61 |
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double trans; /* transmissivity */ |
62 |
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double tdiff, tspec; /* transmitted specular, diffuse */ |
63 |
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FVECT pnorm; /* perturbed surface normal */ |
64 |
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double pdot; /* perturbed dot product */ |
65 |
greg |
1.3 |
} NORMDAT; /* normal material data */ |
66 |
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67 |
schorsch |
2.47 |
static srcdirf_t dirnorm; |
68 |
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static void gaussamp(RAY *r, NORMDAT *np); |
69 |
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70 |
greg |
1.3 |
|
71 |
greg |
2.38 |
static void |
72 |
schorsch |
2.47 |
dirnorm( /* compute source contribution */ |
73 |
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COLOR cval, /* returned coefficient */ |
74 |
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void *nnp, /* material data */ |
75 |
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FVECT ldir, /* light source direction */ |
76 |
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double omega /* light source size */ |
77 |
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) |
78 |
greg |
1.3 |
{ |
79 |
schorsch |
2.47 |
register NORMDAT *np = nnp; |
80 |
greg |
1.1 |
double ldot; |
81 |
greg |
2.38 |
double ldiff; |
82 |
greg |
2.16 |
double dtmp, d2; |
83 |
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FVECT vtmp; |
84 |
greg |
1.3 |
COLOR ctmp; |
85 |
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86 |
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setcolor(cval, 0.0, 0.0, 0.0); |
87 |
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88 |
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ldot = DOT(np->pnorm, ldir); |
89 |
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90 |
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if (ldot < 0.0 ? np->trans <= FTINY : np->trans >= 1.0-FTINY) |
91 |
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return; /* wrong side */ |
92 |
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93 |
greg |
2.38 |
/* Fresnel estimate */ |
94 |
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ldiff = np->rdiff; |
95 |
schorsch |
2.45 |
if (np->specfl & SP_PURE && (np->rspec > FTINY) & (ldiff > FTINY)) |
96 |
greg |
2.38 |
ldiff *= 1. - FRESNE(fabs(ldot)); |
97 |
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98 |
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if (ldot > FTINY && ldiff > FTINY) { |
99 |
greg |
1.3 |
/* |
100 |
greg |
1.4 |
* Compute and add diffuse reflected component to returned |
101 |
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* color. The diffuse reflected component will always be |
102 |
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* modified by the color of the material. |
103 |
greg |
1.3 |
*/ |
104 |
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copycolor(ctmp, np->mcolor); |
105 |
greg |
2.48 |
dtmp = ldot * omega * ldiff * (1.0/PI); |
106 |
greg |
1.3 |
scalecolor(ctmp, dtmp); |
107 |
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addcolor(cval, ctmp); |
108 |
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} |
109 |
greg |
2.2 |
if (ldot > FTINY && (np->specfl&(SP_REFL|SP_PURE)) == SP_REFL) { |
110 |
greg |
1.3 |
/* |
111 |
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* Compute specular reflection coefficient using |
112 |
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* gaussian distribution model. |
113 |
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*/ |
114 |
greg |
2.3 |
/* roughness */ |
115 |
greg |
2.16 |
dtmp = np->alpha2; |
116 |
greg |
2.3 |
/* + source if flat */ |
117 |
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if (np->specfl & SP_FLAT) |
118 |
greg |
2.48 |
dtmp += omega * (0.25/PI); |
119 |
greg |
2.23 |
/* half vector */ |
120 |
greg |
2.18 |
vtmp[0] = ldir[0] - np->rp->rdir[0]; |
121 |
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vtmp[1] = ldir[1] - np->rp->rdir[1]; |
122 |
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vtmp[2] = ldir[2] - np->rp->rdir[2]; |
123 |
greg |
2.16 |
d2 = DOT(vtmp, np->pnorm); |
124 |
greg |
2.23 |
d2 *= d2; |
125 |
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d2 = (DOT(vtmp,vtmp) - d2) / d2; |
126 |
greg |
1.3 |
/* gaussian */ |
127 |
greg |
2.48 |
dtmp = exp(-d2/dtmp)/(4.*PI * np->pdot * dtmp); |
128 |
greg |
1.3 |
/* worth using? */ |
129 |
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if (dtmp > FTINY) { |
130 |
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copycolor(ctmp, np->scolor); |
131 |
greg |
2.48 |
dtmp *= omega; |
132 |
greg |
1.3 |
scalecolor(ctmp, dtmp); |
133 |
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addcolor(cval, ctmp); |
134 |
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} |
135 |
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} |
136 |
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if (ldot < -FTINY && np->tdiff > FTINY) { |
137 |
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/* |
138 |
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* Compute diffuse transmission. |
139 |
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*/ |
140 |
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copycolor(ctmp, np->mcolor); |
141 |
greg |
2.48 |
dtmp = -ldot * omega * np->tdiff * (1.0/PI); |
142 |
greg |
1.3 |
scalecolor(ctmp, dtmp); |
143 |
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addcolor(cval, ctmp); |
144 |
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} |
145 |
greg |
2.2 |
if (ldot < -FTINY && (np->specfl&(SP_TRAN|SP_PURE)) == SP_TRAN) { |
146 |
greg |
1.3 |
/* |
147 |
greg |
1.4 |
* Compute specular transmission. Specular transmission |
148 |
greg |
1.13 |
* is always modified by material color. |
149 |
greg |
1.3 |
*/ |
150 |
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/* roughness + source */ |
151 |
greg |
2.48 |
dtmp = np->alpha2 + omega*(1.0/PI); |
152 |
greg |
1.3 |
/* gaussian */ |
153 |
greg |
2.48 |
dtmp = exp((2.*DOT(np->prdir,ldir)-2.)/dtmp) / |
154 |
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(PI*np->pdot*dtmp); |
155 |
greg |
1.3 |
/* worth using? */ |
156 |
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if (dtmp > FTINY) { |
157 |
greg |
1.13 |
copycolor(ctmp, np->mcolor); |
158 |
greg |
2.48 |
dtmp *= np->tspec * omega; |
159 |
greg |
1.13 |
scalecolor(ctmp, dtmp); |
160 |
greg |
1.3 |
addcolor(cval, ctmp); |
161 |
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} |
162 |
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} |
163 |
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} |
164 |
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165 |
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166 |
schorsch |
2.47 |
extern int |
167 |
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m_normal( /* color a ray that hit something normal */ |
168 |
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register OBJREC *m, |
169 |
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register RAY *r |
170 |
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) |
171 |
greg |
1.3 |
{ |
172 |
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NORMDAT nd; |
173 |
greg |
2.38 |
double fest; |
174 |
greg |
1.9 |
double transtest, transdist; |
175 |
greg |
2.29 |
double mirtest, mirdist; |
176 |
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int hastexture; |
177 |
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double d; |
178 |
greg |
1.1 |
COLOR ctmp; |
179 |
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register int i; |
180 |
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/* easy shadow test */ |
181 |
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if (r->crtype & SHADOW && m->otype != MAT_TRANS) |
182 |
greg |
2.27 |
return(1); |
183 |
greg |
2.2 |
|
184 |
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if (m->oargs.nfargs != (m->otype == MAT_TRANS ? 7 : 5)) |
185 |
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objerror(m, USER, "bad number of arguments"); |
186 |
greg |
2.29 |
/* check for back side */ |
187 |
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if (r->rod < 0.0) { |
188 |
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if (!backvis && m->otype != MAT_TRANS) { |
189 |
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raytrans(r); |
190 |
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return(1); |
191 |
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} |
192 |
greg |
2.40 |
raytexture(r, m->omod); |
193 |
greg |
2.29 |
flipsurface(r); /* reorient if backvis */ |
194 |
greg |
2.40 |
} else |
195 |
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raytexture(r, m->omod); |
196 |
greg |
1.3 |
nd.mp = m; |
197 |
greg |
2.16 |
nd.rp = r; |
198 |
greg |
1.1 |
/* get material color */ |
199 |
greg |
1.3 |
setcolor(nd.mcolor, m->oargs.farg[0], |
200 |
greg |
1.1 |
m->oargs.farg[1], |
201 |
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m->oargs.farg[2]); |
202 |
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/* get roughness */ |
203 |
greg |
2.2 |
nd.specfl = 0; |
204 |
greg |
1.3 |
nd.alpha2 = m->oargs.farg[4]; |
205 |
greg |
2.2 |
if ((nd.alpha2 *= nd.alpha2) <= FTINY) |
206 |
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nd.specfl |= SP_PURE; |
207 |
greg |
2.40 |
|
208 |
schorsch |
2.45 |
if ( (hastexture = (DOT(r->pert,r->pert) > FTINY*FTINY)) ) { |
209 |
greg |
2.29 |
nd.pdot = raynormal(nd.pnorm, r); /* perturb normal */ |
210 |
greg |
2.41 |
} else { |
211 |
greg |
2.29 |
VCOPY(nd.pnorm, r->ron); |
212 |
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nd.pdot = r->rod; |
213 |
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} |
214 |
greg |
2.42 |
if (r->ro != NULL && isflat(r->ro->otype)) |
215 |
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nd.specfl |= SP_FLAT; |
216 |
greg |
1.13 |
if (nd.pdot < .001) |
217 |
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nd.pdot = .001; /* non-zero for dirnorm() */ |
218 |
greg |
1.3 |
multcolor(nd.mcolor, r->pcol); /* modify material color */ |
219 |
greg |
2.29 |
mirtest = transtest = 0; |
220 |
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mirdist = transdist = r->rot; |
221 |
greg |
2.30 |
nd.rspec = m->oargs.farg[3]; |
222 |
greg |
2.38 |
/* compute Fresnel approx. */ |
223 |
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if (nd.specfl & SP_PURE && nd.rspec > FTINY) { |
224 |
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fest = FRESNE(r->rod); |
225 |
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nd.rspec += fest*(1. - nd.rspec); |
226 |
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} else |
227 |
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fest = 0.; |
228 |
greg |
1.3 |
/* compute transmission */ |
229 |
greg |
1.1 |
if (m->otype == MAT_TRANS) { |
230 |
greg |
1.3 |
nd.trans = m->oargs.farg[5]*(1.0 - nd.rspec); |
231 |
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nd.tspec = nd.trans * m->oargs.farg[6]; |
232 |
|
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nd.tdiff = nd.trans - nd.tspec; |
233 |
greg |
2.2 |
if (nd.tspec > FTINY) { |
234 |
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nd.specfl |= SP_TRAN; |
235 |
greg |
2.5 |
/* check threshold */ |
236 |
greg |
2.25 |
if (!(nd.specfl & SP_PURE) && |
237 |
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specthresh >= nd.tspec-FTINY) |
238 |
greg |
2.5 |
nd.specfl |= SP_TBLT; |
239 |
greg |
2.29 |
if (!hastexture || r->crtype & SHADOW) { |
240 |
greg |
2.2 |
VCOPY(nd.prdir, r->rdir); |
241 |
|
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transtest = 2; |
242 |
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} else { |
243 |
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for (i = 0; i < 3; i++) /* perturb */ |
244 |
greg |
2.19 |
nd.prdir[i] = r->rdir[i] - r->pert[i]; |
245 |
greg |
2.7 |
if (DOT(nd.prdir, r->ron) < -FTINY) |
246 |
|
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normalize(nd.prdir); /* OK */ |
247 |
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else |
248 |
|
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VCOPY(nd.prdir, r->rdir); |
249 |
greg |
2.2 |
} |
250 |
greg |
1.14 |
} |
251 |
greg |
1.1 |
} else |
252 |
greg |
1.3 |
nd.tdiff = nd.tspec = nd.trans = 0.0; |
253 |
greg |
1.1 |
/* transmitted ray */ |
254 |
gregl |
2.36 |
if ((nd.specfl&(SP_TRAN|SP_PURE|SP_TBLT)) == (SP_TRAN|SP_PURE)) { |
255 |
greg |
1.3 |
RAY lr; |
256 |
|
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if (rayorigin(&lr, r, TRANS, nd.tspec) == 0) { |
257 |
greg |
1.14 |
VCOPY(lr.rdir, nd.prdir); |
258 |
greg |
1.1 |
rayvalue(&lr); |
259 |
greg |
1.3 |
scalecolor(lr.rcol, nd.tspec); |
260 |
greg |
1.8 |
multcolor(lr.rcol, nd.mcolor); /* modified by color */ |
261 |
greg |
1.1 |
addcolor(r->rcol, lr.rcol); |
262 |
greg |
1.9 |
transtest *= bright(lr.rcol); |
263 |
|
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transdist = r->rot + lr.rt; |
264 |
greg |
1.1 |
} |
265 |
greg |
2.11 |
} else |
266 |
|
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transtest = 0; |
267 |
greg |
2.2 |
|
268 |
greg |
2.29 |
if (r->crtype & SHADOW) { /* the rest is shadow */ |
269 |
|
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r->rt = transdist; |
270 |
greg |
2.27 |
return(1); |
271 |
greg |
2.30 |
} |
272 |
|
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/* get specular reflection */ |
273 |
|
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if (nd.rspec > FTINY) { |
274 |
|
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nd.specfl |= SP_REFL; |
275 |
|
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/* compute specular color */ |
276 |
greg |
2.38 |
if (m->otype != MAT_METAL) { |
277 |
|
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setcolor(nd.scolor, nd.rspec, nd.rspec, nd.rspec); |
278 |
|
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} else if (fest > FTINY) { |
279 |
|
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d = nd.rspec*(1. - fest); |
280 |
|
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for (i = 0; i < 3; i++) |
281 |
|
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nd.scolor[i] = fest + nd.mcolor[i]*d; |
282 |
|
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} else { |
283 |
greg |
2.30 |
copycolor(nd.scolor, nd.mcolor); |
284 |
greg |
2.38 |
scalecolor(nd.scolor, nd.rspec); |
285 |
|
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} |
286 |
greg |
2.30 |
/* check threshold */ |
287 |
|
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if (!(nd.specfl & SP_PURE) && specthresh >= nd.rspec-FTINY) |
288 |
|
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nd.specfl |= SP_RBLT; |
289 |
|
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/* compute reflected ray */ |
290 |
|
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for (i = 0; i < 3; i++) |
291 |
|
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nd.vrefl[i] = r->rdir[i] + 2.*nd.pdot*nd.pnorm[i]; |
292 |
|
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/* penetration? */ |
293 |
|
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if (hastexture && DOT(nd.vrefl, r->ron) <= FTINY) |
294 |
|
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for (i = 0; i < 3; i++) /* safety measure */ |
295 |
|
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nd.vrefl[i] = r->rdir[i] + 2.*r->rod*r->ron[i]; |
296 |
gregl |
2.36 |
} |
297 |
|
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/* reflected ray */ |
298 |
|
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if ((nd.specfl&(SP_REFL|SP_PURE|SP_RBLT)) == (SP_REFL|SP_PURE)) { |
299 |
|
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RAY lr; |
300 |
|
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if (rayorigin(&lr, r, REFLECTED, nd.rspec) == 0) { |
301 |
|
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VCOPY(lr.rdir, nd.vrefl); |
302 |
|
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rayvalue(&lr); |
303 |
|
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multcolor(lr.rcol, nd.scolor); |
304 |
|
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addcolor(r->rcol, lr.rcol); |
305 |
|
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if (!hastexture && nd.specfl & SP_FLAT) { |
306 |
|
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mirtest = 2.*bright(lr.rcol); |
307 |
|
|
mirdist = r->rot + lr.rt; |
308 |
greg |
2.30 |
} |
309 |
|
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} |
310 |
greg |
2.29 |
} |
311 |
greg |
1.1 |
/* diffuse reflection */ |
312 |
greg |
1.3 |
nd.rdiff = 1.0 - nd.trans - nd.rspec; |
313 |
greg |
1.1 |
|
314 |
greg |
2.2 |
if (nd.specfl & SP_PURE && nd.rdiff <= FTINY && nd.tdiff <= FTINY) |
315 |
greg |
2.27 |
return(1); /* 100% pure specular */ |
316 |
greg |
2.3 |
|
317 |
gregl |
2.36 |
if (!(nd.specfl & SP_PURE)) |
318 |
|
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gaussamp(r, &nd); /* checks *BLT flags */ |
319 |
greg |
2.2 |
|
320 |
greg |
1.3 |
if (nd.rdiff > FTINY) { /* ambient from this side */ |
321 |
greg |
2.31 |
ambient(ctmp, r, hastexture?nd.pnorm:r->ron); |
322 |
greg |
2.5 |
if (nd.specfl & SP_RBLT) |
323 |
|
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scalecolor(ctmp, 1.0-nd.trans); |
324 |
|
|
else |
325 |
|
|
scalecolor(ctmp, nd.rdiff); |
326 |
greg |
1.3 |
multcolor(ctmp, nd.mcolor); /* modified by material color */ |
327 |
greg |
1.2 |
addcolor(r->rcol, ctmp); /* add to returned color */ |
328 |
|
|
} |
329 |
greg |
1.3 |
if (nd.tdiff > FTINY) { /* ambient from other side */ |
330 |
greg |
1.1 |
flipsurface(r); |
331 |
greg |
2.32 |
if (hastexture) { |
332 |
|
|
FVECT bnorm; |
333 |
|
|
bnorm[0] = -nd.pnorm[0]; |
334 |
|
|
bnorm[1] = -nd.pnorm[1]; |
335 |
|
|
bnorm[2] = -nd.pnorm[2]; |
336 |
|
|
ambient(ctmp, r, bnorm); |
337 |
|
|
} else |
338 |
|
|
ambient(ctmp, r, r->ron); |
339 |
greg |
2.5 |
if (nd.specfl & SP_TBLT) |
340 |
|
|
scalecolor(ctmp, nd.trans); |
341 |
|
|
else |
342 |
|
|
scalecolor(ctmp, nd.tdiff); |
343 |
greg |
1.13 |
multcolor(ctmp, nd.mcolor); /* modified by color */ |
344 |
greg |
1.1 |
addcolor(r->rcol, ctmp); |
345 |
|
|
flipsurface(r); |
346 |
|
|
} |
347 |
greg |
1.3 |
/* add direct component */ |
348 |
|
|
direct(r, dirnorm, &nd); |
349 |
greg |
1.9 |
/* check distance */ |
350 |
greg |
2.29 |
d = bright(r->rcol); |
351 |
|
|
if (transtest > d) |
352 |
greg |
1.9 |
r->rt = transdist; |
353 |
greg |
2.29 |
else if (mirtest > d) |
354 |
|
|
r->rt = mirdist; |
355 |
greg |
2.27 |
|
356 |
|
|
return(1); |
357 |
greg |
2.2 |
} |
358 |
|
|
|
359 |
|
|
|
360 |
greg |
2.38 |
static void |
361 |
schorsch |
2.47 |
gaussamp( /* sample gaussian specular */ |
362 |
|
|
RAY *r, |
363 |
|
|
register NORMDAT *np |
364 |
|
|
) |
365 |
greg |
2.2 |
{ |
366 |
|
|
RAY sr; |
367 |
|
|
FVECT u, v, h; |
368 |
|
|
double rv[2]; |
369 |
|
|
double d, sinp, cosp; |
370 |
greg |
2.34 |
int niter; |
371 |
greg |
2.2 |
register int i; |
372 |
greg |
2.13 |
/* quick test */ |
373 |
|
|
if ((np->specfl & (SP_REFL|SP_RBLT)) != SP_REFL && |
374 |
|
|
(np->specfl & (SP_TRAN|SP_TBLT)) != SP_TRAN) |
375 |
|
|
return; |
376 |
greg |
2.2 |
/* set up sample coordinates */ |
377 |
|
|
v[0] = v[1] = v[2] = 0.0; |
378 |
|
|
for (i = 0; i < 3; i++) |
379 |
|
|
if (np->pnorm[i] < 0.6 && np->pnorm[i] > -0.6) |
380 |
|
|
break; |
381 |
|
|
v[i] = 1.0; |
382 |
|
|
fcross(u, v, np->pnorm); |
383 |
|
|
normalize(u); |
384 |
|
|
fcross(v, np->pnorm, u); |
385 |
|
|
/* compute reflection */ |
386 |
greg |
2.5 |
if ((np->specfl & (SP_REFL|SP_RBLT)) == SP_REFL && |
387 |
greg |
2.2 |
rayorigin(&sr, r, SPECULAR, np->rspec) == 0) { |
388 |
|
|
dimlist[ndims++] = (int)np->mp; |
389 |
greg |
2.34 |
for (niter = 0; niter < MAXITER; niter++) { |
390 |
|
|
if (niter) |
391 |
|
|
d = frandom(); |
392 |
|
|
else |
393 |
|
|
d = urand(ilhash(dimlist,ndims)+samplendx); |
394 |
|
|
multisamp(rv, 2, d); |
395 |
|
|
d = 2.0*PI * rv[0]; |
396 |
gwlarson |
2.37 |
cosp = tcos(d); |
397 |
|
|
sinp = tsin(d); |
398 |
greg |
2.34 |
rv[1] = 1.0 - specjitter*rv[1]; |
399 |
|
|
if (rv[1] <= FTINY) |
400 |
|
|
d = 1.0; |
401 |
|
|
else |
402 |
|
|
d = sqrt( np->alpha2 * -log(rv[1]) ); |
403 |
|
|
for (i = 0; i < 3; i++) |
404 |
|
|
h[i] = np->pnorm[i] + d*(cosp*u[i] + sinp*v[i]); |
405 |
|
|
d = -2.0 * DOT(h, r->rdir) / (1.0 + d*d); |
406 |
|
|
for (i = 0; i < 3; i++) |
407 |
|
|
sr.rdir[i] = r->rdir[i] + d*h[i]; |
408 |
|
|
if (DOT(sr.rdir, r->ron) > FTINY) { |
409 |
|
|
rayvalue(&sr); |
410 |
|
|
multcolor(sr.rcol, np->scolor); |
411 |
|
|
addcolor(r->rcol, sr.rcol); |
412 |
|
|
break; |
413 |
|
|
} |
414 |
|
|
} |
415 |
greg |
2.2 |
ndims--; |
416 |
|
|
} |
417 |
|
|
/* compute transmission */ |
418 |
greg |
2.8 |
if ((np->specfl & (SP_TRAN|SP_TBLT)) == SP_TRAN && |
419 |
|
|
rayorigin(&sr, r, SPECULAR, np->tspec) == 0) { |
420 |
|
|
dimlist[ndims++] = (int)np->mp; |
421 |
greg |
2.34 |
for (niter = 0; niter < MAXITER; niter++) { |
422 |
|
|
if (niter) |
423 |
|
|
d = frandom(); |
424 |
|
|
else |
425 |
|
|
d = urand(ilhash(dimlist,ndims)+1823+samplendx); |
426 |
|
|
multisamp(rv, 2, d); |
427 |
|
|
d = 2.0*PI * rv[0]; |
428 |
gwlarson |
2.37 |
cosp = tcos(d); |
429 |
|
|
sinp = tsin(d); |
430 |
greg |
2.34 |
rv[1] = 1.0 - specjitter*rv[1]; |
431 |
|
|
if (rv[1] <= FTINY) |
432 |
|
|
d = 1.0; |
433 |
|
|
else |
434 |
gwlarson |
2.37 |
d = sqrt( np->alpha2 * -log(rv[1]) ); |
435 |
greg |
2.34 |
for (i = 0; i < 3; i++) |
436 |
|
|
sr.rdir[i] = np->prdir[i] + d*(cosp*u[i] + sinp*v[i]); |
437 |
|
|
if (DOT(sr.rdir, r->ron) < -FTINY) { |
438 |
|
|
normalize(sr.rdir); /* OK, normalize */ |
439 |
|
|
rayvalue(&sr); |
440 |
|
|
scalecolor(sr.rcol, np->tspec); |
441 |
|
|
multcolor(sr.rcol, np->mcolor); /* modified */ |
442 |
|
|
addcolor(r->rcol, sr.rcol); |
443 |
|
|
break; |
444 |
|
|
} |
445 |
|
|
} |
446 |
greg |
2.8 |
ndims--; |
447 |
|
|
} |
448 |
greg |
1.1 |
} |