1 |
greg |
2.1 |
#ifndef lint |
2 |
greg |
2.43 |
static const char RCSid[] = "$Id: aniso.c,v 2.42 2004/09/20 17:32:04 greg Exp $"; |
3 |
greg |
2.1 |
#endif |
4 |
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/* |
5 |
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* Shading functions for anisotropic materials. |
6 |
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*/ |
7 |
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8 |
greg |
2.35 |
#include "copyright.h" |
9 |
greg |
2.34 |
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10 |
greg |
2.1 |
#include "ray.h" |
11 |
greg |
2.40 |
#include "ambient.h" |
12 |
greg |
2.1 |
#include "otypes.h" |
13 |
schorsch |
2.41 |
#include "rtotypes.h" |
14 |
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#include "source.h" |
15 |
greg |
2.1 |
#include "func.h" |
16 |
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#include "random.h" |
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18 |
greg |
2.32 |
#ifndef MAXITER |
19 |
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#define MAXITER 10 /* maximum # specular ray attempts */ |
20 |
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#endif |
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22 |
greg |
2.1 |
/* |
23 |
greg |
2.22 |
* This routine implements the anisotropic Gaussian |
24 |
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* model described by Ward in Siggraph `92 article. |
25 |
greg |
2.1 |
* We orient the surface towards the incoming ray, so a single |
26 |
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* surface can be used to represent an infinitely thin object. |
27 |
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* |
28 |
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* Arguments for MAT_PLASTIC2 and MAT_METAL2 are: |
29 |
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* 4+ ux uy uz funcfile [transform...] |
30 |
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* 0 |
31 |
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* 6 red grn blu specular-frac. u-facet-slope v-facet-slope |
32 |
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* |
33 |
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* Real arguments for MAT_TRANS2 are: |
34 |
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* 8 red grn blu rspec u-rough v-rough trans tspec |
35 |
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*/ |
36 |
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37 |
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/* specularity flags */ |
38 |
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#define SP_REFL 01 /* has reflected specular component */ |
39 |
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#define SP_TRAN 02 /* has transmitted specular */ |
40 |
greg |
2.10 |
#define SP_FLAT 04 /* reflecting surface is flat */ |
41 |
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#define SP_RBLT 010 /* reflection below sample threshold */ |
42 |
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#define SP_TBLT 020 /* transmission below threshold */ |
43 |
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#define SP_BADU 040 /* bad u direction calculation */ |
44 |
greg |
2.1 |
|
45 |
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typedef struct { |
46 |
greg |
2.2 |
OBJREC *mp; /* material pointer */ |
47 |
greg |
2.1 |
RAY *rp; /* ray pointer */ |
48 |
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short specfl; /* specularity flags, defined above */ |
49 |
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COLOR mcolor; /* color of this material */ |
50 |
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COLOR scolor; /* color of specular component */ |
51 |
greg |
2.6 |
FVECT vrefl; /* vector in reflected direction */ |
52 |
greg |
2.1 |
FVECT prdir; /* vector in transmitted direction */ |
53 |
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FVECT u, v; /* u and v vectors orienting anisotropy */ |
54 |
greg |
2.18 |
double u_alpha; /* u roughness */ |
55 |
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double v_alpha; /* v roughness */ |
56 |
greg |
2.1 |
double rdiff, rspec; /* reflected specular, diffuse */ |
57 |
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double trans; /* transmissivity */ |
58 |
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double tdiff, tspec; /* transmitted specular, diffuse */ |
59 |
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FVECT pnorm; /* perturbed surface normal */ |
60 |
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double pdot; /* perturbed dot product */ |
61 |
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} ANISODAT; /* anisotropic material data */ |
62 |
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63 |
schorsch |
2.41 |
static srcdirf_t diraniso; |
64 |
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static void getacoords(RAY *r, ANISODAT *np); |
65 |
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static void agaussamp(RAY *r, ANISODAT *np); |
66 |
greg |
2.34 |
|
67 |
greg |
2.1 |
|
68 |
greg |
2.34 |
static void |
69 |
schorsch |
2.41 |
diraniso( /* compute source contribution */ |
70 |
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COLOR cval, /* returned coefficient */ |
71 |
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void *nnp, /* material data */ |
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FVECT ldir, /* light source direction */ |
73 |
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double omega /* light source size */ |
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) |
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greg |
2.1 |
{ |
76 |
schorsch |
2.41 |
register ANISODAT *np = nnp; |
77 |
greg |
2.1 |
double ldot; |
78 |
greg |
2.16 |
double dtmp, dtmp1, dtmp2; |
79 |
greg |
2.1 |
FVECT h; |
80 |
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double au2, av2; |
81 |
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COLOR ctmp; |
82 |
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83 |
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setcolor(cval, 0.0, 0.0, 0.0); |
84 |
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85 |
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ldot = DOT(np->pnorm, ldir); |
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87 |
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if (ldot < 0.0 ? np->trans <= FTINY : np->trans >= 1.0-FTINY) |
88 |
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return; /* wrong side */ |
89 |
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90 |
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if (ldot > FTINY && np->rdiff > FTINY) { |
91 |
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/* |
92 |
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* Compute and add diffuse reflected component to returned |
93 |
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* color. The diffuse reflected component will always be |
94 |
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* modified by the color of the material. |
95 |
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*/ |
96 |
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copycolor(ctmp, np->mcolor); |
97 |
greg |
2.42 |
dtmp = ldot * omega * np->rdiff * (1.0/PI); |
98 |
greg |
2.1 |
scalecolor(ctmp, dtmp); |
99 |
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addcolor(cval, ctmp); |
100 |
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} |
101 |
greg |
2.10 |
if (ldot > FTINY && (np->specfl&(SP_REFL|SP_BADU)) == SP_REFL) { |
102 |
greg |
2.1 |
/* |
103 |
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* Compute specular reflection coefficient using |
104 |
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* anisotropic gaussian distribution model. |
105 |
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*/ |
106 |
greg |
2.2 |
/* add source width if flat */ |
107 |
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if (np->specfl & SP_FLAT) |
108 |
greg |
2.42 |
au2 = av2 = omega * (0.25/PI); |
109 |
greg |
2.2 |
else |
110 |
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au2 = av2 = 0.0; |
111 |
greg |
2.18 |
au2 += np->u_alpha*np->u_alpha; |
112 |
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av2 += np->v_alpha*np->v_alpha; |
113 |
greg |
2.1 |
/* half vector */ |
114 |
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h[0] = ldir[0] - np->rp->rdir[0]; |
115 |
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h[1] = ldir[1] - np->rp->rdir[1]; |
116 |
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h[2] = ldir[2] - np->rp->rdir[2]; |
117 |
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/* ellipse */ |
118 |
greg |
2.16 |
dtmp1 = DOT(np->u, h); |
119 |
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dtmp1 *= dtmp1 / au2; |
120 |
greg |
2.1 |
dtmp2 = DOT(np->v, h); |
121 |
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dtmp2 *= dtmp2 / av2; |
122 |
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/* gaussian */ |
123 |
greg |
2.23 |
dtmp = DOT(np->pnorm, h); |
124 |
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dtmp = (dtmp1 + dtmp2) / (dtmp*dtmp); |
125 |
greg |
2.42 |
dtmp = exp(-dtmp) / (4.0*PI * np->pdot * sqrt(au2*av2)); |
126 |
greg |
2.1 |
/* worth using? */ |
127 |
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if (dtmp > FTINY) { |
128 |
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copycolor(ctmp, np->scolor); |
129 |
greg |
2.16 |
dtmp *= omega; |
130 |
greg |
2.1 |
scalecolor(ctmp, dtmp); |
131 |
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addcolor(cval, ctmp); |
132 |
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} |
133 |
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} |
134 |
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if (ldot < -FTINY && np->tdiff > FTINY) { |
135 |
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/* |
136 |
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* Compute diffuse transmission. |
137 |
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*/ |
138 |
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copycolor(ctmp, np->mcolor); |
139 |
greg |
2.42 |
dtmp = -ldot * omega * np->tdiff * (1.0/PI); |
140 |
greg |
2.1 |
scalecolor(ctmp, dtmp); |
141 |
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addcolor(cval, ctmp); |
142 |
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} |
143 |
greg |
2.10 |
if (ldot < -FTINY && (np->specfl&(SP_TRAN|SP_BADU)) == SP_TRAN) { |
144 |
greg |
2.1 |
/* |
145 |
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* Compute specular transmission. Specular transmission |
146 |
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* is always modified by material color. |
147 |
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*/ |
148 |
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/* roughness + source */ |
149 |
greg |
2.42 |
au2 = av2 = omega * (1.0/PI); |
150 |
greg |
2.18 |
au2 += np->u_alpha*np->u_alpha; |
151 |
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av2 += np->v_alpha*np->v_alpha; |
152 |
greg |
2.16 |
/* "half vector" */ |
153 |
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h[0] = ldir[0] - np->prdir[0]; |
154 |
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h[1] = ldir[1] - np->prdir[1]; |
155 |
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h[2] = ldir[2] - np->prdir[2]; |
156 |
greg |
2.19 |
dtmp = DOT(h,h); |
157 |
greg |
2.16 |
if (dtmp > FTINY*FTINY) { |
158 |
greg |
2.19 |
dtmp1 = DOT(h,np->pnorm); |
159 |
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dtmp = 1.0 - dtmp1*dtmp1/dtmp; |
160 |
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if (dtmp > FTINY*FTINY) { |
161 |
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dtmp1 = DOT(h,np->u); |
162 |
greg |
2.23 |
dtmp1 *= dtmp1 / au2; |
163 |
greg |
2.19 |
dtmp2 = DOT(h,np->v); |
164 |
greg |
2.23 |
dtmp2 *= dtmp2 / av2; |
165 |
greg |
2.19 |
dtmp = (dtmp1 + dtmp2) / dtmp; |
166 |
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} |
167 |
greg |
2.16 |
} else |
168 |
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dtmp = 0.0; |
169 |
greg |
2.1 |
/* gaussian */ |
170 |
greg |
2.42 |
dtmp = exp(-dtmp) / (PI * np->pdot * sqrt(au2*av2)); |
171 |
greg |
2.1 |
/* worth using? */ |
172 |
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if (dtmp > FTINY) { |
173 |
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copycolor(ctmp, np->mcolor); |
174 |
greg |
2.16 |
dtmp *= np->tspec * omega; |
175 |
greg |
2.1 |
scalecolor(ctmp, dtmp); |
176 |
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addcolor(cval, ctmp); |
177 |
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} |
178 |
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} |
179 |
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} |
180 |
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181 |
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182 |
schorsch |
2.41 |
extern int |
183 |
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m_aniso( /* shade ray that hit something anisotropic */ |
184 |
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register OBJREC *m, |
185 |
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register RAY *r |
186 |
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) |
187 |
greg |
2.1 |
{ |
188 |
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ANISODAT nd; |
189 |
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COLOR ctmp; |
190 |
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register int i; |
191 |
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/* easy shadow test */ |
192 |
greg |
2.10 |
if (r->crtype & SHADOW) |
193 |
greg |
2.27 |
return(1); |
194 |
greg |
2.1 |
|
195 |
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if (m->oargs.nfargs != (m->otype == MAT_TRANS2 ? 8 : 6)) |
196 |
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objerror(m, USER, "bad number of real arguments"); |
197 |
greg |
2.36 |
/* check for back side */ |
198 |
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if (r->rod < 0.0) { |
199 |
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if (!backvis && m->otype != MAT_TRANS2) { |
200 |
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raytrans(r); |
201 |
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return(1); |
202 |
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} |
203 |
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raytexture(r, m->omod); |
204 |
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flipsurface(r); /* reorient if backvis */ |
205 |
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} else |
206 |
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raytexture(r, m->omod); |
207 |
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/* get material color */ |
208 |
greg |
2.2 |
nd.mp = m; |
209 |
greg |
2.1 |
nd.rp = r; |
210 |
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setcolor(nd.mcolor, m->oargs.farg[0], |
211 |
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m->oargs.farg[1], |
212 |
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m->oargs.farg[2]); |
213 |
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/* get roughness */ |
214 |
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nd.specfl = 0; |
215 |
greg |
2.18 |
nd.u_alpha = m->oargs.farg[4]; |
216 |
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nd.v_alpha = m->oargs.farg[5]; |
217 |
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if (nd.u_alpha < FTINY || nd.v_alpha <= FTINY) |
218 |
greg |
2.10 |
objerror(m, USER, "roughness too small"); |
219 |
greg |
2.36 |
|
220 |
greg |
2.1 |
nd.pdot = raynormal(nd.pnorm, r); /* perturb normal */ |
221 |
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if (nd.pdot < .001) |
222 |
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nd.pdot = .001; /* non-zero for diraniso() */ |
223 |
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multcolor(nd.mcolor, r->pcol); /* modify material color */ |
224 |
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/* get specular component */ |
225 |
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if ((nd.rspec = m->oargs.farg[3]) > FTINY) { |
226 |
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nd.specfl |= SP_REFL; |
227 |
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/* compute specular color */ |
228 |
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if (m->otype == MAT_METAL2) |
229 |
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copycolor(nd.scolor, nd.mcolor); |
230 |
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else |
231 |
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setcolor(nd.scolor, 1.0, 1.0, 1.0); |
232 |
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scalecolor(nd.scolor, nd.rspec); |
233 |
greg |
2.4 |
/* check threshold */ |
234 |
greg |
2.25 |
if (specthresh >= nd.rspec-FTINY) |
235 |
greg |
2.4 |
nd.specfl |= SP_RBLT; |
236 |
greg |
2.6 |
/* compute refl. direction */ |
237 |
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for (i = 0; i < 3; i++) |
238 |
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nd.vrefl[i] = r->rdir[i] + 2.0*nd.pdot*nd.pnorm[i]; |
239 |
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if (DOT(nd.vrefl, r->ron) <= FTINY) /* penetration? */ |
240 |
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for (i = 0; i < 3; i++) /* safety measure */ |
241 |
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nd.vrefl[i] = r->rdir[i] + 2.*r->rod*r->ron[i]; |
242 |
greg |
2.1 |
} |
243 |
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/* compute transmission */ |
244 |
greg |
2.16 |
if (m->otype == MAT_TRANS2) { |
245 |
greg |
2.1 |
nd.trans = m->oargs.farg[6]*(1.0 - nd.rspec); |
246 |
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nd.tspec = nd.trans * m->oargs.farg[7]; |
247 |
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nd.tdiff = nd.trans - nd.tspec; |
248 |
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if (nd.tspec > FTINY) { |
249 |
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nd.specfl |= SP_TRAN; |
250 |
greg |
2.4 |
/* check threshold */ |
251 |
greg |
2.25 |
if (specthresh >= nd.tspec-FTINY) |
252 |
greg |
2.4 |
nd.specfl |= SP_TBLT; |
253 |
greg |
2.10 |
if (DOT(r->pert,r->pert) <= FTINY*FTINY) { |
254 |
greg |
2.1 |
VCOPY(nd.prdir, r->rdir); |
255 |
|
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} else { |
256 |
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for (i = 0; i < 3; i++) /* perturb */ |
257 |
greg |
2.17 |
nd.prdir[i] = r->rdir[i] - r->pert[i]; |
258 |
greg |
2.6 |
if (DOT(nd.prdir, r->ron) < -FTINY) |
259 |
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normalize(nd.prdir); /* OK */ |
260 |
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else |
261 |
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VCOPY(nd.prdir, r->rdir); |
262 |
greg |
2.1 |
} |
263 |
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} |
264 |
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} else |
265 |
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nd.tdiff = nd.tspec = nd.trans = 0.0; |
266 |
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267 |
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/* diffuse reflection */ |
268 |
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nd.rdiff = 1.0 - nd.trans - nd.rspec; |
269 |
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|
270 |
greg |
2.39 |
if (r->ro != NULL && isflat(r->ro->otype)) |
271 |
greg |
2.4 |
nd.specfl |= SP_FLAT; |
272 |
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|
273 |
greg |
2.1 |
getacoords(r, &nd); /* set up coordinates */ |
274 |
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|
275 |
greg |
2.10 |
if (nd.specfl & (SP_REFL|SP_TRAN) && !(nd.specfl & SP_BADU)) |
276 |
greg |
2.1 |
agaussamp(r, &nd); |
277 |
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278 |
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if (nd.rdiff > FTINY) { /* ambient from this side */ |
279 |
greg |
2.43 |
copycolor(ctmp, nd.mcolor); /* modified by material color */ |
280 |
greg |
2.4 |
if (nd.specfl & SP_RBLT) |
281 |
|
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scalecolor(ctmp, 1.0-nd.trans); |
282 |
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else |
283 |
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scalecolor(ctmp, nd.rdiff); |
284 |
greg |
2.43 |
multambient(ctmp, r, nd.pnorm); |
285 |
greg |
2.1 |
addcolor(r->rcol, ctmp); /* add to returned color */ |
286 |
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} |
287 |
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if (nd.tdiff > FTINY) { /* ambient from other side */ |
288 |
greg |
2.31 |
FVECT bnorm; |
289 |
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|
290 |
greg |
2.1 |
flipsurface(r); |
291 |
greg |
2.31 |
bnorm[0] = -nd.pnorm[0]; |
292 |
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bnorm[1] = -nd.pnorm[1]; |
293 |
|
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bnorm[2] = -nd.pnorm[2]; |
294 |
greg |
2.43 |
copycolor(ctmp, nd.mcolor); /* modified by color */ |
295 |
greg |
2.4 |
if (nd.specfl & SP_TBLT) |
296 |
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scalecolor(ctmp, nd.trans); |
297 |
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else |
298 |
|
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scalecolor(ctmp, nd.tdiff); |
299 |
greg |
2.43 |
multambient(ctmp, r, bnorm); |
300 |
greg |
2.1 |
addcolor(r->rcol, ctmp); |
301 |
|
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flipsurface(r); |
302 |
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} |
303 |
|
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/* add direct component */ |
304 |
|
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direct(r, diraniso, &nd); |
305 |
greg |
2.27 |
|
306 |
|
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return(1); |
307 |
greg |
2.1 |
} |
308 |
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|
309 |
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|
310 |
greg |
2.34 |
static void |
311 |
schorsch |
2.41 |
getacoords( /* set up coordinate system */ |
312 |
|
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RAY *r, |
313 |
|
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register ANISODAT *np |
314 |
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) |
315 |
greg |
2.1 |
{ |
316 |
|
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register MFUNC *mf; |
317 |
|
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register int i; |
318 |
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|
319 |
|
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mf = getfunc(np->mp, 3, 0x7, 1); |
320 |
|
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setfunc(np->mp, r); |
321 |
|
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errno = 0; |
322 |
|
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for (i = 0; i < 3; i++) |
323 |
|
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np->u[i] = evalue(mf->ep[i]); |
324 |
greg |
2.37 |
if (errno == EDOM || errno == ERANGE) { |
325 |
greg |
2.1 |
objerror(np->mp, WARNING, "compute error"); |
326 |
|
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np->specfl |= SP_BADU; |
327 |
|
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return; |
328 |
|
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} |
329 |
greg |
2.16 |
if (mf->f != &unitxf) |
330 |
|
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multv3(np->u, np->u, mf->f->xfm); |
331 |
greg |
2.1 |
fcross(np->v, np->pnorm, np->u); |
332 |
|
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if (normalize(np->v) == 0.0) { |
333 |
|
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objerror(np->mp, WARNING, "illegal orientation vector"); |
334 |
|
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np->specfl |= SP_BADU; |
335 |
|
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return; |
336 |
|
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} |
337 |
|
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fcross(np->u, np->v, np->pnorm); |
338 |
|
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} |
339 |
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|
340 |
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|
341 |
greg |
2.34 |
static void |
342 |
schorsch |
2.41 |
agaussamp( /* sample anisotropic gaussian specular */ |
343 |
|
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RAY *r, |
344 |
|
|
register ANISODAT *np |
345 |
|
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) |
346 |
greg |
2.1 |
{ |
347 |
|
|
RAY sr; |
348 |
|
|
FVECT h; |
349 |
|
|
double rv[2]; |
350 |
|
|
double d, sinp, cosp; |
351 |
greg |
2.32 |
int niter; |
352 |
greg |
2.1 |
register int i; |
353 |
|
|
/* compute reflection */ |
354 |
greg |
2.4 |
if ((np->specfl & (SP_REFL|SP_RBLT)) == SP_REFL && |
355 |
greg |
2.43 |
rayorigin(&sr, SPECULAR, r, np->scolor) == 0) { |
356 |
greg |
2.1 |
dimlist[ndims++] = (int)np->mp; |
357 |
greg |
2.32 |
for (niter = 0; niter < MAXITER; niter++) { |
358 |
|
|
if (niter) |
359 |
|
|
d = frandom(); |
360 |
|
|
else |
361 |
|
|
d = urand(ilhash(dimlist,ndims)+samplendx); |
362 |
|
|
multisamp(rv, 2, d); |
363 |
|
|
d = 2.0*PI * rv[0]; |
364 |
gwlarson |
2.33 |
cosp = tcos(d) * np->u_alpha; |
365 |
|
|
sinp = tsin(d) * np->v_alpha; |
366 |
greg |
2.32 |
d = sqrt(cosp*cosp + sinp*sinp); |
367 |
|
|
cosp /= d; |
368 |
|
|
sinp /= d; |
369 |
|
|
rv[1] = 1.0 - specjitter*rv[1]; |
370 |
|
|
if (rv[1] <= FTINY) |
371 |
|
|
d = 1.0; |
372 |
|
|
else |
373 |
|
|
d = sqrt(-log(rv[1]) / |
374 |
|
|
(cosp*cosp/(np->u_alpha*np->u_alpha) + |
375 |
|
|
sinp*sinp/(np->v_alpha*np->v_alpha))); |
376 |
|
|
for (i = 0; i < 3; i++) |
377 |
|
|
h[i] = np->pnorm[i] + |
378 |
|
|
d*(cosp*np->u[i] + sinp*np->v[i]); |
379 |
|
|
d = -2.0 * DOT(h, r->rdir) / (1.0 + d*d); |
380 |
|
|
for (i = 0; i < 3; i++) |
381 |
|
|
sr.rdir[i] = r->rdir[i] + d*h[i]; |
382 |
|
|
if (DOT(sr.rdir, r->ron) > FTINY) { |
383 |
|
|
rayvalue(&sr); |
384 |
greg |
2.43 |
multcolor(sr.rcol, sr.rcoef); |
385 |
greg |
2.32 |
addcolor(r->rcol, sr.rcol); |
386 |
|
|
break; |
387 |
|
|
} |
388 |
|
|
} |
389 |
greg |
2.1 |
ndims--; |
390 |
|
|
} |
391 |
|
|
/* compute transmission */ |
392 |
greg |
2.43 |
copycolor(sr.rcoef, np->mcolor); /* modify by material color */ |
393 |
|
|
scalecolor(sr.rcoef, np->tspec); |
394 |
greg |
2.7 |
if ((np->specfl & (SP_TRAN|SP_TBLT)) == SP_TRAN && |
395 |
greg |
2.43 |
rayorigin(&sr, SPECULAR, r, sr.rcoef) == 0) { |
396 |
greg |
2.7 |
dimlist[ndims++] = (int)np->mp; |
397 |
greg |
2.32 |
for (niter = 0; niter < MAXITER; niter++) { |
398 |
|
|
if (niter) |
399 |
|
|
d = frandom(); |
400 |
|
|
else |
401 |
|
|
d = urand(ilhash(dimlist,ndims)+1823+samplendx); |
402 |
|
|
multisamp(rv, 2, d); |
403 |
|
|
d = 2.0*PI * rv[0]; |
404 |
gwlarson |
2.33 |
cosp = tcos(d) * np->u_alpha; |
405 |
|
|
sinp = tsin(d) * np->v_alpha; |
406 |
greg |
2.32 |
d = sqrt(cosp*cosp + sinp*sinp); |
407 |
|
|
cosp /= d; |
408 |
|
|
sinp /= d; |
409 |
|
|
rv[1] = 1.0 - specjitter*rv[1]; |
410 |
|
|
if (rv[1] <= FTINY) |
411 |
|
|
d = 1.0; |
412 |
|
|
else |
413 |
|
|
d = sqrt(-log(rv[1]) / |
414 |
|
|
(cosp*cosp/(np->u_alpha*np->u_alpha) + |
415 |
gwlarson |
2.33 |
sinp*sinp/(np->v_alpha*np->v_alpha))); |
416 |
greg |
2.32 |
for (i = 0; i < 3; i++) |
417 |
|
|
sr.rdir[i] = np->prdir[i] + |
418 |
|
|
d*(cosp*np->u[i] + sinp*np->v[i]); |
419 |
|
|
if (DOT(sr.rdir, r->ron) < -FTINY) { |
420 |
|
|
normalize(sr.rdir); /* OK, normalize */ |
421 |
|
|
rayvalue(&sr); |
422 |
greg |
2.43 |
multcolor(sr.rcol, sr.rcoef); |
423 |
greg |
2.32 |
addcolor(r->rcol, sr.rcol); |
424 |
|
|
break; |
425 |
|
|
} |
426 |
|
|
} |
427 |
greg |
2.7 |
ndims--; |
428 |
|
|
} |
429 |
greg |
2.1 |
} |