1 |
greg |
2.1 |
#ifndef lint |
2 |
greg |
2.34 |
static const char RCSid[] = "$Id$"; |
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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*/ |
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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" |
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#include "otypes.h" |
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#include "func.h" |
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#include "random.h" |
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greg |
2.32 |
#ifndef MAXITER |
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#define MAXITER 10 /* maximum # specular ray attempts */ |
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#endif |
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22 |
greg |
2.1 |
/* |
23 |
greg |
2.22 |
* This routine implements the anisotropic Gaussian |
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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. |
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* |
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* Arguments for MAT_PLASTIC2 and MAT_METAL2 are: |
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* 4+ ux uy uz funcfile [transform...] |
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* 0 |
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* 6 red grn blu specular-frac. u-facet-slope v-facet-slope |
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* |
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* Real arguments for MAT_TRANS2 are: |
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* 8 red grn blu rspec u-rough v-rough trans tspec |
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*/ |
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37 |
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/* specularity flags */ |
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#define SP_REFL 01 /* has reflected specular component */ |
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#define SP_TRAN 02 /* has transmitted specular */ |
40 |
greg |
2.10 |
#define SP_FLAT 04 /* reflecting surface is flat */ |
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#define SP_RBLT 010 /* reflection below sample threshold */ |
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#define SP_TBLT 020 /* transmission below threshold */ |
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#define SP_BADU 040 /* bad u direction calculation */ |
44 |
greg |
2.1 |
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45 |
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typedef struct { |
46 |
greg |
2.2 |
OBJREC *mp; /* material pointer */ |
47 |
greg |
2.1 |
RAY *rp; /* ray pointer */ |
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short specfl; /* specularity flags, defined above */ |
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COLOR mcolor; /* color of this material */ |
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COLOR scolor; /* color of specular component */ |
51 |
greg |
2.6 |
FVECT vrefl; /* vector in reflected direction */ |
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greg |
2.1 |
FVECT prdir; /* vector in transmitted direction */ |
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FVECT u, v; /* u and v vectors orienting anisotropy */ |
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greg |
2.18 |
double u_alpha; /* u roughness */ |
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double v_alpha; /* v roughness */ |
56 |
greg |
2.1 |
double rdiff, rspec; /* reflected specular, diffuse */ |
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double trans; /* transmissivity */ |
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double tdiff, tspec; /* transmitted specular, diffuse */ |
59 |
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FVECT pnorm; /* perturbed surface normal */ |
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double pdot; /* perturbed dot product */ |
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} ANISODAT; /* anisotropic material data */ |
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63 |
greg |
2.34 |
static void getacoords(); |
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static void agaussamp(); |
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greg |
2.1 |
|
67 |
greg |
2.34 |
static void |
68 |
greg |
2.1 |
diraniso(cval, np, ldir, omega) /* compute source contribution */ |
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COLOR cval; /* returned coefficient */ |
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register ANISODAT *np; /* material data */ |
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FVECT ldir; /* light source direction */ |
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double omega; /* light source size */ |
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{ |
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double ldot; |
75 |
greg |
2.16 |
double dtmp, dtmp1, dtmp2; |
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greg |
2.1 |
FVECT h; |
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double au2, av2; |
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COLOR ctmp; |
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80 |
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setcolor(cval, 0.0, 0.0, 0.0); |
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82 |
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ldot = DOT(np->pnorm, ldir); |
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if (ldot < 0.0 ? np->trans <= FTINY : np->trans >= 1.0-FTINY) |
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return; /* wrong side */ |
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87 |
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if (ldot > FTINY && np->rdiff > FTINY) { |
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/* |
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* Compute and add diffuse reflected component to returned |
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* color. The diffuse reflected component will always be |
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* modified by the color of the material. |
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*/ |
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copycolor(ctmp, np->mcolor); |
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dtmp = ldot * omega * np->rdiff / PI; |
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scalecolor(ctmp, dtmp); |
96 |
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addcolor(cval, ctmp); |
97 |
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} |
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greg |
2.10 |
if (ldot > FTINY && (np->specfl&(SP_REFL|SP_BADU)) == SP_REFL) { |
99 |
greg |
2.1 |
/* |
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* Compute specular reflection coefficient using |
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* anisotropic gaussian distribution model. |
102 |
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*/ |
103 |
greg |
2.2 |
/* add source width if flat */ |
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if (np->specfl & SP_FLAT) |
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au2 = av2 = omega/(4.0*PI); |
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else |
107 |
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au2 = av2 = 0.0; |
108 |
greg |
2.18 |
au2 += np->u_alpha*np->u_alpha; |
109 |
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av2 += np->v_alpha*np->v_alpha; |
110 |
greg |
2.1 |
/* half vector */ |
111 |
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h[0] = ldir[0] - np->rp->rdir[0]; |
112 |
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h[1] = ldir[1] - np->rp->rdir[1]; |
113 |
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h[2] = ldir[2] - np->rp->rdir[2]; |
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/* ellipse */ |
115 |
greg |
2.16 |
dtmp1 = DOT(np->u, h); |
116 |
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dtmp1 *= dtmp1 / au2; |
117 |
greg |
2.1 |
dtmp2 = DOT(np->v, h); |
118 |
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dtmp2 *= dtmp2 / av2; |
119 |
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/* gaussian */ |
120 |
greg |
2.23 |
dtmp = DOT(np->pnorm, h); |
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dtmp = (dtmp1 + dtmp2) / (dtmp*dtmp); |
122 |
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dtmp = exp(-dtmp) * (0.25/PI) |
123 |
greg |
2.16 |
* sqrt(ldot/(np->pdot*au2*av2)); |
124 |
greg |
2.1 |
/* worth using? */ |
125 |
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if (dtmp > FTINY) { |
126 |
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copycolor(ctmp, np->scolor); |
127 |
greg |
2.16 |
dtmp *= omega; |
128 |
greg |
2.1 |
scalecolor(ctmp, dtmp); |
129 |
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addcolor(cval, ctmp); |
130 |
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} |
131 |
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} |
132 |
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if (ldot < -FTINY && np->tdiff > FTINY) { |
133 |
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/* |
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* Compute diffuse transmission. |
135 |
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*/ |
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copycolor(ctmp, np->mcolor); |
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dtmp = -ldot * omega * np->tdiff / PI; |
138 |
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scalecolor(ctmp, dtmp); |
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addcolor(cval, ctmp); |
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} |
141 |
greg |
2.10 |
if (ldot < -FTINY && (np->specfl&(SP_TRAN|SP_BADU)) == SP_TRAN) { |
142 |
greg |
2.1 |
/* |
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* Compute specular transmission. Specular transmission |
144 |
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* is always modified by material color. |
145 |
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*/ |
146 |
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/* roughness + source */ |
147 |
greg |
2.16 |
au2 = av2 = omega / PI; |
148 |
greg |
2.18 |
au2 += np->u_alpha*np->u_alpha; |
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av2 += np->v_alpha*np->v_alpha; |
150 |
greg |
2.16 |
/* "half vector" */ |
151 |
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h[0] = ldir[0] - np->prdir[0]; |
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h[1] = ldir[1] - np->prdir[1]; |
153 |
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h[2] = ldir[2] - np->prdir[2]; |
154 |
greg |
2.19 |
dtmp = DOT(h,h); |
155 |
greg |
2.16 |
if (dtmp > FTINY*FTINY) { |
156 |
greg |
2.19 |
dtmp1 = DOT(h,np->pnorm); |
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dtmp = 1.0 - dtmp1*dtmp1/dtmp; |
158 |
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if (dtmp > FTINY*FTINY) { |
159 |
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dtmp1 = DOT(h,np->u); |
160 |
greg |
2.23 |
dtmp1 *= dtmp1 / au2; |
161 |
greg |
2.19 |
dtmp2 = DOT(h,np->v); |
162 |
greg |
2.23 |
dtmp2 *= dtmp2 / av2; |
163 |
greg |
2.19 |
dtmp = (dtmp1 + dtmp2) / dtmp; |
164 |
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} |
165 |
greg |
2.16 |
} else |
166 |
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dtmp = 0.0; |
167 |
greg |
2.1 |
/* gaussian */ |
168 |
greg |
2.21 |
dtmp = exp(-dtmp) * (1.0/PI) |
169 |
greg |
2.16 |
* sqrt(-ldot/(np->pdot*au2*av2)); |
170 |
greg |
2.1 |
/* worth using? */ |
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if (dtmp > FTINY) { |
172 |
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copycolor(ctmp, np->mcolor); |
173 |
greg |
2.16 |
dtmp *= np->tspec * omega; |
174 |
greg |
2.1 |
scalecolor(ctmp, dtmp); |
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addcolor(cval, ctmp); |
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} |
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} |
178 |
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} |
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180 |
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181 |
greg |
2.34 |
int |
182 |
greg |
2.1 |
m_aniso(m, r) /* shade ray that hit something anisotropic */ |
183 |
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register OBJREC *m; |
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register RAY *r; |
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{ |
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ANISODAT nd; |
187 |
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COLOR ctmp; |
188 |
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register int i; |
189 |
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/* easy shadow test */ |
190 |
greg |
2.10 |
if (r->crtype & SHADOW) |
191 |
greg |
2.27 |
return(1); |
192 |
greg |
2.1 |
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193 |
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if (m->oargs.nfargs != (m->otype == MAT_TRANS2 ? 8 : 6)) |
194 |
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objerror(m, USER, "bad number of real arguments"); |
195 |
greg |
2.36 |
/* check for back side */ |
196 |
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if (r->rod < 0.0) { |
197 |
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if (!backvis && m->otype != MAT_TRANS2) { |
198 |
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raytrans(r); |
199 |
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return(1); |
200 |
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} |
201 |
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raytexture(r, m->omod); |
202 |
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flipsurface(r); /* reorient if backvis */ |
203 |
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} else |
204 |
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raytexture(r, m->omod); |
205 |
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/* get material color */ |
206 |
greg |
2.2 |
nd.mp = m; |
207 |
greg |
2.1 |
nd.rp = r; |
208 |
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setcolor(nd.mcolor, m->oargs.farg[0], |
209 |
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m->oargs.farg[1], |
210 |
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m->oargs.farg[2]); |
211 |
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/* get roughness */ |
212 |
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nd.specfl = 0; |
213 |
greg |
2.18 |
nd.u_alpha = m->oargs.farg[4]; |
214 |
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nd.v_alpha = m->oargs.farg[5]; |
215 |
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if (nd.u_alpha < FTINY || nd.v_alpha <= FTINY) |
216 |
greg |
2.10 |
objerror(m, USER, "roughness too small"); |
217 |
greg |
2.36 |
|
218 |
greg |
2.1 |
nd.pdot = raynormal(nd.pnorm, r); /* perturb normal */ |
219 |
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if (nd.pdot < .001) |
220 |
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nd.pdot = .001; /* non-zero for diraniso() */ |
221 |
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multcolor(nd.mcolor, r->pcol); /* modify material color */ |
222 |
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/* get specular component */ |
223 |
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if ((nd.rspec = m->oargs.farg[3]) > FTINY) { |
224 |
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nd.specfl |= SP_REFL; |
225 |
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/* compute specular color */ |
226 |
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if (m->otype == MAT_METAL2) |
227 |
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copycolor(nd.scolor, nd.mcolor); |
228 |
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else |
229 |
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setcolor(nd.scolor, 1.0, 1.0, 1.0); |
230 |
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scalecolor(nd.scolor, nd.rspec); |
231 |
greg |
2.4 |
/* check threshold */ |
232 |
greg |
2.25 |
if (specthresh >= nd.rspec-FTINY) |
233 |
greg |
2.4 |
nd.specfl |= SP_RBLT; |
234 |
greg |
2.6 |
/* compute refl. direction */ |
235 |
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for (i = 0; i < 3; i++) |
236 |
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nd.vrefl[i] = r->rdir[i] + 2.0*nd.pdot*nd.pnorm[i]; |
237 |
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if (DOT(nd.vrefl, r->ron) <= FTINY) /* penetration? */ |
238 |
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for (i = 0; i < 3; i++) /* safety measure */ |
239 |
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nd.vrefl[i] = r->rdir[i] + 2.*r->rod*r->ron[i]; |
240 |
greg |
2.1 |
} |
241 |
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/* compute transmission */ |
242 |
greg |
2.16 |
if (m->otype == MAT_TRANS2) { |
243 |
greg |
2.1 |
nd.trans = m->oargs.farg[6]*(1.0 - nd.rspec); |
244 |
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nd.tspec = nd.trans * m->oargs.farg[7]; |
245 |
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nd.tdiff = nd.trans - nd.tspec; |
246 |
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if (nd.tspec > FTINY) { |
247 |
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nd.specfl |= SP_TRAN; |
248 |
greg |
2.4 |
/* check threshold */ |
249 |
greg |
2.25 |
if (specthresh >= nd.tspec-FTINY) |
250 |
greg |
2.4 |
nd.specfl |= SP_TBLT; |
251 |
greg |
2.10 |
if (DOT(r->pert,r->pert) <= FTINY*FTINY) { |
252 |
greg |
2.1 |
VCOPY(nd.prdir, r->rdir); |
253 |
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} else { |
254 |
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for (i = 0; i < 3; i++) /* perturb */ |
255 |
greg |
2.17 |
nd.prdir[i] = r->rdir[i] - r->pert[i]; |
256 |
greg |
2.6 |
if (DOT(nd.prdir, r->ron) < -FTINY) |
257 |
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normalize(nd.prdir); /* OK */ |
258 |
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else |
259 |
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VCOPY(nd.prdir, r->rdir); |
260 |
greg |
2.1 |
} |
261 |
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} |
262 |
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} else |
263 |
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nd.tdiff = nd.tspec = nd.trans = 0.0; |
264 |
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265 |
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/* diffuse reflection */ |
266 |
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nd.rdiff = 1.0 - nd.trans - nd.rspec; |
267 |
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268 |
greg |
2.29 |
if (r->ro != NULL && isflat(r->ro->otype)) |
269 |
greg |
2.4 |
nd.specfl |= SP_FLAT; |
270 |
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271 |
greg |
2.1 |
getacoords(r, &nd); /* set up coordinates */ |
272 |
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273 |
greg |
2.10 |
if (nd.specfl & (SP_REFL|SP_TRAN) && !(nd.specfl & SP_BADU)) |
274 |
greg |
2.1 |
agaussamp(r, &nd); |
275 |
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276 |
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if (nd.rdiff > FTINY) { /* ambient from this side */ |
277 |
greg |
2.30 |
ambient(ctmp, r, nd.pnorm); |
278 |
greg |
2.4 |
if (nd.specfl & SP_RBLT) |
279 |
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scalecolor(ctmp, 1.0-nd.trans); |
280 |
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else |
281 |
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scalecolor(ctmp, nd.rdiff); |
282 |
greg |
2.1 |
multcolor(ctmp, nd.mcolor); /* modified by material color */ |
283 |
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addcolor(r->rcol, ctmp); /* add to returned color */ |
284 |
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} |
285 |
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if (nd.tdiff > FTINY) { /* ambient from other side */ |
286 |
greg |
2.31 |
FVECT bnorm; |
287 |
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288 |
greg |
2.1 |
flipsurface(r); |
289 |
greg |
2.31 |
bnorm[0] = -nd.pnorm[0]; |
290 |
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bnorm[1] = -nd.pnorm[1]; |
291 |
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bnorm[2] = -nd.pnorm[2]; |
292 |
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ambient(ctmp, r, bnorm); |
293 |
greg |
2.4 |
if (nd.specfl & SP_TBLT) |
294 |
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scalecolor(ctmp, nd.trans); |
295 |
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else |
296 |
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scalecolor(ctmp, nd.tdiff); |
297 |
greg |
2.1 |
multcolor(ctmp, nd.mcolor); /* modified by color */ |
298 |
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addcolor(r->rcol, ctmp); |
299 |
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flipsurface(r); |
300 |
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} |
301 |
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/* add direct component */ |
302 |
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direct(r, diraniso, &nd); |
303 |
greg |
2.27 |
|
304 |
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return(1); |
305 |
greg |
2.1 |
} |
306 |
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307 |
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308 |
greg |
2.34 |
static void |
309 |
greg |
2.1 |
getacoords(r, np) /* set up coordinate system */ |
310 |
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RAY *r; |
311 |
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register ANISODAT *np; |
312 |
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{ |
313 |
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register MFUNC *mf; |
314 |
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register int i; |
315 |
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316 |
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mf = getfunc(np->mp, 3, 0x7, 1); |
317 |
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setfunc(np->mp, r); |
318 |
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errno = 0; |
319 |
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for (i = 0; i < 3; i++) |
320 |
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np->u[i] = evalue(mf->ep[i]); |
321 |
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if (errno) { |
322 |
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objerror(np->mp, WARNING, "compute error"); |
323 |
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np->specfl |= SP_BADU; |
324 |
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return; |
325 |
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} |
326 |
greg |
2.16 |
if (mf->f != &unitxf) |
327 |
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multv3(np->u, np->u, mf->f->xfm); |
328 |
greg |
2.1 |
fcross(np->v, np->pnorm, np->u); |
329 |
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if (normalize(np->v) == 0.0) { |
330 |
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objerror(np->mp, WARNING, "illegal orientation vector"); |
331 |
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np->specfl |= SP_BADU; |
332 |
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return; |
333 |
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} |
334 |
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fcross(np->u, np->v, np->pnorm); |
335 |
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} |
336 |
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337 |
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338 |
greg |
2.34 |
static void |
339 |
greg |
2.1 |
agaussamp(r, np) /* sample anisotropic gaussian specular */ |
340 |
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RAY *r; |
341 |
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register ANISODAT *np; |
342 |
|
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{ |
343 |
|
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RAY sr; |
344 |
|
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FVECT h; |
345 |
|
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double rv[2]; |
346 |
|
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double d, sinp, cosp; |
347 |
greg |
2.32 |
int niter; |
348 |
greg |
2.1 |
register int i; |
349 |
|
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/* compute reflection */ |
350 |
greg |
2.4 |
if ((np->specfl & (SP_REFL|SP_RBLT)) == SP_REFL && |
351 |
greg |
2.1 |
rayorigin(&sr, r, SPECULAR, np->rspec) == 0) { |
352 |
|
|
dimlist[ndims++] = (int)np->mp; |
353 |
greg |
2.32 |
for (niter = 0; niter < MAXITER; niter++) { |
354 |
|
|
if (niter) |
355 |
|
|
d = frandom(); |
356 |
|
|
else |
357 |
|
|
d = urand(ilhash(dimlist,ndims)+samplendx); |
358 |
|
|
multisamp(rv, 2, d); |
359 |
|
|
d = 2.0*PI * rv[0]; |
360 |
gwlarson |
2.33 |
cosp = tcos(d) * np->u_alpha; |
361 |
|
|
sinp = tsin(d) * np->v_alpha; |
362 |
greg |
2.32 |
d = sqrt(cosp*cosp + sinp*sinp); |
363 |
|
|
cosp /= d; |
364 |
|
|
sinp /= d; |
365 |
|
|
rv[1] = 1.0 - specjitter*rv[1]; |
366 |
|
|
if (rv[1] <= FTINY) |
367 |
|
|
d = 1.0; |
368 |
|
|
else |
369 |
|
|
d = sqrt(-log(rv[1]) / |
370 |
|
|
(cosp*cosp/(np->u_alpha*np->u_alpha) + |
371 |
|
|
sinp*sinp/(np->v_alpha*np->v_alpha))); |
372 |
|
|
for (i = 0; i < 3; i++) |
373 |
|
|
h[i] = np->pnorm[i] + |
374 |
|
|
d*(cosp*np->u[i] + sinp*np->v[i]); |
375 |
|
|
d = -2.0 * DOT(h, r->rdir) / (1.0 + d*d); |
376 |
|
|
for (i = 0; i < 3; i++) |
377 |
|
|
sr.rdir[i] = r->rdir[i] + d*h[i]; |
378 |
|
|
if (DOT(sr.rdir, r->ron) > FTINY) { |
379 |
|
|
rayvalue(&sr); |
380 |
|
|
multcolor(sr.rcol, np->scolor); |
381 |
|
|
addcolor(r->rcol, sr.rcol); |
382 |
|
|
break; |
383 |
|
|
} |
384 |
|
|
} |
385 |
greg |
2.1 |
ndims--; |
386 |
|
|
} |
387 |
|
|
/* compute transmission */ |
388 |
greg |
2.7 |
if ((np->specfl & (SP_TRAN|SP_TBLT)) == SP_TRAN && |
389 |
|
|
rayorigin(&sr, r, SPECULAR, np->tspec) == 0) { |
390 |
|
|
dimlist[ndims++] = (int)np->mp; |
391 |
greg |
2.32 |
for (niter = 0; niter < MAXITER; niter++) { |
392 |
|
|
if (niter) |
393 |
|
|
d = frandom(); |
394 |
|
|
else |
395 |
|
|
d = urand(ilhash(dimlist,ndims)+1823+samplendx); |
396 |
|
|
multisamp(rv, 2, d); |
397 |
|
|
d = 2.0*PI * rv[0]; |
398 |
gwlarson |
2.33 |
cosp = tcos(d) * np->u_alpha; |
399 |
|
|
sinp = tsin(d) * np->v_alpha; |
400 |
greg |
2.32 |
d = sqrt(cosp*cosp + sinp*sinp); |
401 |
|
|
cosp /= d; |
402 |
|
|
sinp /= d; |
403 |
|
|
rv[1] = 1.0 - specjitter*rv[1]; |
404 |
|
|
if (rv[1] <= FTINY) |
405 |
|
|
d = 1.0; |
406 |
|
|
else |
407 |
|
|
d = sqrt(-log(rv[1]) / |
408 |
|
|
(cosp*cosp/(np->u_alpha*np->u_alpha) + |
409 |
gwlarson |
2.33 |
sinp*sinp/(np->v_alpha*np->v_alpha))); |
410 |
greg |
2.32 |
for (i = 0; i < 3; i++) |
411 |
|
|
sr.rdir[i] = np->prdir[i] + |
412 |
|
|
d*(cosp*np->u[i] + sinp*np->v[i]); |
413 |
|
|
if (DOT(sr.rdir, r->ron) < -FTINY) { |
414 |
|
|
normalize(sr.rdir); /* OK, normalize */ |
415 |
|
|
rayvalue(&sr); |
416 |
|
|
scalecolor(sr.rcol, np->tspec); |
417 |
|
|
multcolor(sr.rcol, np->mcolor); /* modify */ |
418 |
|
|
addcolor(r->rcol, sr.rcol); |
419 |
|
|
break; |
420 |
|
|
} |
421 |
|
|
} |
422 |
greg |
2.7 |
ndims--; |
423 |
|
|
} |
424 |
greg |
2.1 |
} |