1 |
greg |
1.1 |
#ifndef lint |
2 |
greg |
2.15 |
static const char RCSid[] = "$Id$"; |
3 |
greg |
1.1 |
#endif |
4 |
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/* |
5 |
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* Shading for materials with arbitrary BRDF's |
6 |
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*/ |
7 |
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8 |
greg |
2.16 |
#include "copyright.h" |
9 |
greg |
2.15 |
|
10 |
greg |
1.1 |
#include "ray.h" |
11 |
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12 |
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#include "data.h" |
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14 |
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#include "otypes.h" |
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16 |
greg |
2.2 |
#include "func.h" |
17 |
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18 |
greg |
1.1 |
/* |
19 |
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* Arguments to this material include the color and specularity. |
20 |
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* String arguments include the reflection function and files. |
21 |
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* The BRDF is currently used just for the specular component to light |
22 |
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* sources. Reflectance values or data coordinates are functions |
23 |
greg |
2.7 |
* of the direction to the light source. (Data modification functions |
24 |
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* are passed the source direction as args 2-4.) |
25 |
greg |
1.1 |
* 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_PFUNC and MAT_MFUNC are: |
29 |
greg |
1.4 |
* 2+ func funcfile transform |
30 |
greg |
1.1 |
* 0 |
31 |
greg |
1.4 |
* 4+ red grn blu specularity A5 .. |
32 |
greg |
1.1 |
* |
33 |
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* Arguments for MAT_PDATA and MAT_MDATA are: |
34 |
greg |
1.4 |
* 4+ func datafile funcfile v0 .. transform |
35 |
greg |
1.1 |
* 0 |
36 |
greg |
1.4 |
* 4+ red grn blu specularity A5 .. |
37 |
greg |
1.5 |
* |
38 |
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* Arguments for MAT_TFUNC are: |
39 |
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* 2+ func funcfile transform |
40 |
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* 0 |
41 |
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* 4+ red grn blu rspec trans tspec A7 .. |
42 |
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* |
43 |
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* Arguments for MAT_TDATA are: |
44 |
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* 4+ func datafile funcfile v0 .. transform |
45 |
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* 0 |
46 |
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* 4+ red grn blu rspec trans tspec A7 .. |
47 |
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* |
48 |
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* Arguments for the more general MAT_BRTDF are: |
49 |
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* 10+ rrefl grefl brefl |
50 |
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* rtrns gtrns btrns |
51 |
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* rbrtd gbrtd bbrtd |
52 |
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* funcfile transform |
53 |
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* 0 |
54 |
greg |
2.6 |
* 9+ rdf gdf bdf |
55 |
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* rdb gdb bdb |
56 |
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* rdt gdt bdt A10 .. |
57 |
greg |
1.5 |
* |
58 |
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* In addition to the normal variables available to functions, |
59 |
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* we define the following: |
60 |
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* NxP, NyP, NzP - perturbed surface normal |
61 |
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* RdotP - perturbed ray dot product |
62 |
greg |
2.6 |
* CrP, CgP, CbP - perturbed material color (or pattern) |
63 |
greg |
1.1 |
*/ |
64 |
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65 |
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typedef struct { |
66 |
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OBJREC *mp; /* material pointer */ |
67 |
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RAY *pr; /* intersected ray */ |
68 |
greg |
1.5 |
DATARRAY *dp; /* data array for PDATA, MDATA or TDATA */ |
69 |
greg |
2.6 |
COLOR mcolor; /* material (or pattern) color */ |
70 |
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COLOR rdiff; /* diffuse reflection */ |
71 |
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COLOR tdiff; /* diffuse transmission */ |
72 |
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double rspec; /* specular reflectance (1 for BRDTF) */ |
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double trans; /* transmissivity (.5 for BRDTF) */ |
74 |
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double tspec; /* specular transmittance (1 for BRDTF) */ |
75 |
greg |
1.1 |
FVECT pnorm; /* perturbed surface normal */ |
76 |
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double pdot; /* perturbed dot product */ |
77 |
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} BRDFDAT; /* BRDF material data */ |
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80 |
greg |
2.15 |
static void |
81 |
greg |
1.1 |
dirbrdf(cval, np, ldir, omega) /* compute source contribution */ |
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COLOR cval; /* returned coefficient */ |
83 |
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register BRDFDAT *np; /* material data */ |
84 |
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FVECT ldir; /* light source direction */ |
85 |
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double omega; /* light source size */ |
86 |
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{ |
87 |
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double ldot; |
88 |
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double dtmp; |
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COLOR ctmp; |
90 |
greg |
1.4 |
FVECT ldx; |
91 |
greg |
2.12 |
static double vldx[5], pt[MAXDIM]; |
92 |
greg |
1.5 |
register char **sa; |
93 |
greg |
1.1 |
register int i; |
94 |
greg |
2.12 |
#define lddx (vldx+1) |
95 |
greg |
1.1 |
|
96 |
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setcolor(cval, 0.0, 0.0, 0.0); |
97 |
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98 |
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ldot = DOT(np->pnorm, ldir); |
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100 |
greg |
1.5 |
if (ldot <= FTINY && ldot >= -FTINY) |
101 |
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return; /* too close to grazing */ |
102 |
greg |
2.6 |
|
103 |
greg |
1.5 |
if (ldot < 0.0 ? np->trans <= FTINY : np->trans >= 1.0-FTINY) |
104 |
greg |
1.1 |
return; /* wrong side */ |
105 |
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106 |
greg |
2.6 |
if (ldot > 0.0) { |
107 |
greg |
1.1 |
/* |
108 |
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* Compute and add diffuse reflected component to returned |
109 |
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* color. The diffuse reflected component will always be |
110 |
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* modified by the color of the material. |
111 |
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*/ |
112 |
greg |
2.6 |
copycolor(ctmp, np->rdiff); |
113 |
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dtmp = ldot * omega / PI; |
114 |
greg |
1.1 |
scalecolor(ctmp, dtmp); |
115 |
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addcolor(cval, ctmp); |
116 |
greg |
2.6 |
} else { |
117 |
greg |
1.1 |
/* |
118 |
greg |
1.5 |
* Diffuse transmitted component. |
119 |
greg |
1.1 |
*/ |
120 |
greg |
2.6 |
copycolor(ctmp, np->tdiff); |
121 |
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dtmp = -ldot * omega / PI; |
122 |
greg |
1.5 |
scalecolor(ctmp, dtmp); |
123 |
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addcolor(cval, ctmp); |
124 |
greg |
1.1 |
} |
125 |
greg |
1.5 |
if (ldot > 0.0 ? np->rspec <= FTINY : np->tspec <= FTINY) |
126 |
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return; /* no specular component */ |
127 |
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/* set up function */ |
128 |
greg |
1.10 |
setbrdfunc(np); |
129 |
greg |
1.5 |
sa = np->mp->oargs.sarg; |
130 |
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errno = 0; |
131 |
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/* transform light vector */ |
132 |
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multv3(ldx, ldir, funcxf.xfm); |
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for (i = 0; i < 3; i++) |
134 |
greg |
2.3 |
lddx[i] = ldx[i]/funcxf.sca; |
135 |
greg |
2.12 |
lddx[3] = omega; |
136 |
greg |
1.5 |
/* compute BRTDF */ |
137 |
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if (np->mp->otype == MAT_BRTDF) { |
138 |
greg |
2.6 |
if (sa[6][0] == '0') /* special case */ |
139 |
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colval(ctmp,RED) = 0.0; |
140 |
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else |
141 |
greg |
2.12 |
colval(ctmp,RED) = funvalue(sa[6], 4, lddx); |
142 |
greg |
1.7 |
if (!strcmp(sa[7],sa[6])) |
143 |
greg |
1.5 |
colval(ctmp,GRN) = colval(ctmp,RED); |
144 |
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else |
145 |
greg |
2.12 |
colval(ctmp,GRN) = funvalue(sa[7], 4, lddx); |
146 |
greg |
1.7 |
if (!strcmp(sa[8],sa[6])) |
147 |
greg |
1.5 |
colval(ctmp,BLU) = colval(ctmp,RED); |
148 |
greg |
1.7 |
else if (!strcmp(sa[8],sa[7])) |
149 |
greg |
1.5 |
colval(ctmp,BLU) = colval(ctmp,GRN); |
150 |
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else |
151 |
greg |
2.12 |
colval(ctmp,BLU) = funvalue(sa[8], 4, lddx); |
152 |
greg |
1.5 |
dtmp = bright(ctmp); |
153 |
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} else if (np->dp == NULL) { |
154 |
greg |
2.12 |
dtmp = funvalue(sa[0], 4, lddx); |
155 |
greg |
1.5 |
setcolor(ctmp, dtmp, dtmp, dtmp); |
156 |
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} else { |
157 |
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for (i = 0; i < np->dp->nd; i++) |
158 |
greg |
2.12 |
pt[i] = funvalue(sa[3+i], 4, lddx); |
159 |
greg |
2.7 |
vldx[0] = datavalue(np->dp, pt); |
160 |
greg |
2.12 |
dtmp = funvalue(sa[0], 5, vldx); |
161 |
greg |
1.5 |
setcolor(ctmp, dtmp, dtmp, dtmp); |
162 |
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} |
163 |
greg |
2.2 |
if (errno) { |
164 |
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objerror(np->mp, WARNING, "compute error"); |
165 |
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return; |
166 |
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} |
167 |
greg |
1.5 |
if (dtmp <= FTINY) |
168 |
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return; |
169 |
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if (ldot > 0.0) { |
170 |
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/* |
171 |
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* Compute reflected non-diffuse component. |
172 |
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*/ |
173 |
greg |
2.6 |
if (np->mp->otype == MAT_MFUNC | np->mp->otype == MAT_MDATA) |
174 |
greg |
1.6 |
multcolor(ctmp, np->mcolor); |
175 |
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dtmp = ldot * omega * np->rspec; |
176 |
greg |
1.5 |
scalecolor(ctmp, dtmp); |
177 |
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addcolor(cval, ctmp); |
178 |
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} else { |
179 |
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/* |
180 |
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* Compute transmitted non-diffuse component. |
181 |
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*/ |
182 |
greg |
2.6 |
if (np->mp->otype == MAT_TFUNC | np->mp->otype == MAT_TDATA) |
183 |
greg |
1.6 |
multcolor(ctmp, np->mcolor); |
184 |
greg |
1.5 |
dtmp = -ldot * omega * np->tspec; |
185 |
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scalecolor(ctmp, dtmp); |
186 |
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addcolor(cval, ctmp); |
187 |
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} |
188 |
greg |
2.12 |
#undef lddx |
189 |
greg |
1.1 |
} |
190 |
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191 |
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192 |
greg |
2.15 |
int |
193 |
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m_brdf(m, r) /* color a ray that hit a BRDTfunc material */ |
194 |
greg |
1.1 |
register OBJREC *m; |
195 |
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register RAY *r; |
196 |
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{ |
197 |
greg |
2.15 |
int hitfront = 1; |
198 |
greg |
1.1 |
BRDFDAT nd; |
199 |
greg |
2.6 |
RAY sr; |
200 |
greg |
1.7 |
double transtest, transdist; |
201 |
greg |
2.6 |
int hasrefl, hastrans; |
202 |
greg |
1.1 |
COLOR ctmp; |
203 |
greg |
2.14 |
FVECT vtmp; |
204 |
greg |
2.6 |
register MFUNC *mf; |
205 |
greg |
1.1 |
register int i; |
206 |
greg |
1.5 |
/* check arguments */ |
207 |
greg |
2.6 |
if (m->oargs.nsargs < 10 | m->oargs.nfargs < 9) |
208 |
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objerror(m, USER, "bad # arguments"); |
209 |
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nd.mp = m; |
210 |
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nd.pr = r; |
211 |
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/* dummy values */ |
212 |
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nd.rspec = nd.tspec = 1.0; |
213 |
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nd.trans = 0.5; |
214 |
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/* diffuse reflectance */ |
215 |
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if (r->rod > 0.0) |
216 |
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setcolor(nd.rdiff, m->oargs.farg[0], |
217 |
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m->oargs.farg[1], |
218 |
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m->oargs.farg[2]); |
219 |
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else |
220 |
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setcolor(nd.rdiff, m->oargs.farg[3], |
221 |
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m->oargs.farg[4], |
222 |
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m->oargs.farg[5]); |
223 |
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/* diffuse transmittance */ |
224 |
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setcolor(nd.tdiff, m->oargs.farg[6], |
225 |
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m->oargs.farg[7], |
226 |
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m->oargs.farg[8]); |
227 |
greg |
2.17 |
/* get modifiers */ |
228 |
greg |
2.6 |
raytexture(r, m->omod); |
229 |
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nd.pdot = raynormal(nd.pnorm, r); /* perturb normal */ |
230 |
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if (r->rod < 0.0) { /* orient perturbed values */ |
231 |
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nd.pdot = -nd.pdot; |
232 |
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for (i = 0; i < 3; i++) { |
233 |
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nd.pnorm[i] = -nd.pnorm[i]; |
234 |
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r->pert[i] = -r->pert[i]; |
235 |
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} |
236 |
greg |
2.15 |
hitfront = 0; |
237 |
greg |
1.5 |
} |
238 |
greg |
2.6 |
copycolor(nd.mcolor, r->pcol); /* get pattern color */ |
239 |
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multcolor(nd.rdiff, nd.mcolor); /* modify diffuse values */ |
240 |
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multcolor(nd.tdiff, nd.mcolor); |
241 |
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hasrefl = bright(nd.rdiff) > FTINY; |
242 |
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hastrans = bright(nd.tdiff) > FTINY; |
243 |
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/* load cal file */ |
244 |
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nd.dp = NULL; |
245 |
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mf = getfunc(m, 9, 0x3f, 0); |
246 |
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/* compute transmitted ray */ |
247 |
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setbrdfunc(&nd); |
248 |
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transtest = 0; |
249 |
greg |
2.8 |
transdist = r->rot; |
250 |
greg |
2.6 |
errno = 0; |
251 |
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setcolor(ctmp, evalue(mf->ep[3]), |
252 |
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evalue(mf->ep[4]), |
253 |
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evalue(mf->ep[5])); |
254 |
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if (errno) |
255 |
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objerror(m, WARNING, "compute error"); |
256 |
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else if (rayorigin(&sr, r, TRANS, bright(ctmp)) == 0) { |
257 |
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if (!(r->crtype & SHADOW) && |
258 |
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DOT(r->pert,r->pert) > FTINY*FTINY) { |
259 |
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for (i = 0; i < 3; i++) /* perturb direction */ |
260 |
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sr.rdir[i] = r->rdir[i] - .75*r->pert[i]; |
261 |
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if (normalize(sr.rdir) == 0.0) { |
262 |
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objerror(m, WARNING, "illegal perturbation"); |
263 |
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VCOPY(sr.rdir, r->rdir); |
264 |
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} |
265 |
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} else { |
266 |
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VCOPY(sr.rdir, r->rdir); |
267 |
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transtest = 2; |
268 |
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} |
269 |
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rayvalue(&sr); |
270 |
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multcolor(sr.rcol, ctmp); |
271 |
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addcolor(r->rcol, sr.rcol); |
272 |
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transtest *= bright(sr.rcol); |
273 |
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transdist = r->rot + sr.rt; |
274 |
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} |
275 |
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if (r->crtype & SHADOW) /* the rest is shadow */ |
276 |
greg |
2.10 |
return(1); |
277 |
greg |
2.6 |
/* compute reflected ray */ |
278 |
|
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setbrdfunc(&nd); |
279 |
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errno = 0; |
280 |
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setcolor(ctmp, evalue(mf->ep[0]), |
281 |
|
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evalue(mf->ep[1]), |
282 |
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evalue(mf->ep[2])); |
283 |
|
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if (errno) |
284 |
|
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objerror(m, WARNING, "compute error"); |
285 |
|
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else if (rayorigin(&sr, r, REFLECTED, bright(ctmp)) == 0) { |
286 |
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for (i = 0; i < 3; i++) |
287 |
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sr.rdir[i] = r->rdir[i] + 2.0*nd.pdot*nd.pnorm[i]; |
288 |
|
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rayvalue(&sr); |
289 |
|
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multcolor(sr.rcol, ctmp); |
290 |
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addcolor(r->rcol, sr.rcol); |
291 |
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} |
292 |
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/* compute ambient */ |
293 |
|
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if (hasrefl) { |
294 |
greg |
2.15 |
if (!hitfront) |
295 |
greg |
2.6 |
flipsurface(r); |
296 |
greg |
2.15 |
ambient(ctmp, r, nd.pnorm); |
297 |
greg |
2.6 |
multcolor(ctmp, nd.rdiff); |
298 |
|
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addcolor(r->rcol, ctmp); /* add to returned color */ |
299 |
greg |
2.15 |
if (!hitfront) |
300 |
greg |
2.6 |
flipsurface(r); |
301 |
|
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} |
302 |
|
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if (hastrans) { /* from other side */ |
303 |
greg |
2.15 |
if (hitfront) |
304 |
greg |
2.6 |
flipsurface(r); |
305 |
greg |
2.15 |
vtmp[0] = -nd.pnorm[0]; |
306 |
|
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vtmp[1] = -nd.pnorm[1]; |
307 |
|
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vtmp[2] = -nd.pnorm[2]; |
308 |
greg |
2.14 |
ambient(ctmp, r, vtmp); |
309 |
greg |
2.6 |
multcolor(ctmp, nd.tdiff); |
310 |
|
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addcolor(r->rcol, ctmp); |
311 |
greg |
2.15 |
if (hitfront) |
312 |
greg |
2.6 |
flipsurface(r); |
313 |
|
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} |
314 |
|
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if (hasrefl | hastrans || m->oargs.sarg[6][0] != '0') |
315 |
|
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direct(r, dirbrdf, &nd); /* add direct component */ |
316 |
|
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/* check distance */ |
317 |
|
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if (transtest > bright(r->rcol)) |
318 |
|
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r->rt = transdist; |
319 |
greg |
2.10 |
|
320 |
|
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return(1); |
321 |
greg |
2.6 |
} |
322 |
|
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|
323 |
|
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|
324 |
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|
325 |
greg |
2.15 |
int |
326 |
|
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m_brdf2(m, r) /* color a ray that hit a BRDF material */ |
327 |
greg |
2.6 |
register OBJREC *m; |
328 |
|
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register RAY *r; |
329 |
|
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{ |
330 |
|
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BRDFDAT nd; |
331 |
|
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COLOR ctmp; |
332 |
greg |
2.14 |
FVECT vtmp; |
333 |
greg |
2.6 |
double dtmp; |
334 |
|
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/* always a shadow */ |
335 |
|
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if (r->crtype & SHADOW) |
336 |
greg |
2.10 |
return(1); |
337 |
greg |
2.6 |
/* check arguments */ |
338 |
|
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if (m->oargs.nsargs < (hasdata(m->otype)?4:2) | m->oargs.nfargs < |
339 |
|
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(m->otype==MAT_TFUNC|m->otype==MAT_TDATA?6:4)) |
340 |
greg |
1.1 |
objerror(m, USER, "bad # arguments"); |
341 |
greg |
2.17 |
/* check for back side */ |
342 |
|
|
if (r->rod < 0.0) { |
343 |
|
|
if (!backvis && m->otype != MAT_TFUNC |
344 |
|
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&& m->otype != MAT_TDATA) { |
345 |
|
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raytrans(r); |
346 |
|
|
return(1); |
347 |
|
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} |
348 |
|
|
raytexture(r, m->omod); |
349 |
|
|
flipsurface(r); /* reorient if backvis */ |
350 |
|
|
} else |
351 |
|
|
raytexture(r, m->omod); |
352 |
|
|
|
353 |
greg |
1.1 |
nd.mp = m; |
354 |
|
|
nd.pr = r; |
355 |
greg |
2.6 |
/* get material color */ |
356 |
|
|
setcolor(nd.mcolor, m->oargs.farg[0], |
357 |
|
|
m->oargs.farg[1], |
358 |
|
|
m->oargs.farg[2]); |
359 |
greg |
1.5 |
/* get specular component */ |
360 |
|
|
nd.rspec = m->oargs.farg[3]; |
361 |
greg |
2.6 |
/* compute transmittance */ |
362 |
|
|
if (m->otype == MAT_TFUNC | m->otype == MAT_TDATA) { |
363 |
greg |
1.5 |
nd.trans = m->oargs.farg[4]*(1.0 - nd.rspec); |
364 |
|
|
nd.tspec = nd.trans * m->oargs.farg[5]; |
365 |
greg |
2.6 |
dtmp = nd.trans - nd.tspec; |
366 |
|
|
setcolor(nd.tdiff, dtmp, dtmp, dtmp); |
367 |
|
|
} else { |
368 |
|
|
nd.tspec = nd.trans = 0.0; |
369 |
|
|
setcolor(nd.tdiff, 0.0, 0.0, 0.0); |
370 |
|
|
} |
371 |
|
|
/* compute reflectance */ |
372 |
|
|
dtmp = 1.0 - nd.trans - nd.rspec; |
373 |
|
|
setcolor(nd.rdiff, dtmp, dtmp, dtmp); |
374 |
greg |
1.5 |
nd.pdot = raynormal(nd.pnorm, r); /* perturb normal */ |
375 |
|
|
multcolor(nd.mcolor, r->pcol); /* modify material color */ |
376 |
greg |
2.6 |
multcolor(nd.rdiff, nd.mcolor); |
377 |
|
|
multcolor(nd.tdiff, nd.mcolor); |
378 |
greg |
1.1 |
/* load auxiliary files */ |
379 |
greg |
2.2 |
if (hasdata(m->otype)) { |
380 |
greg |
1.1 |
nd.dp = getdata(m->oargs.sarg[1]); |
381 |
greg |
2.6 |
getfunc(m, 2, 0, 0); |
382 |
greg |
1.1 |
} else { |
383 |
|
|
nd.dp = NULL; |
384 |
greg |
2.6 |
getfunc(m, 1, 0, 0); |
385 |
greg |
1.1 |
} |
386 |
|
|
/* compute ambient */ |
387 |
greg |
2.6 |
if (nd.trans < 1.0-FTINY) { |
388 |
greg |
2.13 |
ambient(ctmp, r, nd.pnorm); |
389 |
greg |
2.6 |
scalecolor(ctmp, 1.0-nd.trans); |
390 |
greg |
1.1 |
multcolor(ctmp, nd.mcolor); /* modified by material color */ |
391 |
|
|
addcolor(r->rcol, ctmp); /* add to returned color */ |
392 |
greg |
1.5 |
} |
393 |
greg |
2.6 |
if (nd.trans > FTINY) { /* from other side */ |
394 |
greg |
1.5 |
flipsurface(r); |
395 |
greg |
2.14 |
vtmp[0] = -nd.pnorm[0]; |
396 |
|
|
vtmp[1] = -nd.pnorm[1]; |
397 |
|
|
vtmp[2] = -nd.pnorm[2]; |
398 |
|
|
ambient(ctmp, r, vtmp); |
399 |
greg |
2.6 |
scalecolor(ctmp, nd.trans); |
400 |
greg |
1.5 |
multcolor(ctmp, nd.mcolor); |
401 |
|
|
addcolor(r->rcol, ctmp); |
402 |
|
|
flipsurface(r); |
403 |
greg |
1.1 |
} |
404 |
|
|
/* add direct component */ |
405 |
|
|
direct(r, dirbrdf, &nd); |
406 |
greg |
2.10 |
|
407 |
|
|
return(1); |
408 |
greg |
1.10 |
} |
409 |
|
|
|
410 |
|
|
|
411 |
greg |
2.15 |
int |
412 |
greg |
1.10 |
setbrdfunc(np) /* set up brdf function and variables */ |
413 |
|
|
register BRDFDAT *np; |
414 |
|
|
{ |
415 |
|
|
FVECT vec; |
416 |
|
|
|
417 |
|
|
if (setfunc(np->mp, np->pr) == 0) |
418 |
|
|
return(0); /* it's OK, setfunc says we're done */ |
419 |
|
|
/* else (re)assign special variables */ |
420 |
|
|
multv3(vec, np->pnorm, funcxf.xfm); |
421 |
|
|
varset("NxP", '=', vec[0]/funcxf.sca); |
422 |
|
|
varset("NyP", '=', vec[1]/funcxf.sca); |
423 |
|
|
varset("NzP", '=', vec[2]/funcxf.sca); |
424 |
greg |
1.11 |
varset("RdotP", '=', np->pdot <= -1.0 ? -1.0 : |
425 |
|
|
np->pdot >= 1.0 ? 1.0 : np->pdot); |
426 |
greg |
1.10 |
varset("CrP", '=', colval(np->mcolor,RED)); |
427 |
|
|
varset("CgP", '=', colval(np->mcolor,GRN)); |
428 |
|
|
varset("CbP", '=', colval(np->mcolor,BLU)); |
429 |
|
|
return(1); |
430 |
greg |
1.1 |
} |