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root/radiance/ray/src/px/pcond4.c
Revision: 3.4
Committed: Fri Oct 4 17:51:41 1996 UTC (27 years, 7 months ago) by greg
Content type: text/plain
Branch: MAIN
Changes since 3.3: +7 -3 lines
Log Message:
fixed problem with fisheye views
made veil computation faster with approximation to acos()

File Contents

# User Rev Content
1 greg 3.1 /* Copyright (c) 1996 Regents of the University of California */
2    
3     #ifndef lint
4     static char SCCSid[] = "$SunId$ LBL";
5     #endif
6    
7     /*
8     * Routines for veiling glare and loss of acuity.
9     */
10    
11     #include "pcond.h"
12    
13 greg 3.3 /************** VEILING STUFF *****************/
14 greg 3.1
15     #define VADAPT 0.08 /* fraction of adaptation from veil */
16    
17     extern COLOR *fovimg; /* foveal (1 degree) averaged image */
18     extern short fvxr, fvyr; /* foveal image resolution */
19    
20     #define fovscan(y) (fovimg+(y)*fvxr)
21    
22     static COLOR *veilimg; /* veiling image */
23    
24     #define veilscan(y) (veilimg+(y)*fvxr)
25    
26 greg 3.2 static float (*raydir)[3] = NULL; /* ray direction for each pixel */
27 greg 3.1
28     #define rdirscan(y) (raydir+(y)*fvxr)
29    
30    
31     compraydir() /* compute ray directions */
32     {
33 greg 3.2 FVECT rorg, rdir;
34 greg 3.1 double h, v;
35     register int x, y;
36    
37     if (raydir != NULL) /* already done? */
38     return;
39 greg 3.2 raydir = (float (*)[3])malloc(fvxr*fvyr*3*sizeof(float));
40 greg 3.1 if (raydir == NULL)
41     syserror("malloc");
42    
43     for (y = 0; y < fvyr; y++) {
44     switch (inpres.or) {
45     case YMAJOR: case YMAJOR|XDECR:
46     v = (y+.5)/fvyr; break;
47     case YMAJOR|YDECR: case YMAJOR|YDECR|XDECR:
48     v = 1. - (y+.5)/fvyr; break;
49     case 0: case YDECR:
50     h = (y+.5)/fvyr; break;
51     case XDECR: case XDECR|YDECR:
52     h = 1. - (y+.5)/fvyr; break;
53     }
54     for (x = 0; x < fvxr; x++) {
55     switch (inpres.or) {
56     case YMAJOR: case YMAJOR|YDECR:
57     h = (x+.5)/fvxr; break;
58     case YMAJOR|XDECR: case YMAJOR|XDECR|YDECR:
59     h = 1. - (x+.5)/fvxr; break;
60     case 0: case XDECR:
61     v = (x+.5)/fvxr; break;
62     case YDECR: case YDECR|XDECR:
63     v = 1. - (x+.5)/fvxr; break;
64     }
65 greg 3.2 if (viewray(rorg, rdir, &ourview, h, v)
66     >= -FTINY) {
67     rdirscan(y)[x][0] = rdir[0];
68     rdirscan(y)[x][1] = rdir[1];
69     rdirscan(y)[x][2] = rdir[2];
70     } else {
71 greg 3.1 rdirscan(y)[x][0] =
72     rdirscan(y)[x][1] =
73     rdirscan(y)[x][2] = 0.0;
74     }
75     }
76     }
77     }
78    
79    
80     compveil() /* compute veiling image */
81     {
82     double t2, t2sum;
83     COLOR ctmp, vsum;
84     int px, py;
85     register int x, y;
86     /* compute ray directions */
87     compraydir();
88     /* compute veil image */
89     veilimg = (COLOR *)malloc(fvxr*fvyr*sizeof(COLOR));
90     if (veilimg == NULL)
91     syserror("malloc");
92     for (py = 0; py < fvyr; py++)
93     for (px = 0; px < fvxr; px++) {
94     t2sum = 0.;
95     setcolor(vsum, 0., 0., 0.);
96     for (y = 0; y < fvyr; y++)
97     for (x = 0; x < fvxr; x++) {
98     if (x == px && y == py) continue;
99     t2 = DOT(rdirscan(py)[px],
100     rdirscan(y)[x]);
101     if (t2 <= FTINY) continue;
102 greg 3.4 /* use approximation instead
103 greg 3.1 t2 = acos(t2);
104     t2 = 1./(t2*t2);
105 greg 3.4 */
106     t2 = .5 / (1. - t2);
107 greg 3.1 copycolor(ctmp, fovscan(y)[x]);
108     scalecolor(ctmp, t2);
109     addcolor(vsum, ctmp);
110     t2sum += t2;
111     }
112     /* VADAPT of original is subtracted in addveil() */
113     scalecolor(vsum, VADAPT/t2sum);
114     copycolor(veilscan(py)[px], vsum);
115     }
116     }
117    
118    
119     addveil(sl, y) /* add veil to scanline */
120     COLOR *sl;
121     int y;
122     {
123     int vx, vy;
124     double dx, dy;
125     double lv, uv;
126     register int x, i;
127    
128     vy = dy = (y+.5)/numscans(&inpres)*fvyr - .5;
129     if (vy >= fvyr-1) vy--;
130     dy -= (double)vy;
131     for (x = 0; x < scanlen(&inpres); x++) {
132     vx = dx = (x+.5)/scanlen(&inpres)*fvxr - .5;
133     if (vx >= fvxr-1) vx--;
134     dx -= (double)vx;
135     for (i = 0; i < 3; i++) {
136     lv = (1.-dy)*colval(veilscan(vy)[vx],i) +
137     dy*colval(veilscan(vy+1)[vx],i);
138     uv = (1.-dy)*colval(veilscan(vy)[vx+1],i) +
139     dy*colval(veilscan(vy+1)[vx+1],i);
140     colval(sl[x],i) = (1.-VADAPT)*colval(sl[x],i) +
141     (1.-dx)*lv + dx*uv;
142     }
143     }
144 greg 3.3 }
145    
146    
147     /****************** ACUITY STUFF *******************/
148    
149     typedef struct scanbar {
150     short sampr; /* sample area size (power of 2) */
151     short nscans; /* number of scanlines in this bar */
152     int len; /* individual scanline length */
153     struct scanbar *next; /* next higher resolution scanbar */
154     int nread; /* number of scanlines loaded */
155     /* followed by the scanline data */
156     } SCANBAR;
157    
158     #define bscan(sb,y) ((COLOR *)((sb)+1)+((y)%(sb)->nscans)*(sb)->len)
159    
160     SCANBAR *rootbar; /* root scan bar (lowest resolution) */
161    
162     float *inpacuD; /* input acuity data (cycles/degree) */
163    
164     #define tsampr(x,y) inpacuD[(y)*fvxr+(x)]
165    
166    
167     double
168     hacuity(La) /* return visual acuity in cycles/degree */
169     double La;
170     { /* data due to S. Shaler (we should fit it!) */
171     #define NPOINTS 20
172     static float l10lum[NPOINTS] = {
173     -3.10503,-2.66403,-2.37703,-2.09303,-1.64403,-1.35803,
174     -1.07403,-0.67203,-0.38503,-0.10103,0.29397,0.58097,0.86497,
175     1.25697,1.54397,1.82797,2.27597,2.56297,2.84697,3.24897
176     };
177     static float resfreq[NPOINTS] = {
178     2.09,3.28,3.79,4.39,6.11,8.83,10.94,18.66,23.88,31.05,37.42,
179     37.68,41.60,43.16,45.30,47.00,48.43,48.32,51.06,51.09
180     };
181     double l10La;
182     register int i;
183     /* interpolate/extrapolate data */
184     l10La = log10(La);
185     for (i = 0; i < NPOINTS-2 && l10lum[i+1] <= l10La; i++)
186     ;
187     return( ( (l10lum[i+1] - l10La)*resfreq[i] +
188     (l10La - l10lum[i])*resfreq[i+1] ) /
189     (l10lum[i+1] - l10lum[i]) );
190     #undef NPOINTS
191     }
192    
193    
194     COLOR *
195     getascan(sb, y) /* find/read scanline y for scanbar sb */
196     register SCANBAR *sb;
197     int y;
198     {
199     register COLOR *sl0, *sl1, *mysl;
200     register int i;
201    
202     if (y < sb->nread - sb->nscans) {
203     fprintf(stderr, "%s: internal - cannot backspace in getascan\n",
204     progname);
205     exit(1);
206     }
207     for ( ; y >= sb->nread; sb->nread++) { /* read as necessary */
208     mysl = bscan(sb, sb->nread);
209     if (sb->sampr == 1) {
210     if (freadscan(mysl, sb->len, infp) < 0) {
211     fprintf(stderr, "%s: %s: scanline read error\n",
212     progname, infn);
213     exit(1);
214     }
215     } else {
216     sl0 = getascan(sb->next, 2*y);
217     sl1 = getascan(sb->next, 2*y+1);
218     for (i = 0; i < sb->len; i++) {
219     copycolor(mysl[i], sl0[2*i]);
220     addcolor(mysl[i], sl0[2*i+1]);
221     addcolor(mysl[i], sl1[2*i]);
222     addcolor(mysl[i], sl1[2*i+1]);
223     scalecolor(mysl[i], 0.25);
224     }
225     }
226     }
227     return(bscan(sb, y));
228     }
229    
230    
231     acuscan(scln, y) /* get acuity-sampled scanline */
232     COLOR *scln;
233     int y;
234     {
235     double sr;
236     double dx, dy;
237     int ix, iy;
238     register int x;
239     /* compute foveal y position */
240     iy = dy = (y+.5)/numscans(&inpres)*fvyr - .5;
241     if (iy >= fvyr-1) iy--;
242     dy -= (double)iy;
243     for (x = 0; x < scanlen(&inpres); x++) {
244     /* compute foveal x position */
245     ix = dx = (x+.5)/scanlen(&inpres)*fvxr - .5;
246     if (ix >= fvxr-1) ix--;
247     dx -= (double)ix;
248     /* interpolate sample rate */
249     sr = (1.-dy)*((1.-dx)*tsampr(ix,iy) + dx*tsampr(ix+1,iy)) +
250     dy*((1.-dx)*tsampr(ix,iy+1) + dx*tsampr(ix+1,iy+1));
251    
252     acusample(scln[x], x, y, sr); /* compute sample */
253     }
254     }
255    
256    
257     acusample(col, x, y, sr) /* interpolate sample at (x,y) using rate sr */
258     COLOR col;
259     int x, y;
260     double sr;
261     {
262     COLOR c1;
263     double d;
264     register SCANBAR *sb0;
265    
266     for (sb0 = rootbar; sb0->next != NULL && sb0->next->sampr > sr;
267     sb0 = sb0->next)
268     ;
269     ascanval(col, x, y, sb0);
270     if (sb0->next == NULL) /* don't extrapolate highest */
271     return;
272     ascanval(c1, x, y, sb0->next);
273     d = (sb0->sampr - sr)/(sb0->sampr - sb0->next->sampr);
274     scalecolor(col, 1.-d);
275     scalecolor(c1, d);
276     addcolor(col, c1);
277     }
278    
279    
280     ascanval(col, x, y, sb) /* interpolate scanbar at orig. coords (x,y) */
281     COLOR col;
282     int x, y;
283     SCANBAR *sb;
284     {
285     COLOR *sl0, *sl1, c1, c1y;
286     double dx, dy;
287     int ix, iy;
288    
289     ix = dx = (x+.5)/sb->sampr - .5;
290     if (ix >= sb->len-1) ix--;
291     dx -= (double)ix;
292     iy = dy = (y+.5)/sb->sampr - .5;
293     if (iy >= numscans(&inpres)/sb->sampr-1) iy--;
294     dy -= (double)iy;
295     /* get scanlines */
296     sl0 = getascan(sb, iy);
297     sl1 = getascan(sb, iy+1);
298     /* 2D linear interpolation */
299     copycolor(col, sl0[ix]);
300     scalecolor(col, 1.-dx);
301     copycolor(c1, sl0[ix+1]);
302     scalecolor(c1, dx);
303     addcolor(col, c1);
304     copycolor(c1y, sl1[ix]);
305     scalecolor(c1y, 1.-dx);
306     copycolor(c1, sl1[ix+1]);
307     scalecolor(c1, dx);
308     addcolor(c1y, c1);
309     scalecolor(col, 1.-dy);
310     scalecolor(c1y, dy);
311     addcolor(col, c1y);
312     }
313    
314    
315     SCANBAR *
316     sballoc(sr, ns, sl) /* allocate scanbar */
317     int sr; /* sampling rate */
318     int ns; /* number of scanlines */
319     int sl; /* original scanline length */
320     {
321     register SCANBAR *sb;
322    
323     sb = (SCANBAR *)malloc(sizeof(SCANBAR)+(sl/sr)*ns*sizeof(COLOR));
324     if (sb == NULL)
325     syserror("malloc");
326     sb->nscans = ns;
327     sb->len = sl/sr;
328     sb->nread = 0;
329     if ((sb->sampr = sr) > 1)
330     sb->next = sballoc(sr/2, ns*2, sl);
331     else
332     sb->next = NULL;
333     return(sb);
334     }
335    
336    
337     initacuity() /* initialize variable acuity sampling */
338     {
339     FVECT diffx, diffy, cp;
340     double omega, maxsr;
341     register int x, y, i;
342    
343     compraydir(); /* compute ray directions */
344    
345     inpacuD = (float *)malloc(fvxr*fvyr*sizeof(float));
346     if (inpacuD == NULL)
347     syserror("malloc");
348     maxsr = 1.; /* compute internal sample rates */
349     for (y = 1; y < fvyr-1; y++)
350     for (x = 1; x < fvxr-1; x++) {
351     for (i = 0; i < 3; i++) {
352     diffx[i] = 0.5*fvxr/scanlen(&inpres) *
353     (rdirscan(y)[x+1][i] -
354     rdirscan(y)[x-1][i]);
355     diffy[i] = 0.5*fvyr/numscans(&inpres) *
356     (rdirscan(y+1)[x][i] -
357     rdirscan(y-1)[x][i]);
358     }
359     fcross(cp, diffx, diffy);
360     omega = 0.5 * sqrt(DOT(cp,cp));
361 greg 3.4 if (omega <= FTINY)
362     tsampr(x,y) = 1.;
363     else if ((tsampr(x,y) = PI/180. / sqrt(omega) /
364     hacuity(plum(fovscan(y)[x]))) > maxsr)
365 greg 3.3 maxsr = tsampr(x,y);
366     }
367     /* copy perimeter (easier) */
368     for (x = 1; x < fvxr-1; x++) {
369     tsampr(x,0) = tsampr(x,1);
370     tsampr(x,fvyr-1) = tsampr(x,fvyr-2);
371     }
372     for (y = 0; y < fvyr; y++) {
373     tsampr(y,0) = tsampr(y,1);
374     tsampr(y,fvxr-1) = tsampr(y,fvxr-2);
375     }
376     /* initialize with next power of two */
377     rootbar = sballoc(2<<(int)(log(maxsr)/log(2.)), 2, scanlen(&inpres));
378 greg 3.1 }