ViewVC Help
View File | Revision Log | Show Annotations | Download File | Root Listing
root/radiance/ray/src/px/pcond4.c
Revision: 3.15
Committed: Wed Aug 13 11:24:48 1997 UTC (26 years, 8 months ago) by gregl
Content type: text/plain
Branch: MAIN
Changes since 3.14: +2 -1 lines
Log Message:
fixed bug in veil computation for fisheye views (divide by zero)

File Contents

# User Rev Content
1 greg 3.13 /* Copyright (c) 1997 Regents of the University of California */
2 greg 3.1
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 greg 3.11 static COLOR *veilimg = NULL; /* veiling image */
18 greg 3.1
19     #define veilscan(y) (veilimg+(y)*fvxr)
20    
21 greg 3.2 static float (*raydir)[3] = NULL; /* ray direction for each pixel */
22 greg 3.1
23     #define rdirscan(y) (raydir+(y)*fvxr)
24    
25    
26     compraydir() /* compute ray directions */
27     {
28 greg 3.2 FVECT rorg, rdir;
29 greg 3.1 double h, v;
30     register int x, y;
31    
32     if (raydir != NULL) /* already done? */
33     return;
34 greg 3.2 raydir = (float (*)[3])malloc(fvxr*fvyr*3*sizeof(float));
35 greg 3.1 if (raydir == NULL)
36     syserror("malloc");
37    
38     for (y = 0; y < fvyr; y++) {
39     switch (inpres.or) {
40     case YMAJOR: case YMAJOR|XDECR:
41     v = (y+.5)/fvyr; break;
42     case YMAJOR|YDECR: case YMAJOR|YDECR|XDECR:
43     v = 1. - (y+.5)/fvyr; break;
44     case 0: case YDECR:
45     h = (y+.5)/fvyr; break;
46     case XDECR: case XDECR|YDECR:
47     h = 1. - (y+.5)/fvyr; break;
48     }
49     for (x = 0; x < fvxr; x++) {
50     switch (inpres.or) {
51     case YMAJOR: case YMAJOR|YDECR:
52     h = (x+.5)/fvxr; break;
53     case YMAJOR|XDECR: case YMAJOR|XDECR|YDECR:
54     h = 1. - (x+.5)/fvxr; break;
55     case 0: case XDECR:
56     v = (x+.5)/fvxr; break;
57     case YDECR: case YDECR|XDECR:
58     v = 1. - (x+.5)/fvxr; break;
59     }
60 greg 3.2 if (viewray(rorg, rdir, &ourview, h, v)
61     >= -FTINY) {
62     rdirscan(y)[x][0] = rdir[0];
63     rdirscan(y)[x][1] = rdir[1];
64     rdirscan(y)[x][2] = rdir[2];
65     } else {
66 greg 3.1 rdirscan(y)[x][0] =
67     rdirscan(y)[x][1] =
68     rdirscan(y)[x][2] = 0.0;
69     }
70     }
71     }
72     }
73    
74    
75     compveil() /* compute veiling image */
76     {
77     double t2, t2sum;
78     COLOR ctmp, vsum;
79     int px, py;
80     register int x, y;
81 greg 3.11
82     if (veilimg != NULL) /* already done? */
83     return;
84 greg 3.1 /* compute ray directions */
85     compraydir();
86     /* compute veil image */
87     veilimg = (COLOR *)malloc(fvxr*fvyr*sizeof(COLOR));
88     if (veilimg == NULL)
89     syserror("malloc");
90     for (py = 0; py < fvyr; py++)
91     for (px = 0; px < fvxr; px++) {
92     t2sum = 0.;
93     setcolor(vsum, 0., 0., 0.);
94     for (y = 0; y < fvyr; y++)
95     for (x = 0; x < fvxr; x++) {
96     if (x == px && y == py) continue;
97     t2 = DOT(rdirscan(py)[px],
98     rdirscan(y)[x]);
99     if (t2 <= FTINY) continue;
100 greg 3.4 /* use approximation instead
101 greg 3.12 t3 = acos(t2);
102     t2 = t2/(t3*t3);
103 greg 3.4 */
104 greg 3.12 t2 *= .5 / (1. - t2);
105 greg 3.1 copycolor(ctmp, fovscan(y)[x]);
106     scalecolor(ctmp, t2);
107     addcolor(vsum, ctmp);
108     t2sum += t2;
109     }
110     /* VADAPT of original is subtracted in addveil() */
111 gregl 3.15 if (t2sum > FTINY)
112     scalecolor(vsum, VADAPT/t2sum);
113 greg 3.1 copycolor(veilscan(py)[px], vsum);
114     }
115 greg 3.11 /* modify FOV sample image */
116     for (y = 0; y < fvyr; y++)
117     for (x = 0; x < fvxr; x++) {
118     scalecolor(fovscan(y)[x], 1.-VADAPT);
119     addcolor(fovscan(y)[x], veilscan(y)[x]);
120     }
121     comphist(); /* recompute histogram */
122 greg 3.1 }
123    
124    
125     addveil(sl, y) /* add veil to scanline */
126     COLOR *sl;
127     int y;
128     {
129     int vx, vy;
130     double dx, dy;
131     double lv, uv;
132     register int x, i;
133    
134     vy = dy = (y+.5)/numscans(&inpres)*fvyr - .5;
135 greg 3.7 while (vy >= fvyr-1) vy--;
136 greg 3.1 dy -= (double)vy;
137     for (x = 0; x < scanlen(&inpres); x++) {
138     vx = dx = (x+.5)/scanlen(&inpres)*fvxr - .5;
139 greg 3.7 while (vx >= fvxr-1) vx--;
140 greg 3.1 dx -= (double)vx;
141     for (i = 0; i < 3; i++) {
142     lv = (1.-dy)*colval(veilscan(vy)[vx],i) +
143     dy*colval(veilscan(vy+1)[vx],i);
144     uv = (1.-dy)*colval(veilscan(vy)[vx+1],i) +
145     dy*colval(veilscan(vy+1)[vx+1],i);
146     colval(sl[x],i) = (1.-VADAPT)*colval(sl[x],i) +
147     (1.-dx)*lv + dx*uv;
148     }
149     }
150 greg 3.3 }
151    
152    
153     /****************** ACUITY STUFF *******************/
154    
155 greg 3.8 typedef struct {
156     short sampe; /* sample area size (exponent of 2) */
157 greg 3.3 short nscans; /* number of scanlines in this bar */
158     int len; /* individual scanline length */
159     int nread; /* number of scanlines loaded */
160 greg 3.8 COLOR *sdata; /* scanbar data */
161 greg 3.3 } SCANBAR;
162    
163 greg 3.8 #define bscan(sb,y) ((COLOR *)(sb)->sdata+((y)%(sb)->nscans)*(sb)->len)
164 greg 3.3
165     SCANBAR *rootbar; /* root scan bar (lowest resolution) */
166    
167     float *inpacuD; /* input acuity data (cycles/degree) */
168    
169     #define tsampr(x,y) inpacuD[(y)*fvxr+(x)]
170    
171    
172     double
173     hacuity(La) /* return visual acuity in cycles/degree */
174     double La;
175 greg 3.13 {
176     /* functional fit */
177     return(17.25*atan(1.4*log10(La) + 0.35) + 25.72);
178 greg 3.3 }
179    
180    
181     COLOR *
182     getascan(sb, y) /* find/read scanline y for scanbar sb */
183     register SCANBAR *sb;
184     int y;
185     {
186     register COLOR *sl0, *sl1, *mysl;
187     register int i;
188    
189 greg 3.6 if (y < sb->nread - sb->nscans) /* too far back? */
190     return(NULL);
191 greg 3.3 for ( ; y >= sb->nread; sb->nread++) { /* read as necessary */
192     mysl = bscan(sb, sb->nread);
193 greg 3.8 if (sb->sampe == 0) {
194 greg 3.3 if (freadscan(mysl, sb->len, infp) < 0) {
195     fprintf(stderr, "%s: %s: scanline read error\n",
196     progname, infn);
197     exit(1);
198     }
199     } else {
200 greg 3.8 sl0 = getascan(sb+1, 2*y);
201 greg 3.6 if (sl0 == NULL)
202     return(NULL);
203 greg 3.8 sl1 = getascan(sb+1, 2*y+1);
204 greg 3.3 for (i = 0; i < sb->len; i++) {
205     copycolor(mysl[i], sl0[2*i]);
206     addcolor(mysl[i], sl0[2*i+1]);
207     addcolor(mysl[i], sl1[2*i]);
208     addcolor(mysl[i], sl1[2*i+1]);
209     scalecolor(mysl[i], 0.25);
210     }
211     }
212     }
213     return(bscan(sb, y));
214     }
215    
216    
217     acuscan(scln, y) /* get acuity-sampled scanline */
218     COLOR *scln;
219     int y;
220     {
221     double sr;
222     double dx, dy;
223     int ix, iy;
224     register int x;
225     /* compute foveal y position */
226     iy = dy = (y+.5)/numscans(&inpres)*fvyr - .5;
227 greg 3.9 while (iy >= fvyr-1) iy--;
228 greg 3.3 dy -= (double)iy;
229     for (x = 0; x < scanlen(&inpres); x++) {
230     /* compute foveal x position */
231     ix = dx = (x+.5)/scanlen(&inpres)*fvxr - .5;
232 greg 3.9 while (ix >= fvxr-1) ix--;
233 greg 3.3 dx -= (double)ix;
234     /* interpolate sample rate */
235     sr = (1.-dy)*((1.-dx)*tsampr(ix,iy) + dx*tsampr(ix+1,iy)) +
236     dy*((1.-dx)*tsampr(ix,iy+1) + dx*tsampr(ix+1,iy+1));
237    
238     acusample(scln[x], x, y, sr); /* compute sample */
239     }
240     }
241    
242    
243     acusample(col, x, y, sr) /* interpolate sample at (x,y) using rate sr */
244     COLOR col;
245     int x, y;
246     double sr;
247     {
248     COLOR c1;
249     double d;
250     register SCANBAR *sb0;
251    
252 greg 3.8 for (sb0 = rootbar; sb0->sampe != 0 && 1<<sb0[1].sampe > sr; sb0++)
253 greg 3.3 ;
254     ascanval(col, x, y, sb0);
255 greg 3.8 if (sb0->sampe == 0) /* don't extrapolate highest */
256 greg 3.3 return;
257 greg 3.8 ascanval(c1, x, y, sb0+1);
258     d = ((1<<sb0->sampe) - sr)/(1<<sb0[1].sampe);
259 greg 3.3 scalecolor(col, 1.-d);
260     scalecolor(c1, d);
261     addcolor(col, c1);
262     }
263    
264    
265     ascanval(col, x, y, sb) /* interpolate scanbar at orig. coords (x,y) */
266     COLOR col;
267     int x, y;
268     SCANBAR *sb;
269     {
270     COLOR *sl0, *sl1, c1, c1y;
271     double dx, dy;
272     int ix, iy;
273    
274 greg 3.8 if (sb->sampe == 0) { /* no need to interpolate */
275 greg 3.6 sl0 = getascan(sb, y);
276     copycolor(col, sl0[x]);
277     return;
278     }
279     /* compute coordinates for sb */
280 greg 3.8 ix = dx = (x+.5)/(1<<sb->sampe) - .5;
281 greg 3.7 while (ix >= sb->len-1) ix--;
282 greg 3.3 dx -= (double)ix;
283 greg 3.8 iy = dy = (y+.5)/(1<<sb->sampe) - .5;
284     while (iy >= (numscans(&inpres)>>sb->sampe)-1) iy--;
285 greg 3.3 dy -= (double)iy;
286     /* get scanlines */
287     sl0 = getascan(sb, iy);
288 greg 3.9 #ifdef DEBUG
289 greg 3.14 if (sl0 == NULL)
290     error(INTERNAL, "cannot backspace in ascanval");
291 greg 3.9 #endif
292 greg 3.3 sl1 = getascan(sb, iy+1);
293     /* 2D linear interpolation */
294     copycolor(col, sl0[ix]);
295     scalecolor(col, 1.-dx);
296     copycolor(c1, sl0[ix+1]);
297     scalecolor(c1, dx);
298     addcolor(col, c1);
299     copycolor(c1y, sl1[ix]);
300     scalecolor(c1y, 1.-dx);
301     copycolor(c1, sl1[ix+1]);
302     scalecolor(c1, dx);
303     addcolor(c1y, c1);
304     scalecolor(col, 1.-dy);
305     scalecolor(c1y, dy);
306     addcolor(col, c1y);
307 greg 3.9 for (ix = 0; ix < 3; ix++) /* make sure no negative */
308     if (colval(col,ix) < 0.)
309     colval(col,ix) = 0.;
310 greg 3.3 }
311    
312    
313     SCANBAR *
314 greg 3.9 sballoc(se, ns, sl) /* allocate scanbar */
315     int se; /* sampling rate exponent */
316 greg 3.3 int ns; /* number of scanlines */
317     int sl; /* original scanline length */
318     {
319 greg 3.8 SCANBAR *sbarr;
320 greg 3.3 register SCANBAR *sb;
321    
322 greg 3.9 sbarr = sb = (SCANBAR *)malloc((se+1)*sizeof(SCANBAR));
323 greg 3.3 if (sb == NULL)
324     syserror("malloc");
325 greg 3.8 do {
326 greg 3.9 sb->sampe = se;
327     sb->len = sl>>se;
328     sb->nscans = ns;
329     sb->sdata = (COLOR *)malloc(sb->len*ns*sizeof(COLOR));
330 greg 3.8 if (sb->sdata == NULL)
331     syserror("malloc");
332     sb->nread = 0;
333     ns <<= 1;
334     sb++;
335 greg 3.9 } while (--se >= 0);
336 greg 3.8 return(sbarr);
337 greg 3.3 }
338    
339    
340     initacuity() /* initialize variable acuity sampling */
341     {
342     FVECT diffx, diffy, cp;
343     double omega, maxsr;
344     register int x, y, i;
345    
346     compraydir(); /* compute ray directions */
347    
348     inpacuD = (float *)malloc(fvxr*fvyr*sizeof(float));
349     if (inpacuD == NULL)
350     syserror("malloc");
351     maxsr = 1.; /* compute internal sample rates */
352     for (y = 1; y < fvyr-1; y++)
353     for (x = 1; x < fvxr-1; x++) {
354     for (i = 0; i < 3; i++) {
355     diffx[i] = 0.5*fvxr/scanlen(&inpres) *
356     (rdirscan(y)[x+1][i] -
357     rdirscan(y)[x-1][i]);
358     diffy[i] = 0.5*fvyr/numscans(&inpres) *
359     (rdirscan(y+1)[x][i] -
360     rdirscan(y-1)[x][i]);
361     }
362     fcross(cp, diffx, diffy);
363     omega = 0.5 * sqrt(DOT(cp,cp));
364 greg 3.10 if (omega <= FTINY*FTINY)
365 greg 3.4 tsampr(x,y) = 1.;
366     else if ((tsampr(x,y) = PI/180. / sqrt(omega) /
367     hacuity(plum(fovscan(y)[x]))) > maxsr)
368 greg 3.3 maxsr = tsampr(x,y);
369     }
370     /* copy perimeter (easier) */
371     for (x = 1; x < fvxr-1; x++) {
372     tsampr(x,0) = tsampr(x,1);
373     tsampr(x,fvyr-1) = tsampr(x,fvyr-2);
374     }
375     for (y = 0; y < fvyr; y++) {
376 greg 3.9 tsampr(0,y) = tsampr(1,y);
377     tsampr(fvxr-1,y) = tsampr(fvxr-2,y);
378 greg 3.3 }
379     /* initialize with next power of two */
380 greg 3.8 rootbar = sballoc((int)(log(maxsr)/log(2.))+1, 2, scanlen(&inpres));
381 greg 3.1 }