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root/radiance/ray/src/common/image.c
Revision: 1.6
Committed: Tue Jan 9 09:08:09 1990 UTC (34 years, 3 months ago) by greg
Content type: text/plain
Branch: MAIN
Changes since 1.5: +16 -0 lines
Log Message:
added routine for computing image size and pixel aspect ratios

File Contents

# User Rev Content
1 greg 1.1 /* Copyright (c) 1986 Regents of the University of California */
2    
3     #ifndef lint
4     static char SCCSid[] = "$SunId$ LBL";
5     #endif
6    
7     /*
8     * image.c - routines for image generation.
9     *
10     * 10/17/85
11     */
12    
13     #include "standard.h"
14    
15     #include "view.h"
16    
17 greg 1.5 VIEW stdview = STDVIEW; /* default view parameters */
18 greg 1.1
19    
20     char *
21 greg 1.5 setview(v) /* set hvec and vvec, return message on error */
22     register VIEW *v;
23 greg 1.3 {
24 greg 1.5 extern double tan(), normalize();
25 greg 1.3
26 greg 1.1 if (normalize(v->vdir) == 0.0) /* normalize direction */
27     return("zero view direction");
28    
29 greg 1.5 fcross(v->hvec, v->vdir, v->vup); /* compute horiz dir */
30    
31     if (normalize(v->hvec) == 0.0)
32 greg 1.1 return("illegal view up vector");
33    
34 greg 1.5 fcross(v->vvec, v->hvec, v->vdir); /* compute vert dir */
35    
36 greg 1.1 if (v->type == VT_PAR)
37 greg 1.5 v->hn2 = v->horiz;
38 greg 1.1 else if (v->type == VT_PER)
39 greg 1.5 v->hn2 = 2.0 * tan(v->horiz*(PI/180.0/2.0));
40 greg 1.1 else
41     return("unknown view type");
42    
43 greg 1.5 if (v->hn2 <= FTINY || v->hn2 >= FHUGE)
44 greg 1.1 return("illegal horizontal view size");
45    
46 greg 1.5 v->hvec[0] *= v->hn2;
47     v->hvec[1] *= v->hn2;
48     v->hvec[2] *= v->hn2;
49     v->hn2 *= v->hn2;
50 greg 1.1
51     if (v->type == VT_PAR)
52 greg 1.5 v->vn2 = v->vert;
53 greg 1.1 else
54 greg 1.5 v->vn2 = 2.0 * tan(v->vert*(PI/180.0/2.0));
55 greg 1.1
56 greg 1.5 if (v->vn2 <= FTINY || v->vn2 >= FHUGE)
57 greg 1.1 return("illegal vertical view size");
58    
59 greg 1.5 v->vvec[0] *= v->vn2;
60     v->vvec[1] *= v->vn2;
61     v->vvec[2] *= v->vn2;
62     v->vn2 *= v->vn2;
63 greg 1.1
64     return(NULL);
65     }
66    
67    
68 greg 1.6 normaspect(vp, ap, xp, yp) /* fix pixel aspect or resolution */
69     VIEW *vp;
70     double *ap;
71     int *xp, *yp;
72     {
73     double va = viewaspect(vp);
74    
75     if (*ap <= FTINY)
76     *ap = (double)*yp / *xp / va; /* compute pixel aspect */
77     else if (va * *xp > *ap * *yp)
78     *xp = *yp / va * *ap; /* reduce x resolution */
79     else
80     *yp = *xp * va / *ap; /* reduce y resolution */
81     }
82    
83    
84 greg 1.5 viewray(orig, direc, v, x, y) /* compute ray origin and direction */
85 greg 1.1 FVECT orig, direc;
86     register VIEW *v;
87     double x, y;
88     {
89 greg 1.5 x += v->hoff - 0.5;
90     y += v->voff - 0.5;
91 greg 1.1
92     if (v->type == VT_PAR) { /* parallel view */
93 greg 1.5 orig[0] = v->vp[0] + x*v->hvec[0] + y*v->vvec[0];
94     orig[1] = v->vp[1] + x*v->hvec[1] + y*v->vvec[1];
95     orig[2] = v->vp[2] + x*v->hvec[2] + y*v->vvec[2];
96 greg 1.1 VCOPY(direc, v->vdir);
97     } else { /* perspective view */
98     VCOPY(orig, v->vp);
99 greg 1.5 direc[0] = v->vdir[0] + x*v->hvec[0] + y*v->vvec[0];
100     direc[1] = v->vdir[1] + x*v->hvec[1] + y*v->vvec[1];
101     direc[2] = v->vdir[2] + x*v->hvec[2] + y*v->vvec[2];
102 greg 1.1 normalize(direc);
103     }
104     }
105    
106    
107 greg 1.5 viewpixel(xp, yp, zp, v, p) /* find image location for point */
108 greg 1.3 double *xp, *yp, *zp;
109     register VIEW *v;
110     FVECT p;
111     {
112     extern double sqrt();
113     double d;
114     FVECT disp;
115 greg 1.5
116 greg 1.3 disp[0] = p[0] - v->vp[0];
117     disp[1] = p[1] - v->vp[1];
118     disp[2] = p[2] - v->vp[2];
119    
120     if (v->type == VT_PAR) { /* parallel view */
121     if (zp != NULL)
122     *zp = DOT(disp,v->vdir);
123     } else { /* perspective view */
124     d = 1.0/DOT(disp,v->vdir);
125     if (zp != NULL) {
126     *zp = sqrt(DOT(disp,disp));
127     if (d < 0.0)
128     *zp = -*zp;
129     }
130     disp[0] *= d;
131     disp[1] *= d;
132     disp[2] *= d;
133     }
134 greg 1.5 *xp = DOT(disp,v->hvec)/v->hn2 + 0.5 - v->hoff;
135     *yp = DOT(disp,v->vvec)/v->vn2 + 0.5 - v->voff;
136 greg 1.3 }
137    
138    
139 greg 1.5 int
140     getviewopt(v, ac, av) /* process view argument */
141     register VIEW *v;
142     int ac;
143     register char *av[];
144     {
145     #define check(c,n) if ((av[0][c]&&av[0][c]!=' ') || n>=ac) return(-1)
146     extern double atof();
147    
148     if (av[0][0] != '-' || av[0][1] != 'v')
149     return(-1);
150     switch (av[0][2]) {
151     case 't': /* type */
152     if (!av[0][3] || av[0][3]==' ')
153     return(-1);
154     check(4,0);
155     v->type = av[0][3];
156     return(0);
157     case 'p': /* point */
158     check(3,3);
159     v->vp[0] = atof(av[1]);
160     v->vp[1] = atof(av[2]);
161     v->vp[2] = atof(av[3]);
162     return(3);
163     case 'd': /* direction */
164     check(3,3);
165     v->vdir[0] = atof(av[1]);
166     v->vdir[1] = atof(av[2]);
167     v->vdir[2] = atof(av[3]);
168     return(3);
169     case 'u': /* up */
170     check(3,3);
171     v->vup[0] = atof(av[1]);
172     v->vup[1] = atof(av[2]);
173     v->vup[2] = atof(av[3]);
174     return(3);
175     case 'h': /* horizontal size */
176     check(3,1);
177     v->horiz = atof(av[1]);
178     return(1);
179     case 'v': /* vertical size */
180     check(3,1);
181     v->vert = atof(av[1]);
182     return(1);
183     case 's': /* shift */
184     check(3,1);
185     v->hoff = atof(av[1]);
186     return(1);
187     case 'l': /* lift */
188     check(3,1);
189     v->voff = atof(av[1]);
190     return(1);
191     default:
192     return(-1);
193     }
194     #undef check
195     }
196    
197    
198     int
199     sscanview(vp, s) /* get view parameters from string */
200     VIEW *vp;
201 greg 1.1 register char *s;
202     {
203 greg 1.5 int ac;
204     char *av[4];
205     int na;
206     int nvopts = 0;
207    
208     while (*s == ' ')
209     s++;
210     do {
211     ac = 0;
212     do {
213     av[ac++] = s;
214     while (*s && *s != ' ')
215     s++;
216     while (*s == ' ')
217     s++;
218     } while (*s && ac < 4);
219     if ((na = getviewopt(vp, ac, av)) >= 0) {
220     if (na+1 < ac)
221     s = av[na+1];
222     nvopts++;
223 greg 1.1 }
224 greg 1.5 } while (*s);
225     return(nvopts);
226 greg 1.1 }
227    
228    
229     fprintview(vp, fp) /* write out view parameters */
230     register VIEW *vp;
231     FILE *fp;
232     {
233     fprintf(fp, " -vt%c", vp->type);
234     fprintf(fp, " -vp %.6g %.6g %.6g", vp->vp[0], vp->vp[1], vp->vp[2]);
235     fprintf(fp, " -vd %.6g %.6g %.6g", vp->vdir[0], vp->vdir[1], vp->vdir[2]);
236     fprintf(fp, " -vu %.6g %.6g %.6g", vp->vup[0], vp->vup[1], vp->vup[2]);
237     fprintf(fp, " -vh %.6g -vv %.6g", vp->horiz, vp->vert);
238 greg 1.5 fprintf(fp, " -vs %d -vl %d", vp->hoff, vp->voff);
239 greg 1.1 }
240    
241    
242     static VIEW *hview; /* view from header */
243     static int gothview; /* success indicator */
244 greg 1.3 static char *altname[] = {NULL,"rpict","rview","pinterp",VIEWSTR,NULL};
245 greg 1.1
246    
247     static
248     gethview(s) /* get view from header */
249     char *s;
250     {
251     register char **an;
252    
253     for (an = altname; *an != NULL; an++)
254     if (!strncmp(*an, s, strlen(*an))) {
255 greg 1.5 if (sscanview(hview, s+strlen(*an)) > 0)
256 greg 1.1 gothview++;
257     return;
258     }
259     }
260    
261    
262     int
263     viewfile(fname, vp) /* get view from file */
264     char *fname;
265     VIEW *vp;
266     {
267     extern char *progname;
268     FILE *fp;
269    
270     if ((fp = fopen(fname, "r")) == NULL)
271     return(-1);
272    
273     altname[0] = progname;
274     hview = vp;
275     gothview = 0;
276    
277     getheader(fp, gethview);
278    
279     fclose(fp);
280    
281     return(gothview);
282     }