src/common/image.c

/* Copyright (c) 1986 Regents of the University of California */

#ifndef lint
static char SCCSid[] = "$SunId$ LBL";
#endif

/*
 *  image.c - routines for image generation.
 *
 *     10/17/85
 */

#include  "standard.h"

#include  "view.h"

VIEW  stdview = STDVIEW;                /* default view parameters */


char *
setview(v)              /* set hvec and vvec, return message on error */
register VIEW  *v;
{
        extern double  tan(), normalize();

        if (normalize(v->vdir) == 0.0)          /* normalize direction */
                return("zero view direction");

        fcross(v->hvec, v->vdir, v->vup);       /* compute horiz dir */

        if (normalize(v->hvec) == 0.0)
                return("illegal view up vector");

        fcross(v->vvec, v->hvec, v->vdir);      /* compute vert dir */

        if (v->type == VT_PAR)
                v->hn2 = v->horiz;
        else if (v->type == VT_PER)
                v->hn2 = 2.0 * tan(v->horiz*(PI/180.0/2.0));
        else
                return("unknown view type");

        if (v->hn2 <= FTINY || v->hn2 >= FHUGE)
                return("illegal horizontal view size");

        v->hvec[0] *= v->hn2;
        v->hvec[1] *= v->hn2;
        v->hvec[2] *= v->hn2;
        v->hn2 *= v->hn2;

        if (v->type == VT_PAR)
                v->vn2 = v->vert;
        else
                v->vn2 = 2.0 * tan(v->vert*(PI/180.0/2.0));

        if (v->vn2 <= FTINY || v->vn2 >= FHUGE)
                return("illegal vertical view size");

        v->vvec[0] *= v->vn2;
        v->vvec[1] *= v->vn2;
        v->vvec[2] *= v->vn2;
        v->vn2 *= v->vn2;

        return(NULL);
}


normaspect(va, ap, xp, yp)              /* fix pixel aspect or resolution */
double  va;                     /* view aspect ratio */
double  *ap;                    /* pixel aspect in (or out if 0) */
int  *xp, *yp;                  /* x and y resolution in (or out if *ap!=0) */
{
        if (*ap <= FTINY)
                *ap = va * *xp / *yp;           /* compute pixel aspect */
        else if (va * *xp > *ap * *yp)
                *xp = *yp / va * *ap;           /* reduce x resolution */
        else
                *yp = *xp * va / *ap;           /* reduce y resolution */
}


viewray(orig, direc, v, x, y)           /* compute ray origin and direction */
FVECT  orig, direc;
register VIEW  *v;
double  x, y;
{
        x += v->hoff - 0.5;
        y += v->voff - 0.5;

        if (v->type == VT_PAR) {        /* parallel view */
                orig[0] = v->vp[0] + x*v->hvec[0] + y*v->vvec[0];
                orig[1] = v->vp[1] + x*v->hvec[1] + y*v->vvec[1];
                orig[2] = v->vp[2] + x*v->hvec[2] + y*v->vvec[2];
                VCOPY(direc, v->vdir);
        } else {                        /* perspective view */
                VCOPY(orig, v->vp);
                direc[0] = v->vdir[0] + x*v->hvec[0] + y*v->vvec[0];
                direc[1] = v->vdir[1] + x*v->hvec[1] + y*v->vvec[1];
                direc[2] = v->vdir[2] + x*v->hvec[2] + y*v->vvec[2];
                normalize(direc);
        }
}


viewpixel(xp, yp, zp, v, p)             /* find image location for point */
double  *xp, *yp, *zp;
register VIEW  *v;
FVECT  p;
{
        extern double  sqrt();
        double  d;
        FVECT  disp;

        disp[0] = p[0] - v->vp[0];
        disp[1] = p[1] - v->vp[1];
        disp[2] = p[2] - v->vp[2];

        if (v->type == VT_PAR) {        /* parallel view */
                if (zp != NULL)
                        *zp = DOT(disp,v->vdir);
        } else {                        /* perspective view */
                d = 1.0/DOT(disp,v->vdir);
                if (zp != NULL) {
                        *zp = sqrt(DOT(disp,disp));
                        if (d < 0.0)
                                *zp = -*zp;
                }
                disp[0] *= d;
                disp[1] *= d;
                disp[2] *= d;
        }
        *xp = DOT(disp,v->hvec)/v->hn2 + 0.5 - v->hoff;
        *yp = DOT(disp,v->vvec)/v->vn2 + 0.5 - v->voff;
}


int
getviewopt(v, ac, av)                   /* process view argument */
register VIEW  *v;
int  ac;
register char  *av[];
{
#define check(c,n)      if ((av[0][c]&&av[0][c]!=' ') || n>=ac) return(-1)
        extern double  atof();

        if (av[0][0] != '-' || av[0][1] != 'v')
                return(-1);
        switch (av[0][2]) {
        case 't':                       /* type */
                if (!av[0][3] || av[0][3]==' ')
                        return(-1);
                check(4,0);
                v->type = av[0][3];
                return(0);
        case 'p':                       /* point */
                check(3,3);
                v->vp[0] = atof(av[1]);
                v->vp[1] = atof(av[2]);
                v->vp[2] = atof(av[3]);
                return(3);
        case 'd':                       /* direction */
                check(3,3);
                v->vdir[0] = atof(av[1]);
                v->vdir[1] = atof(av[2]);
                v->vdir[2] = atof(av[3]);
                return(3);
        case 'u':                       /* up */
                check(3,3);
                v->vup[0] = atof(av[1]);
                v->vup[1] = atof(av[2]);
                v->vup[2] = atof(av[3]);
                return(3);
        case 'h':                       /* horizontal size */
                check(3,1);
                v->horiz = atof(av[1]);
                return(1);
        case 'v':                       /* vertical size */
                check(3,1);
                v->vert = atof(av[1]);
                return(1);
        case 's':                       /* shift */
                check(3,1);
                v->hoff = atof(av[1]);
                return(1);
        case 'l':                       /* lift */
                check(3,1);
                v->voff = atof(av[1]);
                return(1);
        default:
                return(-1);
        }
#undef check
}


int
sscanview(vp, s)                        /* get view parameters from string */
VIEW  *vp;
register char  *s;
{
        int  ac;
        char  *av[4];
        int  na;
        int  nvopts = 0;

        while (*s == ' ')
                s++;
        do {
                ac = 0;
                do {
                        av[ac++] = s;
                        while (*s && *s != ' ')
                                s++;
                        while (*s == ' ')
                                s++;
                } while (*s && ac < 4);
                if ((na = getviewopt(vp, ac, av)) >= 0) {
                        if (na+1 < ac)
                                s = av[na+1];
                        nvopts++;
                }
        } while (*s);
        return(nvopts);
}


fprintview(vp, fp)                      /* write out view parameters */
register VIEW  *vp;
FILE  *fp;
{
        fprintf(fp, " -vt%c", vp->type);
        fprintf(fp, " -vp %.6g %.6g %.6g", vp->vp[0], vp->vp[1], vp->vp[2]);
        fprintf(fp, " -vd %.6g %.6g %.6g", vp->vdir[0], vp->vdir[1], vp->vdir[2]);
        fprintf(fp, " -vu %.6g %.6g %.6g", vp->vup[0], vp->vup[1], vp->vup[2]);
        fprintf(fp, " -vh %.6g -vv %.6g", vp->horiz, vp->vert);
        fprintf(fp, " -vs %d -vl %d", vp->hoff, vp->voff);
}


static VIEW  *hview;                    /* view from header */
static int  gothview;                   /* success indicator */
static char  *altname[] = {NULL,"rpict","rview","pinterp",VIEWSTR,NULL};


static
gethview(s)                             /* get view from header */
char  *s;
{
        register char  **an;

        for (an = altname; *an != NULL; an++)
                if (!strncmp(*an, s, strlen(*an))) {
                        if (sscanview(hview, s+strlen(*an)) > 0)
                                gothview++;
                        return;
                }
}


int
viewfile(fname, vp)                     /* get view from file */
char  *fname;
VIEW  *vp;
{
        extern char  *progname;
        FILE  *fp;

        if ((fp = fopen(fname, "r")) == NULL)
                return(-1);

        altname[0] = progname;
        hview = vp;
        gothview = 0;

        getheader(fp, gethview);

        fclose(fp);

        return(gothview);
}
Revision:	1.7
Committed:	Tue Jan 9 11:37:50 1990 UTC (35 years, 10 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 1.6:	+5 -7 lines
Log Message:	fixed routine for computing pixel ratio
#	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	1.7	normaspect(va, ap, xp, yp) /* fix pixel aspect or resolution */
69			double va; /* view aspect ratio */
70			double ap; / pixel aspect in (or out if 0) */
71			int xp, yp; /* x and y resolution in (or out if ap!=0) /
72	greg	1.6	{
73			if (*ap <= FTINY)
74	greg	1.7	ap = va xp / yp; /* compute pixel aspect */
75	greg	1.6	else if (va * xp > ap * *yp)
76			xp = yp / va * ap; / reduce x resolution */
77			else
78			yp = xp * va / ap; / reduce y resolution */
79			}
80
81
82	greg	1.5	viewray(orig, direc, v, x, y) /* compute ray origin and direction */
83	greg	1.1	FVECT orig, direc;
84			register VIEW *v;
85			double x, y;
86			{
87	greg	1.5	x += v->hoff - 0.5;
88			y += v->voff - 0.5;
89	greg	1.1
90			if (v->type == VT_PAR) { /* parallel view */
91	greg	1.5	orig[0] = v->vp[0] + xv->hvec[0] + yv->vvec[0];
92			orig[1] = v->vp[1] + xv->hvec[1] + yv->vvec[1];
93			orig[2] = v->vp[2] + xv->hvec[2] + yv->vvec[2];
94	greg	1.1	VCOPY(direc, v->vdir);
95			} else { /* perspective view */
96			VCOPY(orig, v->vp);
97	greg	1.5	direc[0] = v->vdir[0] + xv->hvec[0] + yv->vvec[0];
98			direc[1] = v->vdir[1] + xv->hvec[1] + yv->vvec[1];
99			direc[2] = v->vdir[2] + xv->hvec[2] + yv->vvec[2];
100	greg	1.1	normalize(direc);
101			}
102			}
103
104
105	greg	1.5	viewpixel(xp, yp, zp, v, p) /* find image location for point */
106	greg	1.3	double xp, yp, *zp;
107			register VIEW *v;
108			FVECT p;
109			{
110			extern double sqrt();
111			double d;
112			FVECT disp;
113	greg	1.5
114	greg	1.3	disp[0] = p[0] - v->vp[0];
115			disp[1] = p[1] - v->vp[1];
116			disp[2] = p[2] - v->vp[2];
117
118			if (v->type == VT_PAR) { /* parallel view */
119			if (zp != NULL)
120			*zp = DOT(disp,v->vdir);
121			} else { /* perspective view */
122			d = 1.0/DOT(disp,v->vdir);
123			if (zp != NULL) {
124			*zp = sqrt(DOT(disp,disp));
125			if (d < 0.0)
126			zp = -zp;
127			}
128			disp[0] *= d;
129			disp[1] *= d;
130			disp[2] *= d;
131			}
132	greg	1.5	*xp = DOT(disp,v->hvec)/v->hn2 + 0.5 - v->hoff;
133			*yp = DOT(disp,v->vvec)/v->vn2 + 0.5 - v->voff;
134	greg	1.3	}
135
136
137	greg	1.5	int
138			getviewopt(v, ac, av) /* process view argument */
139			register VIEW *v;
140			int ac;
141			register char *av[];
142			{
143			#define check(c,n) if ((av[0][c]&&av[0][c]!=' ') \|\| n>=ac) return(-1)
144			extern double atof();
145
146			if (av[0][0] != '-' \|\| av[0][1] != 'v')
147			return(-1);
148			switch (av[0][2]) {
149			case 't': /* type */
150			if (!av[0][3] \|\| av[0][3]==' ')
151			return(-1);
152			check(4,0);
153			v->type = av[0][3];
154			return(0);
155			case 'p': /* point */
156			check(3,3);
157			v->vp[0] = atof(av[1]);
158			v->vp[1] = atof(av[2]);
159			v->vp[2] = atof(av[3]);
160			return(3);
161			case 'd': /* direction */
162			check(3,3);
163			v->vdir[0] = atof(av[1]);
164			v->vdir[1] = atof(av[2]);
165			v->vdir[2] = atof(av[3]);
166			return(3);
167			case 'u': /* up */
168			check(3,3);
169			v->vup[0] = atof(av[1]);
170			v->vup[1] = atof(av[2]);
171			v->vup[2] = atof(av[3]);
172			return(3);
173			case 'h': /* horizontal size */
174			check(3,1);
175			v->horiz = atof(av[1]);
176			return(1);
177			case 'v': /* vertical size */
178			check(3,1);
179			v->vert = atof(av[1]);
180			return(1);
181			case 's': /* shift */
182			check(3,1);
183			v->hoff = atof(av[1]);
184			return(1);
185			case 'l': /* lift */
186			check(3,1);
187			v->voff = atof(av[1]);
188			return(1);
189			default:
190			return(-1);
191			}
192			#undef check
193			}
194
195
196			int
197			sscanview(vp, s) /* get view parameters from string */
198			VIEW *vp;
199	greg	1.1	register char *s;
200			{
201	greg	1.5	int ac;
202			char *av[4];
203			int na;
204			int nvopts = 0;
205
206			while (*s == ' ')
207			s++;
208			do {
209			ac = 0;
210			do {
211			av[ac++] = s;
212			while (s && s != ' ')
213			s++;
214			while (*s == ' ')
215			s++;
216			} while (*s && ac < 4);
217			if ((na = getviewopt(vp, ac, av)) >= 0) {
218			if (na+1 < ac)
219			s = av[na+1];
220			nvopts++;
221	greg	1.1	}
222	greg	1.5	} while (*s);
223			return(nvopts);
224	greg	1.1	}
225
226
227			fprintview(vp, fp) /* write out view parameters */
228			register VIEW *vp;
229			FILE *fp;
230			{
231			fprintf(fp, " -vt%c", vp->type);
232			fprintf(fp, " -vp %.6g %.6g %.6g", vp->vp[0], vp->vp[1], vp->vp[2]);
233			fprintf(fp, " -vd %.6g %.6g %.6g", vp->vdir[0], vp->vdir[1], vp->vdir[2]);
234			fprintf(fp, " -vu %.6g %.6g %.6g", vp->vup[0], vp->vup[1], vp->vup[2]);
235			fprintf(fp, " -vh %.6g -vv %.6g", vp->horiz, vp->vert);
236	greg	1.5	fprintf(fp, " -vs %d -vl %d", vp->hoff, vp->voff);
237	greg	1.1	}
238
239
240			static VIEW hview; / view from header */
241			static int gothview; /* success indicator */
242	greg	1.3	static char *altname[] = {NULL,"rpict","rview","pinterp",VIEWSTR,NULL};
243	greg	1.1
244
245			static
246			gethview(s) /* get view from header */
247			char *s;
248			{
249			register char **an;
250
251			for (an = altname; *an != NULL; an++)
252			if (!strncmp(an, s, strlen(an))) {
253	greg	1.5	if (sscanview(hview, s+strlen(*an)) > 0)
254	greg	1.1	gothview++;
255			return;
256			}
257			}
258
259
260			int
261			viewfile(fname, vp) /* get view from file */
262			char *fname;
263			VIEW *vp;
264			{
265			extern char *progname;
266			FILE *fp;
267
268			if ((fp = fopen(fname, "r")) == NULL)
269			return(-1);
270
271			altname[0] = progname;
272			hview = vp;
273			gothview = 0;
274
275			getheader(fp, gethview);
276
277			fclose(fp);
278
279			return(gothview);
280			}