Warning: Attempt to read property "date" on null in /usr/local/www/websvn.planix.org/blame.php on line 247

Warning: Attempt to read property "msg" on null in /usr/local/www/websvn.planix.org/blame.php on line 247
WebSVN – planix.SVN – Blame – /os/branches/feature_tlsv12/sys/src/cmd/map/libmap/perspective.c – Rev 2

Subversion Repositories planix.SVN

Rev

Go to most recent revision | Details | Last modification | View Log | RSS feed

Rev Author Line No. Line
2 - 1 
#include <u.h>
2 
#include <libc.h>
3 
#include "map.h"
4 
 
5 
#define ORTHRAD 1000
6 
static double viewpt;
7 
 
8 
static int
9 
Xperspective(struct place *place, double *x, double *y)
10 
{
11 
	double r;
12 
	if(viewpt<=1+FUZZ && fabs(place->nlat.s<=viewpt+.01))
13 
		return(-1);
14 
	r = place->nlat.c*(viewpt - 1.)/(viewpt - place->nlat.s);
15 
	*x = - r*place->wlon.s;
16 
	*y = - r*place->wlon.c;
17 
	if(r>4.)
18 
		return(-1);
19 
	if(fabs(viewpt)>1 && place->nlat.s<1/viewpt ||
20 
	   fabs(viewpt)<=1 && place->nlat.s<viewpt)
21 
			return 0;
22 
	return(1);
23 
}
24 
 
25 
proj
26 
perspective(double radius)
27 
{
28 
	viewpt = radius;
29 
	if(viewpt >= ORTHRAD)
30 
		return(Xorthographic);
31 
	if(fabs(viewpt-1.)<.0001)
32 
		return(0);
33 
	return(Xperspective);
34 
}
35 
 
36 
	/* called from various conformal projections,
37 
           but not from stereographic itself */
38 
int
39 
Xstereographic(struct place *place, double *x, double *y)
40 
{
41 
	double v = viewpt;
42 
	int retval;
43 
	viewpt = -1;
44 
	retval = Xperspective(place, x, y);
45 
	viewpt = v;
46 
	return retval;
47 
}
48 
 
49 
proj
50 
stereographic(void)
51 
{
52 
	viewpt = -1.;
53 
	return(Xperspective);
54 
}
55 
 
56 
proj
57 
gnomonic(void)
58 
{
59 
	viewpt = 0.;
60 
	return(Xperspective);
61 
}
62 
 
63 
int
64 
plimb(double *lat, double *lon, double res)
65 
{
66 
	static first = 1;
67 
	if(viewpt >= ORTHRAD)
68 
		return olimb(lat, lon, res);
69 
	if(first) {
70 
		first = 0;
71 
		*lon = -180;
72 
		if(fabs(viewpt) < .01)
73 
			*lat = 0;
74 
		else if(fabs(viewpt)<=1)
75 
			*lat = asin(viewpt)/RAD;
76 
		else
77 
			*lat = asin(1/viewpt)/RAD;
78 
	} else
79 
		*lon += res;
80 
	if(*lon <= 180)
81 
		return 1;
82 
	first = 1;
83 
	return -1;
84 
}