Subversion Repositories planix.SVN

#include <u.h>
#include <libc.h>
#include "map.h"
/* refractive fisheye, not logarithmic */

static double n;

static int
Xfisheye(struct place *place, double *x, double *y)
{
        double r;
        double u = sin(PI/4-place->nlat.l/2)/n;
        if(fabs(u) > .97)
                return -1;
        r = tan(asin(u));
        *x = -r*place->wlon.s;
        *y = -r*place->wlon.c;
        return 1;
}

proj
fisheye(double par)
{
        n = par;
        return n<.1? 0: Xfisheye;
}