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#include <u.h>
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#include <libc.h>
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#include "map.h"
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/* refractive fisheye, not logarithmic */
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static double n;
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static int
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Xfisheye(struct place *place, double *x, double *y)
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{
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	double r;
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	double u = sin(PI/4-place->nlat.l/2)/n;
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	if(fabs(u) > .97)
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		return -1;
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	r = tan(asin(u));
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	*x = -r*place->wlon.s;
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	*y = -r*place->wlon.c;
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	return 1;
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}
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proj
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fisheye(double par)
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{
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	n = par;
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	return n<.1? 0: Xfisheye;
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}