/*  * This file is part of the UCB release of Plan 9. It is subject to the license * terms in the LICENSE file found in the top-level directory of this * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No * part of the UCB release of Plan 9, including this file, may be copied, * modified, propagated, or distributed except according to the terms contained * in the LICENSE file. */ #include <u.h>#include <libc.h>#include "map.h" static struct place gywhem, gyehem;static struct coord gytwist;static double gyconst, gykc, gyside;  static voiddosquare(double z1, double z2, double *x, double *y){	double w1,w2;	w1 = z1 -1;	if(fabs(w1*w1+z2*z2)>.000001) {		cdiv(z1+1,z2,w1,z2,&w1,&w2);		w1 *= gyconst;		w2 *= gyconst;		if(w1<0)			w1 = 0;		elco2(w1,w2,gykc,1.,1.,x,y);	} else {		*x = gyside;		*y = 0;	}} intXguyou(struct place *place, double *x, double *y){	int ew;		/*which hemisphere*/	double z1,z2;	struct place pl;	ew = place->wlon.l<0;	copyplace(place,&pl);	norm(&pl,ew?&gyehem:&gywhem,&gytwist);	Xstereographic(&pl,&z1,&z2);	dosquare(z1/2,z2/2,x,y);	if(!ew)		*x -= gyside;	return(1);} projguyou(void){	double junk;	gykc = 1/(3+2*sqrt(2.));	gyconst = -(1+sqrt(2.));	elco2(-gyconst,0.,gykc,1.,1.,&gyside,&junk);	gyside *= 2;	latlon(0.,90.,&gywhem);	latlon(0.,-90.,&gyehem);	deg2rad(0.,&gytwist);	return(Xguyou);} intguycut(struct place *g, struct place *og, double *cutlon){	int c;	c = picut(g,og,cutlon);	if(c!=1)		return(c);	*cutlon = 0.;	if(g->nlat.c<.7071||og->nlat.c<.7071)		return(ckcut(g,og,0.));	return(1);} static intXsquare(struct place *place, double *x, double *y){	double z1,z2;	double r, theta;	struct place p;	copyplace(place,&p);	if(place->nlat.l<0) {		p.nlat.l = -p.nlat.l;		p.nlat.s = -p.nlat.s;	}	if(p.nlat.l<FUZZ && fabs(p.wlon.l)>PI-FUZZ){		*y = -gyside/2;		*x = p.wlon.l>0?0:gyside;		return(1);	}	Xstereographic(&p,&z1,&z2);	r = sqrt(sqrt(hypot(z1,z2)/2));	theta = atan2(z1,-z2)/4;	dosquare(r*sin(theta),-r*cos(theta),x,y);	if(place->nlat.l<0)		*y = -gyside - *y;	return(1);} projsquare(void){	guyou();	return(Xsquare);}