int
Xtetra(struct place *place, double *x, double *y)
{
int i,j;
struct place pl;
register struct tproj *tpp;
double vr, vi;
double br, bi;
double zr,zi,z2r,z2i,z4r,z4i,sr,si,tr,ti;
twhichp(place,&i,&j);
copyplace(place,&pl);
norm(&pl,&tproj[i][j].projpl,&tproj[i][j].projtw);
Xstereographic(&pl,&vr,&vi);
zr = vr/2;
zi = vi/2;
if(zr<=TFUZZ)
zr = TFUZZ;
csq(zr,zi,&z2r,&z2i);
csq(z2r,z2i,&z4r,&z4i);
z2r *= two_rt3;
z2i *= two_rt3;
cdiv(z4r+z2r-1,z4i+z2i,z4r-z2r-1,z4i-z2i,&sr,&si);
csqrt(sr-1,si,&tr,&ti);
cdiv(tcon*tr,tcon*ti,root3+1-sr,-si,&br,&bi);
if(br<0) {
br = -br;
bi = -bi;
if(!elco2(br,bi,tk,1.,1.,&vr,&vi))
return 0;
vr = fpir - vr;
vi = fpii - vi;
} else
if(!elco2(br,bi,tk,1.,1.,&vr,&vi))
return 0;
if(si>=0) {
tr = f0r - vi;
ti = f0i + vr;
} else {
tr = f0r + vi;
ti = f0i - vr;
}
tpp = &tproj[i][j];
*x = tr*tpp->postrot.c +
ti*tpp->postrot.s + tx[i];
*y = ti*tpp->postrot.c -
tr*tpp->postrot.s + ty[i];
return(1);
}
static int
Xhex(struct place *place, double *x, double *y)
{
int ns;
int i;
double zr,zi;
double sr,si,tr,ti,ur,ui,vr,vi,yr,yi;
struct place p;
copyplace(place,&p);
ns = place->nlat.l >= 0;
if(!ns) {
p.nlat.l = -p.nlat.l;
p.nlat.s = -p.nlat.s;
}
if(p.nlat.l<HFUZZ) {
for(i=0;i<3;i++)
if(fabs(reduce(p.wlon.l-hcut[i]))<HFUZZ) {
if(i==2) {
*x = 2*cr[0] - cr[1];
*y = 0;
} else {
*x = cr[1];
*y = 2*ci[2*i];
}
return(1);
}
p.nlat.l = HFUZZ;
sincos(&p.nlat);
}
norm(&p,&hem,&twist);
Xstereographic(&p,&zr,&zi);
zr /= 2;
zi /= 2;
cdiv(1-zr,-zi,1+zr,zi,&sr,&si);
csq(sr,si,&tr,&ti);
ccubrt(1+3*tr,3*ti,&ur,&ui);
csqrt(ur-1,ui,&vr,&vi);
cdiv(rootroot3+vr,vi,rootroot3-vr,-vi,&yr,&yi);
yr /= rootk;
yi /= rootk;
elco2(fabs(yr),yi,hkc,1.,1.,x,y);
if(yr < 0)
*x = w2 - *x;
if(!ns) reflect(hcut[0]>place->wlon.l?0:
hcut[1]>=place->wlon.l?1:
2,*x,*y,x,y);
return(1);
}
int
elco2(double x, double y, double kc, double a, double b, double *u, double *v)
{
double c,d,dn1,dn2,e,e1,e2,f,f1,f2,h,k,m,m1,m2,sy;
double d1[13],d2[13];
int i,l;
if(kc==0||x<0)
return(0);
sy = y>0? 1: y==0? 0: -1;
y = fabs(y);
csq(x,y,&c,&e2);
d = kc*kc;
k = 1-d;
e1 = 1+c;
cdiv2(1+d*c,d*e2,e1,e2,&f1,&f2);
f2 = -k*x*y*2/f2;
csqr(f1,f2,&dn1,&dn2);
if(f1<0) {
f1 = dn1;
dn1 = -dn2;
dn2 = -f1;
}
if(k<0) {
dn1 = fabs(dn1);
dn2 = fabs(dn2);
}
c = 1+dn1;
cmul(e1,e2,c,dn2,&f1,&f2);
cdiv(x,y,f1,f2,&d1[0],&d2[0]);
h = a-b;
d = f = m = 1;
kc = fabs(kc);
e = a;
a += b;
l = 4;
for(i=1;;i++) {
m1 = (kc+m)/2;
m2 = m1*m1;
k *= f/(m2*4);
b += e*kc;
e = a;
cdiv2(kc+m*dn1,m*dn2,c,dn2,&f1,&f2);
csqr(f1/m1,k*dn2*2/f2,&dn1,&dn2);
cmul(dn1,dn2,x,y,&f1,&f2);
x = fabs(f1);
y = fabs(f2);
a += b/m1;
l *= 2;
c = 1 +dn1;
d *= k/2;
cmul(x,y,x,y,&e1,&e2);
k *= k;
cmul(c,dn2,1+e1*m2,e2*m2,&f1,&f2);
cdiv(d*x,d*y,f1,f2,&d1[i],&d2[i]);
if(k<=CC)
break;
kc = sqrt(m*kc);
f = m2;
m = m1;
}
f1 = f2 = 0;
for(;i>=0;i--) {
f1 += d1[i];
f2 += d2[i];
}
x *= m1;
y *= m1;
cdiv2(1-y,x,1+y,-x,&e1,&e2);
e2 = x*2/e2;
d = a/(m1*l);
*u = atan2(e2,e1);
if(*u<0)
*u += PI;
a = d*sy/2;
*u = d*(*u) + f1*h;
*v = (-1-log(e1*e1+e2*e2))*a + f2*h*sy + a;
return(1);
}
