ref: c3a430e6824a8f1f08f28a8df24b4b64266b06f9
dir: /sys/src/cmd/map/libmap/orthographic.c/
#include <u.h> #include <libc.h> #include "map.h" int Xorthographic(struct place *place, double *x, double *y) { *x = - place->nlat.c * place->wlon.s; *y = - place->nlat.c * place->wlon.c; return(place->nlat.l<0.? 0 : 1); } proj orthographic(void) { return(Xorthographic); } int olimb(double *lat, double *lon, double res) { static first = 1; if(first) { *lat = 0; *lon = -180; first = 0; return 0; } *lon += res; if(*lon <= 180) return 1; first = 1; return -1; }