torthographic.c - plan9port - [fork] Plan 9 from user space
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       ---
       torthographic.c (494B)
       ---
            1 #include <u.h>
            2 #include <libc.h>
            3 #include "map.h"
            4 
            5 
            6 int
            7 Xorthographic(struct place *place, double *x, double *y)
            8 {
            9         *x = - place->nlat.c * place->wlon.s;
           10         *y = - place->nlat.c * place->wlon.c;
           11         return(place->nlat.l<0.? 0 : 1);
           12 }
           13 
           14 proj
           15 orthographic(void)
           16 {
           17         return(Xorthographic);
           18 }
           19 
           20 int
           21 olimb(double *lat, double *lon, double res)
           22 {
           23         static int first  = 1;
           24         if(first) {
           25                 *lat = 0;
           26                 *lon = -180;
           27                 first = 0;
           28                 return 0;
           29         }
           30         *lon += res;
           31         if(*lon <= 180)
           32                 return 1;
           33         first = 1;
           34         return -1;
           35 }