1 files changed, 35 insertions, 0 deletions
diff --git a/src/cmd/map/libmap/orthographic.c b/src/cmd/map/libmap/orthographic.c
new file mode 100644
index 00000000..7aac5b15
--- /dev/null
+++ b/src/cmd/map/libmap/orthographic.c
@@ -0,0 +1,35 @@
+#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 int first  = 1;
+	if(first) {
+		*lat = 0;
+		*lon = -180;
+		first = 0;
+		return 0;
+	}
+	*lon += res;
+	if(*lon <= 180)
+		return 1;
+	first = 1;
+	return -1;
+}