1 files changed, 26 insertions, 0 deletions
diff --git a/src/cmd/map/libmap/fisheye.c b/src/cmd/map/libmap/fisheye.c
new file mode 100644
index 00000000..412d65e7
--- /dev/null
+++ b/src/cmd/map/libmap/fisheye.c
@@ -0,0 +1,26 @@
+#include <u.h>
+#include <libc.h>
+#include "map.h"
+/* refractive fisheye, not logarithmic */
+
+static double n;
+
+static int
+Xfisheye(struct place *place, double *x, double *y)
+{
+	double r;
+	double u = sin(PI/4-place->nlat.l/2)/n;
+	if(fabs(u) > .97)
+		return -1;
+	r = tan(asin(u));
+	*x = -r*place->wlon.s;
+	*y = -r*place->wlon.c;
+	return 1;
+}
+
+proj
+fisheye(double par)
+{
+	n = par;
+	return n<.1? 0: Xfisheye;
+}