fix bug in cylindrical projection

If one peak is "left" and one is "right" of north, cylindrical
projection was not able to compute proper viewing parameters.
This is fixed by adjusting alpha angles of known hills to be increasing
with x.

1 files changed, 20 insertions, 0 deletions

diff --git a/src/Hill.cxx b/src/Hill.cxx
index f45c197..b053568 100644
--- a/src/Hill.cxx
+++ b/src/Hill.cxx
@@ -242,6 +242,23 @@ comp_mountains_label_y(const void *n1, const void *n2) {
 	}
 }
 
+static int
+comp_mountains_x(const void *n1, const void *n2) {
+    Hill *m1 = *(Hill **)n1;
+    Hill *m2 = *(Hill **)n2;
+
+    if (m1 && m2) {
+		if (m2->x < m1->x)
+			return 1;
+		else if (m2->x > m1->x)
+			return -1;
+		else
+			return 0;
+    } else {
+        return 0;
+    }
+}
+
 void
 Hills::sort(SortType t) {
 	int (*cmp)(const void *, const void *);
@@ -262,6 +279,9 @@ Hills::sort(SortType t) {
 		case SORT_LABEL_Y:
 			cmp = comp_mountains_label_y;
 			break;
+		case SORT_X:
+			cmp = comp_mountains_x;
+			break;
 		default:
 			fprintf(stderr, "ERROR: Unknown sort type %d\n", t);
 			return;