[core] Fix LatLngBounds default coordinates

LatLngBounds southwest and northeast coordinate points were inverted, so
they could be extended via LatLngBounds::extend(). However, this looks
confusing and error-prone.

A static LatLngBounds::getExtendable() is added to address cases when we
want to extend LatLngBounds.

1 files changed, 10 insertions, 3 deletions

diff --git a/include/mbgl/util/geo.hpp b/include/mbgl/util/geo.hpp
index 98b5daa6f5..4112b183b2 100644
--- a/include/mbgl/util/geo.hpp
+++ b/include/mbgl/util/geo.hpp
@@ -41,12 +41,19 @@ struct ProjectedMeters {
 };
 
 struct LatLngBounds {
-    LatLng sw = {90, 180};
-    LatLng ne = {-90, -180};
+    LatLng sw = {-90, -180};
+    LatLng ne = {90, 180};
 
-    inline LatLngBounds(const LatLng& sw_ = {90, 180}, const LatLng& ne_ = {-90, -180})
+    inline LatLngBounds() {}
+
+    inline LatLngBounds(const LatLng& sw_, const LatLng& ne_)
         : sw(sw_), ne(ne_) {}
 
+    static inline LatLngBounds getExtendable() {
+        LatLngBounds bounds;
+        return { bounds.ne, bounds.sw };
+    }
+
     inline operator bool() const {
         return sw && ne;
     }