[core] Restored shape annotation z-order

Shapes are once again always added to the top z-index.

Fixes #5691.

platform/ios/CHANGELOG.md

@@ -4,6 +4,7 @@ Mapbox welcomes participation and contributions from everyone.  Please read [CON
 
 ## master
 
+* Fixed an issue causing overlapping polylines and polygons to be drawn in undefined z-order. Shapes are always drawn in the order they are added to the map, from the oldest on the bottom to the newest on the top. ([#5710](https://github.com/mapbox/mapbox-gl-native/pull/5710))
 * Added [quadkey](https://msdn.microsoft.com/en-us/library/bb259689.aspx) support and limited WMS support in raster tile URL templates. ([#5628](https://github.com/mapbox/mapbox-gl-native/pull/5628))
 
 ## 3.3.0

platform/macos/CHANGELOG.md

@@ -3,6 +3,7 @@
 ## master
 
 * Right-clicking to open MGLMapView’s context menu no longer prevents the user from subsequently panning the map by clicking and dragging. ([#5593](https://github.com/mapbox/mapbox-gl-native/pull/5593))
+* Fixed an issue causing overlapping polylines and polygons to be drawn in undefined z-order. Shapes are always drawn in the order they are added to the map, from the oldest on the bottom to the newest on the top. ([#5710](https://github.com/mapbox/mapbox-gl-native/pull/5710))
 * Replaced the wireframe debug mask with an overdraw visualization debug mask to match Mapbox GL JS’s overdraw inspector. ([#5403](https://github.com/mapbox/mapbox-gl-native/pull/5403))
 * Improved the design of the generated API documentation. ([#5306](https://github.com/mapbox/mapbox-gl-native/pull/5306))
 * Added [quadkey](https://msdn.microsoft.com/en-us/library/bb259689.aspx) support and limited WMS support in raster tile URL templates. ([#5628](https://github.com/mapbox/mapbox-gl-native/pull/5628))

src/mbgl/annotation/annotation_manager.hpp

@@ -67,8 +67,10 @@ private:
     AnnotationID nextID = 0;
 
     using SymbolAnnotationTree = boost::geometry::index::rtree<std::shared_ptr<const SymbolAnnotationImpl>, boost::geometry::index::rstar<16, 4>>;
-    using SymbolAnnotationMap = std::unordered_map<AnnotationID, std::shared_ptr<SymbolAnnotationImpl>>;
-    using ShapeAnnotationMap = std::unordered_map<AnnotationID, std::unique_ptr<ShapeAnnotationImpl>>;
+    // Unlike std::unordered_map, std::map is guaranteed to sort by AnnotationID, ensuring that older annotations are below newer annotations.
+    // <https://github.com/mapbox/mapbox-gl-native/issues/5691>
+    using SymbolAnnotationMap = std::map<AnnotationID, std::shared_ptr<SymbolAnnotationImpl>>;
+    using ShapeAnnotationMap = std::map<AnnotationID, std::unique_ptr<ShapeAnnotationImpl>>;
 
     SymbolAnnotationTree symbolTree;
     SymbolAnnotationMap symbolAnnotations;

test/api/annotations.cpp

@@ -79,6 +79,21 @@ TEST(Annotations, FillAnnotation) {
     test.checkRendering("fill_annotation_max_zoom");
 }
 
+TEST(Annotations, OverlappingFillAnnotation) {
+    AnnotationTest test;
+
+    Polygon<double> polygon = {{ {{ { 0, 0 }, { 0, 45 }, { 45, 45 }, { 45, 0 } }} }};
+    FillAnnotation underlaidAnnotation { polygon };
+    underlaidAnnotation.color = { { 0, 255, 0, 1 } };
+    FillAnnotation overlaidAnnotation { polygon };
+    overlaidAnnotation.color = { { 255, 0, 0, 1 } };
+
+    test.map.setStyleJSON(util::read_file("test/fixtures/api/empty.json"));
+    test.map.addAnnotation(underlaidAnnotation);
+    test.map.addAnnotation(overlaidAnnotation);
+    test.checkRendering("overlapping_fill_annotation");
+}
+
 TEST(Annotations, StyleSourcedShapeAnnotation) {
     AnnotationTest test;