[core] Normalize tile coordinates in VectorTile (#4966)

Previously, vector tile coordinates were being normalized to util::EXTENT in each place they were used, and for annotation and GeoJSON sources that don't require normalization.

3 files changed, 2 insertions, 9 deletions

diff --git a/src/mbgl/tile/geometry_tile.hpp b/src/mbgl/tile/geometry_tile.hpp
index 923585028c..676c18e4c9 100644
--- a/src/mbgl/tile/geometry_tile.hpp
+++ b/src/mbgl/tile/geometry_tile.hpp
@@ -34,15 +34,12 @@ using GeometryCollection  = std::vector<GeometryCoordinates>;
 
 class GeometryTileFeature : private util::noncopyable {
 public:
-    static const uint32_t defaultExtent = util::EXTENT;
-
     virtual ~GeometryTileFeature() = default;
     virtual FeatureType getType() const = 0;
     virtual optional<Value> getValue(const std::string& key) const = 0;
     virtual Feature::property_map getProperties() const { return Feature::property_map(); }
     virtual optional<uint64_t> getID() const { return {}; }
     virtual GeometryCollection getGeometries() const = 0;
-    virtual uint32_t getExtent() const { return defaultExtent; }
 };
 
 class GeometryTileLayer : private util::noncopyable {
diff --git a/src/mbgl/tile/vector_tile.cpp b/src/mbgl/tile/vector_tile.cpp
index 27edd85324..343224052a 100644
--- a/src/mbgl/tile/vector_tile.cpp
+++ b/src/mbgl/tile/vector_tile.cpp
@@ -114,6 +114,7 @@ GeometryCollection VectorTileFeature::getGeometries() const {
     uint32_t length = 0;
     int32_t x = 0;
     int32_t y = 0;
+    const float scale = float(util::EXTENT) / layer.extent;
 
     GeometryCollection lines;
 
@@ -139,7 +140,7 @@ GeometryCollection VectorTileFeature::getGeometries() const {
                 line = &lines.back();
             }
 
-            line->emplace_back(x, y);
+            line->emplace_back(::round(x * scale), ::round(y * scale));
 
         } else if (cmd == 7) { // closePolygon
             if (!line->empty()) {
@@ -154,10 +155,6 @@ GeometryCollection VectorTileFeature::getGeometries() const {
     return lines;
 }
 
-uint32_t VectorTileFeature::getExtent() const {
-    return layer.extent;
-}
-
 VectorTile::VectorTile(std::shared_ptr<const std::string> data_)
     : data(std::move(data_)) {
 }
diff --git a/src/mbgl/tile/vector_tile.hpp b/src/mbgl/tile/vector_tile.hpp
index c0892cd243..d41d4f4f34 100644
--- a/src/mbgl/tile/vector_tile.hpp
+++ b/src/mbgl/tile/vector_tile.hpp
@@ -25,7 +25,6 @@ public:
     std::unordered_map<std::string,Value> getProperties() const override;
     optional<uint64_t> getID() const override;
     GeometryCollection getGeometries() const override;
-    uint32_t getExtent() const override;
 
 private:
     const VectorTileLayer& layer;