reduce maxPlacementScale

implements https://github.com/mapbox/mapbox-gl-js/commit/871883d569c932137d00b045eb47e14f4798ebc5

3 files changed, 6 insertions, 4 deletions

diff --git a/include/mbgl/text/placement.hpp b/include/mbgl/text/placement.hpp
index 69a1a10b72..aa03712e30 100644
--- a/include/mbgl/text/placement.hpp
+++ b/include/mbgl/text/placement.hpp
@@ -14,7 +14,7 @@ class StyleBucketText;
 
 class Placement {
 public:
-    Placement(int8_t zoom);
+    Placement(int8_t zoom, float placementDepth);
 
     void addFeature(TextBucket &bucket, const std::vector<Coordinate> &line,
                     const StyleBucketText &info,
diff --git a/src/map/tile_parser.cpp b/src/map/tile_parser.cpp
index 23d819db0b..807e827972 100644
--- a/src/map/tile_parser.cpp
+++ b/src/map/tile_parser.cpp
@@ -42,7 +42,7 @@ TileParser::TileParser(const std::string &data, VectorTileData &tile,
       glyphAtlas(glyphAtlas),
       glyphStore(glyphStore),
       spriteAtlas(spriteAtlas),
-      placement(tile.id.z) {
+      placement(tile.id.z, tile.id.z >= tile.source.max_zoom ? tile.source.max_zoom - tile.id.z : 1) {
 }
 
 void TileParser::parse() {
diff --git a/src/text/placement.cpp b/src/text/placement.cpp
index 40732765f3..b278a8bfb8 100644
--- a/src/text/placement.cpp
+++ b/src/text/placement.cpp
@@ -14,7 +14,7 @@ const int Placement::glyphSize =
     24; // size in pixels of this glyphs in the tile
 const float Placement::minScale = 0.5; // underscale by 1 zoom level
 
-Placement::Placement(int8_t zoom)
+Placement::Placement(int8_t zoom, float placementDepth)
     : zoom(zoom),
       zOffset(log(512.0 / util::tileSize) / log(2)),
 
@@ -27,7 +27,9 @@ Placement::Placement(int8_t zoom)
       // glyphs be placed, slowing down collision checking. Only place labels if
       // they will show up within the intended zoom range of the tile.
       // TODO make this not hardcoded to 3
-      maxPlacementScale(std::exp(log(2) * util::min((25.5 - zoom), 3.0))) {}
+      maxPlacementScale(std::exp(
+          log(2) *
+          util::min(3.0f, util::min(placementDepth > 0 ? placementDepth : 1.0f, 25.5f - zoom)))) {}
 
 bool byScale(const Anchor &a, const Anchor &b) { return a.scale < b.scale; }