[core] sort symbols using symbol-sort-key before placement (#16023)

fix #15964
partially port mapbox/mapbox-gl-js#9054

2 files changed, 22 insertions, 10 deletions

diff --git a/src/mbgl/text/placement.cpp b/src/mbgl/text/placement.cpp
index c927fdd782..57cf1f0f1f 100644
--- a/src/mbgl/text/placement.cpp
+++ b/src/mbgl/text/placement.cpp
@@ -1,11 +1,11 @@
-#include <mbgl/text/placement.hpp>
-
+#include <list>
 #include <mbgl/layout/symbol_layout.hpp>
 #include <mbgl/renderer/bucket.hpp>
 #include <mbgl/renderer/buckets/symbol_bucket.hpp>
 #include <mbgl/renderer/render_layer.hpp>
 #include <mbgl/renderer/render_tile.hpp>
 #include <mbgl/renderer/update_parameters.hpp>
+#include <mbgl/text/placement.hpp>
 #include <mbgl/tile/geometry_tile.hpp>
 #include <mbgl/util/math.hpp>
 #include <utility>
@@ -113,7 +113,12 @@ void Placement::placeLayer(const RenderLayer& layer) {
     std::set<uint32_t> seenCrossTileIDs;
     for (const auto& item : layer.getPlacementData()) {
         Bucket& bucket = item.bucket;
-        BucketPlacementParameters params{item.tile, layer.baseImpl->source, item.featureIndex};
+        BucketPlacementParameters params{item.tile,
+                                         layer.baseImpl->source,
+                                         item.featureIndex,
+                                         item.sortKey,
+                                         item.symbolInstanceStart,
+                                         item.symbolInstanceEnd};
         bucket.place(*this, params, seenCrossTileIDs);
     }
 }
@@ -656,18 +661,20 @@ void Placement::placeBucket(const SymbolBucket& bucket,
         }
 
     } else {
-        for (const SymbolInstance& symbol : bucket.symbolInstances) {
-            placeSymbol(symbol);
+        auto beginIt = bucket.symbolInstances.begin() + params.symbolInstanceStart;
+        auto endIt = bucket.symbolInstances.begin() + params.symbolInstanceEnd;
+        assert(params.symbolInstanceStart < params.symbolInstanceEnd);
+        assert(params.symbolInstanceEnd <= bucket.symbolInstances.size());
+        for (auto it = beginIt; it != endIt; ++it) {
+            placeSymbol(*it);
         }
     }
 
-    bucket.justReloaded = false;
-
     // As long as this placement lives, we have to hold onto this bucket's
     // matching FeatureIndex/data for querying purposes
     retainedQueryData.emplace(std::piecewise_construct,
-                                std::forward_as_tuple(bucket.bucketInstanceId),
-                                std::forward_as_tuple(bucket.bucketInstanceId, params.featureIndex, overscaledID));
+                              std::forward_as_tuple(bucket.bucketInstanceId),
+                              std::forward_as_tuple(bucket.bucketInstanceId, params.featureIndex, overscaledID));
 }
 
 void Placement::commit() {
@@ -737,7 +744,9 @@ void Placement::commit() {
 void Placement::updateLayerBuckets(const RenderLayer& layer, const TransformState& state, bool updateOpacities) const {
     std::set<uint32_t> seenCrossTileIDs;
     for (const auto& item : layer.getPlacementData()) {
-        item.bucket.get().updateVertices(*this, updateOpacities, state, item.tile, seenCrossTileIDs);
+        if (item.firstInBucket) {
+            item.bucket.get().updateVertices(*this, updateOpacities, state, item.tile, seenCrossTileIDs);
+        }
     }
 }
 
diff --git a/src/mbgl/text/placement.hpp b/src/mbgl/text/placement.hpp
index 46d560b673..9fbd6b9743 100644
--- a/src/mbgl/text/placement.hpp
+++ b/src/mbgl/text/placement.hpp
@@ -91,6 +91,9 @@ public:
     const RenderTile& tile;
     std::string sourceId;
     std::shared_ptr<FeatureIndex> featureIndex;
+    float sortKey;
+    size_t symbolInstanceStart;
+    size_t symbolInstanceEnd;
 };
 
 class Placement;