[core] Do not index and place the off-screen symbols for overscaled tiles

For overscaled tiles the viewport might be showing only a small part of the
tile, so we filter out the off-screen symbols to improve the performance.

4 files changed, 9 insertions, 6 deletions

diff --git a/src/mbgl/renderer/bucket.hpp b/src/mbgl/renderer/bucket.hpp
index 3e756a06a4..fc34f55e75 100644
--- a/src/mbgl/renderer/bucket.hpp
+++ b/src/mbgl/renderer/bucket.hpp
@@ -56,7 +56,7 @@ public:
     // Returns a pair, the first element of which is a bucket cross-tile id
     // on success call; `0` otherwise. The second element is `true` if
     // the bucket was originally registered; `false` otherwise.
-    virtual std::pair<uint32_t, bool> registerAtCrossTileIndex(CrossTileSymbolLayerIndex&, const OverscaledTileID&) {
+    virtual std::pair<uint32_t, bool> registerAtCrossTileIndex(CrossTileSymbolLayerIndex&, const RenderTile&) {
         return std::make_pair(0u, false);
     }
     // Places this bucket to the given placement.
diff --git a/src/mbgl/renderer/buckets/symbol_bucket.cpp b/src/mbgl/renderer/buckets/symbol_bucket.cpp
index 382aac6563..55002e7851 100644
--- a/src/mbgl/renderer/buckets/symbol_bucket.cpp
+++ b/src/mbgl/renderer/buckets/symbol_bucket.cpp
@@ -1,6 +1,7 @@
+#include <mbgl/renderer/bucket_parameters.hpp>
 #include <mbgl/renderer/buckets/symbol_bucket.hpp>
 #include <mbgl/renderer/layers/render_symbol_layer.hpp>
-#include <mbgl/renderer/bucket_parameters.hpp>
+#include <mbgl/renderer/render_tile.hpp>
 #include <mbgl/style/layers/symbol_layer_impl.hpp>
 #include <mbgl/text/cross_tile_symbol_index.hpp>
 #include <mbgl/text/glyph_atlas.hpp>
@@ -37,6 +38,7 @@ SymbolBucket::SymbolBucket(Immutable<style::SymbolLayoutProperties::PossiblyEval
       iconsInText(iconsInText_),
       justReloaded(false),
       hasVariablePlacement(false),
+      hasUninitializedSymbols(false),
       symbolInstances(symbolInstances_),
       textSizeBinder(SymbolSizeBinder::create(zoom, textSize, TextSize::defaultValue())),
       iconSizeBinder(SymbolSizeBinder::create(zoom, iconSize, IconSize::defaultValue())),
@@ -296,8 +298,8 @@ bool SymbolBucket::hasFormatSectionOverrides() const {
 }
 
 std::pair<uint32_t, bool> SymbolBucket::registerAtCrossTileIndex(CrossTileSymbolLayerIndex& index,
-                                                                 const OverscaledTileID& tileID) {
-    bool firstTimeAdded = index.addBucket(tileID, *this);
+                                                                 const RenderTile& renderTile) {
+    bool firstTimeAdded = index.addBucket(renderTile.getOverscaledTileID(), renderTile.matrix, *this);
     return std::make_pair(bucketInstanceId, firstTimeAdded);
 }
 
diff --git a/src/mbgl/renderer/buckets/symbol_bucket.hpp b/src/mbgl/renderer/buckets/symbol_bucket.hpp
index 432589a52b..82d8c682aa 100644
--- a/src/mbgl/renderer/buckets/symbol_bucket.hpp
+++ b/src/mbgl/renderer/buckets/symbol_bucket.hpp
@@ -81,7 +81,7 @@ public:
 
     void upload(gfx::UploadPass&) override;
     bool hasData() const override;
-    std::pair<uint32_t, bool> registerAtCrossTileIndex(CrossTileSymbolLayerIndex&, const OverscaledTileID&) override;
+    std::pair<uint32_t, bool> registerAtCrossTileIndex(CrossTileSymbolLayerIndex&, const RenderTile&) override;
     void place(Placement&, const BucketPlacementParameters&, std::set<uint32_t>&) override;
     void updateVertices(
         const Placement&, bool updateOpacities, const TransformState&, const RenderTile&, std::set<uint32_t>&) override;
@@ -114,6 +114,7 @@ public:
     // Set and used by placement.
     mutable bool justReloaded : 1;
     bool hasVariablePlacement : 1;
+    bool hasUninitializedSymbols : 1;
 
     std::vector<SymbolInstance> symbolInstances;
 
diff --git a/src/mbgl/renderer/render_orchestrator.cpp b/src/mbgl/renderer/render_orchestrator.cpp
index 79059164ae..c771bd100b 100644
--- a/src/mbgl/renderer/render_orchestrator.cpp
+++ b/src/mbgl/renderer/render_orchestrator.cpp
@@ -422,7 +422,7 @@ std::unique_ptr<RenderTree> RenderOrchestrator::createRenderTree(
             Mutable<Placement> placement = makeMutable<Placement>(updateParameters);
             for (auto it = layersNeedPlacement.crbegin(); it != layersNeedPlacement.crend(); ++it) {
                 const RenderLayer& layer = *it;
-                crossTileSymbolIndex.addLayer(layer, updateParameters->transformState);
+                crossTileSymbolIndex.addLayer(layer, longitude);
                 placement->placeLayer(layer);
             }
             placement->commit();