Improve rendering performance of symbols with symbol-sort-key (#9751)

* Dont sort symbol features if they dont overlap * Move canOverlap to SymbolBucket constructor * Remove leftover function arguments
mapbox · Aug 11, 2020 · e1e68a8 · e1e68a8
1 parent f8e1238
commit e1e68a8
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Showing 2 changed files with 12 additions and 5 deletions.
diff --git a/src/data/bucket/symbol_bucket.js b/src/data/bucket/symbol_bucket.js
@@ -322,6 +322,7 @@ class SymbolBucket implements Bucket {
     fadeStartTime: number;
     sortFeaturesByKey: boolean;
     sortFeaturesByY: boolean;
+    canOverlap: boolean;
     sortedAngle: number;
     featureSortOrder: Array<number>;
 
@@ -367,10 +368,14 @@ class SymbolBucket implements Bucket {
         const layout = this.layers[0].layout;
         const sortKey = layout.get('symbol-sort-key');
         const zOrder = layout.get('symbol-z-order');
+        this.canOverlap =
+            layout.get('text-allow-overlap') ||
+            layout.get('icon-allow-overlap') ||
+            layout.get('text-ignore-placement') ||
+            layout.get('icon-ignore-placement');
         this.sortFeaturesByKey = zOrder !== 'viewport-y' && sortKey.constantOr(1) !== undefined;
         const zOrderByViewportY = zOrder === 'viewport-y' || (zOrder === 'auto' && !this.sortFeaturesByKey);
-        this.sortFeaturesByY = zOrderByViewportY && (layout.get('text-allow-overlap') || layout.get('icon-allow-overlap') ||
-            layout.get('text-ignore-placement') || layout.get('icon-ignore-placement'));
+        this.sortFeaturesByY = zOrderByViewportY && this.canOverlap;
 
         if (layout.get('symbol-placement') === 'point') {
             this.writingModes = layout.get('text-writing-mode').map(wm => WritingMode[wm]);
@@ -618,7 +623,7 @@ class SymbolBucket implements Bucket {
         const indexArray = arrays.indexArray;
         const layoutVertexArray = arrays.layoutVertexArray;
 
-        const segment = arrays.segments.prepareSegment(4 * quads.length, layoutVertexArray, indexArray, feature.sortKey);
+        const segment = arrays.segments.prepareSegment(4 * quads.length, layoutVertexArray, indexArray, this.canOverlap ? feature.sortKey : undefined);
         const glyphOffsetArrayStart = this.glyphOffsetArray.length;
         const vertexStartIndex = segment.vertexLength;
 

diff --git a/src/render/draw_symbol.js b/src/render/draw_symbol.js
@@ -236,7 +236,8 @@ function drawLayerSymbols(painter, sourceCache, layer, coords, isText, translate
     // Unpitched point labels need to have their rotation applied after projection
     const rotateInShader = rotateWithMap && !pitchWithMap && !alongLine;
 
-    const sortFeaturesByKey = layer.layout.get('symbol-sort-key').constantOr(1) !== undefined;
+    const hasSortKey = layer.layout.get('symbol-sort-key').constantOr(1) !== undefined;
+    let sortFeaturesByKey = false;
 
     const depthMode = painter.depthModeForSublayer(0, DepthMode.ReadOnly);
 
@@ -333,7 +334,8 @@ function drawLayerSymbols(painter, sourceCache, layer, coords, isText, translate
             hasHalo
         };
 
-        if (sortFeaturesByKey) {
+        if (hasSortKey && bucket.canOverlap) {
+            sortFeaturesByKey = true;
             const oldSegments = buffers.segments.get();
             for (const segment of oldSegments) {
                 tileRenderState.push({