Quadtree performance

CHANGES.md

@@ -12,6 +12,7 @@
 - Improved performance and reduced memory usage of `Event` class. [#12896](https://github.com/CesiumGS/cesium/pull/12896)
 - Fixes vertical misalignment of glyphs in labels with small fonts [#8474](https://github.com/CesiumGS/cesium/issues/8474)
 - Prevent runtime errors for certain forms of invalid PNTS files [#12872](https://github.com/CesiumGS/cesium/issues/12872)
+- Improved performance of terrain Quadtree handling of custom data [#12907](https://github.com/CesiumGS/cesium/pull/12907)
 
 #### Additions :tada:
 

packages/engine/Source/Scene/GlobeSurfaceTile.js

@@ -493,10 +493,8 @@ GlobeSurfaceTile.prototype.updateExaggeration = function (
     if (quadtree !== undefined) {
       quadtree._tileToUpdateHeights.push(tile);
       const customData = tile.customData;
-      const customDataLength = customData.length;
-      for (let i = 0; i < customDataLength; i++) {
+      for (const data of customData) {
         // Restart the level so that a height update is triggered
-        const data = customData[i];
         data.level = -1;
       }
     }

packages/engine/Source/Scene/QuadtreePrimitive.js

@@ -90,7 +90,6 @@ function QuadtreePrimitive(options) {
   this._removeHeightCallbacks = [];
 
   this._tileToUpdateHeights = [];
-  this._lastTileIndex = 0;
   this._updateHeightsTimeSlice = 2.0;
 
   // If a culled tile contains _cameraPositionCartographic or _cameraReferenceFrameOriginCartographic, it will be marked
@@ -217,10 +216,8 @@ function invalidateAllTiles(primitive) {
     for (let i = 0; i < levelZeroTiles.length; ++i) {
       const tile = levelZeroTiles[i];
       const customData = tile.customData;
-      const customDataLength = customData.length;
 
-      for (let j = 0; j < customDataLength; ++j) {
-        const data = customData[j];
+      for (const data of customData) {
         data.level = 0;
         primitive._addHeightCallbacks.push(data);
       }
@@ -513,7 +510,6 @@ function selectTilesForRendering(primitive, frameState) {
   tilesToRender.length = 0;
 
   // We can't render anything before the level zero tiles exist.
-  let i;
   const tileProvider = primitive._tileProvider;
   if (!defined(primitive._levelZeroTiles)) {
     const tilingScheme = tileProvider.tilingScheme;
@@ -524,7 +520,7 @@ function selectTilesForRendering(primitive, frameState) {
       const numberOfRootTiles = primitive._levelZeroTiles.length;
       if (rootTraversalDetails.length < numberOfRootTiles) {
         rootTraversalDetails = new Array(numberOfRootTiles);
-        for (i = 0; i < numberOfRootTiles; ++i) {
+        for (let i = 0; i < numberOfRootTiles; ++i) {
           if (rootTraversalDetails[i] === undefined) {
             rootTraversalDetails[i] = new TraversalDetails();
           }
@@ -537,7 +533,6 @@ function selectTilesForRendering(primitive, frameState) {
 
   primitive._occluders.ellipsoid.cameraPosition = frameState.camera.positionWC;
 
-  let tile;
   const levelZeroTiles = primitive._levelZeroTiles;
   const occluders =
     levelZeroTiles.length > 1 ? primitive._occluders : undefined;
@@ -550,18 +545,28 @@ function selectTilesForRendering(primitive, frameState) {
 
   const customDataAdded = primitive._addHeightCallbacks;
   const customDataRemoved = primitive._removeHeightCallbacks;
-  const frameNumber = frameState.frameNumber;
 
-  let len;
-  if (customDataAdded.length > 0 || customDataRemoved.length > 0) {
-    for (i = 0, len = levelZeroTiles.length; i < len; ++i) {
-      tile = levelZeroTiles[i];
-      tile._updateCustomData(frameNumber, customDataAdded, customDataRemoved);
+  customDataAdded.forEach((data) => {
+    const tile = levelZeroTiles.find((tile) =>
+      Rectangle.contains(tile.rectangle, data.positionCartographic),
+    );
+    if (tile) {
+      tile._addedCustomData.push(data);
     }
+  });
 
-    customDataAdded.length = 0;
-    customDataRemoved.length = 0;
-  }
+  customDataRemoved.forEach((data) => {
+    const tile = levelZeroTiles.find((tile) =>
+      Rectangle.contains(tile.rectangle, data.positionCartographic),
+    );
+    if (tile) {
+      tile._removedCustomData.push(data);
+    }
+  });
+
+  levelZeroTiles.forEach((tile) => tile._updateCustomData());
+  customDataAdded.length = 0;
+  customDataRemoved.length = 0;
 
   const camera = frameState.camera;
 
@@ -577,8 +582,8 @@ function selectTilesForRendering(primitive, frameState) {
     );
 
   // Traverse in depth-first, near-to-far order.
-  for (i = 0, len = levelZeroTiles.length; i < len; ++i) {
-    tile = levelZeroTiles[i];
+  for (let i = 0; i < levelZeroTiles.length; ++i) {
+    const tile = levelZeroTiles[i];
     primitive._tileReplacementQueue.markTileRendered(tile);
     if (!tile.renderable) {
       queueTileLoad(primitive, primitive._tileLoadQueueHigh, tile, frameState);
@@ -596,7 +601,7 @@ function selectTilesForRendering(primitive, frameState) {
     }
   }
 
-  primitive._lastSelectionFrameNumber = frameNumber;
+  primitive._lastSelectionFrameNumber = frameState.frameNumber;
 }
 
 function queueTileLoad(primitive, queue, tile, frameState) {
@@ -716,7 +721,7 @@ function visitTile(
   ++debug.tilesVisited;
 
   primitive._tileReplacementQueue.markTileRendered(tile);
-  tile._updateCustomData(frameState.frameNumber);
+  tile._updateCustomData();
 
   if (tile.level > debug.maxDepthVisited) {
     debug.maxDepthVisited = tile.level;
@@ -1417,15 +1422,18 @@ function updateHeights(primitive, frameState) {
       // Ensure stale position cache is cleared
       tile.clearPositionCache();
       tilesToUpdateHeights.shift();
-      primitive._lastTileIndex = 0;
       continue;
     }
     const customData = tile.customData;
-    const customDataLength = customData.length;
+    if (!defined(tile._customDataIterator)) {
+      tile._customDataIterator = customData.values();
+    }
+    const customDataIterator = tile._customDataIterator;
 
     let timeSliceMax = false;
-    for (i = primitive._lastTileIndex; i < customDataLength; ++i) {
-      const data = customData[i];
+    let nextData;
+    while (!(nextData = customDataIterator.next()).done) {
+      const data = nextData.value;
 
       // No need to run this code when the tile is upsampled, because the height will be the same as its parent.
       const terrainData = tile.data.terrainData;
@@ -1543,10 +1551,10 @@ function updateHeights(primitive, frameState) {
     }
 
     if (timeSliceMax) {
-      primitive._lastTileIndex = i;
+      tile._customDataIterator = customDataIterator;
       break;
     } else {
-      primitive._lastTileIndex = 0;
+      tile._customDataIterator = undefined;
       tilesToUpdateHeights.shift();
     }
   }

packages/engine/Source/Scene/QuadtreeTile.js

@@ -1,6 +1,7 @@
 import defined from "../Core/defined.js";
 import DeveloperError from "../Core/DeveloperError.js";
 import Rectangle from "../Core/Rectangle.js";
+import Cartographic from "../Core/Cartographic.js";
 import QuadtreeTileLoadState from "./QuadtreeTileLoadState.js";
 import TileSelectionResult from "./TileSelectionResult.js";
 
@@ -107,8 +108,9 @@ function QuadtreeTile(options) {
   this._distance = 0.0;
   this._loadPriority = 0.0;
 
-  this._customData = [];
-  this._frameUpdated = undefined;
+  this._customData = new Set();
+  this._addedCustomData = [];
+  this._removedCustomData = [];
   this._lastSelectionResult = TileSelectionResult.NONE;
   this._lastSelectionResultFrame = undefined;
   this._loadedCallbacks = {};
@@ -311,52 +313,62 @@ QuadtreeTile.prototype.clearPositionCache = function () {
   }
 };
 
-QuadtreeTile.prototype._updateCustomData = function (
-  frameNumber,
-  added,
-  removed,
-) {
-  let customData = this.customData;
-
-  let i;
-  let data;
-  let rectangle;
-
-  if (defined(added) && defined(removed)) {
-    customData = customData.filter(function (value) {
-      return removed.indexOf(value) === -1;
-    });
-    this._customData = customData;
-
-    rectangle = this._rectangle;
-    for (i = 0; i < added.length; ++i) {
-      data = added[i];
-      if (Rectangle.contains(rectangle, data.positionCartographic)) {
-        customData.push(data);
-      }
-    }
+QuadtreeTile.prototype._updateCustomData = function () {
+  const added = this._addedCustomData;
+  const removed = this._removedCustomData;
+  if (added.length === 0 && removed.length === 0) {
+    return;
+  }
 
-    this._frameUpdated = frameNumber;
-  } else {
-    // interior or leaf tile, update from parent
-    const parent = this._parent;
-    if (defined(parent) && this._frameUpdated !== parent._frameUpdated) {
-      customData.length = 0;
-
-      rectangle = this._rectangle;
-      const parentCustomData = parent.customData;
-      for (i = 0; i < parentCustomData.length; ++i) {
-        data = parentCustomData[i];
-        if (Rectangle.contains(rectangle, data.positionCartographic)) {
-          customData.push(data);
-        }
-      }
+  const customData = this.customData;
+  for (let i = 0; i < added.length; ++i) {
+    const data = added[i];
+    customData.add(data);
+
+    const child = childTileAtPosition(this, data.positionCartographic);
+    child._addedCustomData.push(data);
+  }
+  this._addedCustomData.length = 0;
 
-      this._frameUpdated = parent._frameUpdated;
+  for (let i = 0; i < removed.length; ++i) {
+    const data = removed[i];
+    if (customData.has(data)) {
+      customData.delete(data);
     }
+
+    const child = childTileAtPosition(this, data.positionCartographic);
+    child._removedCustomData.push(data);
   }
+  this._removedCustomData.length = 0;
 };
 
+const centerScratch = new Cartographic();
+
+/**
+ * Determines which child tile that contains the specified position. Assumes the position is within
+ * the bounds of the parent tile.
+ * @private
+ * @param {QuadtreeTile} tile - The parent tile.
+ * @param {Cartographic} positionCartographic - The cartographic position.
+ * @returns {QuadtreeTile} The child tile that contains the position.
+ */
+function childTileAtPosition(tile, positionCartographic) {
+  const center = Rectangle.center(tile.rectangle, centerScratch);
+  const x = positionCartographic.longitude >= center.longitude ? 1 : 0;
+  const y = positionCartographic.latitude < center.latitude ? 1 : 0;
+
+  switch (y * 2 + x) {
+    case 0:
+      return tile.northwestChild;
+    case 1:
+      return tile.northeastChild;
+    case 2:
+      return tile.southwestChild;
+    default:
+      return tile.southeastChild;
+  }
+}
+
 Object.defineProperties(QuadtreeTile.prototype, {
   /**
    * Gets the tiling scheme used to tile the surface.
@@ -522,9 +534,9 @@ Object.defineProperties(QuadtreeTile.prototype, {
   },
 
   /**
-   * An array of objects associated with this tile.
+   * A set of objects associated with this tile.
    * @memberof QuadtreeTile.prototype
-   * @type {Array}
+   * @type {Set}
    */
   customData: {
     get: function () {

packages/engine/Specs/Scene/QuadtreePrimitiveSpec.js

@@ -899,7 +899,7 @@ describe("Scene/QuadtreePrimitive", function () {
 
         let addedCallback = false;
         quadtree.forEachLoadedTile(function (tile) {
-          addedCallback = addedCallback || tile.customData.length > 0;
+          addedCallback = addedCallback || tile.customData.size > 0;
         });
 
         expect(addedCallback).toEqual(true);
@@ -915,7 +915,7 @@ describe("Scene/QuadtreePrimitive", function () {
 
         let removedCallback = true;
         quadtree.forEachLoadedTile(function (tile) {
-          removedCallback = removedCallback && tile.customData.length === 0;
+          removedCallback = removedCallback && tile.customData.size === 0;
         });
 
         expect(removedCallback).toEqual(true);