From b7b4da0e70cee0c86335d80e6679f5197f0f8ce3 Mon Sep 17 00:00:00 2001
From: Marco Hutter <javagl@javagl.de>
Date: Sat, 23 Nov 2024 13:44:08 +0100
Subject: [PATCH 1/9] Draft for handling shared textures in statistics

---
 packages/engine/Source/Renderer/Texture.js    |   2 +-
 .../Source/Scene/Cesium3DTilesetStatistics.js | 110 +++++++++++++++++-
 .../engine/Source/Scene/GltfTextureLoader.js  |  17 ++-
 .../Source/Scene/Model/Model3DTileContent.js  |  10 ++
 .../Source/Scene/Model/ModelStatistics.js     |  24 +++-
 5 files changed, 153 insertions(+), 10 deletions(-)

diff --git a/packages/engine/Source/Renderer/Texture.js b/packages/engine/Source/Renderer/Texture.js
index 8d9135fb7764..5c7088ad7009 100644
--- a/packages/engine/Source/Renderer/Texture.js
+++ b/packages/engine/Source/Renderer/Texture.js
@@ -216,7 +216,7 @@ function Texture(options) {
     ? PixelFormat.compressedTextureSizeInBytes(pixelFormat, width, height)
     : PixelFormat.textureSizeInBytes(pixelFormat, pixelDatatype, width, height);
 
-  this._id = createGuid();
+  this._id = options.id ?? createGuid();
   this._context = context;
   this._textureFilterAnisotropic = context._textureFilterAnisotropic;
   this._textureTarget = gl.TEXTURE_2D;
diff --git a/packages/engine/Source/Scene/Cesium3DTilesetStatistics.js b/packages/engine/Source/Scene/Cesium3DTilesetStatistics.js
index ed80f3fc67fd..fb9db7162efa 100644
--- a/packages/engine/Source/Scene/Cesium3DTilesetStatistics.js
+++ b/packages/engine/Source/Scene/Cesium3DTilesetStatistics.js
@@ -1,4 +1,5 @@
 import defined from "../Core/defined.js";
+import Model3DTileContent from "./Model/Model3DTileContent.js";
 
 /**
  * @private
@@ -29,6 +30,7 @@ function Cesium3DTilesetStatistics() {
   // Memory statistics
   this.geometryByteLength = 0;
   this.texturesByteLength = 0;
+  this.texturesReferenceCounterById = {};
   this.batchTableByteLength = 0; // batch textures and any binary metadata properties not otherwise accounted for
 }
 
@@ -45,6 +47,40 @@ Cesium3DTilesetStatistics.prototype.clear = function () {
   this.numberOfTilesCulledWithChildrenUnion = 0;
 };
 
+/**
+ * Update the given statistics with the information from the given
+ * content.
+ *
+ * This function does vastly different things, depending on how it
+ * is called:
+ *
+ * When the `load` parameter is `false`, then it updates the parts
+ * of the statistics that summarize the `...Selected` elements,
+ * indicating how many elements (features, points, triangles) are
+ * selected for rendering.
+ * (In this case, the `decrement` parameter apparently always has
+ * to be `false` - probably because these value are reset to 0
+ * after each frame or so....)
+ *
+ * When the `load` parameter is `true`, then it updates the parts of
+ * the statistics that summarize the `...Loaded` and `...ByteLength`
+ * properties. These basically describe what is currently loaded
+ * in memory.
+ * In this case, the `decrement` parameter indicates whether the
+ * operation that triggered this update was a "load" or an "unload"
+ * operation: When `decrement===false`, then the operation was a
+ * "load", and the values will be incremented. When `decrement===true`,
+ * then the operation was an "unload", and the values are decremented.
+ *
+ * In any case, this function will be called recursively with the
+ * `innerContents` of the given content.
+ *
+ * @param {Cesium3DTilesetStatistics} statistics - The statistics
+ * @param {Cesium3DTileContent} content - The conetnt
+ * @param {boolean} decrement - Whether the values should be decremented
+ * @param {boolean} load - This is `true` when the update is for a "load"
+ * operation, and `false` when it is for a "selection" operation
+ */
 function updatePointAndFeatureCounts(statistics, content, decrement, load) {
   const contents = content.innerContents;
   const pointsLength = content.pointsLength;
@@ -62,12 +98,60 @@ function updatePointAndFeatureCounts(statistics, content, decrement, load) {
     statistics.geometryByteLength += decrement
       ? -geometryByteLength
       : geometryByteLength;
-    statistics.texturesByteLength += decrement
-      ? -texturesByteLength
-      : texturesByteLength;
     statistics.batchTableByteLength += decrement
       ? -batchTableByteLength
       : batchTableByteLength;
+
+    if (content instanceof Model3DTileContent) {
+      const textureIds = content.getTextureIds();
+      //console.log(`Update stats with ${textureIds} for decrement ${decrement}`);
+
+      let totalTexturesByteLengthChange = 0;
+      if (decrement) {
+        for (const textureId of textureIds) {
+          const referenceCounter =
+            statistics.texturesReferenceCounterById[textureId];
+          const textureByteLength = content.getTextureByteLengthById(textureId);
+
+          // XXX TODO Sanity check
+          if (!defined(referenceCounter) || referenceCounter === 0) {
+            console.log(
+              `ERROR decrement, but referenceCounter is ${referenceCounter} for textureId ${textureId}`,
+            );
+            continue;
+          }
+          if (referenceCounter === 1) {
+            //console.log(`Decrement, referenceCounter dropped to 0 for textureId ${textureId}, reducing by ${textureByteLength} for textureId ${textureId}`);
+            delete statistics.texturesReferenceCounterById[textureId];
+            totalTexturesByteLengthChange -= textureByteLength;
+          } else {
+            //console.log(`Decrement, referenceCounter became ${referenceCounter - 1} for textureId ${textureId}`);
+            statistics.texturesReferenceCounterById[textureId] =
+              referenceCounter - 1;
+          }
+        }
+      } else {
+        for (const textureId of textureIds) {
+          const referenceCounter =
+            statistics.texturesReferenceCounterById[textureId] ?? 0;
+          const textureByteLength = content.getTextureByteLengthById(textureId);
+
+          statistics.texturesReferenceCounterById[textureId] =
+            referenceCounter + 1;
+          if (referenceCounter === 1) {
+            //console.log(`Increment, referenceCounter became ${referenceCounter + 1}, increasing by ${textureByteLength} for textureId ${textureId}`);
+            totalTexturesByteLengthChange += textureByteLength;
+          } else {
+            //console.log(`Increment, referenceCounter became ${referenceCounter + 1} for textureId ${textureId}`);
+          }
+        }
+      }
+      statistics.texturesByteLength += totalTexturesByteLengthChange;
+    } else {
+      statistics.texturesByteLength += decrement
+        ? -texturesByteLength
+        : texturesByteLength;
+    }
   } else {
     statistics.numberOfFeaturesSelected += decrement
       ? -featuresLength
@@ -80,6 +164,22 @@ function updatePointAndFeatureCounts(statistics, content, decrement, load) {
       : trianglesLength;
   }
 
+  // XXX TODO Debug log
+  if (load) {
+    console.log(
+      `After ${decrement ? "unload" : "load  "} statistics.texturesByteLength now ${statistics.texturesByteLength}`,
+    );
+
+    /*/
+    console.log("Details:");
+    const textureIds = Object.keys(statistics.texturesReferenceCounterById);
+    for (const textureId of textureIds) {
+      const referenceCounter = statistics.texturesReferenceCounterById[textureId];
+      console.log(`  referenceCounter ${referenceCounter} for ${textureId}`);
+    }
+    //*/
+  }
+
   if (defined(contents)) {
     const length = contents.length;
     for (let i = 0; i < length; ++i) {
@@ -124,6 +224,10 @@ Cesium3DTilesetStatistics.clone = function (statistics, result) {
     statistics.numberOfTilesCulledWithChildrenUnion;
   result.geometryByteLength = statistics.geometryByteLength;
   result.texturesByteLength = statistics.texturesByteLength;
+  result.texturesByteLengthById = { ...statistics.texturesByteLengthById };
+  result.texturesReferenceCounterById = {
+    ...statistics.texturesReferenceCounterById,
+  };
   result.batchTableByteLength = statistics.batchTableByteLength;
 };
 export default Cesium3DTilesetStatistics;
diff --git a/packages/engine/Source/Scene/GltfTextureLoader.js b/packages/engine/Source/Scene/GltfTextureLoader.js
index 4c07eef67629..e060d03947f4 100644
--- a/packages/engine/Source/Scene/GltfTextureLoader.js
+++ b/packages/engine/Source/Scene/GltfTextureLoader.js
@@ -170,6 +170,7 @@ GltfTextureLoader.prototype.load = async function () {
 function CreateTextureJob() {
   this.gltf = undefined;
   this.textureInfo = undefined;
+  this.textureId = undefined;
   this.image = undefined;
   this.context = undefined;
   this.texture = undefined;
@@ -178,12 +179,14 @@ function CreateTextureJob() {
 CreateTextureJob.prototype.set = function (
   gltf,
   textureInfo,
+  textureId,
   image,
   mipLevels,
   context,
 ) {
   this.gltf = gltf;
   this.textureInfo = textureInfo;
+  this.textureId = textureId;
   this.image = image;
   this.mipLevels = mipLevels;
   this.context = context;
@@ -193,13 +196,21 @@ CreateTextureJob.prototype.execute = function () {
   this.texture = createTexture(
     this.gltf,
     this.textureInfo,
+    this.textureId,
     this.image,
     this.mipLevels,
     this.context,
   );
 };
 
-function createTexture(gltf, textureInfo, image, mipLevels, context) {
+function createTexture(
+  gltf,
+  textureInfo,
+  textureId,
+  image,
+  mipLevels,
+  context,
+) {
   // internalFormat is only defined for CompressedTextureBuffer
   const internalFormat = image.internalFormat;
 
@@ -261,6 +272,7 @@ function createTexture(gltf, textureInfo, image, mipLevels, context) {
     }
 
     texture = Texture.create({
+      id: textureId,
       context: context,
       source: {
         arrayBufferView: image.bufferView, // Only defined for CompressedTextureBuffer
@@ -276,6 +288,7 @@ function createTexture(gltf, textureInfo, image, mipLevels, context) {
       image = resizeImageToNextPowerOfTwo(image);
     }
     texture = Texture.create({
+      id: textureId,
       context: context,
       source: image,
       sampler: sampler,
@@ -332,6 +345,7 @@ GltfTextureLoader.prototype.process = function (frameState) {
     textureJob.set(
       this._gltf,
       this._textureInfo,
+      this.cacheKey,
       this._image,
       this._mipLevels,
       frameState.context,
@@ -346,6 +360,7 @@ GltfTextureLoader.prototype.process = function (frameState) {
     texture = createTexture(
       this._gltf,
       this._textureInfo,
+      this.cacheKey,
       this._image,
       this._mipLevels,
       frameState.context,
diff --git a/packages/engine/Source/Scene/Model/Model3DTileContent.js b/packages/engine/Source/Scene/Model/Model3DTileContent.js
index e4266704bdad..dc6376702be2 100644
--- a/packages/engine/Source/Scene/Model/Model3DTileContent.js
+++ b/packages/engine/Source/Scene/Model/Model3DTileContent.js
@@ -152,6 +152,16 @@ Object.defineProperties(Model3DTileContent.prototype, {
   },
 });
 
+// XXX TODO COMMENT
+Model3DTileContent.prototype.getTextureIds = function () {
+  return this._model.statistics.getTextureIds();
+};
+
+// XXX TODO COMMENT
+Model3DTileContent.prototype.getTextureByteLengthById = function (textureId) {
+  return this._model.statistics.getTextureByteLengthById(textureId);
+};
+
 /**
  * Returns the object that was created for the given extension.
  *
diff --git a/packages/engine/Source/Scene/Model/ModelStatistics.js b/packages/engine/Source/Scene/Model/ModelStatistics.js
index 3188895efc5a..ef90dc6a355a 100644
--- a/packages/engine/Source/Scene/Model/ModelStatistics.js
+++ b/packages/engine/Source/Scene/Model/ModelStatistics.js
@@ -61,7 +61,7 @@ function ModelStatistics() {
   // Sets of buffers and textures that have already been counted.
   // This is to prevent double-counting cached assets.
   this._bufferIdSet = {};
-  this._textureIdSet = {};
+  this._textureIdByteLengths = {};
 
   // Associated array of batch textures that have already been counted.
   // This allows for quick look-up to check if a texture has been counted,
@@ -111,7 +111,7 @@ ModelStatistics.prototype.clear = function () {
   this.propertyTablesByteLength = 0;
 
   this._bufferIdSet = {};
-  this._textureIdSet = {};
+  this._textureIdByteLengths = {};
   this._batchTextureIdMap.removeAll();
 };
 
@@ -160,12 +160,26 @@ ModelStatistics.prototype.addTexture = function (texture) {
   Check.typeOf.object("texture", texture);
   //>>includeEnd('debug');
 
-  if (!this._textureIdSet.hasOwnProperty(texture._id)) {
+  if (!this._textureIdByteLengths.hasOwnProperty(texture._id)) {
     this.texturesByteLength += texture.sizeInBytes;
+    this._textureIdByteLengths[texture._id] = texture.sizeInBytes;
+  } else {
+    // XXX TODO Only a sanity check. It looks like
+    // this function can be called several times
+    // with the same texture (hence the check above)
+    // but that should be OK...
+    //console.log(`XXX ModelStatistics: Texture already tracked ${texture._id}`);
   }
+};
 
-  // Simulate set insertion.
-  this._textureIdSet[texture._id] = true;
+// XXX TODO COMMENT
+ModelStatistics.prototype.getTextureIds = function () {
+  return Object.keys(this._textureIdByteLengths);
+};
+
+// XXX TODO COMMENT
+ModelStatistics.prototype.getTextureByteLengthById = function (textureId) {
+  return this._textureIdByteLengths[textureId];
 };
 
 /**

From 0b1991bae329ebb4f6246b50b95d8dcd1349d2fd Mon Sep 17 00:00:00 2001
From: Marco Hutter <javagl@javagl.de>
Date: Sat, 23 Nov 2024 14:42:57 +0100
Subject: [PATCH 2/9] Remove clone of field that does not exist

---
 packages/engine/Source/Scene/Cesium3DTilesetStatistics.js | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/packages/engine/Source/Scene/Cesium3DTilesetStatistics.js b/packages/engine/Source/Scene/Cesium3DTilesetStatistics.js
index fb9db7162efa..b9c302e4fa66 100644
--- a/packages/engine/Source/Scene/Cesium3DTilesetStatistics.js
+++ b/packages/engine/Source/Scene/Cesium3DTilesetStatistics.js
@@ -170,11 +170,12 @@ function updatePointAndFeatureCounts(statistics, content, decrement, load) {
       `After ${decrement ? "unload" : "load  "} statistics.texturesByteLength now ${statistics.texturesByteLength}`,
     );
 
-    /*/
+    //*/
     console.log("Details:");
     const textureIds = Object.keys(statistics.texturesReferenceCounterById);
     for (const textureId of textureIds) {
-      const referenceCounter = statistics.texturesReferenceCounterById[textureId];
+      const referenceCounter =
+        statistics.texturesReferenceCounterById[textureId];
       console.log(`  referenceCounter ${referenceCounter} for ${textureId}`);
     }
     //*/
@@ -224,7 +225,6 @@ Cesium3DTilesetStatistics.clone = function (statistics, result) {
     statistics.numberOfTilesCulledWithChildrenUnion;
   result.geometryByteLength = statistics.geometryByteLength;
   result.texturesByteLength = statistics.texturesByteLength;
-  result.texturesByteLengthById = { ...statistics.texturesByteLengthById };
   result.texturesReferenceCounterById = {
     ...statistics.texturesReferenceCounterById,
   };

From 9dcb393cc1d237394fd943d645d41ecb829b950b Mon Sep 17 00:00:00 2001
From: Marco Hutter <javagl@javagl.de>
Date: Mon, 25 Nov 2024 21:16:16 +0100
Subject: [PATCH 3/9] Cleanups for shared texture statistics handling

---
 packages/engine/Source/Renderer/Texture.js    |   1 +
 .../Source/Scene/Cesium3DTilesetStatistics.js | 229 ++++++++----------
 .../engine/Source/Scene/GltfTextureLoader.js  |   4 +-
 .../Source/Scene/Model/Model3DTileContent.js  |  18 +-
 .../Source/Scene/Model/ModelStatistics.js     |  24 +-
 5 files changed, 137 insertions(+), 139 deletions(-)

diff --git a/packages/engine/Source/Renderer/Texture.js b/packages/engine/Source/Renderer/Texture.js
index 5c7088ad7009..1e5eed6dd71d 100644
--- a/packages/engine/Source/Renderer/Texture.js
+++ b/packages/engine/Source/Renderer/Texture.js
@@ -27,6 +27,7 @@ import TextureMinificationFilter from "./TextureMinificationFilter.js";
  * @property {number} [width] The pixel width of the texture. If not supplied, must be available from the source.
  * @property {number} [height] The pixel height of the texture. If not supplied, must be available from the source.
  * @property {boolean} [preMultiplyAlpha] If true, the alpha channel will be multiplied into the other channels.
+ * @property {string} [id] A unique identifier for the texture. If this is not given, then a GUID will be created.
  *
  * @private
  */
diff --git a/packages/engine/Source/Scene/Cesium3DTilesetStatistics.js b/packages/engine/Source/Scene/Cesium3DTilesetStatistics.js
index b9c302e4fa66..650bc2c69a85 100644
--- a/packages/engine/Source/Scene/Cesium3DTilesetStatistics.js
+++ b/packages/engine/Source/Scene/Cesium3DTilesetStatistics.js
@@ -48,159 +48,124 @@ Cesium3DTilesetStatistics.prototype.clear = function () {
 };
 
 /**
- * Update the given statistics with the information from the given
- * content.
+ * Increment the counters for the points, triangles, and features
+ * that are currently selected for rendering.
  *
- * This function does vastly different things, depending on how it
- * is called:
+ * This will be called recursively for the given content and
+ * all its inner contents
  *
- * When the `load` parameter is `false`, then it updates the parts
- * of the statistics that summarize the `...Selected` elements,
- * indicating how many elements (features, points, triangles) are
- * selected for rendering.
- * (In this case, the `decrement` parameter apparently always has
- * to be `false` - probably because these value are reset to 0
- * after each frame or so....)
- *
- * When the `load` parameter is `true`, then it updates the parts of
- * the statistics that summarize the `...Loaded` and `...ByteLength`
- * properties. These basically describe what is currently loaded
- * in memory.
- * In this case, the `decrement` parameter indicates whether the
- * operation that triggered this update was a "load" or an "unload"
- * operation: When `decrement===false`, then the operation was a
- * "load", and the values will be incremented. When `decrement===true`,
- * then the operation was an "unload", and the values are decremented.
- *
- * In any case, this function will be called recursively with the
- * `innerContents` of the given content.
- *
- * @param {Cesium3DTilesetStatistics} statistics - The statistics
- * @param {Cesium3DTileContent} content - The conetnt
- * @param {boolean} decrement - Whether the values should be decremented
- * @param {boolean} load - This is `true` when the update is for a "load"
- * operation, and `false` when it is for a "selection" operation
+ * @param {Cesium3DTileContent} content
  */
-function updatePointAndFeatureCounts(statistics, content, decrement, load) {
-  const contents = content.innerContents;
-  const pointsLength = content.pointsLength;
-  const trianglesLength = content.trianglesLength;
-  const featuresLength = content.featuresLength;
-  const geometryByteLength = content.geometryByteLength;
-  const texturesByteLength = content.texturesByteLength;
-  const batchTableByteLength = content.batchTableByteLength;
-
-  if (load) {
-    statistics.numberOfFeaturesLoaded += decrement
-      ? -featuresLength
-      : featuresLength;
-    statistics.numberOfPointsLoaded += decrement ? -pointsLength : pointsLength;
-    statistics.geometryByteLength += decrement
-      ? -geometryByteLength
-      : geometryByteLength;
-    statistics.batchTableByteLength += decrement
-      ? -batchTableByteLength
-      : batchTableByteLength;
-
-    if (content instanceof Model3DTileContent) {
-      const textureIds = content.getTextureIds();
-      //console.log(`Update stats with ${textureIds} for decrement ${decrement}`);
-
-      let totalTexturesByteLengthChange = 0;
-      if (decrement) {
-        for (const textureId of textureIds) {
-          const referenceCounter =
-            statistics.texturesReferenceCounterById[textureId];
-          const textureByteLength = content.getTextureByteLengthById(textureId);
-
-          // XXX TODO Sanity check
-          if (!defined(referenceCounter) || referenceCounter === 0) {
-            console.log(
-              `ERROR decrement, but referenceCounter is ${referenceCounter} for textureId ${textureId}`,
-            );
-            continue;
-          }
-          if (referenceCounter === 1) {
-            //console.log(`Decrement, referenceCounter dropped to 0 for textureId ${textureId}, reducing by ${textureByteLength} for textureId ${textureId}`);
-            delete statistics.texturesReferenceCounterById[textureId];
-            totalTexturesByteLengthChange -= textureByteLength;
-          } else {
-            //console.log(`Decrement, referenceCounter became ${referenceCounter - 1} for textureId ${textureId}`);
-            statistics.texturesReferenceCounterById[textureId] =
-              referenceCounter - 1;
-          }
-        }
-      } else {
-        for (const textureId of textureIds) {
-          const referenceCounter =
-            statistics.texturesReferenceCounterById[textureId] ?? 0;
-          const textureByteLength = content.getTextureByteLengthById(textureId);
+Cesium3DTilesetStatistics.prototype.incrementSelectionCounts = function (
+  content,
+) {
+  this.numberOfFeaturesSelected += content.featuresLength;
+  this.numberOfPointsSelected += content.pointsLength;
+  this.numberOfTrianglesSelected += content.trianglesLength;
 
-          statistics.texturesReferenceCounterById[textureId] =
-            referenceCounter + 1;
-          if (referenceCounter === 1) {
-            //console.log(`Increment, referenceCounter became ${referenceCounter + 1}, increasing by ${textureByteLength} for textureId ${textureId}`);
-            totalTexturesByteLengthChange += textureByteLength;
-          } else {
-            //console.log(`Increment, referenceCounter became ${referenceCounter + 1} for textureId ${textureId}`);
-          }
-        }
-      }
-      statistics.texturesByteLength += totalTexturesByteLengthChange;
-    } else {
-      statistics.texturesByteLength += decrement
-        ? -texturesByteLength
-        : texturesByteLength;
+  // Recursive calls on all inner contents
+  const contents = content.innerContents;
+  if (defined(contents)) {
+    const length = contents.length;
+    for (let i = 0; i < length; ++i) {
+      this.incrementSelectionCounts(contents[i]);
     }
-  } else {
-    statistics.numberOfFeaturesSelected += decrement
-      ? -featuresLength
-      : featuresLength;
-    statistics.numberOfPointsSelected += decrement
-      ? -pointsLength
-      : pointsLength;
-    statistics.numberOfTrianglesSelected += decrement
-      ? -trianglesLength
-      : trianglesLength;
   }
+};
 
-  // XXX TODO Debug log
-  if (load) {
-    console.log(
-      `After ${decrement ? "unload" : "load  "} statistics.texturesByteLength now ${statistics.texturesByteLength}`,
-    );
+/**
+ * Increment the counters for the number of features and points that
+ * are currently loaded, and the lengths (size in bytes) of the
+ * occupied memory.
+ *
+ * This will be called recursively for the given content and
+ * all its inner contents
+ *
+ * @param {Cesium3DTileContent} content
+ */
+Cesium3DTilesetStatistics.prototype.incrementLoadCounts = function (content) {
+  this.numberOfFeaturesLoaded += content.featuresLength;
+  this.numberOfPointsLoaded += content.pointsLength;
+  this.geometryByteLength += content.geometryByteLength;
+  this.batchTableByteLength += content.batchTableByteLength;
 
-    //*/
-    console.log("Details:");
-    const textureIds = Object.keys(statistics.texturesReferenceCounterById);
+  // When the content is not a `Model3DTileContent`, then its
+  // textures byte length is added directly
+  if (!(content instanceof Model3DTileContent)) {
+    this.texturesByteLength += content.texturesByteLength;
+  } else {
+    // When the content is a `Model3DTileContent`, then increment the
+    // reference counter for all its textures. The byte length of any
+    // newly tracked texture to the total textures byte length
+    const textureIds = content.getTextureIds();
     for (const textureId of textureIds) {
       const referenceCounter =
-        statistics.texturesReferenceCounterById[textureId];
-      console.log(`  referenceCounter ${referenceCounter} for ${textureId}`);
+        this.texturesReferenceCounterById[textureId] ?? 0;
+      if (referenceCounter === 0) {
+        const textureByteLength = content.getTextureByteLengthById(textureId);
+        this.texturesByteLength += textureByteLength;
+      }
+      this.texturesReferenceCounterById[textureId] = referenceCounter + 1;
     }
-    //*/
   }
 
+  // Recursive calls on all inner contents
+  const contents = content.innerContents;
   if (defined(contents)) {
     const length = contents.length;
     for (let i = 0; i < length; ++i) {
-      updatePointAndFeatureCounts(statistics, contents[i], decrement, load);
+      this.incrementLoadCounts(contents[i]);
     }
   }
-}
-
-Cesium3DTilesetStatistics.prototype.incrementSelectionCounts = function (
-  content,
-) {
-  updatePointAndFeatureCounts(this, content, false, false);
-};
-
-Cesium3DTilesetStatistics.prototype.incrementLoadCounts = function (content) {
-  updatePointAndFeatureCounts(this, content, false, true);
 };
 
+/**
+ * Decrement the counters for the number of features and points that
+ * are currently loaded, and the lengths (size in bytes) of the
+ * occupied memory.
+ *
+ * This will be called recursively for the given content and
+ * all its inner contents
+ *
+ * @param {Cesium3DTileContent} content
+ */
 Cesium3DTilesetStatistics.prototype.decrementLoadCounts = function (content) {
-  updatePointAndFeatureCounts(this, content, true, true);
+  this.numberOfFeaturesLoaded -= content.featuresLength;
+  this.numberOfPointsLoaded -= content.pointsLength;
+  this.geometryByteLength -= content.geometryByteLength;
+  this.batchTableByteLength -= content.batchTableByteLength;
+
+  // When the content is not a `Model3DTileContent`, then its
+  // textures byte length is subtracted directly
+  if (!(content instanceof Model3DTileContent)) {
+    this.texturesByteLength -= content.texturesByteLength;
+  } else {
+    // When the content is a `Model3DTileContent`, then increment the
+    // reference counter for all its textures. The byte length of any
+    // texture that is no longer references is subtracted from the
+    // total textures byte length
+    const textureIds = content.getTextureIds();
+    for (const textureId of textureIds) {
+      const referenceCounter = this.texturesReferenceCounterById[textureId];
+      if (referenceCounter === 1) {
+        delete this.texturesReferenceCounterById[textureId];
+        const textureByteLength = content.getTextureByteLengthById(textureId);
+        this.texturesByteLength += textureByteLength;
+      } else {
+        this.texturesReferenceCounterById[textureId] = referenceCounter - 1;
+      }
+    }
+  }
+  // Recursive calls on all inner contents
+  const contents = content.innerContents;
+  if (defined(contents)) {
+    const length = contents.length;
+    for (let i = 0; i < length; ++i) {
+      this.decrementLoadCounts(contents[i]);
+    }
+  }
+
+  console.log("after decrementLoadCounts", JSON.stringify(this, null, 2));
 };
 
 Cesium3DTilesetStatistics.clone = function (statistics, result) {
diff --git a/packages/engine/Source/Scene/GltfTextureLoader.js b/packages/engine/Source/Scene/GltfTextureLoader.js
index e060d03947f4..afa6dad8f177 100644
--- a/packages/engine/Source/Scene/GltfTextureLoader.js
+++ b/packages/engine/Source/Scene/GltfTextureLoader.js
@@ -345,7 +345,7 @@ GltfTextureLoader.prototype.process = function (frameState) {
     textureJob.set(
       this._gltf,
       this._textureInfo,
-      this.cacheKey,
+      this._cacheKey,
       this._image,
       this._mipLevels,
       frameState.context,
@@ -360,7 +360,7 @@ GltfTextureLoader.prototype.process = function (frameState) {
     texture = createTexture(
       this._gltf,
       this._textureInfo,
-      this.cacheKey,
+      this._cacheKey,
       this._image,
       this._mipLevels,
       frameState.context,
diff --git a/packages/engine/Source/Scene/Model/Model3DTileContent.js b/packages/engine/Source/Scene/Model/Model3DTileContent.js
index dc6376702be2..143acbe8cb48 100644
--- a/packages/engine/Source/Scene/Model/Model3DTileContent.js
+++ b/packages/engine/Source/Scene/Model/Model3DTileContent.js
@@ -152,12 +152,24 @@ Object.defineProperties(Model3DTileContent.prototype, {
   },
 });
 
-// XXX TODO COMMENT
+/**
+ * Returns an array containing the `texture.id` values for all textures
+ * that are part of this content.
+ *
+ * @returns {string[]} The texture IDs
+ */
 Model3DTileContent.prototype.getTextureIds = function () {
   return this._model.statistics.getTextureIds();
 };
 
-// XXX TODO COMMENT
+/**
+ * Returns the length, in bytes, of the texture data for the texture with
+ * the given ID that is part of this content, or `undefined` if this
+ * content does not contain the texture with the given ID.
+ *
+ * @param {string} textureId The texture ID
+ * @returns {number|undefined} The texture byte length
+ */
 Model3DTileContent.prototype.getTextureByteLengthById = function (textureId) {
   return this._model.statistics.getTextureByteLengthById(textureId);
 };
@@ -167,7 +179,7 @@ Model3DTileContent.prototype.getTextureByteLengthById = function (textureId) {
  *
  * The given name may be the name of a glTF extension, like `"EXT_example_extension"`.
  * If the specified extension was present in the root of the underlying glTF asset,
- * and a loder for the specified extension has processed the extension data, then
+ * and a loader for the specified extension has processed the extension data, then
  * this will return the model representation of the extension.
  *
  * @param {string} extensionName The name of the extension
diff --git a/packages/engine/Source/Scene/Model/ModelStatistics.js b/packages/engine/Source/Scene/Model/ModelStatistics.js
index ef90dc6a355a..6275305ecb64 100644
--- a/packages/engine/Source/Scene/Model/ModelStatistics.js
+++ b/packages/engine/Source/Scene/Model/ModelStatistics.js
@@ -61,6 +61,14 @@ function ModelStatistics() {
   // Sets of buffers and textures that have already been counted.
   // This is to prevent double-counting cached assets.
   this._bufferIdSet = {};
+
+  /**
+   * The mapping from `texture.id` strings to the byte length of the
+   * respective texture
+   *
+   * @type {object}
+   * @private
+   */
   this._textureIdByteLengths = {};
 
   // Associated array of batch textures that have already been counted.
@@ -172,12 +180,24 @@ ModelStatistics.prototype.addTexture = function (texture) {
   }
 };
 
-// XXX TODO COMMENT
+/**
+ * Returns an array containing the `texture.id` values for all textures
+ * that are part of the model.
+ *
+ * @returns {string[]} The texture IDs
+ */
 ModelStatistics.prototype.getTextureIds = function () {
   return Object.keys(this._textureIdByteLengths);
 };
 
-// XXX TODO COMMENT
+/**
+ * Returns the length, in bytes, of the texture data for the texture with
+ * the given ID that is part of the model, or `undefined` if the model
+ * does not contain the texture with the given ID.
+ *
+ * @param {string} textureId The texture ID
+ * @returns {number|undefined} The texture byte length
+ */
 ModelStatistics.prototype.getTextureByteLengthById = function (textureId) {
   return this._textureIdByteLengths[textureId];
 };

From bd074a07e3686cc86e1717b68a2f899b2769e392 Mon Sep 17 00:00:00 2001
From: Marco Hutter <javagl@javagl.de>
Date: Mon, 25 Nov 2024 21:29:24 +0100
Subject: [PATCH 4/9] Remove debug output

---
 packages/engine/Source/Scene/Model/ModelStatistics.js | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/packages/engine/Source/Scene/Model/ModelStatistics.js b/packages/engine/Source/Scene/Model/ModelStatistics.js
index 6275305ecb64..b8a60af26df0 100644
--- a/packages/engine/Source/Scene/Model/ModelStatistics.js
+++ b/packages/engine/Source/Scene/Model/ModelStatistics.js
@@ -171,12 +171,6 @@ ModelStatistics.prototype.addTexture = function (texture) {
   if (!this._textureIdByteLengths.hasOwnProperty(texture._id)) {
     this.texturesByteLength += texture.sizeInBytes;
     this._textureIdByteLengths[texture._id] = texture.sizeInBytes;
-  } else {
-    // XXX TODO Only a sanity check. It looks like
-    // this function can be called several times
-    // with the same texture (hence the check above)
-    // but that should be OK...
-    //console.log(`XXX ModelStatistics: Texture already tracked ${texture._id}`);
   }
 };
 

From bcdc430fc4527dd162404bb35a08588c916dab7a Mon Sep 17 00:00:00 2001
From: Marco Hutter <javagl@javagl.de>
Date: Mon, 25 Nov 2024 21:32:13 +0100
Subject: [PATCH 5/9] Update specs for ModelStatistics

---
 .../Specs/Scene/Model/ModelStatisticsSpec.js  | 20 +++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/packages/engine/Specs/Scene/Model/ModelStatisticsSpec.js b/packages/engine/Specs/Scene/Model/ModelStatisticsSpec.js
index d471effc9773..c83454747c6d 100644
--- a/packages/engine/Specs/Scene/Model/ModelStatisticsSpec.js
+++ b/packages/engine/Specs/Scene/Model/ModelStatisticsSpec.js
@@ -15,7 +15,7 @@ describe("Scene/Model/ModelStatistics", function () {
     expect(statistics.propertyTablesByteLength).toBe(0);
     expect(statistics.batchTexturesByteLength).toBe(0);
     expect(statistics._bufferIdSet).toEqual({});
-    expect(statistics._textureIdSet).toEqual({});
+    expect(statistics._textureIdByteLengths).toEqual({});
     expect(statistics._batchTextureIdMap).toEqual(emptyMap);
   });
 
@@ -27,7 +27,7 @@ describe("Scene/Model/ModelStatistics", function () {
     statistics.texturesByteLength = 10;
     statistics.propertyTablesByteLength = 10;
     statistics._bufferIdSet = { uuid1: true, uuid2: true };
-    statistics._textureIdSet = { uuid3: true };
+    statistics._textureIdByteLengths = { uuid3: 1234 };
 
     const map = new AssociativeArray();
     map.set("uuid", {});
@@ -41,7 +41,7 @@ describe("Scene/Model/ModelStatistics", function () {
     expect(statistics.propertyTablesByteLength).toBe(0);
     expect(statistics.batchTexturesByteLength).toBe(0);
     expect(statistics._bufferIdSet).toEqual({});
-    expect(statistics._textureIdSet).toEqual({});
+    expect(statistics._textureIdByteLengths).toEqual({});
     expect(statistics._batchTextureIdMap).toEqual(emptyMap);
   });
 
@@ -78,7 +78,7 @@ describe("Scene/Model/ModelStatistics", function () {
     expect(statistics.propertyTablesByteLength).toBe(0);
     expect(statistics.batchTexturesByteLength).toBe(0);
     expect(statistics._bufferIdSet).toEqual({ uuid: true });
-    expect(statistics._textureIdSet).toEqual({});
+    expect(statistics._textureIdByteLengths).toEqual({});
     expect(statistics._batchTextureIdMap).toEqual(emptyMap);
   });
 
@@ -99,7 +99,7 @@ describe("Scene/Model/ModelStatistics", function () {
     expect(statistics.propertyTablesByteLength).toBe(0);
     expect(statistics.batchTexturesByteLength).toBe(0);
     expect(statistics._bufferIdSet).toEqual({ uuid: true });
-    expect(statistics._textureIdSet).toEqual({});
+    expect(statistics._textureIdByteLengths).toEqual({});
     expect(statistics._batchTextureIdMap).toEqual(emptyMap);
   });
 
@@ -129,7 +129,7 @@ describe("Scene/Model/ModelStatistics", function () {
     expect(statistics.propertyTablesByteLength).toBe(0);
     expect(statistics.batchTexturesByteLength).toBe(0);
     expect(statistics._bufferIdSet).toEqual({ uuid1: true, uuid2: true });
-    expect(statistics._textureIdSet).toEqual({});
+    expect(statistics._textureIdByteLengths).toEqual({});
     expect(statistics._batchTextureIdMap).toEqual(emptyMap);
   });
 
@@ -158,7 +158,7 @@ describe("Scene/Model/ModelStatistics", function () {
     expect(statistics.propertyTablesByteLength).toBe(0);
     expect(statistics.batchTexturesByteLength).toBe(0);
     expect(statistics._bufferIdSet).toEqual({});
-    expect(statistics._textureIdSet).toEqual({ uuid: true });
+    expect(statistics._textureIdByteLengths).toEqual({ uuid: 10 });
     expect(statistics._batchTextureIdMap).toEqual(emptyMap);
   });
 
@@ -188,7 +188,7 @@ describe("Scene/Model/ModelStatistics", function () {
     expect(statistics.propertyTablesByteLength).toBe(0);
     expect(statistics.batchTexturesByteLength).toBe(0);
     expect(statistics._bufferIdSet).toEqual({});
-    expect(statistics._textureIdSet).toEqual({ uuid1: true, uuid2: true });
+    expect(statistics._textureIdByteLengths).toEqual({ uuid1: 2, uuid2: 3 });
     expect(statistics._batchTextureIdMap).toEqual(emptyMap);
   });
 
@@ -219,7 +219,7 @@ describe("Scene/Model/ModelStatistics", function () {
     expect(statistics.propertyTablesByteLength).toBe(0);
     expect(statistics.batchTexturesByteLength).toBe(0);
     expect(statistics._bufferIdSet).toEqual({});
-    expect(statistics._textureIdSet).toEqual({});
+    expect(statistics._textureIdByteLengths).toEqual({});
     expect(statistics._batchTextureIdMap).toEqual(expectedMap);
 
     // Simulate creating a batch texture
@@ -265,7 +265,7 @@ describe("Scene/Model/ModelStatistics", function () {
     expect(statistics.propertyTablesByteLength).toBe(0);
     expect(statistics.batchTexturesByteLength).toBe(0);
     expect(statistics._bufferIdSet).toEqual({});
-    expect(statistics._textureIdSet).toEqual({});
+    expect(statistics._textureIdByteLengths).toEqual({});
     expect(statistics._batchTextureIdMap).toEqual(expectedMap);
 
     // Simulate creating first batch texture

From 32dd865b95c1323a0e7ef1cbfc88c50cfd8a7c4f Mon Sep 17 00:00:00 2001
From: Marco Hutter <javagl@javagl.de>
Date: Mon, 25 Nov 2024 21:42:29 +0100
Subject: [PATCH 6/9] Draft for shared texture handling specs

---
 .../TilesetWithSharedTextures/plane-0.glb     | Bin 0 -> 1416 bytes
 .../TilesetWithSharedTextures/plane-1.glb     | Bin 0 -> 1416 bytes
 .../TilesetWithSharedTextures/plane-2.glb     | Bin 0 -> 1416 bytes
 .../TilesetWithSharedTextures/plane-3.glb     | Bin 0 -> 1416 bytes
 .../TilesetWithSharedTextures/texture0.png    | Bin 0 -> 1672 bytes
 .../TilesetWithSharedTextures/texture1.png    | Bin 0 -> 1567 bytes
 .../TilesetWithSharedTextures/tileset.json    | 116 ++++++++++++++++++
 .../engine/Specs/Scene/Cesium3DTilesetSpec.js |  43 +++++++
 8 files changed, 159 insertions(+)
 create mode 100644 Specs/Data/Cesium3DTiles/Tilesets/TilesetWithSharedTextures/plane-0.glb
 create mode 100644 Specs/Data/Cesium3DTiles/Tilesets/TilesetWithSharedTextures/plane-1.glb
 create mode 100644 Specs/Data/Cesium3DTiles/Tilesets/TilesetWithSharedTextures/plane-2.glb
 create mode 100644 Specs/Data/Cesium3DTiles/Tilesets/TilesetWithSharedTextures/plane-3.glb
 create mode 100644 Specs/Data/Cesium3DTiles/Tilesets/TilesetWithSharedTextures/texture0.png
 create mode 100644 Specs/Data/Cesium3DTiles/Tilesets/TilesetWithSharedTextures/texture1.png
 create mode 100644 Specs/Data/Cesium3DTiles/Tilesets/TilesetWithSharedTextures/tileset.json

diff --git a/Specs/Data/Cesium3DTiles/Tilesets/TilesetWithSharedTextures/plane-0.glb b/Specs/Data/Cesium3DTiles/Tilesets/TilesetWithSharedTextures/plane-0.glb
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literal 0
HcmV?d00001

diff --git a/Specs/Data/Cesium3DTiles/Tilesets/TilesetWithSharedTextures/texture1.png b/Specs/Data/Cesium3DTiles/Tilesets/TilesetWithSharedTextures/texture1.png
new file mode 100644
index 0000000000000000000000000000000000000000..97288521cd3ca2db40c3a08c43fd7c4e7fde19e9
GIT binary patch
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HcmV?d00001

diff --git a/Specs/Data/Cesium3DTiles/Tilesets/TilesetWithSharedTextures/tileset.json b/Specs/Data/Cesium3DTiles/Tilesets/TilesetWithSharedTextures/tileset.json
new file mode 100644
index 000000000000..280e75b7b61d
--- /dev/null
+++ b/Specs/Data/Cesium3DTiles/Tilesets/TilesetWithSharedTextures/tileset.json
@@ -0,0 +1,116 @@
+{
+  "asset": {
+    "version": "1.1"
+  },
+  "geometricError": 4096,
+  "root": {
+    "boundingVolume": {
+      "box": [
+        3.5,
+        0,
+        0.5,
+        3.5,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0.5
+      ]
+    },
+    "geometricError": 1024,
+    "children": [
+      {
+        "boundingVolume": {
+          "box": [
+            0.5,
+            0,
+            0.5,
+            0.5,
+            0,
+            0,
+            0,
+            0,
+            0,
+            0,
+            0,
+            0.5
+          ]
+        },
+        "geometricError": 512,
+        "content": {
+          "uri": "plane-0.glb"
+        }
+      },
+      {
+        "boundingVolume": {
+          "box": [
+            2.5,
+            0,
+            0.5,
+            0.5,
+            0,
+            0,
+            0,
+            0,
+            0,
+            0,
+            0,
+            0.5
+          ]
+        },
+        "geometricError": 512,
+        "content": {
+          "uri": "plane-1.glb"
+        }
+      },
+      {
+        "boundingVolume": {
+          "box": [
+            4.5,
+            0,
+            0.5,
+            0.5,
+            0,
+            0,
+            0,
+            0,
+            0,
+            0,
+            0,
+            0.5
+          ]
+        },
+        "geometricError": 512,
+        "content": {
+          "uri": "plane-2.glb"
+        }
+      },
+      {
+        "boundingVolume": {
+          "box": [
+            6.5,
+            0,
+            0.5,
+            0.5,
+            0,
+            0,
+            0,
+            0,
+            0,
+            0,
+            0,
+            0.5
+          ]
+        },
+        "geometricError": 512,
+        "content": {
+          "uri": "plane-3.glb"
+        }
+      }
+    ],
+    "refine": "ADD"
+  }
+}
\ No newline at end of file
diff --git a/packages/engine/Specs/Scene/Cesium3DTilesetSpec.js b/packages/engine/Specs/Scene/Cesium3DTilesetSpec.js
index 320870826e3e..99be4573668e 100644
--- a/packages/engine/Specs/Scene/Cesium3DTilesetSpec.js
+++ b/packages/engine/Specs/Scene/Cesium3DTilesetSpec.js
@@ -91,6 +91,10 @@ describe(
     const tilesetOfTilesetsUrl =
       "Data/Cesium3DTiles/Tilesets/TilesetOfTilesets/tileset.json";
 
+    // A tileset that refers to 4 GLB files which share two (external) textures
+    const tilesetUrlWithSharedTextures =
+      "Data/Cesium3DTiles/Tilesets/TilesetWithSharedTextures/tileset.json";
+
     const withoutBatchTableUrl =
       "Data/Cesium3DTiles/Batched/BatchedWithoutBatchTable/tileset.json";
     const withBatchTableUrl =
@@ -963,6 +967,45 @@ describe(
       );
     });
 
+    it("verify memory usage statistics for shared textures", function () {
+      // Basic camera setup
+      const camera = scene.camera;
+      camera.position = new Cartesian3(0, -1, 0);
+      camera.direction = Cartesian3.clone(Cartesian3.UNIT_Y);
+      camera.up = Cartesian3.clone(Cartesian3.UNIT_Z);
+      camera.frustum.near = 0.01;
+      camera.frustum.far = 100.0;
+
+      // Move the camera to see no tiles
+      camera.position = new Cartesian3(100, -1, 100);
+
+      return Cesium3DTilesTester.loadTileset(
+        scene,
+        tilesetUrlWithSharedTextures,
+      ).then(function (tileset) {
+        const statistics = tileset._statistics;
+
+        // No tiles loaded
+        expect(statistics.geometryByteLength).toEqual(0);
+        expect(statistics.texturesByteLength).toEqual(0);
+
+        // Move the camera to stare at the center of the first tile
+        camera.position = new Cartesian3(0.5, -13, 0.5);
+
+        return Cesium3DTilesTester.waitForTilesLoaded(scene, tileset).then(
+          function () {
+            console.log("Statistics ", JSON.stringify(statistics, null, 2));
+            // TODO
+            expect(statistics.geometryByteLength).toEqual(123);
+            expect(statistics.texturesByteLength).toEqual(234);
+
+            // TODO Eventually, trim
+            //tileset.trimLoadedTiles();
+          },
+        );
+      });
+    });
+
     it("verify memory usage statistics for shared resources", function () {
       ResourceCache.statistics.clear();
       // Six tiles total:

From e93f55ac4116f45ae3db02e699cb46da1b1e0c50 Mon Sep 17 00:00:00 2001
From: Marco Hutter <javagl@javagl.de>
Date: Tue, 26 Nov 2024 20:49:06 +0100
Subject: [PATCH 7/9] Remove log output. Fix increment/decrement error.

---
 packages/engine/Source/Scene/Cesium3DTilesetStatistics.js | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/packages/engine/Source/Scene/Cesium3DTilesetStatistics.js b/packages/engine/Source/Scene/Cesium3DTilesetStatistics.js
index 650bc2c69a85..f7c0d93834b9 100644
--- a/packages/engine/Source/Scene/Cesium3DTilesetStatistics.js
+++ b/packages/engine/Source/Scene/Cesium3DTilesetStatistics.js
@@ -140,7 +140,7 @@ Cesium3DTilesetStatistics.prototype.decrementLoadCounts = function (content) {
   if (!(content instanceof Model3DTileContent)) {
     this.texturesByteLength -= content.texturesByteLength;
   } else {
-    // When the content is a `Model3DTileContent`, then increment the
+    // When the content is a `Model3DTileContent`, then decrement the
     // reference counter for all its textures. The byte length of any
     // texture that is no longer references is subtracted from the
     // total textures byte length
@@ -150,7 +150,7 @@ Cesium3DTilesetStatistics.prototype.decrementLoadCounts = function (content) {
       if (referenceCounter === 1) {
         delete this.texturesReferenceCounterById[textureId];
         const textureByteLength = content.getTextureByteLengthById(textureId);
-        this.texturesByteLength += textureByteLength;
+        this.texturesByteLength -= textureByteLength;
       } else {
         this.texturesReferenceCounterById[textureId] = referenceCounter - 1;
       }
@@ -164,8 +164,6 @@ Cesium3DTilesetStatistics.prototype.decrementLoadCounts = function (content) {
       this.decrementLoadCounts(contents[i]);
     }
   }
-
-  console.log("after decrementLoadCounts", JSON.stringify(this, null, 2));
 };
 
 Cesium3DTilesetStatistics.clone = function (statistics, result) {

From 839ff0d8eec6a718d7a9f1de0e2d12e1b6b66424 Mon Sep 17 00:00:00 2001
From: Marco Hutter <javagl@javagl.de>
Date: Tue, 26 Nov 2024 20:50:22 +0100
Subject: [PATCH 8/9] Proper shared textures spec

---
 .../engine/Specs/Scene/Cesium3DTilesetSpec.js | 73 ++++++++++++++-----
 1 file changed, 53 insertions(+), 20 deletions(-)

diff --git a/packages/engine/Specs/Scene/Cesium3DTilesetSpec.js b/packages/engine/Specs/Scene/Cesium3DTilesetSpec.js
index 99be4573668e..a05b1be4dc28 100644
--- a/packages/engine/Specs/Scene/Cesium3DTilesetSpec.js
+++ b/packages/engine/Specs/Scene/Cesium3DTilesetSpec.js
@@ -967,9 +967,25 @@ describe(
       );
     });
 
-    it("verify memory usage statistics for shared textures", function () {
+    it("verify memory usage statistics for shared textures", async function () {
+      // One buffer view with 4 positions, 4 normals, and 4 texture coordinates,
+      // using a common byte stride of 12 (resulting in 144 bytes)
+      // and 2*3 unsigned short indices, resulting in a total of 156 bytes
+      const singleGeometryByteLength = 156;
+
+      // One texture with 128x128 * RGBA pixels = 65536 bytes
+      const singleTexturesByteLength = 65536;
+
       // Basic camera setup
       const camera = scene.camera;
+
+      // NOTE: This is really, really important. There are some
+      // random calls in "beforeEach" and other parts of these
+      // specs that affect the camera transform. And the camera
+      // transform is NOT maintained to be consistent with the
+      // other properties in any way. So reset it here...
+      camera.lookAtTransform(Matrix4.IDENTITY);
+
       camera.position = new Cartesian3(0, -1, 0);
       camera.direction = Cartesian3.clone(Cartesian3.UNIT_Y);
       camera.up = Cartesian3.clone(Cartesian3.UNIT_Z);
@@ -979,31 +995,48 @@ describe(
       // Move the camera to see no tiles
       camera.position = new Cartesian3(100, -1, 100);
 
-      return Cesium3DTilesTester.loadTileset(
+      const tileset = await Cesium3DTilesTester.loadTileset(
         scene,
         tilesetUrlWithSharedTextures,
-      ).then(function (tileset) {
-        const statistics = tileset._statistics;
+      );
 
-        // No tiles loaded
-        expect(statistics.geometryByteLength).toEqual(0);
-        expect(statistics.texturesByteLength).toEqual(0);
+      const statistics = tileset._statistics;
 
-        // Move the camera to stare at the center of the first tile
-        camera.position = new Cartesian3(0.5, -13, 0.5);
+      // No tiles loaded
+      expect(statistics.geometryByteLength).toEqual(0);
+      expect(statistics.texturesByteLength).toEqual(0);
 
-        return Cesium3DTilesTester.waitForTilesLoaded(scene, tileset).then(
-          function () {
-            console.log("Statistics ", JSON.stringify(statistics, null, 2));
-            // TODO
-            expect(statistics.geometryByteLength).toEqual(123);
-            expect(statistics.texturesByteLength).toEqual(234);
+      // Move the camera to stare at the center of the first tile
+      camera.position = new Cartesian3(0.5, -1, 0.5);
+      await Cesium3DTilesTester.waitForTilesLoaded(scene, tileset);
 
-            // TODO Eventually, trim
-            //tileset.trimLoadedTiles();
-          },
-        );
-      });
+      // A single tile and texture was loaded
+      expect(statistics.geometryByteLength).toEqual(singleGeometryByteLength);
+      expect(statistics.texturesByteLength).toEqual(singleTexturesByteLength);
+
+      // Move the camera back to see all tiles
+      camera.position = new Cartesian3(3.5, -14, 0.5);
+      await Cesium3DTilesTester.waitForTilesLoaded(scene, tileset);
+
+      // All tiles have been loaded: 4 times the geometry, BUT
+      // ONLY 2 times the texture
+      expect(statistics.geometryByteLength).toEqual(
+        singleGeometryByteLength * 4,
+      );
+      expect(statistics.texturesByteLength).toEqual(
+        singleTexturesByteLength * 2,
+      );
+
+      // Move the camera back to stare at the center of the first tile again
+      camera.position = new Cartesian3(0.5, -1, 0.5);
+
+      // Trim any previously loaded tiles
+      tileset.trimLoadedTiles();
+      await Cesium3DTilesTester.waitForTilesLoaded(scene, tileset);
+
+      // Again, only a single tile and texture should be loaded
+      expect(statistics.geometryByteLength).toEqual(singleGeometryByteLength);
+      expect(statistics.texturesByteLength).toEqual(singleTexturesByteLength);
     });
 
     it("verify memory usage statistics for shared resources", function () {

From 131ebff6ed565ddce1de98eece9d89c1cd53e22e Mon Sep 17 00:00:00 2001
From: Sean Lilley <lilleyse@gmail.com>
Date: Tue, 26 Nov 2024 18:01:09 -0500
Subject: [PATCH 9/9] Update CHANGES.md [skip ci]

---
 CHANGES.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CHANGES.md b/CHANGES.md
index b68c43afe47a..6c6aca2d2063 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -21,6 +21,7 @@
 
 ##### Fixes :wrench:
 
+- Fixed bug where shared external textures from glTF files were not accounted for in resource statistics. [#12331](https://github.com/CesiumGS/cesium/pull/12331)
 - Fix label rendering bug in WebGL1 contexts. [#12301](https://github.com/CesiumGS/cesium/pull/12301)
 - Fixed lag or crashes when loading many models in the same frame. [#12320](https://github.com/CesiumGS/cesium/pull/12320)
 - Updated WMS example URL in UrlTemplateImageryProvider documentation to use an active service. [#12323](https://github.com/CesiumGS/cesium/pull/12323)