Add 2D / CV support to tilesets using ModelExperimental

CHANGES.md

@@ -13,6 +13,7 @@
 - Added `IndexDatatype.fromTypedArray`. [#10350](https://github.com/CesiumGS/cesium/pull/10350)
 - Added `ModelAnimationCollection.animateWhilePaused` and `ModelAnimation.animationTime` to allow explicit control over a model's animations. [#9339](https://github.com/CesiumGS/cesium/pull/9339)
 - Replaced `options.gltf` with `options.url` in `ModelExperimental.fromGltf`. [#10371](https://github.com/CesiumGS/cesium/pull/10371)
+- Added support for 2D / CV mode for non-instanced tilesets rendered with `ModelExperimental`. [#10384](https://github.com/CesiumGS/cesium/pull/10384)
 
 ##### Fixes :wrench:
 

Source/Scene/FrameState.js

@@ -240,7 +240,7 @@ function FrameState(context, creditDisplay, jobScheduler) {
   this.afterRender = [];
 
   /**
-   * Gets whether or not to optimized for 3D only.
+   * Gets whether or not to optimize for 3D only.
    *
    * @type {Boolean}
    * @default false

Source/Scene/GltfIndexBufferLoader.js

@@ -3,6 +3,7 @@ import ComponentDatatype from "../Core/ComponentDatatype.js";
 import defaultValue from "../Core/defaultValue.js";
 import defer from "../Core/defer.js";
 import defined from "../Core/defined.js";
+import DeveloperError from "../Core/DeveloperError.js";
 import IndexDatatype from "../Core/IndexDatatype.js";
 import Buffer from "../Renderer/Buffer.js";
 import BufferUsage from "../Renderer/BufferUsage.js";
@@ -29,8 +30,8 @@ import ResourceLoaderState from "./ResourceLoaderState.js";
  * @param {Object} [options.draco] The Draco extension object.
  * @param {String} [options.cacheKey] The cache key of the resource.
  * @param {Boolean} [options.asynchronous=true] Determines if WebGL resource creation will be spread out over several frames or block until all WebGL resources are created.
- * @param {Boolean} [options.loadAsTypedArray=false] Load index buffer as a typed array instead of a GPU index buffer.
- * @param {Boolean} [options.loadForWireframe=false] Load index buffer as a typed array in order to generate wireframes in WebGL1. This will be ignored if using WebGL2.
+ * @param {Boolean} [options.loadBuffer=false] Load the index buffer as a GPU index buffer.
+ * @param {Boolean} [options.loadTypedArray=false] Load the index buffer as a typed array.
  * @private
  */
 export default function GltfIndexBufferLoader(options) {
@@ -43,15 +44,20 @@ export default function GltfIndexBufferLoader(options) {
   const draco = options.draco;
   const cacheKey = options.cacheKey;
   const asynchronous = defaultValue(options.asynchronous, true);
-  const loadAsTypedArray = defaultValue(options.loadAsTypedArray, false);
-  const loadForWireframe = defaultValue(options.loadForWireframe, false);
+  const loadBuffer = defaultValue(options.loadBuffer, false);
+  const loadTypedArray = defaultValue(options.loadTypedArray, false);
 
   //>>includeStart('debug', pragmas.debug);
   Check.typeOf.func("options.resourceCache", resourceCache);
   Check.typeOf.object("options.gltf", gltf);
   Check.typeOf.number("options.accessorId", accessorId);
   Check.typeOf.object("options.gltfResource", gltfResource);
   Check.typeOf.object("options.baseResource", baseResource);
+  if (!loadBuffer && !loadTypedArray) {
+    throw new DeveloperError(
+      "At least one of loadBuffer and loadTypedArray must be true."
+    );
+  }
   //>>includeEnd('debug');
 
   const indexDatatype = gltf.accessors[accessorId].componentType;
@@ -65,8 +71,8 @@ export default function GltfIndexBufferLoader(options) {
   this._draco = draco;
   this._cacheKey = cacheKey;
   this._asynchronous = asynchronous;
-  this._loadAsTypedArray = loadAsTypedArray;
-  this._loadForWireframe = loadForWireframe;
+  this._loadBuffer = loadBuffer;
+  this._loadTypedArray = loadTypedArray;
   this._bufferViewLoader = undefined;
   this._dracoLoader = undefined;
   this._typedArray = undefined;
@@ -110,8 +116,7 @@ Object.defineProperties(GltfIndexBufferLoader.prototype, {
     },
   },
   /**
-   * The index buffer. This is only defined when <code>loadAsTypedArray</code> is false
-   * or when <code>loadForWireframe</code> is false while using WebGL1.
+   * The index buffer. This is only defined when <code>loadBuffer</code> is true.
    *
    * @memberof GltfIndexBufferLoader.prototype
    *
@@ -125,8 +130,7 @@ Object.defineProperties(GltfIndexBufferLoader.prototype, {
     },
   },
   /**
-   * The typed array containing indices. This is only defined when <code>loadAsTypedArray</code> is true
-   * or when <code>loadForWireframe</code> is true while using WebGL1.
+   * The typed array containing indices. This is only defined when <code>loadTypedArray</code> is true.
    *
    * @memberof GltfIndexBufferLoader.prototype
    *
@@ -338,25 +342,8 @@ GltfIndexBufferLoader.prototype.process = function (frameState) {
     return;
   }
 
-  // WebGL1 has no way to retrieve the contents of buffers that are
-  // on the GPU. Therefore, the index buffer must be stored in CPU memory
-  // to generate wireframes for models.
-  const useWebgl2 = frameState.context.webgl2;
-  const loadTypedArrayForWireframe = !useWebgl2 && this._loadForWireframe;
-  if (this._loadAsTypedArray || loadTypedArrayForWireframe) {
-    // Unload everything except the typed array
-    this.unload();
-
-    this._typedArray = typedArray;
-    this._state = ResourceLoaderState.READY;
-    this._promise.resolve(this);
-
-    return;
-  }
-
   let buffer;
-
-  if (this._asynchronous) {
+  if (this._loadBuffer && this._asynchronous) {
     const indexBufferJob = scratchIndexBufferJob;
     indexBufferJob.set(typedArray, indexDatatype, frameState.context);
     const jobScheduler = frameState.jobScheduler;
@@ -365,14 +352,15 @@ GltfIndexBufferLoader.prototype.process = function (frameState) {
       return;
     }
     buffer = indexBufferJob.buffer;
-  } else {
+  } else if (this._loadBuffer) {
     buffer = createIndexBuffer(typedArray, indexDatatype, frameState.context);
   }
 
   // Unload everything except the index buffer
   this.unload();
 
   this._buffer = buffer;
+  this._typedArray = this._loadTypedArray ? typedArray : undefined;
   this._state = ResourceLoaderState.READY;
   this._promise.resolve(this);
 };