Add existing to tracked

node_modules/@cesium/engine/Source/Scene/BufferPolygon.js

@@ -0,0 +1,517 @@
+// @ts-check
+
+import assert from "../Core/assert.js";
+import Check from "../Core/Check.js";
+import defined from "../Core/defined.js";
+import BufferPrimitive from "./BufferPrimitive.js";
+import BufferPrimitiveCollection from "./BufferPrimitiveCollection.js";
+
+/** @import { TypedArray, TypedArrayConstructor } from "../Core/globalTypes.js"; */
+/** @import BufferPolygonCollection from "./BufferPolygonCollection.js"; */
+
+const { ERR_CAPACITY, ERR_RESIZE, ERR_OUT_OF_RANGE } =
+  BufferPrimitiveCollection.Error;
+
+/**
+ * View bound to the underlying buffer data of a {@link BufferPolygonCollection}.
+ *
+ * <p>BufferPolygon instances are {@link https://en.wikipedia.org/wiki/Flyweight_pattern|flyweights}:
+ * a single BufferPolygon instance can be temporarily bound to any conceptual
+ * "polygon" in a BufferPolygonCollection, allowing very large collections to be
+ * iterated and updated with a minimal memory footprint.</p>
+ *
+ * <p>Represented as one (1) external linear ring of three (3) or more positions.
+ * May optionally define one or more internal linear rings ("holes") within the
+ * polygon. Each hole is represented as a single index into the positions array,
+ * where the vertex at that index is the start of an internal linear ring that
+ * continues along the following vertices until reaching either the vertex
+ * index of the next hole, or the end of the vertex list. Stores a precomputed
+ * triangulation, represented as three vertex indices per triangle.</p>
+ *
+ * @see BufferPolygonCollection
+ * @see BufferPolygonMaterial
+ * @see BufferPrimitive
+ * @extends BufferPrimitive
+ * @experimental This feature is not final and is subject to change without Cesium's standard deprecation policy.
+ */
+class BufferPolygon extends BufferPrimitive {
+  /**
+   * @type {BufferPolygonCollection}
+   * @ignore
+   */
+  _collection = null;
+
+  /** @ignore */
+  static Layout = {
+    ...BufferPrimitive.Layout,
+
+    /**
+     * Offset in collection position array to first vertex in polygon, number
+     * of VEC3 elements.
+     * @type {number}
+     * @ignore
+     */
+    POSITION_OFFSET_U32: BufferPrimitive.Layout.__BYTE_LENGTH,
+
+    /**
+     * Count of positions (vertices) in this polygon, number of VEC3 elements.
+     * @type {number}
+     * @ignore
+     */
+    POSITION_COUNT_U32: BufferPrimitive.Layout.__BYTE_LENGTH + 4,
+
+    /**
+     * Offset in collection holes array to first hole in polygon, number of
+     * integer elements.
+     * @type {number}
+     * @ignore
+     */
+    HOLE_OFFSET_U32: BufferPrimitive.Layout.__BYTE_LENGTH + 8,
+
+    /**
+     * Count of holes (indices) in this polygon.
+     * @type {number}
+     * @ignore
+     */
+    HOLE_COUNT_U32: BufferPrimitive.Layout.__BYTE_LENGTH + 12,
+
+    /**
+     * Offset in collection triangles array to first triangle in polygon,
+     * number of VEC3 elements.
+     * @type {number}
+     * @ignore
+     */
+    TRIANGLE_OFFSET_U32: BufferPrimitive.Layout.__BYTE_LENGTH + 16,
+
+    /**
+     * Count of triangles in this polygon, number of VEC3 elements.
+     * @type {number}
+     * @ignore
+     */
+    TRIANGLE_COUNT_U32: BufferPrimitive.Layout.__BYTE_LENGTH + 20,
+
+    /**
+     * @type {number}
+     * @ignore
+     */
+    __BYTE_LENGTH: BufferPrimitive.Layout.__BYTE_LENGTH + 24,
+  };
+
+  /////////////////////////////////////////////////////////////////////////////
+  // LIFECYCLE
+
+  /**
+   * Copies data from source polygon to result. If the result polygon is not
+   * new (the last polygon in the collection) then source and result polygons
+   * must have the same vertex counts, hole counts, and triangle counts.
+   *
+   * @param {BufferPolygon} polygon
+   * @param {BufferPolygon} result
+   * @return {BufferPolygon}
+   * @override
+   */
+  static clone(polygon, result) {
+    super.clone(polygon, result);
+    result.setPositions(polygon.getPositions());
+    result.setHoles(polygon.getHoles());
+    result.setTriangles(polygon.getTriangles());
+    return result;
+  }
+
+  /////////////////////////////////////////////////////////////////////////////
+  // GEOMETRY
+
+  /**
+   * Offset in collection position array to first vertex in polygon, number
+   * of VEC3 elements.
+   *
+   * @type {number}
+   * @readonly
+   * @ignore
+   */
+  get vertexOffset() {
+    return this._getUint32(BufferPolygon.Layout.POSITION_OFFSET_U32);
+  }
+
+  /**
+   * Count of positions (vertices) in this polygon, including both outer ring and
+   * internal rings (holes), number of VEC3 elements.
+   *
+   * @type {number}
+   * @readonly
+   */
+  get vertexCount() {
+    return this._getUint32(BufferPolygon.Layout.POSITION_COUNT_U32);
+  }
+
+  /**
+   * Returns an array view of this polygon's vertex positions. If 'result'
+   * argument is given, vertex positions are written to that array and returned.
+   * Otherwise, returns an ArrayView on collection memory — changes to this array
+   * will not trigger render updates, which requires `.setPositions()`.
+   *
+   * @param {TypedArray} [result]
+   * return {TypedArray}
+   */
+  getPositions(result) {
+    return this._getPositionsRange(0, this.vertexCount, result);
+  }
+
+  /** @param {TypedArray} positions */
+  setPositions(positions) {
+    const collection = this._collection;
+    const vertexOffset = this.vertexOffset;
+    const srcCount = this.vertexCount;
+    const dstCount = positions.length / 3;
+    const collectionCount = collection.vertexCount + dstCount - srcCount;
+
+    //>>includeStart('debug', pragmas.debug);
+    assert(srcCount === dstCount || this._isResizable(), ERR_RESIZE);
+    assert(collectionCount <= collection.vertexCountMax, ERR_CAPACITY);
+    //>>includeEnd('debug');
+
+    collection._positionCount = collectionCount;
+    this._setUint32(BufferPolygon.Layout.POSITION_COUNT_U32, dstCount);
+
+    const positionView = collection._positionView;
+    for (let i = 0; i < dstCount; i++) {
+      positionView[(vertexOffset + i) * 3] = positions[i * 3];
+      positionView[(vertexOffset + i) * 3 + 1] = positions[i * 3 + 1];
+      positionView[(vertexOffset + i) * 3 + 2] = positions[i * 3 + 2];
+    }
+
+    this._dirty = true;
+    collection._makeDirtyBoundingVolume();
+  }
+
+  /**
+   * Offset in collection position array to first vertex in polygon's outer
+   * linear ring, number of VEC3 elements.
+   *
+   * @type {number}
+   * @readonly
+   */
+  get outerVertexOffset() {
+    return this.vertexOffset;
+  }
+
+  /**
+   * Count of positions (vertices) in this polygon's outer linear ring, number
+   * of VEC3 elements.
+   *
+   * @type {number}
+   * @readonly
+   */
+  get outerVertexCount() {
+    if (this.holeCount > 0) {
+      return this.getHoles()[0];
+    }
+    return this.vertexCount;
+  }
+
+  /**
+   * Returns an array view of this polygon's outer linear ring vertex positions.
+   * If 'result' argument is given, vertex positions are written to that array
+   * and returned. Otherwise, returns an ArrayView on collection memory —
+   * changes to this array will not trigger render updates, which requires
+   * `.setPositions()`.
+   *
+   * @param {TypedArray} [result]
+   * @returns {TypedArray}
+   */
+  getOuterPositions(result) {
+    return this._getPositionsRange(0, this.outerVertexCount, result);
+  }
+
+  /**
+   * Offset in collection holes array to first hole in polygon, number of
+   * integer elements.
+   *
+   * @type {number}
+   * @readonly
+   * @ignore
+   */
+  get holeOffset() {
+    return this._getUint32(BufferPolygon.Layout.HOLE_OFFSET_U32);
+  }
+
+  /**
+   * Count of holes (indices) in this polygon.
+   *
+   * @type {number}
+   * @readonly
+   */
+  get holeCount() {
+    return this._getUint32(BufferPolygon.Layout.HOLE_COUNT_U32);
+  }
+
+  /**
+   * Gets this polygon's hole indices, with each hole represented as a single
+   * offset into this polygon's positions array. Each hole implicitly
+   * continues along an internal linear ring from that vertex offset until
+   * reaching either the end of the positions array, or the next hole offset.
+   *
+   * If 'result' argument is given, hole indices are written to that array and
+   * returned. Otherwise, returns an ArrayView on collection memory — changes
+   * to this array will not trigger render updates, which requires `.setHoles()`.
+   *
+   * @param {TypedArray} [result]
+   * @returns {TypedArray}
+   */
+  getHoles(result) {
+    const { holeOffset, holeCount } = this;
+    const holeIndexView = this._collection._holeIndexView;
+
+    if (!defined(result)) {
+      const byteOffset =
+        holeIndexView.byteOffset + holeOffset * holeIndexView.BYTES_PER_ELEMENT;
+      const TypedArray = /** @type {TypedArrayConstructor} */ (
+        holeIndexView.constructor
+      );
+      return new TypedArray(
+        /** @type {ArrayBuffer} */ (holeIndexView.buffer),
+        byteOffset,
+        holeCount,
+      );
+    }
+
+    for (let i = 0; i < holeCount; i++) {
+      result[i] = holeIndexView[holeOffset + i];
+    }
+    return result;
+  }
+
+  /**
+   * Sets this polygon's hole indices, with holes represented as a single
+   * offset into this polygon's positions array. Each hole implicitly
+   * continues along an internal linear ring from that vertex offset until
+   * reaching either the end of the positions array, or the next hole offset.
+   *
+   * @param {TypedArray} holes
+   */
+  setHoles(holes) {
+    const collection = this._collection;
+    const holeOffset = this.holeOffset;
+    const srcCount = this.holeCount;
+    const dstCount = holes.length;
+    const collectionCount = collection.holeCount + dstCount - srcCount;
+
+    //>>includeStart('debug', pragmas.debug);
+    assert(srcCount === dstCount || this._isResizable(), ERR_RESIZE);
+    assert(collectionCount <= collection.holeCountMax, ERR_CAPACITY);
+    //>>includeEnd('debug');
+
+    collection._holeCount = collectionCount;
+    this._setUint32(BufferPolygon.Layout.HOLE_COUNT_U32, dstCount);
+
+    const holeIndexView = collection._holeIndexView;
+    for (let i = 0; i < dstCount; i++) {
+      holeIndexView[holeOffset + i] = holes[i];
+    }
+
+    this._dirty = true;
+  }
+
+  /**
+   * Returns the number of (VEC3) vertices in the specified hole.
+   *
+   * @param {number} holeIndex
+   * @returns {number}
+   */
+  getHoleVertexCount(holeIndex) {
+    const holes = this.getHoles();
+
+    //>>includeStart('debug', pragmas.debug);
+    Check.typeOf.number.greaterThanOrEquals("holeIndex", holeIndex, 0);
+    Check.typeOf.number.lessThan("holeIndex", holeIndex, holes.length);
+    //>>includeEnd('debug');
+
+    const holeVertexOffset = holes[holeIndex];
+    return holeIndex === holes.length - 1
+      ? this.vertexCount - holeVertexOffset
+      : holes[holeIndex + 1] - holeVertexOffset;
+  }
+
+  /**
+   * Returns an array view of the inner linear ring vertex positions for the
+   * specified hole. If 'result' argument is given, vertex positions are written
+   * to that array and returned. Otherwise, returns an ArrayView on collection
+   * memory — changes to this array will not trigger render updates, which
+   * requires `.setPositions()`.
+   *
+   * @param {number} holeIndex
+   * @param {TypedArray} [result]
+   * return {TypedArray}
+   */
+  getHolePositions(holeIndex, result) {
+    const holes = this.getHoles();
+
+    //>>includeStart('debug', pragmas.debug);
+    Check.typeOf.number.greaterThanOrEquals("holeIndex", holeIndex, 0);
+    Check.typeOf.number.lessThan("holeIndex", holeIndex, holes.length);
+    //>>includeEnd('debug');
+
+    const holeVertexOffset = holes[holeIndex];
+    const holeVertexCount = this.getHoleVertexCount(holeIndex);
+    return this._getPositionsRange(holeVertexOffset, holeVertexCount, result);
+  }
+
+  /**
+   * Internal helper for accessing vertex positions. 'vertexOffset' argument
+   * is relative to the start of the polygon's vertex block, with 0 being
+   * the first vertex in the polygon. If 'result' argument is given, the
+   * requested range of vertices are written to the result array and returned.
+   * Otherwise, returns an ArrayView on collection memory.
+   *
+   * @param {number} vertexOffset
+   * @param {number} vertexCount
+   * @param {TypedArray} [result]
+   * @returns {TypedArray}
+   * @private
+   */
+  _getPositionsRange(vertexOffset, vertexCount, result) {
+    const collection = this._collection;
+    const positionView = this._collection._positionView;
+
+    const collectionVertexOffset = this.vertexOffset + vertexOffset;
+
+    //>>includeStart('debug', pragmas.debug);
+    assert(collectionVertexOffset >= 0, ERR_OUT_OF_RANGE);
+    assert(collectionVertexOffset < collection.vertexCount, ERR_OUT_OF_RANGE);
+    assert(vertexCount > 0, ERR_OUT_OF_RANGE);
+    assert(vertexCount <= this.vertexCount, ERR_OUT_OF_RANGE);
+    //>>includeEnd('debug');
+
+    if (!defined(result)) {
+      const byteOffset =
+        positionView.byteOffset +
+        collectionVertexOffset * 3 * positionView.BYTES_PER_ELEMENT;
+      const TypedArray = /** @type {TypedArrayConstructor} */ (
+        positionView.constructor
+      );
+      return new TypedArray(
+        /** @type {ArrayBuffer} */ (positionView.buffer),
+        byteOffset,
+        vertexCount * 3,
+      );
+    }
+
+    for (let i = 0; i < vertexCount; i++) {
+      result[i * 3] = positionView[(collectionVertexOffset + i) * 3];
+      result[i * 3 + 1] = positionView[(collectionVertexOffset + i) * 3 + 1];
+      result[i * 3 + 2] = positionView[(collectionVertexOffset + i) * 3 + 2];
+    }
+    return result;
+  }
+
+  /**
+   * Offset in collection triangles array to first triangle in polygon,
+   * number of VEC3 elements.
+   * @type {number}
+   * @readonly
+   * @ignore
+   */
+  get triangleOffset() {
+    return this._getUint32(BufferPolygon.Layout.TRIANGLE_OFFSET_U32);
+  }
+
+  /**
+   * Count of triangles in this polygon, number of VEC3 elements.
+   *
+   * @type {number}
+   * @readonly
+   */
+  get triangleCount() {
+    return this._getUint32(BufferPolygon.Layout.TRIANGLE_COUNT_U32);
+  }
+
+  /**
+   * Returns an array view of this polygon's triangle indices, represented as
+   * three vertex indices per triangle.
+   *
+   * If 'result' argument is given, triangle indices are written to that array
+   * and returned. Otherwise, returns an ArrayView on collection memory —
+   * changes to this array will not trigger render updates, which requires
+   * `.setTriangles()`.
+   *
+   * @param {TypedArray} [result]
+   * @returns {TypedArray}
+   */
+  getTriangles(result) {
+    const { triangleOffset, triangleCount } = this;
+    const indices = this._collection._triangleIndexView;
+
+    if (!defined(result)) {
+      const byteOffset =
+        indices.byteOffset + triangleOffset * 3 * indices.BYTES_PER_ELEMENT;
+      const TypedArray = /** @type {TypedArrayConstructor} */ (
+        indices.constructor
+      );
+      return new TypedArray(
+        /** @type {ArrayBuffer} */ (indices.buffer),
+        byteOffset,
+        triangleCount * 3,
+      );
+    }
+
+    for (let i = 0; i < triangleCount; i++) {
+      result[i * 3] = indices[(triangleOffset + i) * 3];
+      result[i * 3 + 1] = indices[(triangleOffset + i) * 3 + 1];
+      result[i * 3 + 2] = indices[(triangleOffset + i) * 3 + 2];
+    }
+    return result;
+  }
+
+  /**
+   * Sets this polygon's triangle indices, represented as three vertex indices
+   * per triangle.
+   *
+   * @param {TypedArray} indices
+   */
+  setTriangles(indices) {
+    const collection = this._collection;
+    const triangleOffset = this.triangleOffset;
+    const srcCount = this.triangleCount;
+    const dstCount = indices.length / 3;
+    const collectionCount = collection.triangleCount + dstCount - srcCount;
+
+    //>>includeStart('debug', pragmas.debug);
+    assert(srcCount === dstCount || this._isResizable(), ERR_RESIZE);
+    assert(collectionCount <= collection.triangleCountMax, ERR_CAPACITY);
+    //>>includeEnd('debug');
+
+    collection._triangleCount += dstCount - srcCount;
+    this._setUint32(BufferPolygon.Layout.TRIANGLE_COUNT_U32, dstCount);
+
+    const dstIndices = collection._triangleIndexView;
+    for (let i = 0; i < dstCount; i++) {
+      dstIndices[(triangleOffset + i) * 3] = indices[i * 3];
+      dstIndices[(triangleOffset + i) * 3 + 1] = indices[i * 3 + 1];
+      dstIndices[(triangleOffset + i) * 3 + 2] = indices[i * 3 + 2];
+    }
+
+    this._dirty = true;
+  }
+
+  /////////////////////////////////////////////////////////////////////////////
+  // DEBUG
+
+  /**
+   * Returns a JSON-serializable object representing the polygon. This encoding
+   * is not memory-efficient, and should generally be used for debugging and
+   * testing.
+   *
+   * @returns {Object} JSON-serializable object.
+   * @override
+   */
+  toJSON() {
+    return {
+      ...super.toJSON(),
+      positions: Array.from(this.getPositions()),
+      holes: Array.from(this.getHoles()),
+      triangles: Array.from(this.getTriangles()),
+    };
+  }
+}
+
+export default BufferPolygon;