CesiumInstancedMesh 实例

import * as Cesium from 'cesium';// Three.js 风格的 InstancedMesh 类, https://threejs.org/docs/#api/en/objects/InstancedMesh
export class CesiumInstancedMesh {/*** Creates an instance of InstancedMesh.** @param {Cesium.Geometry} geometry - Cesium geometry instance* @param {Cesium.MaterialAppearance} material - Cesium material appearance* @param {number} count - Number of instances*/constructor(geometry, material, count) {this._instances = Array.from({ length: count }, () => ({modelMatrix: null,geometry: null}));this._geometry = geometry;this._material = material;this._primitive = null;}/*** Gets the Cesium Primitive for rendering.* @returns {Cesium.Primitive}*/get primitive() {if (this._primitive) return this._primitive;// 验证所有实例是否有效for (let i = 0; i < this._instances.length; i++) {if (!this._instances[i].modelMatrix || !this._instances[i].geometry) {throw new Error(`Instance at index ${i} is not fully initialized`);}}this._primitive = new Cesium.Primitive({geometryInstances: this._instances.map(instance => new Cesium.GeometryInstance({geometry: instance.geometry,modelMatrix: instance.modelMatrix})),appearance: this._material,asynchronous: false});return this._primitive;}/*** Sets the model matrix for an instance at the specified index.* @param {number} index - Instance index* @param {Cesium.Matrix4} matrix - Model matrix*/setMatrixAt(index, matrix) {if (index < 0 || index >= this._instances.length) {throw new Error(`Index ${index} is out of bounds (0 to ${this._instances.length - 1})`);}this._instances[index].modelMatrix = Cesium.Matrix4.clone(matrix, new Cesium.Matrix4());this._instances[index].geometry = this._geometry;if (this._primitive) {this._primitive.geometryInstances = this._instances.map(instance => new Cesium.GeometryInstance({geometry: instance.geometry,modelMatrix: instance.modelMatrix}));}}/*** Destroys the instance and releases resources.*/destroy() {this._primitive = null;this._instances = null;this._geometry = null;this._material = null;}
}