cesium加载Draco几何压缩数据

 1.1 处理流程

• 利用3d-tiles-tools 或gltf-pipeline 压缩glb 或b3dm。
• cesium 直接加载Draco压缩后的数据。

1.2 遇见的问题

报错找不到draco_decoder.wasm，无法解压数据。

cesium包里有这个文件，但是vue项目中找不到。那大概率是webpack的问题。

接下来看我的 vue.config.js文件。

plugins: [
            new CopyWebpackPlugin({ patterns: [{ from: path.join(cesiumSource, cesiumWorkers), to: 'Workers' }] }),
            new CopyWebpackPlugin({ patterns: [{ from: path.join(cesiumSource, 'Assets'), to: 'Assets' }] }),
            new CopyWebpackPlugin({ patterns: [{ from: path.join(cesiumSource, 'Widgets'), to: 'Widgets' }] }),
            new CopyWebpackPlugin({ patterns: [{ from: path.join(cesiumSource, 'ThirdParty/Workers'), to: 'ThirdParty/Workers' }] })
]

可以看到只处理了ThirdParty/Workers 文件的引用，但是ThirdParty里其他文件没有处理，而draco_decoder.wasm 恰好在这次选项中。那就更改配置。 

        plugins: [
            new CopyWebpackPlugin({ patterns: [{ from: path.join(cesiumSource, cesiumWorkers), to: 'Workers' }] }),
            new CopyWebpackPlugin({ patterns: [{ from: path.join(cesiumSource, 'Assets'), to: 'Assets' }] }),
            new CopyWebpackPlugin({ patterns: [{ from: path.join(cesiumSource, 'Widgets'), to: 'Widgets' }] }),
            new CopyWebpackPlugin({ patterns: [{ from: path.join(cesiumSource, 'ThirdParty/Workers'), to: 'ThirdParty/Workers' }] }),
            new CopyWebpackPlugin({
                patterns: [{
                        from: path.join(cesiumSource, 'ThirdParty'),
                        to: 'ThirdParty',
                        // 只复制 ThirdParty 下的 Workers 目录之外的文件
                        filter: (file) => {
                            return !file.includes('Workers');
                        }
                    },

                ]
            }),]

此时可以加载Draco压缩数据