As all your Asset data must be pre-downloaded before your content starts, you should consider moving Assets out of your main data files and into AssetBundles. This way, you can create a small loader SceneA Scene contains the environments and menus of your game. Think of each unique Scene file as a unique level. In each Scene, you place your environments, obstacles, and decorations, essentially designing and building your game in pieces. More info
See in Glossary for your content which loads quickly. It then dynamically loads Assets on-demand as the user proceeds through your content. AssetBundles also help with Asset data memory management: You can unload Asset data from memory for Assets that you don’t need any more by calling AssetBundle.Unload.
The following considerations apply when using AssetBundles on the WebGLA JavaScript API that renders 2D and 3D graphics in a web browser. The Unity WebGL build option allows Unity to publish content as JavaScript programs which use HTML5 technologies and the WebGL rendering API to run Unity content in a web browser. More info
See in Glossary platform:
When you use class types in your AssetBundle which are not used in your main build, Unity may strip the code for those classes from the build. This can cause a fail when trying to load Assets from the AssetBundle. Use BuildPlayerOptions.assetBundleManifestPath to fix that, or see the section on [Distribution size and code stripping](webgl-distribution size-codestripping.md), below, for other options.
WebGL does not support threading, but http downloads only become available when they have finished downloading. Because of this, Unity WebGL builds need to decompress AssetBundle data on the main thread when the download is done, blocking the main thread. To avoid this interruption, LZMA AssetBundle compression is not available for AssetBundles on WebGL. AssetBundles are compressed using LZ4 instead, which is de-compressed very efficiently on-demand. If you need smaller compressionA method of storing data that reduces the amount of storage space it requires. See Texture Compression, Animation Compression, Audio Compression, Build Compression.
See in Glossary sizes than LZ4 delivers, you can configure your web server to use gzip or Brotli compression (on top of LZ4 compression) on your AssetBundles. See documentation on Deploying compressed builds for more information on how to do this.
WebGL supports AssetBundle caching with UnityWebRequestAssetBundle.GetAssetBundle. This method uses the IndexedDB API from your browser to store a cache on the user’s device. Some browsers might have limited support for IndexedDB and any browsers might request the user’s authorization to store data on the disk. For more information, see WebGL browser compatibility.