Asset bundles in Unity3D are a way to package and load assets at runtime. They allow developers to load assets from external files, which can be downloaded over the internet or loaded from a local file system. Asset bundles are a powerful feature that allows developers to create more efficient and flexible games, by separating game content into smaller, more manageable packages.
Asset bundles can contain any type of asset that can be loaded by Unity3D, including textures, models, animations, audio clips, and more. These assets are stored in a compressed format and can be loaded on demand, reducing the initial load time of the game.
Building a basic Unity3D asset bundle #
To create an asset bundle, developers need to follow these steps:
- Create a new asset bundle by going to Assets > Create > Asset Bundle.
- Drag the assets they want to include in the asset bundle into the new asset bundle folder.
- Select the asset bundle and configure its settings, such as compression method, platform, and variant.
- Build the asset bundle by selecting the asset bundle and going to Assets > Build Asset Bundle.
Once the asset bundle is built, developers can load it at runtime using the AssetBundle class provided by Unity3D. They can also download asset bundles over the internet or load them from a local file system.
Asset Bundle Compression #
Asset bundles can be compressed using different methods, depending on the platform and the type of asset. The available compression methods are LZMA, LZ4, and Uncompressed.
LZMA is the default compression method for asset bundles in Unity3D. It provides the best compression ratio, but also requires more processing power to decompress the assets.
LZ4 is a faster compression method that provides a good balance between compression ratio and processing speed. It is recommended for platforms with limited processing power, such as mobile devices.
Uncompressed asset bundles do not use any compression, which makes them faster to load but increases their size. They are recommended for platforms with high processing power and limited storage space, such as consoles.
Asset Bundle Platforms and Variants #
Asset bundles can be built for different platforms and variants, depending on the requirements of the game. The available platforms are Windows, Mac, iOS, Android, and more. Each platform has its own requirements and limitations, so developers need to optimize their asset bundles for each platform.
Asset bundle variants allow developers to create different versions of an asset bundle, with different content or settings. For example, developers can create an asset bundle for a specific level of the game, with different textures or models depending on the platform. Variants are useful for managing game content and reducing the size of asset bundles.
Asset Bundle Differences Between Platforms #
Asset bundles can be built for different platforms, each with its own requirements and limitations. Here are some of the differences between asset bundles for different platforms:
- Compression method: The recommended compression method may differ between platforms, depending on their processing power and storage space.
- Asset formats: Some platforms may support different asset formats, such as .ogg for Android and .wav for iOS. Developers need to ensure that their asset bundles contain the correct formats for each platform.
- File size: The maximum file size may differ between platforms, which can affect the size and number of asset bundles required.
- Loading speed: The loading speed of asset bundles may differ between platforms, depending on
