Asset Manager Overview

Author: Santy-Wang, Xunyi

During the development of the game, it is generally necessary to use a large number of images, audio and other resources to enrich the entire game, and a large number of resources can cause management difficulties. That's why Creator provides the Asset Manager resource management module to help developers manage the use of their resources and greatly improve the development efficiency and experience.

Asset Manager is a new resource manager from Creator in v2.4 that replaces the previous loader. The new Asset Manager resource management module has features for loading resources, finding resources, destroying resources, caching resources, Asset Bundle, and more. Compared with previous loader, Asset Manager has better performance, easier-to-use APIs, and greater extensibility. All functions and methods are accessible via assetManager and all types and enumerations are accessible via the AssetManager namespace.

Note: we will maintain compatibility with loader for a period of time, but we strongly recommend using Asset Manager consistently for new projects.

Refer to the following documentations for upgrading:

• AssetManager Upgrade Guide
• Asset Bundle Upgrade Guide

Load Resources

Dynamic Loading Of Resources

In addition to applying resources to the corresponding components while editing scenes, Creator also supports dynamic loading and setting up of resources while the game is running. Asset Manager provides two ways to dynamically load resources:

1. By placing resources in the resources directory, and working with APIs such as resources.load to achieve dynamic loading.

2. developers can plan their own resource creation as Asset Bundle and load resources through the Asset Bundle's load family of APIs. For example:

   resources.load('images/background/spriteFrame', SpriteFrame, (err, asset) => {
     this.getComponent(Sprite).spriteFrame = asset;
   });

The relevant APIs are listed below:

Type	Support	Loading	Releasing	Preloading	Querying	Search
Single Asset	Asset Bundle	load	release	preload	get	getInfoWithPath
Directory	Asset Bundle	loadDir	releaseAsset	preloadDir	N/A	getDirWithPath
Scene	Asset Bundle	loadScene	N/A	preloadScene	N/A	getSceneInfo
Single Asset	resources	load	release	preload	get	getInfoWithPath
Directory	resources	loadDir	releaseAsset	preloadDir	N/A	getDirWithPath
Script	Asset Manager	loadScript	N/A	N/A	N/A	N/A
Remote Asset	Asset Manager	loadRemote	releaseAsset	N/A	N/A	N/A

References documentations:

• Dynamic Load Asset

All loaded resources are cached in assetManager.

Preloading

To reduce download latency, assetManager and Asset Bundle not only provides interfaces for loading resources, each interface also provides a corresponding preloaded version. Preloading in a game is an option that then allows finishing loading when it is really need it. Preloading will only download the necessary resources and will not perform deserialization or initialization. Therefore, it consumes less performance and is suitable for use during the game.

start () {
    resources.preload('images/background/spriteFrame', SpriteFrame);
    setTimeOut(this.loadAsset.bind(this), 10000);
}

loadAsset () {
    resources.load('images/background/spriteFrame', SpriteFrame, (err, asset) => {
        this.getComponent(Sprite).spriteFrame = asset;
    });
}

For more information on preloading, please refer to the Preloading and Loading documentation.

Asset Bundle

Partitioning scenes, resources, and code into multiple Asset Bundles and the loading of resources dynamically at runtime results in modularity of resources and allows loading corresponding resources when needed. For example:

assetManager.loadBundle('testBundle', function (err, bundle) {
    bundle.load('textures/background/texture', (err, asset) => {
        // ...
    });
});

Please refer to the Asset Bundle documentation for more information on Asset Bundle.

Release of resources

Asset Manager provides a more convenient mechanism for releasing resources. When releasing a resource, you only need to focus on the resource itself and no longer on its dependent resources. The engine attempts to release its dependent resources based on the number of references, to reduce the complexity of managing resource releases for users. For example:

resources.load('prefabs/enemy', Prefab, function (err, asset) {
    assetManager.releaseAsset(asset);
});

Creator also provides a reference counting mechanism to help you control the reference and release of resources. For example:

• When you need to hold a resource, call addRef to add a reference to ensure that the resource is not automatically released by other references to it.

  resources.load('textures/armor/texture', Texture2D, function (err, texture) {
      texture.addRef();
      this.texture = texture;
  });

• When you no longer need to hold the resource, call decRef to reduce reference, decRef will also attempt an automatic release based on the reference count.

  this.texture.decRef();
  this.texture = null;

Please refer to the Release of Resources documentation for more details.

Cache Manager

On some platforms, such as WeChat, it is possible to use the file system to cache some remote resources because a file system exists. In this case, a cache manager is required to manage all cache resources, such as caching resources, clearing cache resources, modifying cache cycles, etc. . Creator provides a cache manager on all platforms where file systems exist that allows adding, deleting, changing, and checking the cache. For example:

// Get the cache of a resource.
assetManager.cacheManager.getCache('http://example.com/bundle1/import/9a/9aswe123-dsqw-12xe-123xqawe12.json');

// Clear the cache of a resource.
assetManager.cacheManager.removeCache('http://example.com/bundle1/import/9a/9aswe123-dsqw-12xe-123xqawe12.json');

Please refer to the Cache Manager documentation for more information on Cache Manager.

Optional Parameters

Some of the interfaces for assetManager and Asset Bundle have an additional options parameter, which greatly increase the flexibility and extend the space. In addition to configuring the builtin parameters of Creator, it is also possible to customize any of the parameters in options, and these parameters will be provided to the downloader, parser, and loading pipeline.

bundle.loadScene('test', {priority: 3}, callback);

For more information on options parameter, please refer to the Optional Parameters documentation.

If it is not necessary to configure the engine's builtin parameters or custom parameters to extend the engine's functionality, ignore it and use the simpler API interfaces, such as resources.load.

Loading Pipeline

To make it easier to extend the resource loading process, the underlying layer of Asset Manager uses mechanisms called Pipeline and Task and Download and Parse to load resources, greatly increasing flexibility and scalability. To expand the load pipeline or customize it, refer to the following documentation:

• Pipeline and Task
• Download and Parse

More Reference

• Asset Bundle
• Release Of Resources
• Download and Parse
• Loading and Preloading
• Cache Manager
• Optional Parameters
• Pipeline and Task