/// <summary>
/// Load an AssetBundle from the dedicated AssetServer and serve it to the
/// specified Callback-Method.
/// Callback will get a null-argument if an error occured while fetchting the Asset.
/// </summary>
/// <param name="assetURI">AssetBundle to fetch from server (preserves folder hirarchy)</param>
/// <param name="callBack">Method to call once the request is finished</param>
/// <notes>
/// The Asset - or rather GameObject - which gets created and served to the callback is a clone
/// of the asset. You may do whatever you want with it
/// </notes>
public void RequestAsset(string assetURI, AssetLoadedFunc callBack)
{
// Start the download process
Debug.Log(string.Format("Asset Manager: Requesting asset from server: {0}...", assetURI));
UnityWebRequest assetRequest = UnityWebRequest.GetAssetBundle((string.Format("{0}/Bundle/{1}", this.ServerAddress, assetURI)));
StartCoroutine(LoadAsset(assetRequest, callBack, assetURI));
}
IEnumerator LoadAsset(UnityWebRequest assetRequest, AssetLoadedFunc callBack, string assetURI)
{
GameObject gameObject = null;
// Check if asset is already loaded, if it is, just call the callback immediately
if (_gameObjects.ContainsKey(assetURI))
{
gameObject = _gameObjects[assetURI];
}
else
{
// Ensure server download is finished, before continuing
yield return assetRequest.SendWebRequest();
if (assetRequest.isHttpError || assetRequest.isNetworkError)
{
_lastError = assetRequest.error;
if (callBack != null)
callBack(null);
yield break;
}
}
if (gameObject == null)
{
Debug.Log(string.Format("Asset Manager: Asset download completed."));
AssetBundle bundle = ((DownloadHandlerAssetBundle)assetRequest.downloadHandler).assetBundle;
// Build game object from request bundle
// Per definition (or more likely due to technical limitations at this time)
// it has to be the first asset in the bundle
gameObject = bundle.LoadAsset(bundle.GetAllAssetNames()[0]) as GameObject;
// Per definition, every Asset can be saved.
SceneTransfer.SetSavableStatus(gameObject, true).AssetBundleName = bundle.name;
// Add gameobject to caching map
_gameObjects.Add(assetURI, gameObject);
}
gameObject = GameObject.Instantiate(gameObject);
// Dispatch event
if (callBack != null)
callBack(gameObject);
if (OnAssetLoaded != null)
OnAssetLoaded(gameObject);
}