UnityGLTF不支持Android手机端不能读取StreamingAssets目录解决

最近工作比较忙，已经2个多月没有写博客了。最近一直在一个VR办公会议的项目，也积累了一些东东需要写出来。
在项目中用到了gltf资源，用到UntiyGLTF这个开源工具，用来在云上或者StreamingAssets目录下读取文件，并且渲染出来。
但是在使用UnityGLTF时，在Android手机上，不支持读取StreamingAssets目录下的gltf文件。所以写个UnityWebRequestLoader来支持读取文件，使用了Unity的自带的WebRequest。
1、首先UnityWebRequest不支持await等待，需要进行对他进行扩展支持

1. ‹font size="3">  public static class UnityGLTFExtension {
   
2.   public static TaskAwaiter GetAwaiter(this AsyncOperation asyncOp)
   
3.   {
   
4.     var tcs = new TaskCompletionSource‹object>();
   
5.     asyncOp.completed += obj => { tcs.SetResult(null); };
   
6.     return ((Task)tcs.Task).GetAwaiter();
   
7.   }
   
8.   }‹/font>

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2、增加UnityWebRequestLoader的loader插件，支持android读取StreamingAssets目录下的文件

1. ‹font size="3">using System;
   
2. using System.IO;
   
3. using System.Runtime.CompilerServices;
   
4. using System.Threading.Tasks;
   
5. using UnityEngine;
   
6. using UnityEngine.Networking;
   
7. 
   
8. namespace UnityGLTF.Loader
   
9. {
   
10.   public static class UnityGLTFExtension {
    
11.   public static TaskAwaiter GetAwaiter(this AsyncOperation asyncOp)
    
12.   {
    
13.     var tcs = new TaskCompletionSource‹object>();
    
14.     asyncOp.completed += obj => { tcs.SetResult(null); };
    
15.     return ((Task)tcs.Task).GetAwaiter();
    
16.   }
    
17.   }
    
18. 
    
19. 
    
20.   public class UnityWebRequestLoader : ILoader
    
21.   {
    
22.   public Stream LoadedStream { get; private set; }
    
23. 
    
24.   public bool HasSyncLoadMethod => false;
    
25. 
    
26.   private string _rootUri;
    
27. 
    
28.   public UnityWebRequestLoader(string rootUri)
    
29.   {
    
30.     _rootUri = rootUri;
    
31.   }
    
32. 
    
33. 
    
34.   public async Task LoadStream(string gltfFilePath)
    
35.   {
    
36.     if (gltfFilePath == null)
    
37.     {
    
38.       throw new ArgumentNullException(nameof(gltfFilePath));
    
39.     }
    
40. 
    
41.     string pathToLoad = Path.Combine(_rootUri, gltfFilePath);
    
42. 
    
43.     var getRequest = UnityWebRequest.Get(pathToLoad);
    
44.     await getRequest.SendWebRequest();
    
45. 
    
46.     byte[] data = getRequest.downloadHandler.data;
    
47.     if (data == null || data.Length == 0)
    
48.     {
    
49.       throw new InvalidOperationException(string.Format(
    
50.       "Failed to load from '{0}' - file was empty!", pathToLoad));
    
51.     }
    
52.     LoadedStream = new MemoryStream(data.Length);
    
53.     await LoadedStream.WriteAsync(data, 0, data.Length);
    
54.   }
    
55. 
    
56.   public void LoadStreamSync(string jsonFilePath)
    
57.   {
    
58.     throw new NotImplementedException();
    
59.   }
    
60.   }
    
61. }‹/font>

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3、包装一下gltf load，支持http/https，android手机加载，普通pc加载

1. ‹font size="3">  public static async Task‹GameObject> Load(string gltfUrl, Transform parent)
   
2.   {
   
3.   GameObject obj = null;
   
4.   GLTFSceneImporter sceneImporter = null;
   
5.   ILoader loader = null;
   
6.   string directoryPath = URIHelper.GetDirectoryName(gltfUrl);
   
7.   try
   
8.   {
   
9.     if (gltfUrl.StartsWith("http://") || gltfUrl.StartsWith("https://"))
   
10.     {
    
11.       loader = new WebRequestLoader(directoryPath);
    
12. 
    
13.       sceneImporter = new GLTFSceneImporter(
    
14.       URIHelper.GetFileFromUri(new Uri(gltfUrl)),
    
15.       loader,
    
16.       asyncCoroutineHelper
    
17.       );
    
18.     }
    
19.     else if (gltfUrl.StartsWith("jar:file://"))
    
20.     {
    
21.       loader = new UnityWebRequestLoader(directoryPath);
    
22. 
    
23.       sceneImporter = new GLTFSceneImporter(
    
24.       Path.GetFileName(gltfUrl),
    
25.       loader,
    
26.       asyncCoroutineHelper
    
27.       );
    
28.     }
    
29.     else
    
30.     {
    
31.       loader = new FileLoader(directoryPath);
    
32.       sceneImporter = new GLTFSceneImporter(
    
33.       Path.GetFileName(gltfUrl),
    
34.       loader,
    
35.       asyncCoroutineHelper
    
36.       );
    
37.     }
    
38. 
    
39.     sceneImporter.SceneParent = parent;
    
40.     sceneImporter.Collider = GLTFSceneImporter.ColliderType.None;
    
41.     sceneImporter.MaximumLod = 300;
    
42.     sceneImporter.IsMultithreaded = true;
    
43. 
    
44.     await sceneImporter.LoadSceneAsync();
    
45. 
    
46.     obj = sceneImporter.CreatedObject;
    
47.   }
    
48.   finally
    
49.   {
    
50.     if (loader != null)
    
51.     {
    
52.       sceneImporter?.Dispose();
    
53.       sceneImporter = null;
    
54.       loader = null;
    
55.     }
    
56.   }
    
57. 
    
58.   return obj;
    
59.   }‹/font>

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4、根据不同的平台，组装streamingassets目录

1. ‹font size="3">  private string streamingAssetsPath;
   
2.   streamingAssetsPath =
   
3. #if UNITY_EDITOR
   
4.     Application.streamingAssetsPath;
   
5. #else
   
6.     "jar:file://" + Application.dataPath + "!/assets";
   
7. #endif
   
8. 
   
9. GameObject rootObject = await Gltf.Load(streamingAssetsPath + "test.glb", parentTransform);‹/font>

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这样就可以支持android手机也可以在StreamingAssets目录下读取gltf/glb文件了。




来源：网络转载

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