Merge remote-tracking branch 'origin/dev' into dev_lishuo

# Conflicts:
#	Assets/Scripts/App.cs

Assets/Scenes/2-Main.unity.meta

@@ -1,7 +0,0 @@
-fileFormatVersion: 2
-guid: 3dd2c8541f2a842469032565763e427d
-DefaultImporter:
-  externalObjects: {}
-  userData: 
-  assetBundleName: 
-  assetBundleVariant: 

Assets/Scenes/MainScene.unity

@@ -447,6 +447,7 @@ GameObject:
   - component: {fileID: 728460489}
   - component: {fileID: 728460488}
   - component: {fileID: 728460491}
+  - component: {fileID: 728460492}
   m_Layer: 0
   m_Name: Main Camera
   m_TagString: MainCamera
@@ -471,8 +472,8 @@ Camera:
   m_GameObject: {fileID: 728460487}
   m_Enabled: 1
   serializedVersion: 2
-  m_ClearFlags: 2
-  m_BackGroundColor: {r: 0, g: 0, b: 0, a: 0}
+  m_ClearFlags: 1
+  m_BackGroundColor: {r: 0, g: 0, b: 0, a: 0.019607844}
   m_projectionMatrixMode: 1
   m_GateFitMode: 2
   m_FOVAxisMode: 0
@@ -531,6 +532,15 @@ MonoBehaviour:
   m_Script: {fileID: 11500000, guid: 3083a61e316cc854fb0fa28e7fd7e237, type: 3}
   m_Name: 
   m_EditorClassIdentifier: 
+--- !u!45 &728460492
+Skybox:
+  m_ObjectHideFlags: 0
+  m_CorrespondingSourceObject: {fileID: 0}
+  m_PrefabInstance: {fileID: 0}
+  m_PrefabAsset: {fileID: 0}
+  m_GameObject: {fileID: 728460487}
+  m_Enabled: 1
+  m_CustomSkybox: {fileID: 2100000, guid: 471eb98b825444aa4a25747ddb6750fe, type: 2}
 --- !u!1 &730655535
 GameObject:
   m_ObjectHideFlags: 0