实现了多个相机混合渲染

原理:
渲染层级:一.
1.Camera的Depth值
2.SortLayer
3.Order in Layer
三个层级都是值大的遮挡值小的

Assets/Materials/star.mat

@@ -0,0 +1,30 @@
+%YAML 1.1
+%TAG !u! tag:unity3d.com,2011:
+--- !u!21 &2100000
+Material:
+  serializedVersion: 6
+  m_ObjectHideFlags: 0
+  m_CorrespondingSourceObject: {fileID: 0}
+  m_PrefabInstance: {fileID: 0}
+  m_PrefabAsset: {fileID: 0}
+  m_Name: star
+  m_Shader: {fileID: 200, guid: 0000000000000000f000000000000000, type: 0}
+  m_ShaderKeywords: 
+  m_LightmapFlags: 4
+  m_EnableInstancingVariants: 0
+  m_DoubleSidedGI: 0
+  m_CustomRenderQueue: -1
+  stringTagMap: {}
+  disabledShaderPasses: []
+  m_SavedProperties:
+    serializedVersion: 3
+    m_TexEnvs:
+    - _MainTex:
+        m_Texture: {fileID: 2800000, guid: 6793afeb1ba524134ae93ee3038763e0, type: 3}
+        m_Scale: {x: 1, y: 1}
+        m_Offset: {x: 0, y: 0}
+    m_Floats:
+    - _InvFade: 1
+    m_Colors:
+    - _Color: {r: 1, g: 1, b: 1, a: 1}
+    - _TintColor: {r: 0.5, g: 0.5, b: 0.5, a: 0.5}