第二个图形层 (Medium) - 对应于着色器定义 UNITY_HARDWARE_TIER2。
This tier is selected for: * Android devices with OpenGL ES 3.0+ support * iPhone 5S and later * iPod Touch 6th generation * iPad Air and later * iPad Mini 2nd generation and later * Apple TV You can only set a GraphicsTier in the Built-in Render Pipeline.