VisionOS: Immersive space with Metal framework

Hi,

I'm trying to build an app demo with Metal framework on visionOS. I've found out that when I enabled immersive space it was in a fully immersive mode and the Metal was rendering the background with black color. And I've inspected the demo code and the clear color was (0, 0, 0, 0). I wonder if it is possible to render just like RealityKit with mixed reality effect that some 3D models can be rendered in the real world without a black background. Any idea or explanation?