how do I use metal with RealityKit

To use Metal with RealityKit, you can integrate Metal's rendering capabilities into your RealityKit projects to achieve custom rendering effects or to optimize performance. Here are some key points from the WWDC sessions that might help you:

1. Rendering with Metal on visionOS: You can render directly with Metal on visionOS if you need a custom rendering pipeline. This is particularly useful if porting your game or app to RealityKit is not practical. You can run your app in a window, similar to how it would behave on an iPad, allowing it to run alongside other apps in a shared space. For more details, refer to the session Bring your iOS or iPadOS game to visionOS.

2. Metal with Passthrough in visionOS: This session covers how to use Metal APIs along with ARKit and compositor services to create a mixed immersive experience. It involves blending your app's rendered content with the physical surroundings and improving the positioning of rendered content. For more information, see Render Metal with passthrough in visionOS.

3. Low-Level Mesh and Textures: RealityKit now offers new APIs for low-level mesh and textures that work with Metal compute shaders. This provides improved control over how your apps look, enabling fully dynamic models and textures in every frame on visionOS. This is discussed in the Platforms State of the Union.

These sessions provide a comprehensive overview of how you can leverage Metal within RealityKit to enhance your app's rendering capabilities.