init(named:in:)

Declaration

init(named name: String, in library: any MTLLibrary)

Parameters

• name:

  The name of the post-lighting shader function.

• library:

  The Metal library that contains the function.

Discussion

To create a post-lighting shader for a custom material, create a Metal file in your Xcode project. Prefix the function with the keyword [[stitchable]]. The function needs to take two parameters, one of type realitykit::post_lighting_parameters, and the other an arbitrary pointer to valid data.

Here’s what a minimal post-lighting shader function looks like:

#include <metal_stdlib>
#include <RealityKit/RealityKit.h>

// Specify the current default namespace as metal so our code
// doesn't have to to prefix Metal Standard Library symbols.
using namespace metal;

[[stitchable]] void myPostLightingShader(realitykit::post_lighting_parameters params const void *customParams) {
   // Calculate post-lighting effect.
}

To create a custom material using this shader, get a reference to your app’s Metal library:

guard let device = MTLCreateSystemDefaultDevice() else {
    fatalError("Error creating default metal device.")
}
guard let library = maybeDevice.makeDefaultLibrary() else {
    fatalError("Error creating default metal library")
}

Once you have a reference to your Metal library, use it to create the surface shader reference:

let postLightingShader = CustomMaterial.PostLightingShader(
    named: "myPostLightingShader",
    in: library
)

For more information on creating custom materials and writing shader functions, see Modifying RealityKit rendering using custom materials.