ShaderGraphMaterial on entity

Question

Kito7777 OP

Created Jan ’25

Replies 2

Boosts 0

Participants 2

Hi

I try to make a 360 stereo viewer, and I have made a ShaderGraphMaterial on Reality Composer Pro.

Im trying to use that material on a inverted sphere whitch is generated in Swift.

When I try to attach the material I get this error "Type of expression is ambiguous without a type annotation"

Here is the code (sorry im noob =) ):

import SwiftUI import RealityKit import RealityKitContent import PhotosUI

struct ImmersiveView: View {

 @Environment(AppModel.self) var appModel
 
var body: some View {
    RealityView { content in
        // Add the initial RealityKit content
        guard let skyBoxEntity = await createSkybox() else {
            return
        }
        
        content.add(skyBoxEntity)
    }
}

}

private func createSkybox () async -> Entity? {

     var matX = try? await ShaderGraphMaterial(named: 
                                             "/Root/Mat_Stereo360",         
                                              from: "360Stereo.usda",
                                              in: realityKitContentBundle)
   
   let sphere = await MeshResource.generateSphere(radius:1000)
   let entity = await Entity()
 
   entity.components.set(ModelComponent(mesh: sphere, materials: 
                                                                          [matX])). //ERROR HERE: 
                      Type of expression is ambiguous without a type annotation                        
 
   //entity.scale *= .init(x:-1, y:1, z:1)
 
   return entity
}

I hope someone can help me =)

Best regards, Kim

Answered by Vision Pro Engineer in 822016022

Hi @Kito7777

Thanks for the question!

Try initializing matX like this:

 guard let matX = try? await ShaderGraphMaterial(named:
                                                 "/Root/Mat_Stereo360",
                                                        from: "360Stereo.usda",
                                                        in: realityKitContentBundle) else {return nil}

The error occurs because the compiler doesn't know if matX is nil or an instance of ShaderGraphMaterial. One way to remedy this is to unwrap matX.

Also consider changing:

 let sphere = await MeshResource.generateSphere(radius:1000)
let entity = await Entity()

to

 let sphere = MeshResource.generateSphere(radius:1000)
let entity = Entity()

since neither of the operations are asynchronous.

Boost

Answer 1

Vision Pro Engineer OP

Apple

Jan ’25

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