Hello everyone! I am trying to wrap a ViewModifier inside a Swift Package that bundles a metal shader file to be used in the modifier. Everything works as expected in the Preview, in the Simulator and on a real device for iOS. It also works in Preview and in the Simulator for tvOS but not on a real AppleTV. I have tried this on a 4th generation Apple TV running tvOS 26.3 using Xcode 26.2.0.
Xcode logs the following: The metallib is processed and exists in the bundle.
Compiler failed to build request
precondition failure: pipeline error: custom_effect-fg2a5cia7fmha4: error: unresolved visible function reference: custom_fn
Reason: visible function not loaded
Compiler failed to build request
precondition failure: pipeline error: custom_effect-fg2a5cia7fmha4: error: unresolved visible function reference: custom_fn
Reason: visible function not loaded
Compiler failed to build request
precondition failure: pipeline error: custom_effect-fg2a5cia7fmha4: error: unresolved visible function reference: custom_fn
Reason: visible function not loaded
Compiler failed to build request
precondition failure: pipeline error: custom_effect-fg2a5cia7fmha4: error: unresolved visible function reference: custom_fn
Reason: visible function not loaded
Compiler failed to build request
precondition failure: pipeline error: custom_effect-fg2a5cia7fmha4: error: unresolved visible function reference: custom_fn
Reason: visible function not loaded
Compiler failed to build request
precondition failure: pipeline error: custom_effect-fg2a5cia7fmha4: error: unresolved visible function reference: custom_fn
Reason: visible function not loaded
Contents of Package.swift:
import PackageDescription
let package = Package(
name: "Test",
platforms: [
.iOS(.v17),
.tvOS(.v17)
],
products: [
.library(
name: "Test",
targets: [
"Test"
]
)
],
targets: [
.target(
name: "Test",
resources: [
.process("Shaders")
]
),
.testTarget(
name: "TestTests",
dependencies: [
"Test"
]
)
]
)
Content of my metal file:
#include <metal_stdlib>
using namespace metal;
[[ stitchable ]] float2 complexWave(float2 position, float time, float2 size, float speed, float strength, float frequency) {
float2 normalizedPosition = position / size;
float moveAmount = time * speed;
position.x += sin((normalizedPosition.x + moveAmount) * frequency) * strength;
position.y += cos((normalizedPosition.y + moveAmount) * frequency) * strength;
return position;
}
And my ViewModifier:
import MetalKit
import SwiftUI
extension ShaderFunction {
static let complexWave: ShaderFunction = {
ShaderFunction(
library: .bundle(.module),
name: "complexWave"
)
}()
}
extension Shader {
static func complexWave(arguments: [Shader.Argument]) -> Shader {
Shader(function: .complexWave, arguments: arguments)
}
}
struct WaveModifier: ViewModifier {
let start: Date = .now
func body(content: Content) -> some View {
TimelineView(.animation) { context in
let delta = context.date.timeIntervalSince(start)
content
.visualEffect { view, proxy in
view.distortionEffect(
.complexWave(
arguments: [
.float(delta),
.float2(proxy.size),
.float(0.5),
.float(8),
.float(10)
]
),
maxSampleOffset: .zero
)
}
}
.onAppear {
let paths = Bundle.module.paths(forResourcesOfType: "metallib", inDirectory: nil)
print(paths)
}
}
}
extension View {
public func wave() -> some View {
modifier(WaveModifier())
}
}
#Preview {
Image(systemName: "cart")
.wave()
}
Any help is appreciated.