Create a MeshGradient I can use as a view background that’s animated and looks like swirling Northern Lights

To create a MeshGradient that looks like swirling Northern Lights and can be used as a view background in SwiftUI, you can follow the steps outlined in the "Create custom visual effects with SwiftUI" session from WWDC 2024. Here’s a basic example to get you started:

import SwiftUI

struct NorthernLightsView: View {
    @State private var controlPoints: [SIMD2<Float>] = [
        SIMD2<Float>(0.1, 0.1),
        SIMD2<Float>(0.5, 0.1),
        SIMD2<Float>(0.9, 0.1),
        SIMD2<Float>(0.1, 0.5),
        SIMD2<Float>(0.5, 0.5),
        SIMD2<Float>(0.9, 0.5),
        SIMD2<Float>(0.1, 0.9),
        SIMD2<Float>(0.5, 0.9),
        SIMD2<Float>(0.9, 0.9)
    ]
    
    @State private var colors: [Color] = [
        .blue, .green, .purple,
        .cyan, .mint, .pink,
        .indigo, .teal, .orange
    ]
    
    var body: some View {
        MeshGradient(
            colors: colors,
            controlPoints: controlPoints
        )
        .animation(
            Animation.linear(duration: 5)
                .repeatForever(autoreverses: true)
        )
        .onAppear {
            animateControlPoints()
        }
        .ignoresSafeArea()
    }
    
    private func animateControlPoints() {
        withAnimation {
            controlPoints = controlPoints.map { _ in
                SIMD2<Float>(Float.random(in: 0...1), Float.random(in: 0...1))
            }
        }
    }
}

struct ContentView: View {
    var body: some View {
        NorthernLightsView()
    }
}

@main
struct MyApp: App {
    var body: some Scene {
        WindowGroup {
            ContentView()
        }
    }
}

Explanation:

1. MeshGradient Setup: The MeshGradient view is created using a 3x3 grid of control points and corresponding colors.
2. Animation: The control points are animated to move randomly within the grid, creating a dynamic swirling effect.
3. OnAppear: The animateControlPoints function is called when the view appears, starting the animation.

For more details on creating custom visual effects with SwiftUI, you can refer to the Create custom visual effects with SwiftUI (07:10) session from WWDC 2024.