apple/PhysarumApp/Sources/Player/LiveSnapshot.swift

import SwiftUI
import PhysarumEngine

/// A frame-consistent capture of the live player's sim + echo state, plus the
/// render context needed to reproduce the on-screen look at any export size.
struct LiveSnapshot {
    let sim: SimState
    let feedback: FeedbackState?
    let field: FieldSize
    let preset: PresetParams
    let format: SimFormat
    let cover: Bool
}

/// Bridges the SwiftUI-owned RenderCoordinator (created in MetalView.makeCoordinator)
/// to views that need a snapshot (CaptureSheet, the save flow). MetalView.sync sets
/// `coordinator`; callers use `takeSnapshot()`. Weak so it never retains the coordinator.
@Observable
final class LiveSnapshotProvider {
    weak var coordinator: RenderCoordinator?
    func takeSnapshot() -> LiveSnapshot? { coordinator?.takeSnapshot() ?? nil }
}