RenderStateSynchronization.cs

namespace Gondwana.Rendering;

internal static class RenderStateSynchronization
{
    private static readonly ManualResetEventSlim NoPendingGpuRenderers = new(initialState: true);
    private static int _pendingGpuRenderers;
 
    internal static object SyncRoot { get; } = new();
 
    internal static bool HasPendingGpuRenderers =>
        Volatile.Read(ref _pendingGpuRenderers) > 0;

    internal static void WaitForPendingGpuRenderers()
    {
        while (Volatile.Read(ref _pendingGpuRenderers) > 0)
            NoPendingGpuRenderers.Wait();
    }

    internal static void EnterGpuRender()
    {
        if (Interlocked.Increment(ref _pendingGpuRenderers) == 1)
            NoPendingGpuRenderers.Reset();
 
        Monitor.Enter(SyncRoot);
 
        if (Interlocked.Decrement(ref _pendingGpuRenderers) == 0)
            NoPendingGpuRenderers.Set();
    }

    internal static void ExitGpuRender() => Monitor.Exit(SyncRoot);
}