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keijiro/FpsCapper.cs

Last active September 24, 2025 21:29
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  1. keijiro revised this gist Sep 16, 2024. No changes.
  2. keijiro created this gist Sep 16, 2024.
    125 changes: 125 additions & 0 deletions FpsCapper.cs
    View file
    Original file line number Diff line number Diff line change
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    using UnityEditor;
    using UnityEngine;
    using UnityEngine.LowLevel;
    using System.Linq;
    using System.Threading;

    namespace EditorUtils {

    //
    // Serializable settings
    //
    [FilePath("UserSettings/FpsCapperSettings.asset",
    FilePathAttribute.Location.ProjectFolder)]
    public sealed class FpsCapperSettings : ScriptableSingleton<FpsCapperSettings>
    {
    public bool enable = false;
    public int targetFrameRate = 60;
    public void Save() => Save(true);
    void OnDisable() => Save();
    }

    //
    // Settings GUI
    //
    sealed class FpsCapperSettingsProvider : SettingsProvider
    {
    public FpsCapperSettingsProvider()
    : base("Project/FPS Capper", SettingsScope.Project) {}

    public override void OnGUI(string search)
    {
    var settings = FpsCapperSettings.instance;
    var enable = settings.enable;
    var fps = settings.targetFrameRate;

    EditorGUI.BeginChangeCheck();

    enable = EditorGUILayout.Toggle("Enable", enable);
    fps = EditorGUILayout.IntField("Target Frame Rate", fps);

    if (EditorGUI.EndChangeCheck())
    {
    settings.enable = enable;
    settings.targetFrameRate = fps;
    settings.Save();
    }
    }

    [SettingsProvider]
    public static SettingsProvider CreateCustomSettingsProvider()
    => new FpsCapperSettingsProvider();
    }

    //
    // Player loop system
    //
    [UnityEditor.InitializeOnLoad]
    sealed class FpsCapperSystem
    {
    // Synchronization object
    static AutoResetEvent _sync;

    // Interval in milliseconds
    static int IntervalMsec;

    // Interval thread function
    static void IntervalThread()
    {
    _sync = new AutoResetEvent(true);

    while (true)
    {
    Thread.Sleep(Mathf.Max(1, IntervalMsec));
    _sync.Set();
    }
    }

    // Custom system update function
    static void UpdateSystem()
    {
    var cfg = FpsCapperSettings.instance;

    // Property update
    IntervalMsec = 1000 / Mathf.Max(5, cfg.targetFrameRate);

    // Rejection cases
    if (_sync == null) return; // Not ready
    if (!cfg.enable) return; // Not enabled
    if (cfg.targetFrameRate < 1) return; // Wrong FPS value
    if (Time.captureDeltaTime != 0) return; // Recording

    // Synchronization with the interval thread
    _sync.WaitOne();
    }

    // Static constructor (custom system installation)
    static FpsCapperSystem()
    {
    // Interval thread launch
    new Thread(IntervalThread).Start();

    // Custom system definition
    var system = new PlayerLoopSystem()
    { type = typeof(FpsCapperSystem),
    updateDelegate = UpdateSystem };

    // Custom system insertion
    var playerLoop = PlayerLoop.GetCurrentPlayerLoop();

    for (var i = 0; i < playerLoop.subSystemList.Length; i++)
    {
    ref var phase = ref playerLoop.subSystemList[i];
    if (phase.type == typeof(UnityEngine.PlayerLoop.EarlyUpdate))
    {
    phase.subSystemList
    = phase.subSystemList.Concat(new[]{system}).ToArray();
    break;
    }
    }

    PlayerLoop.SetPlayerLoop(playerLoop);
    }
    }

    } // namespace EditorUtils