Add Custom Frame Modification Hook API for Video Rendering

Core/RenderManager.cs

@@ -37,6 +37,7 @@ internal static class RenderContext
     public static string? OutputPath;
         
     public static bool Notification = true;
+    public static readonly List<Action<FrameHookContext>> SessionFrameHooks = new();
         
     private static readonly Func<bool> EndConditionDefault = () => scrController.instance.state == States.Won;
     public static Func<bool> EndCondition = EndConditionDefault;
@@ -64,6 +65,7 @@ internal static class RenderContext
         OutputPath = null;
 
         Notification = true;
+        SessionFrameHooks.Clear();
             
         EndCondition = EndConditionDefault;
         OnComplete = OnCompleteDefault;
@@ -103,6 +105,49 @@ internal class RenderManager : MonoBehaviour
     private AudioSyncCalculator SyncCalculator { get; set; } = null!;
 
     private FrameReader? _frameReader;
+    private FrameHookPipeline? _frameHookPipeline;
+    private readonly List<Action<FrameHookContext>> _activeHooksCache = new();
+    private int _cachedGlobalHooksVersion = -1;
+    private bool _hasActiveHooksCached;
+
+    public bool HasActiveFrameHooks
+    {
+        get
+        {
+            EnsureActiveHooksUpToDate();
+            return _hasActiveHooksCached;
+        }
+    }
+
+    private void EnsureActiveHooksUpToDate()
+    {
+        var globalVersion = RenderSession.GlobalHooksVersion;
+        if (_cachedGlobalHooksVersion == globalVersion) return;
+
+        _cachedGlobalHooksVersion = globalVersion;
+        _activeHooksCache.Clear();
+        if (RenderContext.SessionFrameHooks.Count > 0)
+        {
+            _activeHooksCache.AddRange(RenderContext.SessionFrameHooks);
+        }
+        RenderSession.CopyGlobalFrameHooksTo(_activeHooksCache);
+        _hasActiveHooksCached = _activeHooksCache.Count > 0;
+    }
+
+    private List<Action<FrameHookContext>> GetActiveFrameHooks()
+    {
+        EnsureActiveHooksUpToDate();
+        return _activeHooksCache;
+    }
+
+    private void ResetFrameHookState()
+    {
+        _frameHookPipeline?.Dispose();
+        _frameHookPipeline = null;
+        _activeHooksCache.Clear();
+        _cachedGlobalHooksVersion = -1;
+        _hasActiveHooksCached = false;
+    }
 
     public long frameCountForVideo;
     public long lastVideoFrameIndex = -1;
@@ -160,6 +205,8 @@ internal class RenderManager : MonoBehaviour
             
         AudioSpectrumGenerator.Clear();
 
+        ResetFrameHookState();
+
         if (_activeVideoFFmpeg != null)
         {
             Melon<RenderMod>.Logger.Msg("Game exit or RenderManager destruction detected: Disposing FFmpeg native encoder resources.");
@@ -316,7 +363,23 @@ internal class RenderManager : MonoBehaviour
         {
             lastVideoFrameIndex = videoFrameIndex;
             lastRequestedVideoFrameIndex = videoFrameIndex;
-            _frameReader?.RequestFrameCapture(texture, videoFrameIndex);
+
+            var targetTexture = texture;
+            if (HasActiveFrameHooks && _frameHookPipeline != null)
+            {
+                var videoTime = effectiveVideoFps > 0 ? videoFrameIndex / effectiveVideoFps : 0.0;
+                targetTexture = _frameHookPipeline.Process(
+                    texture,
+                    videoFrameIndex,
+                    currentFrame,
+                    videoTime,
+                    renderFPS,
+                    effectiveVideoFps,
+                    GetActiveFrameHooks()
+                ) ?? texture;
+            }
+
+            _frameReader?.RequestFrameCapture(targetTexture, videoFrameIndex);
         }
     }
 
@@ -387,6 +450,10 @@ internal class RenderManager : MonoBehaviour
             
         _frameReader?.Dispose();
         _frameReader = null;
+        _frameHookPipeline?.Dispose();
+        _frameHookPipeline = new FrameHookPipeline();
+        _cachedGlobalHooksVersion = -1;
+        EnsureActiveHooksUpToDate();
         try
         {
             StartFFmpegThread();
@@ -395,6 +462,7 @@ internal class RenderManager : MonoBehaviour
         catch (Exception ex)
         {
             Melon<RenderMod>.Logger.Error($"Encoder initialization error: {ex}");
+            ResetFrameHookState();
             CommonWarningDialogUI.ShowDialog(
                 "Encoder Error",
                 $"Failed to initialize video encoder.\nError: {ex.Message}",
@@ -687,6 +755,7 @@ internal class RenderManager : MonoBehaviour
             }
                 
             _frameReader?.Dispose();
+            ResetFrameHookState();
 
             // Clean up Debug Monitor UI
             if (_debugMonitorObj)
@@ -776,6 +845,7 @@ internal class RenderManager : MonoBehaviour
         }
 
         _frameReader?.Dispose();
+        ResetFrameHookState();
         AudioMixer?.Reset(); AudioMixer = null;
         SyncCalculator.Reset();