Document Harmony Patches

Patch/Engine/AsyncInputPatches.cs

@@ -3,10 +3,31 @@ using HarmonyLib;
 
 namespace ADOFAIRenderer.Patch.Engine;
 
+/// <summary>
+/// Makes the async input clock offset follow the render clock immediately.
+/// <para>
+/// Patched member: <c>AsyncInputUtils.UpdateOffsetTime(long fixDivider = 1)</c>. The async input system maps wall-clock ticks
+/// (<c>AsyncInputManager.currFrameTick</c> = <c>DateTime.Now.Ticks</c>, 100 ns units) to conductor time with
+/// <c>AsyncInputManager.offsetTick</c> = currFrameTick - <c>scrConductor.dspTime</c> * 10^7. With <c>fixDivider</c> 1 the
+/// offset is set directly; otherwise it moves by 1 / fixDivider of the difference per call. <c>scrConductor</c> calls it every
+/// frame with divider 100 (damped); <c>scrController</c> calls it with divider 1.
+/// </para>
+/// <para>
+/// Active while <see cref="RenderManager.IsActive"/> (stage &gt;= OnScene). From stage Render the conductor time follows the
+/// patched <c>AudioSettings.dspTime</c> (offline render clock, a fixed step per frame independent of wall-clock time), so the
+/// difference changes every frame; the damped update would lag behind it. The prefix always applies the divider-1 update.
+/// </para>
+/// <para>Reference: https://learn.microsoft.com/en-us/dotnet/api/system.datetime.ticks</para>
+/// </summary>
 [HarmonyPatch(typeof(AsyncInputUtils), "UpdateOffsetTime")]
 // ReSharper disable once InconsistentNaming
 public static class AsyncInputPatches
 {
+    /// <summary>
+    /// Prefix of <c>AsyncInputUtils.UpdateOffsetTime</c>. While rendering, sets <c>offsetTick</c> to
+    /// currFrameTick - dspTime * 10^7 (10^7 = 100 ns ticks per second) and <c>offsetTickUpdated</c> to true, for any divider.
+    /// </summary>
+    /// <returns>True to run the original method (not rendering); false to skip it (rendering).</returns>
     [HarmonyPrefix]
     // ReSharper disable once InconsistentNaming
     public static bool Prefix()