Add basic DrawableHitFinisher (no graphics yet, just input).

osu.Game.Modes.Taiko/Objects/Drawable/DrawableHitFinisher.cs

@@ -0,0 +1,80 @@
+using OpenTK.Input;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using osu.Framework.Input;
+
+namespace osu.Game.Modes.Taiko.Objects.Drawable
+{
+    public abstract class DrawableHitFinisher : DrawableHit
+    {
+        /// <summary>
+        /// The lenience for the second key press.
+        /// This does not adjust by map difficulty in ScoreV2 yet.
+        /// </summary>
+        private const double second_hit_window = 30;
+
+        private double firstHitTime;
+        private Key firstHitKey;
+
+        protected DrawableHitFinisher(TaikoHitObject hitObject)
+            : base(hitObject)
+        {
+        }
+
+        protected override void CheckJudgement(bool userTriggered)
+        {
+            if (!Judgement.Result.HasValue)
+            {
+                base.CheckJudgement(userTriggered);
+                return;
+            }
+
+            if (!userTriggered)
+                return;
+
+            // If we get here, we're assured that the key pressed is the correct secondary key
+
+            if (Math.Abs(firstHitTime - Time.Current) < second_hit_window)
+                Judgement.SecondHit = true;
+        }
+
+        protected override bool OnKeyDown(InputState state, KeyDownEventArgs args)
+        {
+            // Check if we've handled the initial key
+            if (!Judgement.Result.HasValue)
+            {
+                bool result = base.OnKeyDown(state, args);
+
+                if (result)
+                {
+                    firstHitTime = Time.Current;
+                    firstHitKey = args.Key;
+                }
+
+                return result;
+            }
+
+            // If we've already hit the second key, don't handle this object any further
+            if (Judgement.SecondHit)
+                return false;
+
+            // Don't handle represses of the same key
+            if (firstHitKey == args.Key)
+                return false;
+
+            // Don't handle invalid hit key presses
+            if (!HitKeys.Contains(args.Key))
+                return false;
+
+            // If we're not holding the first key down still, assume the intention
+            // was not to hit the finisher with both keys simultaneously
+            if (!state.Keyboard.Keys.Contains(firstHitKey))
+                return false;
+
+            return UpdateJudgement(true);
+        }
+    }
+}

osu.Game.Modes.Taiko/osu.Game.Modes.Taiko.csproj

@@ -52,6 +52,7 @@
     <Compile Include="Judgements\TaikoJudgementInfo.cs" />
     <Compile Include="Judgements\TaikoScoreResult.cs" />
     <Compile Include="Objects\Drawable\DrawableHit.cs" />
+    <Compile Include="Objects\Drawable\DrawableHitFinisher.cs" />
     <Compile Include="Objects\Drawable\DrawableTaikoHitObject.cs" />
     <Compile Include="Objects\TaikoHitType.cs" />
     <Compile Include="TaikoDifficultyCalculator.cs" />