Add Bad Apple mod into the osu!catch ruleset

osu.Game.Rulesets.Catch.Tests/Mods/TestSceneCatchModBadApple.cs

@@ -0,0 +1,21 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using NUnit.Framework;
+using osu.Game.Rulesets.Catch.Mods;
+using osu.Game.Tests.Visual;
+
+namespace osu.Game.Rulesets.Catch.Tests.Mods
+{
+    public partial class TestSceneCatchModBadApple : ModTestScene
+    {
+        protected override Ruleset CreatePlayerRuleset() => new CatchRuleset();
+
+        [Test]
+        public void TestBadApple() => CreateModTest(new ModTestData
+        {
+            Mod = new CatchModBadApple(),
+            PassCondition = () => true
+        });
+    }
+}

osu.Game.Rulesets.Catch/CatchRuleset.cs

@@ -155,6 +155,7 @@ public override IEnumerable<Mod> GetModsFor(ModType type)
                         new CatchModMuted(),
                         new CatchModNoScope(),
                         new CatchModMovingFast(),
+                        new CatchModBadApple(),
                     };
 
                 case ModType.System:

osu.Game.Rulesets.Catch/Mods/CatchModBadApple.cs

@@ -0,0 +1,69 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System;
+using osu.Framework.Bindables;
+using osu.Framework.Localisation;
+using osu.Framework.Audio;
+using osu.Game.Configuration;
+using osu.Game.Rulesets.Catch.Objects;
+using osu.Game.Rulesets.Catch.Objects.Drawables;
+using osu.Game.Rulesets.Catch.UI;
+using osu.Game.Rulesets.Objects.Drawables;
+using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.UI;
+using osu.Framework.Graphics;
+
+namespace osu.Game.Rulesets.Catch.Mods
+{
+    public class CatchModBadApple : Mod, IApplicableToDrawableHitObject, IApplicableToDrawableRuleset<CatchHitObject>, IUpdatableByPlayfield
+    {
+        public override string Name => "Bad Apple";
+        public override LocalisableString Description => "The fruit has gone bad... dodge it!";
+        public override double ScoreMultiplier => 1;
+        public override string Acronym => "BA";
+        public override Type[] IncompatibleMods => new[] { typeof(CatchModAutoplay) };
+
+        [SettingSource("Mute hit sounds", "Hit sounds become muted.")]
+        public BindableBool AffectsHitSounds { get; } = new BindableBool(true);
+
+        private Catcher catcher = null!;
+        private readonly BindableNumber<double> hitSoundVolume = new BindableDouble(0);
+
+        public void ApplyToDrawableRuleset(DrawableRuleset<CatchHitObject> drawableRuleset)
+        {
+            catcher = ((CatchPlayfield)drawableRuleset.Playfield).Catcher;
+
+            // Don't show caught fruits as they aren't technically being caught.
+            catcher.CatchFruitOnPlate = false;
+
+            if (AffectsHitSounds.Value)
+            {
+                drawableRuleset.Audio.AddAdjustment(AdjustableProperty.Volume, hitSoundVolume);
+            }
+        }
+
+        public void ApplyToDrawableHitObject(DrawableHitObject drawable)
+        {
+            if (drawable is DrawableCatchHitObject catchHitObject)
+            {
+                catchHitObject.CheckPosition = hitObject => !catcher.CanCatch(hitObject);
+            }
+
+            drawable.ApplyCustomUpdateState += (dho, state) =>
+            {
+                // Keep the existing transforms when hit.
+                if (state is not ArmedState.Hit)
+                    return;
+
+                // When "hit", the DHO is faded out, so to let fruits fall after being caught we fade them back in.
+                dho.FadeIn();
+            };
+        }
+        public void Update(Playfield playfield)
+        {
+            // Block hyperdashing to avoid hyperdashes when two objects appear at the same time.
+            catcher.SetHyperDashState(1, -1);
+        }
+    }
+}