add difficulty adjustment mods

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

@@ -0,0 +1,51 @@
+// 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 osu.Framework.Bindables;
+using osu.Game.Beatmaps;
+using osu.Game.Configuration;
+using osu.Game.Rulesets.Mods;
+
+namespace osu.Game.Rulesets.Catch.Mods
+{
+    public class CatchModDifficultyAdjust : ModDifficultyAdjust
+    {
+        [SettingSource("Drain Rate", "Override the beatmap's set HP")]
+        public override BindableNumber<float> DrainRate { get; } = new BindableFloat
+        {
+            MinValue = 1,
+            MaxValue = 10,
+            Default = 5,
+            Value = 5,
+            Precision = 1F,
+        };
+
+        [SettingSource("Fruit Size", "Override the beatmap's set CS")]
+        public override BindableNumber<float> CircleSize { get; } = new BindableFloat
+        {
+            MinValue = 1,
+            MaxValue = 10,
+            Default = 5,
+            Value = 5,
+            Precision = 0.1F,
+        };
+
+        [SettingSource("Approach Rate", "Override the beatmap's set AR")]
+        public override BindableNumber<float> ApproachRate { get; } = new BindableFloat
+        {
+            MinValue = 1,
+            MaxValue = 10,
+            Default = 5,
+            Value = 5,
+            Precision = 0.1F,
+        };
+
+        public override void ApplyToDifficulty(BeatmapDifficulty difficulty)
+        {
+            difficulty.DrainRate = DrainRate.Value;
+            difficulty.CircleSize = CircleSize.Value;
+            difficulty.ApproachRate = ApproachRate.Value;
+            difficulty.OverallDifficulty = ApproachRate.Value;
+        }
+    }
+}