Rename the mod class to transform.

osu.Game.Rulesets.Osu/Mods/OsuModTransform.cs

@@ -0,0 +1,70 @@
+// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using System;
+using System.Linq;
+using System.Collections.Generic;
+using osu.Framework.Extensions.IEnumerableExtensions;
+using osu.Framework.Graphics;
+using osu.Game.Graphics;
+using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.Objects.Drawables;
+using osu.Game.Rulesets.Osu.Objects;
+using OpenTK;
+using osu.Game.Rulesets.Osu.UI;
+using osu.Game.Rulesets.UI;
+using osu.Game.Rulesets.Osu.Objects.Drawables;
+
+namespace osu.Game.Rulesets.Osu.Mods
+{
+    internal class OsuModTransform : Mod, IApplicableToDrawableHitObjects
+    {
+        public override string Name => "Transform";
+        public override string ShortenedName => "TR";
+        public override FontAwesome Icon => FontAwesome.fa_arrows;
+        public override ModType Type => ModType.Fun;
+        public override string Description => "Everything rotates. EVERYTHING.";
+        public override double ScoreMultiplier => 1;
+
+        private readonly IReadOnlyList<Type> TargetHitObjectTypes = new List<Type>() {
+            typeof(HitCircle),
+            typeof(Slider),
+            typeof(Spinner),
+        };
+
+        public void ApplyToDrawableHitObjects(IEnumerable<DrawableHitObject> drawables)
+        {
+            drawables.ForEach(drawable => 
+                drawable.ApplyCustomUpdateState += drawableOnApplyCustomUpdateState
+            );
+        }
+
+        private float theta;
+
+        private void drawableOnApplyCustomUpdateState(DrawableHitObject drawable, ArmedState state)
+        {
+            var hitObject = (OsuHitObject) drawable.HitObject;
+
+            if (!TargetHitObjectTypes.Contains(hitObject.GetType()))
+                return;
+
+            float appear_distance = (float)hitObject.TimePreempt * 0.5f;
+
+            Vector2 originalPosition = drawable.Position;
+            Vector2 appearOffset = new Vector2((float)Math.Cos(theta), (float)Math.Sin(theta)) * appear_distance;
+
+            //the - 1 and + 1 prevents the hit explosion to appear in the wrong position.
+            double appearTime = hitObject.StartTime - hitObject.TimePreempt - 1;
+            double moveDuration = hitObject.TimePreempt + 1;
+
+            using (drawable.BeginAbsoluteSequence(appearTime, true))
+            {
+                drawable
+                    .MoveToOffset(appearOffset)
+                    .MoveTo(originalPosition, moveDuration, Easing.InOutSine);
+            }
+
+            theta += 0.4f;
+        }
+    }
+}