Added initial AimAssist mod

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

@@ -0,0 +1,97 @@
+// 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 System.Collections.Generic;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Sprites;
+using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.Objects.Drawables;
+using osu.Game.Rulesets.Objects.Types;
+using osu.Game.Rulesets.Osu.Objects.Drawables;
+using osu.Game.Rulesets.UI;
+
+namespace osu.Game.Rulesets.Osu.Mods
+{
+    internal class OsuModAimAssist : Mod, IApplicableToDrawableHitObjects, IUpdatableByPlayfield
+    {
+        public override string Name => "AimAssist";
+        public override string Acronym => "AA";
+        public override IconUsage Icon => FontAwesome.Solid.MousePointer;
+        public override ModType Type => ModType.Fun;
+        public override string Description => "No need to chase the circle, the circle chases you";
+        public override double ScoreMultiplier => 1;
+        public override Type[] IncompatibleMods => new[] { typeof(OsuModAutopilot), typeof(OsuModAutoplay), typeof(OsuModWiggle), typeof(OsuModTransform) };
+
+        private HashSet<DrawableOsuHitObject> movingObjects = new HashSet<DrawableOsuHitObject>();
+        private int updateCounter = 0;
+
+        public void Update(Playfield playfield)
+        {
+            // Avoid crowded judgment displays
+            playfield.DisplayJudgements.Value = false;
+
+            // Object destination updated when cursor updates
+            playfield.Cursor.ActiveCursor.OnUpdate += drawableCursor =>
+            {
+                // ... every 500th cursor update iteration
+                // (lower -> potential lags ; higher -> easier to miss if cursor too fast)
+                if (updateCounter++ < 500) return;
+                updateCounter = 0;
+
+                // First move objects to new destination, then remove them from movingObjects set if they're too old
+                movingObjects.RemoveWhere(d =>
+                {
+                    var currentTime = playfield.Clock.CurrentTime;
+                    var h = d.HitObject;
+                    d.ClearTransforms();
+                    switch (d)
+                    {
+                        case DrawableHitCircle circle:
+                            d.MoveTo(drawableCursor.DrawPosition, Math.Max(0, h.StartTime - currentTime));
+                            return currentTime > h.StartTime;
+                        case DrawableSlider slider:
+
+                            // Move slider to cursor
+                            if (currentTime < h.StartTime)
+                                d.MoveTo(drawableCursor.DrawPosition, Math.Max(0, h.StartTime - currentTime));
+
+                            // Move slider so that sliderball stays on the cursor
+                            else
+                                d.MoveTo(drawableCursor.DrawPosition - slider.Ball.DrawPosition, Math.Max(0, h.StartTime - currentTime));
+                            return currentTime > (h as IHasEndTime).EndTime - 50;
+                        case DrawableSpinner spinner:
+                            // TODO
+                            return true;
+                    }
+                    return true; // never happens(?)
+                });
+            };
+        }
+
+        public void ApplyToDrawableHitObjects(IEnumerable<DrawableHitObject> drawables)
+        {
+            foreach (var drawable in drawables)
+                drawable.ApplyCustomUpdateState += drawableOnApplyCustomUpdateState;
+        }
+
+        private void drawableOnApplyCustomUpdateState(DrawableHitObject drawable, ArmedState state)
+        {
+            if (!(drawable is DrawableOsuHitObject d))
+                return;
+            var h = d.HitObject;
+            using (d.BeginAbsoluteSequence(h.StartTime - h.TimePreempt))
+                movingObjects.Add(d);
+        }
+    }
+
+    /*
+     * TODOs
+     *  - remove object timing glitches / artifacts
+     *  - remove FollowPoints
+     *  - automate sliders
+     *  - combine with OsuModRelax (?)
+     *  - must be some way to make this more effictient
+     *
+     */
+}

osu.Game.Rulesets.Osu/OsuRuleset.cs

@@ -136,6 +136,7 @@ namespace osu.Game.Rulesets.Osu
                         new OsuModSpinIn(),
                         new MultiMod(new OsuModGrow(), new OsuModDeflate()),
                         new MultiMod(new ModWindUp(), new ModWindDown()),
+                        new OsuModAimAssist(),
                     };
 
                 case ModType.System: