OsuModBubbles.cs

// 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.Linq;
using System.Numerics;
using osu.Framework.Bindables;
using osu.Framework.Graphics;
using osu.Framework.Graphics.Colour;
using osu.Framework.Graphics.Containers;
using osu.Framework.Graphics.Effects;
using osu.Framework.Graphics.Pooling;
using osu.Framework.Graphics.Shapes;
using osu.Framework.Graphics.Sprites;
using osu.Framework.Localisation;
using osu.Game.Graphics;
using osu.Game.Rulesets.Mods;
using osu.Game.Rulesets.Objects.Drawables;
using osu.Game.Rulesets.Osu.Objects;
using osu.Game.Rulesets.Osu.Objects.Drawables;
using osu.Game.Rulesets.Scoring;
using osu.Game.Rulesets.UI;
using osu.Game.Scoring;

namespace osu.Game.Rulesets.Osu.Mods
{
    public partial class OsuModBubbles : Mod, IApplicableToDrawableRuleset<OsuHitObject>, IApplicableToDrawableHitObject, IApplicableToScoreProcessor
    {
        public override string Name => "Bubbles";

        public override string Acronym => "BU";

        public override LocalisableString Description => "Don't let their popping distract you!";

        public override IconUsage? Icon => OsuIcon.ModBubbles;

        public override ModType Type => ModType.Fun;

        // Compatibility with these seems potentially feasible in the future, blocked for now because they don't work as one would expect
        public override Type[] IncompatibleMods => new[] { typeof(OsuModBarrelRoll), typeof(OsuModMagnetised), typeof(OsuModRepel) };

        private PlayfieldAdjustmentContainer bubbleContainer = null!;

        private DrawablePool<BubbleDrawable> bubblePool = null!;

        private readonly Bindable<int> currentCombo = new BindableInt();

        private float maxSize;
        private float bubbleSize;
        private double bubbleFade;

        public ScoreRank AdjustRank(ScoreRank rank, double accuracy) => rank;

        public void ApplyToScoreProcessor(ScoreProcessor scoreProcessor)
        {
            currentCombo.BindTo(scoreProcessor.Combo);
            currentCombo.BindValueChanged(combo =>
                maxSize = Math.Min(1.75f, (float)(1.25 + 0.005 * combo.NewValue)), true);
        }

        public void ApplyToDrawableRuleset(DrawableRuleset<OsuHitObject> drawableRuleset)
        {
            OsuHitObject firstObject = drawableRuleset.Beatmap.HitObjects.First();

            // Multiplying by 2 results in an initial size that is too large, hence 1.90 has been chosen
            // Also avoids the HitObject bleeding around the edges of the bubble drawable at minimum size
            bubbleSize = (float)firstObject.Radius * 1.90f;
            bubbleFade = firstObject.TimePreempt * 2;

            // We want to hide the judgements since they are obscured by the BubbleDrawable (due to layering)
            drawableRuleset.Playfield.DisplayJudgements.Value = false;

            bubbleContainer = drawableRuleset.CreatePlayfieldAdjustmentContainer();

            drawableRuleset.Overlays.Add(bubbleContainer);
            drawableRuleset.Overlays.Add(bubblePool = new DrawablePool<BubbleDrawable>(100));
        }

        public void ApplyToDrawableHitObject(DrawableHitObject drawableObject)
        {
            drawableObject.OnNewResult += (drawable, _) =>
            {
                if (drawable is not DrawableOsuHitObject drawableOsuHitObject) return;

                switch (drawableOsuHitObject.HitObject)
                {
                    case Slider:
                    case SpinnerTick:
                        break;

                    default:
                        BubbleDrawable bubble = bubblePool.Get();

                        bubble.WasHit = drawable.IsHit;
                        bubble.Position = getPosition(drawableOsuHitObject);
                        bubble.AccentColour = drawable.AccentColour.Value;
                        bubble.InitialSize = new Vector2(bubbleSize);
                        bubble.FadeTime = bubbleFade;
                        bubble.MaxSize = maxSize;

                        bubbleContainer.Add(bubble);
                        break;
                }
            };

            drawableObject.OnRevertResult += (drawable, _) =>
            {
                if (drawable.HitObject is SpinnerTick or Slider) return;

                // Reverse linear scan avoids the OfType<BubbleDrawable>().LastOrDefault() LINQ allocations.
                BubbleDrawable? lastBubble = null;

                for (int i = bubbleContainer.Children.Count - 1; i >= 0; i--)
                {
                    if (bubbleContainer.Children[i] is BubbleDrawable b)
                    {
                        lastBubble = b;
                        break;
                    }
                }

                lastBubble?.ClearTransforms();
                lastBubble?.Expire(true);
            };
        }

        private Vector2 getPosition(DrawableOsuHitObject drawableObject)
        {
            switch (drawableObject)
            {
                // SliderHeads are derived from HitCircles,
                // so we must handle them before to avoid them using the wrong positioning logic
                case DrawableSliderHead:
                    return drawableObject.HitObject.Position;

                // Using hitobject position will cause issues with HitCircle placement due to stack leniency.
                case DrawableHitCircle:
                    return drawableObject.Position;

                default:
                    return drawableObject.HitObject.Position;
            }
        }

        #region Pooled Bubble drawable

        private partial class BubbleDrawable : PoolableDrawable
        {
            public Vector2 InitialSize { get; set; }

            public float MaxSize { get; set; }

            public double FadeTime { get; set; }

            public bool WasHit { get; set; }

            public Colour4 AccentColour { get; set; }

            private readonly Box colourBox;
            private readonly CircularContainer content;

            public BubbleDrawable()
            {
                Origin = Anchor.Centre;
                InternalChild = content = new CircularContainer
                {
                    Anchor = Anchor.Centre,
                    Origin = Anchor.Centre,
                    RelativeSizeAxes = Axes.Both,
                    MaskingSmoothness = 2,
                    BorderThickness = 0,
                    BorderColour = Colour4.White,
                    Masking = true,
                    EdgeEffect = new EdgeEffectParameters
                    {
                        Type = EdgeEffectType.Shadow,
                        Radius = 3,
                        Colour = Colour4.Black.Opacity(0.05f),
                    },
                    Child = colourBox = new Box { RelativeSizeAxes = Axes.Both, }
                };
            }

            protected override void PrepareForUse()
            {
                Colour = WasHit ? Colour4.White : Colour4.Black;
                Scale = new Vector2(1);
                Size = InitialSize;

                //We want to fade to a darker colour to avoid colours such as white hiding the "ripple" effect.
                ColourInfo colourDarker = AccentColour.Darken(0.1f);

                // The absolute length of the bubble's animation, can be used in fractions for animations of partial length
                double duration = 1700 + Math.Pow(FadeTime, 1.07f);

                // Main bubble scaling based on combo
                this.FadeTo(1)
                    .ScaleTo(MaxSize, duration * 0.8f)
                    .Then()
                    // Pop at the end of the bubbles life time
                    .ScaleTo(MaxSize * 1.5f, duration * 0.2f, Easing.OutQuint)
                    .FadeOut(duration * 0.2f, Easing.OutCirc).Expire();

                if (!WasHit) return;

                content.BorderThickness = InitialSize.X / 3.5f;
                content.BorderColour = Colour4.White;

                colourBox.FadeColour(colourDarker);

                content.TransformTo(nameof(BorderColour), colourDarker, duration * 0.3f, Easing.OutQuint);
                // Ripple effect utilises the border to reduce drawable count
                content.TransformTo(nameof(BorderThickness), 2f, duration * 0.3f, Easing.OutQuint)
                       .Then()
                       // Avoids transparency overlap issues during the bubble "pop"
                       .TransformTo(nameof(BorderThickness), 0f);
            }
        }

        #endregion
    }
}