osu-lazer/osu.Game/Beatmaps/BeatmapProcessor.cs

// 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.Linq;
using osu.Game.Rulesets.Objects.Types;

namespace osu.Game.Beatmaps
{
    public interface IBeatmapProcessor
    {
        IBeatmap Beatmap { get; }

        /// <summary>
        /// Post-processes <see cref="Beatmap"/> to add mode-specific components that aren't added during conversion.
        /// <para>
        /// An example of such a usage is for combo colours.
        /// </para>
        /// </summary>
        void PostProcess();
    }

    /// <summary>
    /// Processes a post-converted Beatmap.
    /// </summary>
    /// <typeparam name="TObject">The type of HitObject contained in the Beatmap.</typeparam>
    public class BeatmapProcessor : IBeatmapProcessor
    {
        public IBeatmap Beatmap { get; }

        public BeatmapProcessor(IBeatmap beatmap)
        {
            Beatmap = beatmap;
        }

        /// <summary>
        /// Post-processes a Beatmap to add mode-specific components that aren't added during conversion.
        /// <para>
        /// An example of such a usage is for combo colours.
        /// </para>
        /// </summary>
        public virtual void PostProcess()
        {
            IHasComboInformation lastObj = null;

            foreach (var obj in Beatmap.HitObjects.OfType<IHasComboInformation>())
            {
                if (obj.NewCombo)
                {
                    obj.IndexInCurrentCombo = 0;
                    if (lastObj != null)
                    {
                        lastObj.LastInCombo = true;
                        obj.ComboIndex = lastObj.ComboIndex + 1;
                    }
                }
                else if (lastObj != null)
                {
                    obj.IndexInCurrentCombo = lastObj.IndexInCurrentCombo + 1;
                    obj.ComboIndex = lastObj.ComboIndex;
                }

                lastObj = obj;
            }
        }
    }
}