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osu-lazer/osu.Game.Rulesets.Osu/UI/StartTimeOrderedHitPolicy.cs
2022-06-17 16:37:17 +09:00

95 lines
3.7 KiB
C#

// 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.
#nullable disable
using System;
using System.Collections.Generic;
using osu.Game.Rulesets.Objects;
using osu.Game.Rulesets.Objects.Drawables;
using osu.Game.Rulesets.Osu.Objects.Drawables;
using osu.Game.Rulesets.UI;
namespace osu.Game.Rulesets.Osu.UI
{
/// <summary>
/// Ensures that <see cref="HitObject"/>s are hit in-order of their start times. Affectionately known as "note lock".
/// If a <see cref="HitObject"/> is hit out of order:
/// <list type="number">
/// <item><description>The hit is blocked if it occurred earlier than the previous <see cref="HitObject"/>'s start time.</description></item>
/// <item><description>The hit causes all previous <see cref="HitObject"/>s to missed otherwise.</description></item>
/// </list>
/// </summary>
public class StartTimeOrderedHitPolicy : IHitPolicy
{
public IHitObjectContainer HitObjectContainer { get; set; }
public bool IsHittable(DrawableHitObject hitObject, double time)
{
DrawableHitObject blockingObject = null;
foreach (var obj in enumerateHitObjectsUpTo(hitObject.HitObject.StartTime))
{
if (hitObjectCanBlockFutureHits(obj))
blockingObject = obj;
}
// If there is no previous hitobject, allow the hit.
if (blockingObject == null)
return true;
// A hit is allowed if:
// 1. The last blocking hitobject has been judged.
// 2. The current time is after the last hitobject's start time.
// Hits at exactly the same time as the blocking hitobject are allowed for maps that contain simultaneous hitobjects (e.g. /b/372245).
return blockingObject.Judged || time >= blockingObject.HitObject.StartTime;
}
public void HandleHit(DrawableHitObject hitObject)
{
// Hitobjects which themselves don't block future hitobjects don't cause misses (e.g. slider ticks, spinners).
if (!hitObjectCanBlockFutureHits(hitObject))
return;
if (!IsHittable(hitObject, hitObject.HitObject.StartTime + hitObject.Result.TimeOffset))
throw new InvalidOperationException($"A {hitObject} was hit before it became hittable!");
// Miss all hitobjects prior to the hit one.
foreach (var obj in enumerateHitObjectsUpTo(hitObject.HitObject.StartTime))
{
if (obj.Judged)
continue;
if (hitObjectCanBlockFutureHits(obj))
((DrawableOsuHitObject)obj).MissForcefully();
}
}
/// <summary>
/// Whether a <see cref="HitObject"/> blocks hits on future <see cref="HitObject"/>s until its start time is reached.
/// </summary>
/// <param name="hitObject">The <see cref="HitObject"/> to test.</param>
private static bool hitObjectCanBlockFutureHits(DrawableHitObject hitObject)
=> hitObject is DrawableHitCircle;
private IEnumerable<DrawableHitObject> enumerateHitObjectsUpTo(double targetTime)
{
foreach (var obj in HitObjectContainer.AliveObjects)
{
if (obj.HitObject.StartTime >= targetTime)
yield break;
yield return obj;
foreach (var nestedObj in obj.NestedHitObjects)
{
if (nestedObj.HitObject.StartTime >= targetTime)
break;
yield return nestedObj;
}
}
}
}
}