osu/osu.Game/Rulesets/Mods/RateAdjustModHelper.cs

85 lines
3.1 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.
using System;
using osu.Framework.Audio;
using osu.Framework.Bindables;
namespace osu.Game.Rulesets.Mods
{
/// <summary>
/// Provides common functionality shared across various rate adjust mods.
/// </summary>
public class RateAdjustModHelper : IApplicableToTrack
{
public readonly IBindableNumber<double> SpeedChange;
private IAdjustableAudioComponent? track;
private BindableBool? adjustPitch;
/// <summary>
/// The score multiplier for the current <see cref="SpeedChange"/>.
/// </summary>
public double ScoreMultiplier
{
get
{
// Round to the nearest multiple of 0.1.
double value = (int)(SpeedChange.Value * 10) / 10.0;
// Offset back to 0.
value -= 1;
if (SpeedChange.Value >= 1)
return 1 + value / 5;
else
return 0.6 + value;
}
}
/// <summary>
/// Construct a new <see cref="RateAdjustModHelper"/>.
/// </summary>
/// <param name="speedChange">The main speed adjust parameter which is exposed to the user.</param>
public RateAdjustModHelper(IBindableNumber<double> speedChange)
{
SpeedChange = speedChange;
}
/// <summary>
/// Setup audio track adjustments for a rate adjust mod.
/// Importantly, <see cref="ApplyToTrack"/> must be called when a track is obtained/changed for this to work.
/// </summary>
/// <param name="adjustPitch">The "adjust pitch" setting as exposed to the user.</param>
public void HandleAudioAdjustments(BindableBool adjustPitch)
{
this.adjustPitch = adjustPitch;
// When switching between pitch adjust, we need to update adjustments to time-shift or frequency-scale.
adjustPitch.BindValueChanged(adjustPitchSetting =>
{
track?.RemoveAdjustment(adjustmentForPitchSetting(adjustPitchSetting.OldValue), SpeedChange);
track?.AddAdjustment(adjustmentForPitchSetting(adjustPitchSetting.NewValue), SpeedChange);
AdjustableProperty adjustmentForPitchSetting(bool adjustPitchSettingValue)
=> adjustPitchSettingValue ? AdjustableProperty.Frequency : AdjustableProperty.Tempo;
});
}
/// <summary>
/// Should be invoked when a track is obtained / changed.
/// </summary>
/// <param name="track">The new track.</param>
/// <exception cref="InvalidOperationException">If this method is called before <see cref="HandleAudioAdjustments"/>.</exception>
public void ApplyToTrack(IAdjustableAudioComponent track)
{
if (adjustPitch == null)
throw new InvalidOperationException($"Must call {nameof(HandleAudioAdjustments)} first");
this.track = track;
adjustPitch.TriggerChange();
}
}
}