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osu-lazer/osu.Game.Rulesets.Taiko/Difficulty/Evaluators/ColourEvaluator.cs
2022-10-28 13:07:44 +09:00

68 lines
3.2 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.Game.Rulesets.Difficulty.Preprocessing;
using osu.Game.Rulesets.Taiko.Difficulty.Preprocessing;
using osu.Game.Rulesets.Taiko.Difficulty.Preprocessing.Colour;
using osu.Game.Rulesets.Taiko.Difficulty.Preprocessing.Colour.Data;
namespace osu.Game.Rulesets.Taiko.Difficulty.Evaluators
{
public class ColourEvaluator
{
/// <summary>
/// A sigmoid function. It gives a value between (middle - height/2) and (middle + height/2).
/// </summary>
/// <param name="val">The input value.</param>
/// <param name="center">The center of the sigmoid, where the largest gradient occurs and value is equal to middle.</param>
/// <param name="width">The radius of the sigmoid, outside of which values are near the minimum/maximum.</param>
/// <param name="middle">The middle of the sigmoid output.</param>
/// <param name="height">The height of the sigmoid output. This will be equal to max value - min value.</param>
private static double sigmoid(double val, double center, double width, double middle, double height)
{
double sigmoid = Math.Tanh(Math.E * -(val - center) / width);
return sigmoid * (height / 2) + middle;
}
/// <summary>
/// Evaluate the difficulty of the first note of a <see cref="MonoStreak"/>.
/// </summary>
public static double EvaluateDifficultyOf(MonoStreak monoStreak)
{
return sigmoid(monoStreak.Index, 2, 2, 0.5, 1) * EvaluateDifficultyOf(monoStreak.Parent) * 0.5;
}
/// <summary>
/// Evaluate the difficulty of the first note of a <see cref="AlternatingMonoPattern"/>.
/// </summary>
public static double EvaluateDifficultyOf(AlternatingMonoPattern alternatingMonoPattern)
{
return sigmoid(alternatingMonoPattern.Index, 2, 2, 0.5, 1) * EvaluateDifficultyOf(alternatingMonoPattern.Parent);
}
/// <summary>
/// Evaluate the difficulty of the first note of a <see cref="RepeatingHitPatterns"/>.
/// </summary>
public static double EvaluateDifficultyOf(RepeatingHitPatterns repeatingHitPattern)
{
return 2 * (1 - sigmoid(repeatingHitPattern.RepetitionInterval, 2, 2, 0.5, 1));
}
public static double EvaluateDifficultyOf(DifficultyHitObject hitObject)
{
TaikoDifficultyHitObjectColour colour = ((TaikoDifficultyHitObject)hitObject).Colour;
double difficulty = 0.0d;
if (colour.MonoStreak?.FirstHitObject == hitObject) // Difficulty for MonoStreak
difficulty += EvaluateDifficultyOf(colour.MonoStreak);
if (colour.AlternatingMonoPattern?.FirstHitObject == hitObject) // Difficulty for AlternatingMonoPattern
difficulty += EvaluateDifficultyOf(colour.AlternatingMonoPattern);
if (colour.RepeatingHitPattern?.FirstHitObject == hitObject) // Difficulty for RepeatingHitPattern
difficulty += EvaluateDifficultyOf(colour.RepeatingHitPattern);
return difficulty;
}
}
}