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osu-lazer/osu.Game.Rulesets.Mania/Beatmaps/Patterns/Legacy/PatternGenerator.cs
2018-01-05 20:21:19 +09:00

115 lines
4.8 KiB
C#

// 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;
using System.Linq;
using osu.Game.Beatmaps;
using osu.Game.Rulesets.Mania.MathUtils;
using osu.Game.Rulesets.Objects;
using OpenTK;
namespace osu.Game.Rulesets.Mania.Beatmaps.Patterns.Legacy
{
/// <summary>
/// A pattern generator for legacy hit objects.
/// </summary>
internal abstract class PatternGenerator : Patterns.PatternGenerator
{
/// <summary>
/// The column index at which to start generating random notes.
/// </summary>
protected readonly int RandomStart;
/// <summary>
/// The random number generator to use.
/// </summary>
protected readonly FastRandom Random;
protected PatternGenerator(FastRandom random, HitObject hitObject, ManiaBeatmap beatmap, Pattern previousPattern)
: base(hitObject, beatmap, previousPattern)
{
if (random == null) throw new ArgumentNullException(nameof(random));
if (beatmap == null) throw new ArgumentNullException(nameof(beatmap));
if (previousPattern == null) throw new ArgumentNullException(nameof(previousPattern));
Random = random;
RandomStart = TotalColumns == 8 ? 1 : 0;
}
/// <summary>
/// Converts an x-position into a column.
/// </summary>
/// <param name="position">The x-position.</param>
/// <param name="allowSpecial">Whether to treat as 7K + 1.</param>
/// <returns>The column.</returns>
protected int GetColumn(float position, bool allowSpecial = false)
{
if (allowSpecial && TotalColumns == 8)
{
const float local_x_divisor = 512f / 7;
return MathHelper.Clamp((int)Math.Floor(position / local_x_divisor), 0, 6) + 1;
}
float localXDivisor = 512f / TotalColumns;
return MathHelper.Clamp((int)Math.Floor(position / localXDivisor), 0, TotalColumns - 1);
}
/// <summary>
/// Generates a count of notes to be generated from probabilities.
/// </summary>
/// <param name="p2">Probability for 2 notes to be generated.</param>
/// <param name="p3">Probability for 3 notes to be generated.</param>
/// <param name="p4">Probability for 4 notes to be generated.</param>
/// <param name="p5">Probability for 5 notes to be generated.</param>
/// <param name="p6">Probability for 6 notes to be generated.</param>
/// <returns>The amount of notes to be generated.</returns>
protected int GetRandomNoteCount(double p2, double p3, double p4 = 0, double p5 = 0, double p6 = 0)
{
if (p2 < 0 || p2 > 1) throw new ArgumentOutOfRangeException(nameof(p2));
if (p3 < 0 || p3 > 1) throw new ArgumentOutOfRangeException(nameof(p3));
if (p4 < 0 || p4 > 1) throw new ArgumentOutOfRangeException(nameof(p4));
if (p5 < 0 || p5 > 1) throw new ArgumentOutOfRangeException(nameof(p5));
if (p6 < 0 || p6 > 1) throw new ArgumentOutOfRangeException(nameof(p6));
double val = Random.NextDouble();
if (val >= 1 - p6)
return 6;
if (val >= 1 - p5)
return 5;
if (val >= 1 - p4)
return 4;
if (val >= 1 - p3)
return 3;
return val >= 1 - p2 ? 2 : 1;
}
private double? conversionDifficulty;
/// <summary>
/// A difficulty factor used for various conversion methods from osu!stable.
/// </summary>
protected double ConversionDifficulty
{
get
{
if (conversionDifficulty != null)
return conversionDifficulty.Value;
HitObject lastObject = Beatmap.HitObjects.LastOrDefault();
HitObject firstObject = Beatmap.HitObjects.FirstOrDefault();
double drainTime = (lastObject?.StartTime ?? 0) - (firstObject?.StartTime ?? 0);
drainTime -= Beatmap.TotalBreakTime;
if (drainTime == 0)
drainTime = 10000;
BeatmapDifficulty difficulty = Beatmap.BeatmapInfo.BaseDifficulty;
conversionDifficulty = ((difficulty.DrainRate + MathHelper.Clamp(difficulty.ApproachRate, 4, 7)) / 1.5 + Beatmap.HitObjects.Count / drainTime * 9f) / 38f * 5f / 1.15;
conversionDifficulty = Math.Min(conversionDifficulty.Value, 12);
return conversionDifficulty.Value;
}
}
}
}