// 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.Linq;
using JetBrains.Annotations;
using osu.Game.Beatmaps;
using osu.Game.Rulesets.Objects;
using osu.Game.Utils;
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 LegacyRandom Random;
protected PatternGenerator(LegacyRandom random, HitObject hitObject, IBeatmap beatmap, Pattern previousPattern, int totalColumns)
: base(hitObject, beatmap, totalColumns, previousPattern)
{
ArgumentNullException.ThrowIfNull(random);
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 Math.Clamp((int)MathF.Floor(position / local_x_divisor), 0, 6) + 1;
}
float localXDivisor = 512f / TotalColumns;
return Math.Clamp((int)MathF.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();
// Drain time in seconds
int drainTime = (int)(((lastObject?.StartTime ?? 0) - (firstObject?.StartTime ?? 0) - Beatmap.TotalBreakTime) / 1000);
if (drainTime == 0)
drainTime = 10000;
IBeatmapDifficultyInfo difficulty = Beatmap.Difficulty;
conversionDifficulty = ((difficulty.DrainRate + Math.Clamp(difficulty.ApproachRate, 4, 7)) / 1.5 + (double)Beatmap.HitObjects.Count / drainTime * 9f) / 38f * 5f / 1.15;
conversionDifficulty = Math.Min(conversionDifficulty.Value, 12);
return conversionDifficulty.Value;
}
}
/// <summary>
/// Finds a new column in which a <see cref="HitObject"/> can be placed.
/// This uses <see cref="GetRandomColumn"/> to pick the next candidate column.
/// </summary>
/// <param name="initialColumn">The initial column to test. This may be returned if it is already a valid column.</param>
/// <param name="patterns">A list of patterns for which the validity of a column should be checked against.
/// A column is not a valid candidate if a <see cref="HitObject"/> occupies the same column in any of the patterns.</param>
/// <returns>A column for which there are no <see cref="HitObject"/>s in any of <paramref name="patterns"/> occupying the same column.</returns>
/// <exception cref="NotEnoughColumnsException">If there are no valid candidate columns.</exception>
protected int FindAvailableColumn(int initialColumn, params Pattern[] patterns)
=> FindAvailableColumn(initialColumn, null, patterns: patterns);
/// <summary>
/// Finds a new column in which a <see cref="HitObject"/> can be placed.
/// </summary>
/// <param name="initialColumn">The initial column to test. This may be returned if it is already a valid column.</param>
/// <param name="nextColumn">A function to retrieve the next column. If null, a randomisation scheme will be used.</param>
/// <param name="validation">A function to perform additional validation checks to determine if a column is a valid candidate for a <see cref="HitObject"/>.</param>
/// <param name="lowerBound">The minimum column index. If null, <see cref="RandomStart"/> is used.</param>
/// <param name="upperBound">The maximum column index. If null, <see cref="Patterns.PatternGenerator.TotalColumns">TotalColumns</see> is used.</param>
/// <param name="patterns">A list of patterns for which the validity of a column should be checked against.
/// A column is not a valid candidate if a <see cref="HitObject"/> occupies the same column in any of the patterns.</param>
/// <returns>A column which has passed the <paramref name="validation"/> check and for which there are no
/// <see cref="HitObject"/>s in any of <paramref name="patterns"/> occupying the same column.</returns>
/// <exception cref="NotEnoughColumnsException">If there are no valid candidate columns.</exception>
protected int FindAvailableColumn(int initialColumn, int? lowerBound = null, int? upperBound = null, Func<int, int> nextColumn = null, [InstantHandle] Func<int, bool> validation = null,
params Pattern[] patterns)
{
lowerBound ??= RandomStart;
upperBound ??= TotalColumns;
nextColumn ??= _ => GetRandomColumn(lowerBound, upperBound);
// Check for the initial column
if (isValid(initialColumn))
return initialColumn;
// Ensure that we have at least one free column, so that an endless loop is avoided
bool hasValidColumns = false;
for (int i = lowerBound.Value; i < upperBound.Value; i++)
{
hasValidColumns = isValid(i);
if (hasValidColumns)
break;
}
if (!hasValidColumns)
throw new NotEnoughColumnsException();
// Iterate until a valid column is found. This is a random iteration in the default case.
do
{
initialColumn = nextColumn(initialColumn);
} while (!isValid(initialColumn));
return initialColumn;
bool isValid(int column)
{
if (validation?.Invoke(column) == false)
return false;
foreach (var p in patterns)
{
if (p.ColumnHasObject(column))
return false;
}
return true;
}
}
/// <summary>
/// Returns a random column index in the range [<paramref name="lowerBound"/>, <paramref name="upperBound"/>).
/// </summary>
/// <param name="lowerBound">The minimum column index. If null, <see cref="RandomStart"/> is used.</param>
/// <param name="upperBound">The maximum column index. If null, <see cref="Patterns.PatternGenerator.TotalColumns"/> is used.</param>
protected int GetRandomColumn(int? lowerBound = null, int? upperBound = null) => Random.Next(lowerBound ?? RandomStart, upperBound ?? TotalColumns);
/// <summary>
/// Occurs when mania conversion is stuck in an infinite loop unable to find columns to place new hitobjects in.
/// </summary>
public class NotEnoughColumnsException : Exception
{
public NotEnoughColumnsException()
: base("There were not enough columns to complete conversion.")
{
}
}
}
}