From 85d2b1232a22f900187731033a7b753ea1429225 Mon Sep 17 00:00:00 2001 From: Samuel Cattini-Schultz Date: Sat, 3 Apr 2021 20:52:36 +1100 Subject: [PATCH] Refactor to abstract out strain logic into StrainSkill class While it is the case for the existing official Skills, Skill implementations shouldn't be required to conform to a strain based approach. There are other valid approaches to calculating skill difficulty that can be supported by abstracting the strain logic into its own StrainSkill class. --- .../Difficulty/Skills/Movement.cs | 2 +- .../Difficulty/Skills/Strain.cs | 2 +- .../Difficulty/Skills/Aim.cs | 2 +- .../Difficulty/Skills/Speed.cs | 2 +- .../Difficulty/Skills/Colour.cs | 2 +- .../Difficulty/Skills/Rhythm.cs | 2 +- .../Difficulty/Skills/Stamina.cs | 2 +- osu.Game/Rulesets/Difficulty/Skills/Skill.cs | 115 +-------------- .../Rulesets/Difficulty/Skills/StrainSkill.cs | 137 ++++++++++++++++++ 9 files changed, 150 insertions(+), 116 deletions(-) create mode 100644 osu.Game/Rulesets/Difficulty/Skills/StrainSkill.cs diff --git a/osu.Game.Rulesets.Catch/Difficulty/Skills/Movement.cs b/osu.Game.Rulesets.Catch/Difficulty/Skills/Movement.cs index 7222166535..75e17f6c48 100644 --- a/osu.Game.Rulesets.Catch/Difficulty/Skills/Movement.cs +++ b/osu.Game.Rulesets.Catch/Difficulty/Skills/Movement.cs @@ -9,7 +9,7 @@ using osu.Game.Rulesets.Mods; namespace osu.Game.Rulesets.Catch.Difficulty.Skills { - public class Movement : Skill + public class Movement : StrainSkill { private const float absolute_player_positioning_error = 16f; private const float normalized_hitobject_radius = 41.0f; diff --git a/osu.Game.Rulesets.Mania/Difficulty/Skills/Strain.cs b/osu.Game.Rulesets.Mania/Difficulty/Skills/Strain.cs index 0761724e83..2ba2ee6b4a 100644 --- a/osu.Game.Rulesets.Mania/Difficulty/Skills/Strain.cs +++ b/osu.Game.Rulesets.Mania/Difficulty/Skills/Strain.cs @@ -10,7 +10,7 @@ using osu.Game.Rulesets.Mods; namespace osu.Game.Rulesets.Mania.Difficulty.Skills { - public class Strain : Skill + public class Strain : StrainSkill { private const double individual_decay_base = 0.125; private const double overall_decay_base = 0.30; diff --git a/osu.Game.Rulesets.Osu/Difficulty/Skills/Aim.cs b/osu.Game.Rulesets.Osu/Difficulty/Skills/Aim.cs index 90cba13c7c..cb819ec090 100644 --- a/osu.Game.Rulesets.Osu/Difficulty/Skills/Aim.cs +++ b/osu.Game.Rulesets.Osu/Difficulty/Skills/Aim.cs @@ -13,7 +13,7 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Skills /// /// Represents the skill required to correctly aim at every object in the map with a uniform CircleSize and normalized distances. /// - public class Aim : Skill + public class Aim : StrainSkill { private const double angle_bonus_begin = Math.PI / 3; private const double timing_threshold = 107; diff --git a/osu.Game.Rulesets.Osu/Difficulty/Skills/Speed.cs b/osu.Game.Rulesets.Osu/Difficulty/Skills/Speed.cs index 200bc7997d..fbac080fc6 100644 --- a/osu.Game.Rulesets.Osu/Difficulty/Skills/Speed.cs +++ b/osu.Game.Rulesets.Osu/Difficulty/Skills/Speed.cs @@ -13,7 +13,7 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Skills /// /// Represents the skill required to press keys with regards to keeping up with the speed at which objects need to be hit. /// - public class Speed : Skill + public class Speed : StrainSkill { private const double single_spacing_threshold = 125; diff --git a/osu.Game.Rulesets.Taiko/Difficulty/Skills/Colour.cs b/osu.Game.Rulesets.Taiko/Difficulty/Skills/Colour.cs index cc0738e252..769d021362 100644 --- a/osu.Game.Rulesets.Taiko/Difficulty/Skills/Colour.cs +++ b/osu.Game.Rulesets.Taiko/Difficulty/Skills/Colour.cs @@ -14,7 +14,7 @@ namespace osu.Game.Rulesets.Taiko.Difficulty.Skills /// /// Calculates the colour coefficient of taiko difficulty. /// - public class Colour : Skill + public class Colour : StrainSkill { protected override double SkillMultiplier => 1; protected override double StrainDecayBase => 0.4; diff --git a/osu.Game.Rulesets.Taiko/Difficulty/Skills/Rhythm.cs b/osu.Game.Rulesets.Taiko/Difficulty/Skills/Rhythm.cs index f2b8309ac5..a32f6ebe0d 100644 --- a/osu.Game.Rulesets.Taiko/Difficulty/Skills/Rhythm.cs +++ b/osu.Game.Rulesets.Taiko/Difficulty/Skills/Rhythm.cs @@ -14,7 +14,7 @@ namespace osu.Game.Rulesets.Taiko.Difficulty.Skills /// /// Calculates the rhythm coefficient of taiko difficulty. /// - public class Rhythm : Skill + public class Rhythm : StrainSkill { protected override double SkillMultiplier => 10; protected override double StrainDecayBase => 0; diff --git a/osu.Game.Rulesets.Taiko/Difficulty/Skills/Stamina.cs b/osu.Game.Rulesets.Taiko/Difficulty/Skills/Stamina.cs index c34cce0cd6..4cceadb23f 100644 --- a/osu.Game.Rulesets.Taiko/Difficulty/Skills/Stamina.cs +++ b/osu.Game.Rulesets.Taiko/Difficulty/Skills/Stamina.cs @@ -17,7 +17,7 @@ namespace osu.Game.Rulesets.Taiko.Difficulty.Skills /// /// The reference play style chosen uses two hands, with full alternating (the hand changes after every hit). /// - public class Stamina : Skill + public class Stamina : StrainSkill { protected override double SkillMultiplier => 1; protected override double StrainDecayBase => 0.4; diff --git a/osu.Game/Rulesets/Difficulty/Skills/Skill.cs b/osu.Game/Rulesets/Difficulty/Skills/Skill.cs index aa187c6afd..b3d7ce3c40 100644 --- a/osu.Game/Rulesets/Difficulty/Skills/Skill.cs +++ b/osu.Game/Rulesets/Difficulty/Skills/Skill.cs @@ -1,9 +1,7 @@ // Copyright (c) ppy Pty Ltd . Licensed under the MIT Licence. // See the LICENCE file in the repository root for full licence text. -using System; using System.Collections.Generic; -using System.Linq; using osu.Game.Rulesets.Difficulty.Preprocessing; using osu.Game.Rulesets.Difficulty.Utils; using osu.Game.Rulesets.Mods; @@ -11,140 +9,39 @@ using osu.Game.Rulesets.Mods; namespace osu.Game.Rulesets.Difficulty.Skills { /// - /// Used to processes strain values of s, keep track of strain levels caused by the processed objects - /// and to calculate a final difficulty value representing the difficulty of hitting all the processed objects. + /// A bare minimal abstract skill for fully custom skill implementations. /// public abstract class Skill { - /// - /// Strain values are multiplied by this number for the given skill. Used to balance the value of different skills between each other. - /// - protected abstract double SkillMultiplier { get; } - - /// - /// Determines how quickly strain decays for the given skill. - /// For example a value of 0.15 indicates that strain decays to 15% of its original value in one second. - /// - protected abstract double StrainDecayBase { get; } - - /// - /// The weight by which each strain value decays. - /// - protected virtual double DecayWeight => 0.9; - /// /// s that were processed previously. They can affect the strain values of the following objects. /// protected readonly LimitedCapacityStack Previous = new LimitedCapacityStack(2); // Contained objects not used yet - /// - /// The current strain level. - /// - protected double CurrentStrain { get; private set; } = 1; - - /// - /// The length of each strain section. - /// - protected virtual int SectionLength => 400; - + /// /// Mods for use in skill calculations. /// protected IReadOnlyList Mods => mods; - private double currentSectionPeak = 1; // We also keep track of the peak strain level in the current section. - - private double currentSectionEnd; - - private readonly List strainPeaks = new List(); - private readonly Mod[] mods; - protected Skill(Mod[] mods) { this.mods = mods; } /// - /// Process a and update current strain values accordingly. + /// Process a . /// - public void Process(DifficultyHitObject current) + /// The to process. + public virtual void Process(DifficultyHitObject current) { - // The first object doesn't generate a strain, so we begin with an incremented section end - if (Previous.Count == 0) - currentSectionEnd = Math.Ceiling(current.StartTime / SectionLength) * SectionLength; - - while (current.StartTime > currentSectionEnd) - { - saveCurrentPeak(); - startNewSectionFrom(currentSectionEnd); - currentSectionEnd += SectionLength; - } - - CurrentStrain *= strainDecay(current.DeltaTime); - CurrentStrain += StrainValueOf(current) * SkillMultiplier; - - currentSectionPeak = Math.Max(CurrentStrain, currentSectionPeak); - Previous.Push(current); } - /// - /// Saves the current peak strain level to the list of strain peaks, which will be used to calculate an overall difficulty. - /// - private void saveCurrentPeak() - { - strainPeaks.Add(currentSectionPeak); - } - - /// - /// Sets the initial strain level for a new section. - /// - /// The beginning of the new section in milliseconds. - private void startNewSectionFrom(double time) - { - // The maximum strain of the new section is not zero by default, strain decays as usual regardless of section boundaries. - // This means we need to capture the strain level at the beginning of the new section, and use that as the initial peak level. - currentSectionPeak = GetPeakStrain(time); - } - - /// - /// Retrieves the peak strain at a point in time. - /// - /// The time to retrieve the peak strain at, adjusted by clockrate. - /// The peak strain. - protected virtual double GetPeakStrain(double time) => CurrentStrain * strainDecay(time - Previous[0].StartTime); - - /// - /// Returns a live enumerable of the peak strains for each section of the beatmap, - /// including the peak of the current section. - /// - public IEnumerable GetCurrentStrainPeaks() => strainPeaks.Append(currentSectionPeak); - /// /// Returns the calculated difficulty value representing all s that have been processed up to this point. /// - public double DifficultyValue() - { - double difficulty = 0; - double weight = 1; - - // Difficulty is the weighted sum of the highest strains from every section. - // We're sorting from highest to lowest strain. - foreach (double strain in GetCurrentStrainPeaks().OrderByDescending(d => d)) - { - difficulty += strain * weight; - weight *= DecayWeight; - } - - return difficulty; - } - - /// - /// Calculates the strain value of a . This value is affected by previously processed objects. - /// - protected abstract double StrainValueOf(DifficultyHitObject current); - - private double strainDecay(double ms) => Math.Pow(StrainDecayBase, ms / 1000); + public abstract double DifficultyValue(); } } diff --git a/osu.Game/Rulesets/Difficulty/Skills/StrainSkill.cs b/osu.Game/Rulesets/Difficulty/Skills/StrainSkill.cs new file mode 100644 index 0000000000..c324f8e414 --- /dev/null +++ b/osu.Game/Rulesets/Difficulty/Skills/StrainSkill.cs @@ -0,0 +1,137 @@ +// Copyright (c) ppy Pty Ltd . Licensed under the MIT Licence. +// See the LICENCE file in the repository root for full licence text. + +using System; +using System.Collections.Generic; +using System.Linq; +using osu.Game.Rulesets.Difficulty.Preprocessing; +using osu.Game.Rulesets.Mods; + +namespace osu.Game.Rulesets.Difficulty.Skills +{ + /// + /// Used to processes strain values of s, keep track of strain levels caused by the processed objects + /// and to calculate a final difficulty value representing the difficulty of hitting all the processed objects. + /// + public abstract class StrainSkill : Skill + { + /// + /// Strain values are multiplied by this number for the given skill. Used to balance the value of different skills between each other. + /// + protected abstract double SkillMultiplier { get; } + + /// + /// Determines how quickly strain decays for the given skill. + /// For example a value of 0.15 indicates that strain decays to 15% of its original value in one second. + /// + protected abstract double StrainDecayBase { get; } + + /// + /// The weight by which each strain value decays. + /// + protected virtual double DecayWeight => 0.9; + + /// + /// The current strain level. + /// + protected double CurrentStrain { get; private set; } = 1; + + /// + /// The length of each strain section. + /// + protected virtual int SectionLength => 400; + + private double currentSectionPeak = 1; // We also keep track of the peak strain level in the current section. + + private double currentSectionEnd; + + private readonly List strainPeaks = new List(); + + protected StrainSkill(Mod[] mods) + : base(mods) + { + } + + /// + /// Process a and update current strain values accordingly. + /// + public sealed override void Process(DifficultyHitObject current) + { + // The first object doesn't generate a strain, so we begin with an incremented section end + if (Previous.Count == 0) + currentSectionEnd = Math.Ceiling(current.StartTime / SectionLength) * SectionLength; + + while (current.StartTime > currentSectionEnd) + { + saveCurrentPeak(); + startNewSectionFrom(currentSectionEnd); + currentSectionEnd += SectionLength; + } + + CurrentStrain *= strainDecay(current.DeltaTime); + CurrentStrain += StrainValueOf(current) * SkillMultiplier; + + currentSectionPeak = Math.Max(CurrentStrain, currentSectionPeak); + + base.Process(current); + } + + /// + /// Saves the current peak strain level to the list of strain peaks, which will be used to calculate an overall difficulty. + /// + private void saveCurrentPeak() + { + strainPeaks.Add(currentSectionPeak); + } + + /// + /// Sets the initial strain level for a new section. + /// + /// The beginning of the new section in milliseconds. + private void startNewSectionFrom(double time) + { + // The maximum strain of the new section is not zero by default, strain decays as usual regardless of section boundaries. + // This means we need to capture the strain level at the beginning of the new section, and use that as the initial peak level. + currentSectionPeak = GetPeakStrain(time); + } + + /// + /// Retrieves the peak strain at a point in time. + /// + /// The time to retrieve the peak strain at. + /// The peak strain. + protected virtual double GetPeakStrain(double time) => CurrentStrain * strainDecay(time - Previous[0].StartTime); + + /// + /// Returns a live enumerable of the peak strains for each section of the beatmap, + /// including the peak of the current section. + /// + public IEnumerable GetCurrentStrainPeaks() => strainPeaks.Append(currentSectionPeak); + + /// + /// Returns the calculated difficulty value representing all s that have been processed up to this point. + /// + public sealed override double DifficultyValue() + { + double difficulty = 0; + double weight = 1; + + // Difficulty is the weighted sum of the highest strains from every section. + // We're sorting from highest to lowest strain. + foreach (double strain in GetCurrentStrainPeaks().OrderByDescending(d => d)) + { + difficulty += strain * weight; + weight *= DecayWeight; + } + + return difficulty; + } + + /// + /// Calculates the strain value of a . This value is affected by previously processed objects. + /// + protected abstract double StrainValueOf(DifficultyHitObject current); + + private double strainDecay(double ms) => Math.Pow(StrainDecayBase, ms / 1000); + } +}