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Code Issues Releases Wiki Activity

Refactor ppv2 to allow integration of pp+ features.

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Péter Nemes 2017-06-05 23:45:22 +02:00
parent 2fbad58866
commit c624712f2f
11 changed files with 429 additions and 395 deletions
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201
osu.Game.Rulesets.Osu/Objects/OsuHitObjectDifficulty.cs
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// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
using OpenTK;
using System;
using System.Diagnostics;
using System.Linq;
namespace osu.Game.Rulesets.Osu.Objects
{
internal class OsuHitObjectDifficulty
{
/// <summary>
/// Factor by how much speed / aim strain decays per second.
/// </summary>
/// <remarks>
/// These values are results of tweaking a lot and taking into account general feedback.
/// Opinionated observation: Speed is easier to maintain than accurate jumps.
/// </remarks>
internal static readonly double[] DECAY_BASE = { 0.3, 0.15 };
/// <summary>
/// Pseudo threshold values to distinguish between "singles" and "streams"
/// </summary>
/// <remarks>
/// Of course the border can not be defined clearly, therefore the algorithm has a smooth transition between those values.
/// They also are based on tweaking and general feedback.
/// </remarks>
private const double stream_spacing_threshold = 110,
single_spacing_threshold = 125;
/// <summary>
/// Scaling values for weightings to keep aim and speed difficulty in balance.
/// </summary>
/// <remarks>
/// Found from testing a very large map pool (containing all ranked maps) and keeping the average values the same.
/// </remarks>
private static readonly double[] spacing_weight_scaling = { 1400, 26.25 };
/// <summary>
/// Almost the normed diameter of a circle (104 osu pixel). That is -after- position transforming.
/// </summary>
private const double almost_diameter = 90;
internal OsuHitObject BaseHitObject;
internal double[] Strains = { 1, 1 };
internal int MaxCombo = 1;
private readonly float scalingFactor;
private float lazySliderLength;
private readonly Vector2 startPosition;
private readonly Vector2 endPosition;
internal OsuHitObjectDifficulty(OsuHitObject baseHitObject)
{
BaseHitObject = baseHitObject;
float circleRadius = baseHitObject.Scale * 64;
Slider slider = BaseHitObject as Slider;
if (slider != null)
MaxCombo += slider.Ticks.Count();
// We will scale everything by this factor, so we can assume a uniform CircleSize among beatmaps.
scalingFactor = 52.0f / circleRadius;
if (circleRadius < 30)
{
float smallCircleBonus = Math.Min(30.0f - circleRadius, 5.0f) / 50.0f;
scalingFactor *= 1.0f + smallCircleBonus;
}
lazySliderLength = 0;
startPosition = baseHitObject.StackedPosition;
// Calculate approximation of lazy movement on the slider
if (slider != null)
{
float sliderFollowCircleRadius = circleRadius * 3; // Not sure if this is correct, but here we do not need 100% exact values. This comes pretty darn close in my tests.
// For simplifying this step we use actual osu! coordinates and simply scale the length, that we obtain by the ScalingFactor later
Vector2 cursorPos = startPosition;
Action<Vector2> addSliderVertex = delegate (Vector2 pos)
{
Vector2 difference = pos - cursorPos;
float distance = difference.Length;
// Did we move away too far?
if (distance > sliderFollowCircleRadius)
{
// Yep, we need to move the cursor
difference.Normalize(); // Obtain the direction of difference. We do no longer need the actual difference
distance -= sliderFollowCircleRadius;
cursorPos += difference * distance; // We move the cursor just as far as needed to stay in the follow circle
lazySliderLength += distance;
}
};
// Actual computation of the first lazy curve
foreach (var tick in slider.Ticks)
addSliderVertex(tick.StackedPosition);
addSliderVertex(baseHitObject.StackedEndPosition);
lazySliderLength *= scalingFactor;
endPosition = cursorPos;
}
// We have a normal HitCircle or a spinner
else
endPosition = startPosition;
}
internal void CalculateStrains(OsuHitObjectDifficulty previousHitObject, double timeRate)
{
calculateSpecificStrain(previousHitObject, OsuDifficultyCalculator.DifficultyType.Speed, timeRate);
calculateSpecificStrain(previousHitObject, OsuDifficultyCalculator.DifficultyType.Aim, timeRate);
}
// Caution: The subjective values are strong with this one
private static double spacingWeight(double distance, OsuDifficultyCalculator.DifficultyType type)
{
switch (type)
{
case OsuDifficultyCalculator.DifficultyType.Speed:
if (distance > single_spacing_threshold)
return 2.5;
else if (distance > stream_spacing_threshold)
return 1.6 + 0.9 * (distance - stream_spacing_threshold) / (single_spacing_threshold - stream_spacing_threshold);
else if (distance > almost_diameter)
return 1.2 + 0.4 * (distance - almost_diameter) / (stream_spacing_threshold - almost_diameter);
else if (distance > almost_diameter / 2)
return 0.95 + 0.25 * (distance - almost_diameter / 2) / (almost_diameter / 2);
else
return 0.95;
case OsuDifficultyCalculator.DifficultyType.Aim:
return Math.Pow(distance, 0.99);
}
Debug.Assert(false, "Invalid osu difficulty hit object type.");
return 0;
}
private void calculateSpecificStrain(OsuHitObjectDifficulty previousHitObject, OsuDifficultyCalculator.DifficultyType type, double timeRate)
{
double addition = 0;
double timeElapsed = (BaseHitObject.StartTime - previousHitObject.BaseHitObject.StartTime) / timeRate;
double decay = Math.Pow(DECAY_BASE[(int)type], timeElapsed / 1000);
if (BaseHitObject is Spinner)
{
// Do nothing for spinners
}
else if (BaseHitObject is Slider)
{
switch (type)
{
case OsuDifficultyCalculator.DifficultyType.Speed:
// For speed strain we treat the whole slider as a single spacing entity, since "Speed" is about how hard it is to click buttons fast.
// The spacing weight exists to differentiate between being able to easily alternate or having to single.
addition =
spacingWeight(previousHitObject.lazySliderLength +
DistanceTo(previousHitObject), type) *
spacing_weight_scaling[(int)type];
break;
case OsuDifficultyCalculator.DifficultyType.Aim:
// For Aim strain we treat each slider segment and the jump after the end of the slider as separate jumps, since movement-wise there is no difference
// to multiple jumps.
addition =
(
spacingWeight(previousHitObject.lazySliderLength, type) +
spacingWeight(DistanceTo(previousHitObject), type)
) *
spacing_weight_scaling[(int)type];
break;
}
}
else if (BaseHitObject is HitCircle)
{
addition = spacingWeight(DistanceTo(previousHitObject), type) * spacing_weight_scaling[(int)type];
}
// Scale addition by the time, that elapsed. Filter out HitObjects that are too close to be played anyway to avoid crazy values by division through close to zero.
// You will never find maps that require this amongst ranked maps.
addition /= Math.Max(timeElapsed, 50);
Strains[(int)type] = previousHitObject.Strains[(int)type] * decay + addition;
}
internal double DistanceTo(OsuHitObjectDifficulty other)
{
// Scale the distance by circle size.
return (startPosition - other.endPosition).Length * scalingFactor;
}
}
}

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osu.Game.Rulesets.Osu/OsuDifficulty/OsuDifficultyCalculator.cs Normal file
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// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
using System;
using System.Collections.Generic;
using osu.Game.Beatmaps;
using osu.Game.Rulesets.Beatmaps;
using osu.Game.Rulesets.Osu.Beatmaps;
using osu.Game.Rulesets.Osu.Objects;
using osu.Game.Rulesets.Osu.OsuDifficulty.Preprocessing;
using osu.Game.Rulesets.Osu.OsuDifficulty.Skills;
namespace osu.Game.Rulesets.Osu.OsuDifficulty
{
public class OsuDifficultyCalculator : DifficultyCalculator<OsuHitObject>
{
private const int section_length = 400;
private const double difficulty_multiplier = 0.0675;
public OsuDifficultyCalculator(Beatmap beatmap) : base(beatmap)
{
}
protected override void PreprocessHitObjects()
{
foreach (OsuHitObject h in Objects)
(h as Slider)?.Curve?.Calculate();
}
protected override double CalculateInternal(Dictionary<string, string> categoryDifficulty)
{
OsuDifficulyBeatmap beatmap = new OsuDifficulyBeatmap(Objects);
Skill[] skills = new Skill[2]
{
new Aim(),
new Speed()
};
double sectionEnd = section_length / TimeRate;
foreach (OsuDifficultyHitObject h in beatmap)
{
while (h.BaseObject.StartTime > sectionEnd)
{
foreach (Skill s in skills)
{
s.SaveCurrentPeak();
s.StartNewSectionFrom(sectionEnd);
}
sectionEnd += section_length;
}
foreach (Skill s in skills)
s.Process(h);
}
double aimRating = Math.Sqrt(skills[0].DifficultyValue()) * difficulty_multiplier;
double speedRating = Math.Sqrt(skills[1].DifficultyValue()) * difficulty_multiplier;
double starRating = aimRating + speedRating + Math.Abs(aimRating - speedRating) / 2;
if (categoryDifficulty != null)
{
categoryDifficulty.Add("Aim", aimRating.ToString("0.00"));
categoryDifficulty.Add("Speed", speedRating.ToString("0.00"));
}
return starRating;
}
protected override BeatmapConverter<OsuHitObject> CreateBeatmapConverter() => new OsuBeatmapConverter();
}
}

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osu.Game.Rulesets.Osu/OsuDifficulty/Preprocessing/OsuDifficultyBeatmap.cs Normal file
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// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
using System.Collections;
using System.Collections.Generic;
using osu.Game.Rulesets.Osu.Objects;
namespace osu.Game.Rulesets.Osu.OsuDifficulty.Preprocessing
{
public class OsuDifficulyBeatmap : IEnumerable<OsuDifficultyHitObject>
{
IEnumerator<OsuDifficultyHitObject> difficultyObjects;
private Queue<OsuDifficultyHitObject> onScreen = new Queue<OsuDifficultyHitObject>();
public OsuDifficulyBeatmap(List<OsuHitObject> objects)
{
// Sort HitObjects by StartTime - they are not correctly ordered in some cases.
// This should probably happen before the objects reach the difficulty calculator.
objects.Sort((a, b) => a.StartTime.CompareTo(b.StartTime));
difficultyObjects = createDifficultyObjectEnumerator(objects);
}
public IEnumerator<OsuDifficultyHitObject> GetEnumerator()
{
do
{
// Add upcoming notes to the queue until we have at least one note that had been hit and can be dequeued.
// This means there is always at least one note in the queue unless we reached the end of the map.
bool hasNext;
do
{
hasNext = difficultyObjects.MoveNext();
if (onScreen.Count == 0 && !hasNext)
yield break; // Stop if we have an empty enumerator.
if (hasNext)
{
OsuDifficultyHitObject latest = difficultyObjects.Current;
// Calculate flow values here
foreach (OsuDifficultyHitObject h in onScreen)
{
h.MSUntilHit -= latest.MS;
// Calculate reading strain here
}
onScreen.Enqueue(latest);
}
}
while (onScreen.Peek().MSUntilHit > 0 && hasNext); // Keep adding new notes on screen while there is still time before we have to hit the next one.
yield return onScreen.Dequeue(); // Remove and return notes one by one that had to be hit before the latest note appeared.
}
while (onScreen.Count > 0);
}
IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
IEnumerator<OsuDifficultyHitObject> createDifficultyObjectEnumerator(List<OsuHitObject> objects)
{
// We will process HitObjects in groups of three to form a triangle, so we can calculate an angle for each note.
OsuHitObject[] triangle = new OsuHitObject[3];
// Difficulty object construction requires three components, an extra copy of the first object is used at the beginning.
if (objects.Count > 1)
{
triangle[1] = objects[0]; // This copy will get shifted to the last spot in the triangle.
triangle[0] = objects[0]; // This is the real first note.
}
// The final component of the first triangle will be the second note, which forms the first jump.
// If the beatmap has less than two HitObjects, the enumerator will not return anything.
for (int i = 1; i < objects.Count; ++i)
{
triangle[2] = triangle[1];
triangle[1] = triangle[0];
triangle[0] = objects[i];
yield return new OsuDifficultyHitObject(triangle);
}
}
}
}

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osu.Game.Rulesets.Osu/OsuDifficulty/Preprocessing/OsuDifficultyHitObject.cs Normal file
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// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
using System;
using osu.Game.Rulesets.Osu.Objects;
namespace osu.Game.Rulesets.Osu.OsuDifficulty.Preprocessing
{
public class OsuDifficultyHitObject
{
public OsuHitObject BaseObject { get; }
/// <summary>
/// Normalized distance from the StartPosition of the previous note.
/// </summary>
public double Distance { get; private set; }
/// <summary>
/// Milliseconds elapsed since the StartTime of the previous note.
/// </summary>
public double MS { get; private set; }
public double MSUntilHit { get; set; }
private const int normalized_radius = 52;
private OsuHitObject[] t;
public OsuDifficultyHitObject(OsuHitObject[] triangle)
{
t = triangle;
BaseObject = t[0];
setDistances();
setTimingValues();
// Calculate angle here
}
private void setDistances()
{
// We will scale distances by this factor, so we can assume a uniform CircleSize among beatmaps.
double scalingFactor = normalized_radius / BaseObject.Radius;
if (BaseObject.Radius < 30)
{
double smallCircleBonus = Math.Min(30 - BaseObject.Radius, 5) / 50;
scalingFactor *= 1 + smallCircleBonus;
}
Distance = (t[0].StackedPosition - t[1].StackedPosition).Length * scalingFactor;
}
private void setTimingValues()
{
// Every timing inverval is hard capped at the equivalent of 375 BPM streaming speed as a safety measure.
MS = Math.Max(40, t[0].StartTime - t[1].StartTime);
MSUntilHit = 450; // BaseObject.PreEmpt;
}
}
}

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osu.Game.Rulesets.Osu/OsuDifficulty/Skills/Aim.cs Normal file
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// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
using System;
namespace osu.Game.Rulesets.Osu.OsuDifficulty.Skills
{
public class Aim : Skill
{
protected override double skillMultiplier => 26.25;
protected override double strainDecayBase => 0.15;
protected override double strainValue() => Math.Pow(current.Distance, 0.99) / current.MS;
}
}

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osu.Game.Rulesets.Osu/OsuDifficulty/Skills/Skill.cs Normal file
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// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
using System;
using System.Collections.Generic;
using osu.Game.Rulesets.Osu.Objects;
using osu.Game.Rulesets.Osu.OsuDifficulty.Preprocessing;
using osu.Game.Rulesets.Osu.OsuDifficulty.Utils;
namespace osu.Game.Rulesets.Osu.OsuDifficulty.Skills
{
public abstract class Skill
{
protected abstract double skillMultiplier { get; }
protected abstract double strainDecayBase { get; }
protected OsuDifficultyHitObject current;
protected History<OsuDifficultyHitObject> previous = new History<OsuDifficultyHitObject>(2); // Contained objects not used yet
private double currentStrain = 1; // We keep track of the strain level at all times throughout the beatmap.
private double currentSectionPeak = 1; // We also keep track of the peak strain level in the current section.
private List<double> strainPeaks = new List<double>();
/// <summary>
/// Process a HitObject and update current strain values accordingly.
/// </summary>
public void Process(OsuDifficultyHitObject h)
{
current = h;
currentStrain *= strainDecay(current.MS);
if (!(current.BaseObject is Spinner))
currentStrain += strainValue() * skillMultiplier;
currentSectionPeak = Math.Max(currentStrain, currentSectionPeak);
previous.Push(current);
}
/// <summary>
/// Saves the current peak strain level to the list of strain peaks, which will be used to calculate an overall difficulty.
/// </summary>
public void SaveCurrentPeak()
{
if (previous.Count > 0)
strainPeaks.Add(currentSectionPeak);
}
/// <summary>
/// Sets the initial strain level for a new section.
/// </summary>
/// <param name="offset">The beginning of the new section in milliseconds</param>
public void StartNewSectionFrom(double offset)
{
// 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.
if (previous.Count > 0)
currentSectionPeak = currentStrain * strainDecay(offset - previous[0].BaseObject.StartTime);
}
/// <summary>
/// Returns the calculated difficulty value representing all currently processed HitObjects.
/// </summary>
public double DifficultyValue()
{
strainPeaks.Sort((a, b) => b.CompareTo(a)); // Sort from highest to lowest strain.
double difficulty = 0;
double weight = 1;
// Difficulty is the weighted sum of the highest strains from every section.
foreach (double strain in strainPeaks)
{
difficulty += strain * weight;
weight *= 0.9;
}
return difficulty;
}
protected abstract double strainValue();
private double strainDecay(double ms) => Math.Pow(strainDecayBase, ms / 1000);
}
}

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osu.Game.Rulesets.Osu/OsuDifficulty/Skills/Speed.cs Normal file
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// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
namespace osu.Game.Rulesets.Osu.OsuDifficulty.Skills
{
public class Speed : Skill
{
protected override double skillMultiplier => 1400;
protected override double strainDecayBase => 0.3;
private const double single_spacing_threshold = 125;
private const double stream_spacing_threshold = 110;
private const double almost_diameter = 90;
protected override double strainValue()
{
double distance = current.Distance;
double speedValue;
if (distance > single_spacing_threshold)
speedValue = 2.5;
else if (distance > stream_spacing_threshold)
speedValue = 1.6 + 0.9 * (distance - stream_spacing_threshold) / (single_spacing_threshold - stream_spacing_threshold);
else if (distance > almost_diameter)
speedValue = 1.2 + 0.4 * (distance - almost_diameter) / (stream_spacing_threshold - almost_diameter);
else if (distance > almost_diameter / 2)
speedValue = 0.95 + 0.25 * (distance - almost_diameter / 2) / (almost_diameter / 2);
else
speedValue = 0.95;
return speedValue / current.MS;
}
}
}

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osu.Game.Rulesets.Osu/OsuDifficulty/Utils/History.cs Normal file
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// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
using System;
using System.Collections;
using System.Collections.Generic;
namespace osu.Game.Rulesets.Osu.OsuDifficulty.Utils
{
/// <summary>
/// An indexed stack with Push() only, which disposes items at the bottom once the size limit has been reached.
/// Indexing starts at the top of the stack.
/// </summary>
public class History<T> : IEnumerable<T>
{
public int Count { get; private set; } = 0;
private T[] array;
private int size;
private int marker; // Marks the position of the most recently added item.
public History(int size)
{
this.size = size;
array = new T[size];
marker = size; // Set marker to the end of the array, outside of the indexed range by one.
}
public T this[int i] // Index 0 returns the most recently added item.
{
get
{
if (i > Count - 1)
throw new IndexOutOfRangeException();
i += marker;
if (i > size - 1)
i -= size;
return array[i];
}
}
/// <summary>
/// Adds the element as the most recent one in the history.
/// The oldest element is disposed if the history is full.
/// </summary>
public void Push(T item) // Overwrite the oldest item instead of shifting every item by one with every addition.
{
if (marker == 0)
marker = size - 1;
else
--marker;
array[marker] = item;
if (Count < size)
++Count;
}
public IEnumerator<T> GetEnumerator()
{
for (int i = marker; i < size; ++i)
yield return array[i];
if (Count == size)
for (int i = 0; i < marker; ++i)
yield return array[i];
}
IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
}
}

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osu.Game.Rulesets.Osu/OsuDifficultyCalculator.cs
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// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
using osu.Game.Beatmaps;
using osu.Game.Rulesets.Beatmaps;
using osu.Game.Rulesets.Osu.Beatmaps;
using osu.Game.Rulesets.Osu.Objects;
using System;
using System.Collections.Generic;
namespace osu.Game.Rulesets.Osu
{
public class OsuDifficultyCalculator : DifficultyCalculator<OsuHitObject>
{
private const double star_scaling_factor = 0.0675;
private const double extreme_scaling_factor = 0.5;
/// <summary>
/// HitObjects are stored as a member variable.
/// </summary>
internal List<OsuHitObjectDifficulty> DifficultyHitObjects = new List<OsuHitObjectDifficulty>();
public OsuDifficultyCalculator(Beatmap beatmap) : base(beatmap)
{
}
protected override void PreprocessHitObjects()
{
foreach (var h in Objects)
(h as Slider)?.Curve?.Calculate();
}
protected override double CalculateInternal(Dictionary<string, string> categoryDifficulty)
{
// Fill our custom DifficultyHitObject class, that carries additional information
DifficultyHitObjects.Clear();
foreach (var hitObject in Objects)
DifficultyHitObjects.Add(new OsuHitObjectDifficulty(hitObject));
// Sort DifficultyHitObjects by StartTime of the HitObjects - just to make sure.
DifficultyHitObjects.Sort((a, b) => a.BaseHitObject.StartTime.CompareTo(b.BaseHitObject.StartTime));
if (!CalculateStrainValues()) return 0;
double speedDifficulty = CalculateDifficulty(DifficultyType.Speed);
double aimDifficulty = CalculateDifficulty(DifficultyType.Aim);
// OverallDifficulty is not considered in this algorithm and neither is HpDrainRate. That means, that in this form the algorithm determines how hard it physically is
// to play the map, assuming, that too much of an error will not lead to a death.
// It might be desirable to include OverallDifficulty into map difficulty, but in my personal opinion it belongs more to the weighting of the actual peformance
// and is superfluous in the beatmap difficulty rating.
// If it were to be considered, then I would look at the hit window of normal HitCircles only, since Sliders and Spinners are (almost) "free" 300s and take map length
// into account as well.
// The difficulty can be scaled by any desired metric.
// In osu!tp it gets squared to account for the rapid increase in difficulty as the limit of a human is approached. (Of course it also gets scaled afterwards.)
// It would not be suitable for a star rating, therefore:
// The following is a proposal to forge a star rating from 0 to 5. It consists of taking the square root of the difficulty, since by simply scaling the easier
// 5-star maps would end up with one star.
double speedStars = Math.Sqrt(speedDifficulty) * star_scaling_factor;
double aimStars = Math.Sqrt(aimDifficulty) * star_scaling_factor;
if (categoryDifficulty != null)
{
categoryDifficulty.Add("Aim", aimStars.ToString("0.00"));
categoryDifficulty.Add("Speed", speedStars.ToString("0.00"));
double hitWindow300 = 30/*HitObjectManager.HitWindow300*/ / TimeRate;
double preEmpt = 450/*HitObjectManager.PreEmpt*/ / TimeRate;
categoryDifficulty.Add("OD", (-(hitWindow300 - 80.0) / 6.0).ToString("0.00"));
categoryDifficulty.Add("AR", (preEmpt > 1200.0 ? -(preEmpt - 1800.0) / 120.0 : -(preEmpt - 1200.0) / 150.0 + 5.0).ToString("0.00"));
int maxCombo = 0;
foreach (OsuHitObjectDifficulty hitObject in DifficultyHitObjects)
maxCombo += hitObject.MaxCombo;
categoryDifficulty.Add("Max combo", maxCombo.ToString());
}
// Again, from own observations and from the general opinion of the community a map with high speed and low aim (or vice versa) difficulty is harder,
// than a map with mediocre difficulty in both. Therefore we can not just add both difficulties together, but will introduce a scaling that favors extremes.
double starRating = speedStars + aimStars + Math.Abs(speedStars - aimStars) * extreme_scaling_factor;
// Another approach to this would be taking Speed and Aim separately to a chosen power, which again would be equivalent. This would be more convenient if
// the hit window size is to be considered as well.
// Note: The star rating is tuned extremely tight! Airman (/b/104229) and Freedom Dive (/b/126645), two of the hardest ranked maps, both score ~4.66 stars.
// Expect the easier kind of maps that officially get 5 stars to obtain around 2 by this metric. The tutorial still scores about half a star.
// Tune by yourself as you please. ;)
return starRating;
}
protected bool CalculateStrainValues()
{
// Traverse hitObjects in pairs to calculate the strain value of NextHitObject from the strain value of CurrentHitObject and environment.
using (List<OsuHitObjectDifficulty>.Enumerator hitObjectsEnumerator = DifficultyHitObjects.GetEnumerator())
{
if (!hitObjectsEnumerator.MoveNext()) return false;
OsuHitObjectDifficulty current = hitObjectsEnumerator.Current;
// First hitObject starts at strain 1. 1 is the default for strain values, so we don't need to set it here. See DifficultyHitObject.
while (hitObjectsEnumerator.MoveNext())
{
var next = hitObjectsEnumerator.Current;
next?.CalculateStrains(current, TimeRate);
current = next;
}
return true;
}
}
/// <summary>
/// In milliseconds. For difficulty calculation we will only look at the highest strain value in each time interval of size STRAIN_STEP.
/// This is to eliminate higher influence of stream over aim by simply having more HitObjects with high strain.
/// The higher this value, the less strains there will be, indirectly giving long beatmaps an advantage.
/// </summary>
protected const double STRAIN_STEP = 400;
/// <summary>
/// The weighting of each strain value decays to this number * it's previous value
/// </summary>
protected const double DECAY_WEIGHT = 0.9;
protected double CalculateDifficulty(DifficultyType type)
{
double actualStrainStep = STRAIN_STEP * TimeRate;
// Find the highest strain value within each strain step
List<double> highestStrains = new List<double>();
double intervalEndTime = actualStrainStep;
double maximumStrain = 0; // We need to keep track of the maximum strain in the current interval
OsuHitObjectDifficulty previousHitObject = null;
foreach (OsuHitObjectDifficulty hitObject in DifficultyHitObjects)
{
// While we are beyond the current interval push the currently available maximum to our strain list
while (hitObject.BaseHitObject.StartTime > intervalEndTime)
{
highestStrains.Add(maximumStrain);
// The maximum strain of the next interval is not zero by default! We need to take the last hitObject we encountered, take its strain and apply the decay
// until the beginning of the next interval.
if (previousHitObject == null)
{
maximumStrain = 0;
}
else
{
double decay = Math.Pow(OsuHitObjectDifficulty.DECAY_BASE[(int)type], (intervalEndTime - previousHitObject.BaseHitObject.StartTime) / 1000);
maximumStrain = previousHitObject.Strains[(int)type] * decay;
}
// Go to the next time interval
intervalEndTime += actualStrainStep;
}
// Obtain maximum strain
maximumStrain = Math.Max(hitObject.Strains[(int)type], maximumStrain);
previousHitObject = hitObject;
}
// Build the weighted sum over the highest strains for each interval
double difficulty = 0;
double weight = 1;
highestStrains.Sort((a, b) => b.CompareTo(a)); // Sort from highest to lowest strain.
foreach (double strain in highestStrains)
{
difficulty += weight * strain;
weight *= DECAY_WEIGHT;
}
return difficulty;
}
protected override BeatmapConverter<OsuHitObject> CreateBeatmapConverter() => new OsuBeatmapConverter();
// Those values are used as array indices. Be careful when changing them!
public enum DifficultyType
{
Speed = 0,
Aim,
};
}
}

1
osu.Game.Rulesets.Osu/OsuRuleset.cs
View File

@ -7,6 +7,7 @@ using osu.Game.Graphics;
using osu.Game.Rulesets.Mods;
using osu.Game.Rulesets.Osu.Mods;
using osu.Game.Rulesets.Osu.Objects;
using osu.Game.Rulesets.Osu.OsuDifficulty;
using osu.Game.Rulesets.Osu.UI;
using osu.Game.Rulesets.UI;
using osu.Game.Screens.Play;

9
osu.Game.Rulesets.Osu/osu.Game.Rulesets.Osu.csproj
View File

@ -68,9 +68,14 @@
<Compile Include="Objects\Drawables\Pieces\TrianglesPiece.cs" />
<Compile Include="Objects\Drawables\Pieces\SliderBall.cs" />
<Compile Include="Objects\Drawables\Pieces\SliderBody.cs" />
<Compile Include="Objects\OsuHitObjectDifficulty.cs" />
<Compile Include="Objects\SliderTick.cs" />
<Compile Include="OsuDifficultyCalculator.cs" />
<Compile Include="OsuDifficulty\OsuDifficultyCalculator.cs" />
<Compile Include="OsuDifficulty\Preprocessing\OsuDifficultyBeatmap.cs" />
<Compile Include="OsuDifficulty\Preprocessing\OsuDifficultyHitObject.cs" />
<Compile Include="OsuDifficulty\Skills\Aim.cs" />
<Compile Include="OsuDifficulty\Skills\Skill.cs" />
<Compile Include="OsuDifficulty\Skills\Speed.cs" />
<Compile Include="OsuDifficulty\Utils\History.cs" />
<Compile Include="OsuKeyConversionInputManager.cs" />
<Compile Include="Scoring\OsuScoreProcessor.cs" />
<Compile Include="UI\OsuHitRenderer.cs" />