osu/osu.Game.Rulesets.Osu/Difficulty/Skills/Speed.cs
Samuel Cattini-Schultz 85d2b1232a 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.
2021-04-03 20:52:39 +11:00

70 lines
2.7 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.Difficulty.Skills;
using osu.Game.Rulesets.Mods;
using osu.Game.Rulesets.Osu.Difficulty.Preprocessing;
using osu.Game.Rulesets.Osu.Objects;
namespace osu.Game.Rulesets.Osu.Difficulty.Skills
{
/// <summary>
/// Represents the skill required to press keys with regards to keeping up with the speed at which objects need to be hit.
/// </summary>
public class Speed : StrainSkill
{
private const double single_spacing_threshold = 125;
private const double angle_bonus_begin = 5 * Math.PI / 6;
private const double pi_over_4 = Math.PI / 4;
private const double pi_over_2 = Math.PI / 2;
protected override double SkillMultiplier => 1400;
protected override double StrainDecayBase => 0.3;
private const double min_speed_bonus = 75; // ~200BPM
private const double max_speed_bonus = 45; // ~330BPM
private const double speed_balancing_factor = 40;
public Speed(Mod[] mods)
: base(mods)
{
}
protected override double StrainValueOf(DifficultyHitObject current)
{
if (current.BaseObject is Spinner)
return 0;
var osuCurrent = (OsuDifficultyHitObject)current;
double distance = Math.Min(single_spacing_threshold, osuCurrent.TravelDistance + osuCurrent.JumpDistance);
double deltaTime = Math.Max(max_speed_bonus, current.DeltaTime);
double speedBonus = 1.0;
if (deltaTime < min_speed_bonus)
speedBonus = 1 + Math.Pow((min_speed_bonus - deltaTime) / speed_balancing_factor, 2);
double angleBonus = 1.0;
if (osuCurrent.Angle != null && osuCurrent.Angle.Value < angle_bonus_begin)
{
angleBonus = 1 + Math.Pow(Math.Sin(1.5 * (angle_bonus_begin - osuCurrent.Angle.Value)), 2) / 3.57;
if (osuCurrent.Angle.Value < pi_over_2)
{
angleBonus = 1.28;
if (distance < 90 && osuCurrent.Angle.Value < pi_over_4)
angleBonus += (1 - angleBonus) * Math.Min((90 - distance) / 10, 1);
else if (distance < 90)
angleBonus += (1 - angleBonus) * Math.Min((90 - distance) / 10, 1) * Math.Sin((pi_over_2 - osuCurrent.Angle.Value) / pi_over_4);
}
}
return (1 + (speedBonus - 1) * 0.75) * angleBonus * (0.95 + speedBonus * Math.Pow(distance / single_spacing_threshold, 3.5)) / osuCurrent.StrainTime;
}
}
}