osu/osu.Game.Rulesets.Osu/Difficulty/Evaluators/AimEvaluator.cs

136 lines
7.6 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.Osu.Difficulty.Preprocessing;
using osu.Game.Rulesets.Osu.Objects;
namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators
{
public static class AimEvaluator
{
private const double wide_angle_multiplier = 1.5;
private const double acute_angle_multiplier = 1.95;
private const double slider_multiplier = 1.35;
private const double velocity_change_multiplier = 0.75;
/// <summary>
/// Evaluates the difficulty of aiming the current object, based on:
/// <list type="bullet">
/// <item><description>cursor velocity to the current object,</description></item>
/// <item><description>angle difficulty,</description></item>
/// <item><description>sharp velocity increases,</description></item>
/// <item><description>and slider difficulty.</description></item>
/// </list>
/// </summary>
public static double EvaluateDifficultyOf(DifficultyHitObject current, bool withSliderTravelDistance)
{
if (current.BaseObject is Spinner || current.Index <= 1 || current.Previous(0).BaseObject is Spinner)
return 0;
var osuCurrObj = (OsuDifficultyHitObject)current;
var osuLastObj = (OsuDifficultyHitObject)current.Previous(0);
var osuLastLastObj = (OsuDifficultyHitObject)current.Previous(1);
// Calculate the velocity to the current hitobject, which starts with a base distance / time assuming the last object is a hitcircle.
double currVelocity = osuCurrObj.LazyJumpDistance / osuCurrObj.StrainTime;
// But if the last object is a slider, then we extend the travel velocity through the slider into the current object.
if (osuLastObj.BaseObject is Slider && withSliderTravelDistance)
{
double travelVelocity = osuLastObj.TravelDistance / osuLastObj.TravelTime; // calculate the slider velocity from slider head to slider end.
double movementVelocity = osuCurrObj.MinimumJumpDistance / osuCurrObj.MinimumJumpTime; // calculate the movement velocity from slider end to current object
currVelocity = Math.Max(currVelocity, movementVelocity + travelVelocity); // take the larger total combined velocity.
}
// As above, do the same for the previous hitobject.
double prevVelocity = osuLastObj.LazyJumpDistance / osuLastObj.StrainTime;
if (osuLastLastObj.BaseObject is Slider && withSliderTravelDistance)
{
double travelVelocity = osuLastLastObj.TravelDistance / osuLastLastObj.TravelTime;
double movementVelocity = osuLastObj.MinimumJumpDistance / osuLastObj.MinimumJumpTime;
prevVelocity = Math.Max(prevVelocity, movementVelocity + travelVelocity);
}
double wideAngleBonus = 0;
double acuteAngleBonus = 0;
double sliderBonus = 0;
double velocityChangeBonus = 0;
double aimStrain = currVelocity; // Start strain with regular velocity.
if (Math.Max(osuCurrObj.StrainTime, osuLastObj.StrainTime) < 1.25 * Math.Min(osuCurrObj.StrainTime, osuLastObj.StrainTime)) // If rhythms are the same.
{
if (osuCurrObj.Angle != null && osuLastObj.Angle != null && osuLastLastObj.Angle != null)
{
double currAngle = osuCurrObj.Angle.Value;
double lastAngle = osuLastObj.Angle.Value;
double lastLastAngle = osuLastLastObj.Angle.Value;
// Rewarding angles, take the smaller velocity as base.
double angleBonus = Math.Min(currVelocity, prevVelocity);
wideAngleBonus = calcWideAngleBonus(currAngle);
acuteAngleBonus = calcAcuteAngleBonus(currAngle);
if (osuCurrObj.StrainTime > 100) // Only buff deltaTime exceeding 300 bpm 1/2.
acuteAngleBonus = 0;
else
{
acuteAngleBonus *= calcAcuteAngleBonus(lastAngle) // Multiply by previous angle, we don't want to buff unless this is a wiggle type pattern.
* Math.Min(angleBonus, 125 / osuCurrObj.StrainTime) // The maximum velocity we buff is equal to 125 / strainTime
* Math.Pow(Math.Sin(Math.PI / 2 * Math.Min(1, (100 - osuCurrObj.StrainTime) / 25)), 2) // scale buff from 150 bpm 1/4 to 200 bpm 1/4
* Math.Pow(Math.Sin(Math.PI / 2 * (Math.Clamp(osuCurrObj.LazyJumpDistance, 50, 100) - 50) / 50), 2); // Buff distance exceeding 50 (radius) up to 100 (diameter).
}
// Penalize wide angles if they're repeated, reducing the penalty as the lastAngle gets more acute.
wideAngleBonus *= angleBonus * (1 - Math.Min(wideAngleBonus, Math.Pow(calcWideAngleBonus(lastAngle), 3)));
// Penalize acute angles if they're repeated, reducing the penalty as the lastLastAngle gets more obtuse.
acuteAngleBonus *= 0.5 + 0.5 * (1 - Math.Min(acuteAngleBonus, Math.Pow(calcAcuteAngleBonus(lastLastAngle), 3)));
}
}
if (Math.Max(prevVelocity, currVelocity) != 0)
{
// We want to use the average velocity over the whole object when awarding differences, not the individual jump and slider path velocities.
prevVelocity = (osuLastObj.LazyJumpDistance + osuLastLastObj.TravelDistance) / osuLastObj.StrainTime;
currVelocity = (osuCurrObj.LazyJumpDistance + osuLastObj.TravelDistance) / osuCurrObj.StrainTime;
// Scale with ratio of difference compared to 0.5 * max dist.
double distRatio = Math.Pow(Math.Sin(Math.PI / 2 * Math.Abs(prevVelocity - currVelocity) / Math.Max(prevVelocity, currVelocity)), 2);
// Reward for % distance up to 125 / strainTime for overlaps where velocity is still changing.
double overlapVelocityBuff = Math.Min(125 / Math.Min(osuCurrObj.StrainTime, osuLastObj.StrainTime), Math.Abs(prevVelocity - currVelocity));
velocityChangeBonus = overlapVelocityBuff * distRatio;
// Penalize for rhythm changes.
velocityChangeBonus *= Math.Pow(Math.Min(osuCurrObj.StrainTime, osuLastObj.StrainTime) / Math.Max(osuCurrObj.StrainTime, osuLastObj.StrainTime), 2);
}
if (osuLastObj.BaseObject is Slider)
{
// Reward sliders based on velocity.
sliderBonus = osuLastObj.TravelDistance / osuLastObj.TravelTime;
}
// Add in acute angle bonus or wide angle bonus + velocity change bonus, whichever is larger.
aimStrain += Math.Max(acuteAngleBonus * acute_angle_multiplier, wideAngleBonus * wide_angle_multiplier + velocityChangeBonus * velocity_change_multiplier);
// Add in additional slider velocity bonus.
if (withSliderTravelDistance)
aimStrain += sliderBonus * slider_multiplier;
return aimStrain;
}
private static double calcWideAngleBonus(double angle) => Math.Pow(Math.Sin(3.0 / 4 * (Math.Min(5.0 / 6 * Math.PI, Math.Max(Math.PI / 6, angle)) - Math.PI / 6)), 2);
private static double calcAcuteAngleBonus(double angle) => 1 - calcWideAngleBonus(angle);
}
}