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osu-lazer/osu.Game.Rulesets.Osu/Mods/OsuModRandom.cs
2021-06-03 18:16:11 +02:00

281 lines
12 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 System.Linq;
using osu.Framework.Graphics;
using osu.Framework.Utils;
using osu.Game.Beatmaps;
using osu.Game.Rulesets.Mods;
using osu.Game.Rulesets.Objects;
using osu.Game.Rulesets.Osu.Beatmaps;
using osu.Game.Rulesets.Osu.Objects;
using osu.Game.Rulesets.Osu.UI;
using osuTK;
namespace osu.Game.Rulesets.Osu.Mods
{
/// <summary>
/// Mod that randomises the positions of the <see cref="HitObject"/>s
/// </summary>
public class OsuModRandom : ModRandom, IApplicableToBeatmap
{
public override string Description => "It never gets boring!";
public override bool Ranked => false;
// The relative distance to the edge of the playfield before objects' positions should start to "turn around" and curve towards the middle.
// The closer the hit objects draw to the border, the sharper the turn
private const float playfield_edge_ratio = 0.375f;
private static readonly float border_distance_x = OsuPlayfield.BASE_SIZE.X * playfield_edge_ratio;
private static readonly float border_distance_y = OsuPlayfield.BASE_SIZE.Y * playfield_edge_ratio;
private static readonly Vector2 playfield_middle = Vector2.Divide(OsuPlayfield.BASE_SIZE, 2);
private static readonly float playfield_diagonal = OsuPlayfield.BASE_SIZE.LengthFast;
private Random rng;
public void ApplyToBeatmap(IBeatmap beatmap)
{
if (!(beatmap is OsuBeatmap osuBeatmap))
return;
var hitObjects = osuBeatmap.HitObjects;
Seed.Value ??= RNG.Next();
rng = new Random((int)Seed.Value);
RandomObjectInfo previous = null;
float rateOfChangeMultiplier = 0;
for (int i = 0; i < hitObjects.Count; i++)
{
var hitObject = hitObjects[i];
var current = new RandomObjectInfo(hitObject);
// rateOfChangeMultiplier only changes every i iterations to prevent shaky-line-shaped streams
if (i % 3 == 0)
rateOfChangeMultiplier = (float)rng.NextDouble() * 2 - 1;
if (hitObject is Spinner)
{
previous = null;
continue;
}
applyRandomisation(rateOfChangeMultiplier, previous, current);
hitObject.Position = current.PositionRandomised;
// update end position as it may have changed as a result of the position update.
current.EndPositionRandomised = current.PositionRandomised;
switch (hitObject)
{
case Slider slider:
// Shift nested objects the same distance as the slider got shifted in the randomisation process
// so that moveSliderIntoPlayfield() can determine their relative distances to slider.Position and thus minMargin
shiftNestedObjects(slider, Vector2.Subtract(slider.Position, current.PositionOriginal));
var oldPos = new Vector2(slider.Position.X, slider.Position.Y);
moveSliderIntoPlayfield(slider, current);
// Shift them again to move them to their final position after the slider got moved into the playfield
shiftNestedObjects(slider, Vector2.Subtract(slider.Position, oldPos));
break;
}
previous = current;
}
}
/// <summary>
/// Returns the final position of the hit object
/// </summary>
/// <returns>Final position of the hit object</returns>
private void applyRandomisation(float rateOfChangeMultiplier, RandomObjectInfo previous, RandomObjectInfo current)
{
if (previous == null)
{
var playfieldSize = OsuPlayfield.BASE_SIZE;
current.AngleRad = (float)(rng.NextDouble() * 2 * Math.PI - Math.PI);
current.PositionRandomised = new Vector2((float)rng.NextDouble() * playfieldSize.X, (float)rng.NextDouble() * playfieldSize.Y);
return;
}
float distanceToPrev = Vector2.Distance(previous.EndPositionOriginal, current.PositionOriginal);
// The max. angle (relative to the angle of the vector pointing from the 2nd last to the last hit object)
// is proportional to the distance between the last and the current hit object
// to allow jumps and prevent too sharp turns during streams.
var randomAngleRad = rateOfChangeMultiplier * 2 * Math.PI * distanceToPrev / playfield_diagonal;
current.AngleRad = (float)randomAngleRad + previous.AngleRad;
if (current.AngleRad < 0)
current.AngleRad += 2 * (float)Math.PI;
var posRelativeToPrev = new Vector2(
distanceToPrev * (float)Math.Cos(current.AngleRad),
distanceToPrev * (float)Math.Sin(current.AngleRad)
);
posRelativeToPrev = getRotatedVector(previous.EndPositionRandomised, posRelativeToPrev);
current.AngleRad = (float)Math.Atan2(posRelativeToPrev.Y, posRelativeToPrev.X);
var position = Vector2.Add(previous.EndPositionRandomised, posRelativeToPrev);
// Move hit objects back into the playfield if they are outside of it,
// which would sometimes happen during big jumps otherwise.
position.X = MathHelper.Clamp(position.X, 0, OsuPlayfield.BASE_SIZE.X);
position.Y = MathHelper.Clamp(position.Y, 0, OsuPlayfield.BASE_SIZE.Y);
current.PositionRandomised = position;
}
/// <summary>
/// Moves the <see cref="Slider"/> and all necessary nested <see cref="OsuHitObject"/>s into the <see cref="OsuPlayfield"/> if they aren't already.
/// </summary>
private void moveSliderIntoPlayfield(Slider slider, RandomObjectInfo currentObjectInfo)
{
// Min. distances from the slider's position to the playfield border
var minMargin = new MarginPadding();
foreach (var hitObject in slider.NestedHitObjects.Where(o => o is SliderTick || o is SliderEndCircle))
{
if (!(hitObject is OsuHitObject osuHitObject))
continue;
var relativePos = Vector2.Subtract(osuHitObject.Position, slider.Position);
minMargin.Left = Math.Max(minMargin.Left, -relativePos.X);
minMargin.Right = Math.Max(minMargin.Right, relativePos.X);
minMargin.Top = Math.Max(minMargin.Top, -relativePos.Y);
minMargin.Bottom = Math.Max(minMargin.Bottom, relativePos.Y);
}
if (slider.Position.X < minMargin.Left)
slider.Position = new Vector2(minMargin.Left, slider.Position.Y);
else if (slider.Position.X + minMargin.Right > OsuPlayfield.BASE_SIZE.X)
slider.Position = new Vector2(OsuPlayfield.BASE_SIZE.X - minMargin.Right, slider.Position.Y);
if (slider.Position.Y < minMargin.Top)
slider.Position = new Vector2(slider.Position.X, minMargin.Top);
else if (slider.Position.Y + minMargin.Bottom > OsuPlayfield.BASE_SIZE.Y)
slider.Position = new Vector2(slider.Position.X, OsuPlayfield.BASE_SIZE.Y - minMargin.Bottom);
currentObjectInfo.PositionRandomised = slider.Position;
currentObjectInfo.EndPositionRandomised = slider.EndPosition;
}
/// <summary>
/// Shifts all nested <see cref="SliderTick"/>s and <see cref="SliderRepeat"/>s by the specified shift.
/// </summary>
/// <param name="slider"><see cref="Slider"/> whose nested <see cref="SliderTick"/>s and <see cref="SliderRepeat"/>s should be shifted</param>
/// <param name="shift">The <see cref="Vector2"/> the <see cref="Slider"/>'s nested <see cref="SliderTick"/>s and <see cref="SliderRepeat"/>s should be shifted by</param>
private void shiftNestedObjects(Slider slider, Vector2 shift)
{
foreach (var hitObject in slider.NestedHitObjects.Where(o => o is SliderTick || o is SliderRepeat))
{
if (!(hitObject is OsuHitObject osuHitObject))
continue;
osuHitObject.Position = Vector2.Add(osuHitObject.Position, shift);
}
}
/// <summary>
/// Determines the position of the current hit object relative to the previous one.
/// </summary>
/// <returns>The position of the current hit object relative to the previous one</returns>
private Vector2 getRotatedVector(Vector2 prevPosChanged, Vector2 posRelativeToPrev)
{
var relativeRotationDistance = 0f;
if (prevPosChanged.X < playfield_middle.X)
{
relativeRotationDistance = Math.Max(
(border_distance_x - prevPosChanged.X) / border_distance_x,
relativeRotationDistance
);
}
else
{
relativeRotationDistance = Math.Max(
(prevPosChanged.X - (OsuPlayfield.BASE_SIZE.X - border_distance_x)) / border_distance_x,
relativeRotationDistance
);
}
if (prevPosChanged.Y < playfield_middle.Y)
{
relativeRotationDistance = Math.Max(
(border_distance_y - prevPosChanged.Y) / border_distance_y,
relativeRotationDistance
);
}
else
{
relativeRotationDistance = Math.Max(
(prevPosChanged.Y - (OsuPlayfield.BASE_SIZE.Y - border_distance_y)) / border_distance_y,
relativeRotationDistance
);
}
return rotateVectorTowardsVector(posRelativeToPrev, playfield_middle - prevPosChanged, relativeRotationDistance / 2);
}
/// <summary>
/// Rotates vector "initial" towards vector "destinantion"
/// </summary>
/// <param name="initial">Vector to rotate to "destination"</param>
/// <param name="destination">Vector "initial" should be rotated to</param>
/// <param name="relativeDistance">The angle the vector should be rotated relative to the difference between the angles of the the two vectors.</param>
/// <returns>Resulting vector</returns>
private Vector2 rotateVectorTowardsVector(Vector2 initial, Vector2 destination, float relativeDistance)
{
var initialAngleRad = Math.Atan2(initial.Y, initial.X);
var destAngleRad = Math.Atan2(destination.Y, destination.X);
var diff = destAngleRad - initialAngleRad;
while (diff < -Math.PI) diff += 2 * Math.PI;
while (diff > Math.PI) diff -= 2 * Math.PI;
var finalAngleRad = initialAngleRad + relativeDistance * diff;
return new Vector2(
initial.Length * (float)Math.Cos(finalAngleRad),
initial.Length * (float)Math.Sin(finalAngleRad)
);
}
private class RandomObjectInfo
{
public float AngleRad { get; set; }
public Vector2 PositionOriginal { get; }
public Vector2 PositionRandomised { get; set; }
public Vector2 EndPositionOriginal { get; }
public Vector2 EndPositionRandomised { get; set; }
public RandomObjectInfo(OsuHitObject hitObject)
{
PositionRandomised = PositionOriginal = hitObject.Position;
EndPositionRandomised = EndPositionOriginal = hitObject.EndPosition;
AngleRad = 0;
}
}
}
}