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osu-lazer/osu.Game.Rulesets.Osu/Mods/OsuModRandom.cs
Dan Balasescu 353b251d38 Attempt to merge conditional expression
Hoping to fix CI error, caused by older R# version.
2022-03-09 17:46:42 +09:00

372 lines
16 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.
#nullable enable
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using osu.Framework.Graphics.Primitives;
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 osu.Game.Rulesets.Osu.Utils;
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!";
private static readonly float playfield_diagonal = OsuPlayfield.BASE_SIZE.LengthFast;
private static readonly Vector2 playfield_centre = OsuPlayfield.BASE_SIZE / 2;
/// <summary>
/// Number of previous hitobjects to be shifted together when another object is being moved.
/// </summary>
private const int preceding_hitobjects_to_shift = 10;
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);
var randomObjects = randomiseObjects(hitObjects);
applyRandomisation(hitObjects, randomObjects);
}
/// <summary>
/// Randomise the position of each hit object and return a list of <see cref="RandomObjectInfo"/>s describing how each hit object should be placed.
/// </summary>
/// <param name="hitObjects">A list of <see cref="OsuHitObject"/>s to have their positions randomised.</param>
/// <returns>A list of <see cref="RandomObjectInfo"/>s describing how each hit object should be placed.</returns>
private List<RandomObjectInfo> randomiseObjects(IEnumerable<OsuHitObject> hitObjects)
{
Debug.Assert(rng != null, $"{nameof(ApplyToBeatmap)} was not called before randomising objects");
var randomObjects = new List<RandomObjectInfo>();
RandomObjectInfo? previous = null;
float rateOfChangeMultiplier = 0;
foreach (OsuHitObject hitObject in hitObjects)
{
var current = new RandomObjectInfo(hitObject);
randomObjects.Add(current);
// rateOfChangeMultiplier only changes every 5 iterations in a combo
// to prevent shaky-line-shaped streams
if (hitObject.IndexInCurrentCombo % 5 == 0)
rateOfChangeMultiplier = (float)rng.NextDouble() * 2 - 1;
if (previous == null)
{
current.DistanceFromPrevious = (float)(rng.NextDouble() * OsuPlayfield.BASE_SIZE.X / 2);
current.RelativeAngle = (float)(rng.NextDouble() * 2 * Math.PI - Math.PI);
}
else
{
current.DistanceFromPrevious = 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.
// Allow maximum jump angle when jump distance is more than half of playfield diagonal length
current.RelativeAngle = rateOfChangeMultiplier * 2 * (float)Math.PI * Math.Min(1f, current.DistanceFromPrevious / (playfield_diagonal * 0.5f));
}
previous = current;
}
return randomObjects;
}
/// <summary>
/// Reposition the hit objects according to the information in <paramref name="randomObjects"/>.
/// </summary>
/// <param name="hitObjects">The hit objects to be repositioned.</param>
/// <param name="randomObjects">A list of <see cref="RandomObjectInfo"/> describing how each hit object should be placed.</param>
private void applyRandomisation(IReadOnlyList<OsuHitObject> hitObjects, IReadOnlyList<RandomObjectInfo> randomObjects)
{
RandomObjectInfo? previous = null;
for (int i = 0; i < hitObjects.Count; i++)
{
var hitObject = hitObjects[i];
var current = randomObjects[i];
if (hitObject is Spinner)
{
previous = null;
continue;
}
computeRandomisedPosition(current, previous, i > 1 ? randomObjects[i - 2] : null);
// Move hit objects back into the playfield if they are outside of it
Vector2 shift = Vector2.Zero;
switch (hitObject)
{
case HitCircle circle:
shift = clampHitCircleToPlayfield(circle, current);
break;
case Slider slider:
shift = clampSliderToPlayfield(slider, current);
break;
}
if (shift != Vector2.Zero)
{
var toBeShifted = new List<OsuHitObject>();
for (int j = i - 1; j >= i - preceding_hitobjects_to_shift && j >= 0; j--)
{
// only shift hit circles
if (!(hitObjects[j] is HitCircle)) break;
toBeShifted.Add(hitObjects[j]);
}
if (toBeShifted.Count > 0)
applyDecreasingShift(toBeShifted, shift);
}
previous = current;
}
}
/// <summary>
/// Compute the randomised position of a hit object while attempting to keep it inside the playfield.
/// </summary>
/// <param name="current">The <see cref="RandomObjectInfo"/> representing the hit object to have the randomised position computed for.</param>
/// <param name="previous">The <see cref="RandomObjectInfo"/> representing the hit object immediately preceding the current one.</param>
/// <param name="beforePrevious">The <see cref="RandomObjectInfo"/> representing the hit object immediately preceding the <paramref name="previous"/> one.</param>
private void computeRandomisedPosition(RandomObjectInfo current, RandomObjectInfo? previous, RandomObjectInfo? beforePrevious)
{
float previousAbsoluteAngle = 0f;
if (previous != null)
{
Vector2 earliestPosition = beforePrevious?.HitObject.EndPosition ?? playfield_centre;
Vector2 relativePosition = previous.HitObject.Position - earliestPosition;
previousAbsoluteAngle = (float)Math.Atan2(relativePosition.Y, relativePosition.X);
}
float absoluteAngle = previousAbsoluteAngle + current.RelativeAngle;
var posRelativeToPrev = new Vector2(
current.DistanceFromPrevious * (float)Math.Cos(absoluteAngle),
current.DistanceFromPrevious * (float)Math.Sin(absoluteAngle)
);
Vector2 lastEndPosition = previous?.EndPositionRandomised ?? playfield_centre;
posRelativeToPrev = OsuHitObjectGenerationUtils.RotateAwayFromEdge(lastEndPosition, posRelativeToPrev);
current.PositionRandomised = lastEndPosition + posRelativeToPrev;
}
/// <summary>
/// Move the randomised position of a hit circle so that it fits inside the playfield.
/// </summary>
/// <returns>The deviation from the original randomised position in order to fit within the playfield.</returns>
private Vector2 clampHitCircleToPlayfield(HitCircle circle, RandomObjectInfo objectInfo)
{
var previousPosition = objectInfo.PositionRandomised;
objectInfo.EndPositionRandomised = objectInfo.PositionRandomised = clampToPlayfieldWithPadding(
objectInfo.PositionRandomised,
(float)circle.Radius
);
circle.Position = objectInfo.PositionRandomised;
return objectInfo.PositionRandomised - previousPosition;
}
/// <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>
/// <returns>The deviation from the original randomised position in order to fit within the playfield.</returns>
private Vector2 clampSliderToPlayfield(Slider slider, RandomObjectInfo objectInfo)
{
var possibleMovementBounds = calculatePossibleMovementBounds(slider);
var previousPosition = objectInfo.PositionRandomised;
// Clamp slider position to the placement area
// If the slider is larger than the playfield, force it to stay at the original position
float newX = possibleMovementBounds.Width < 0
? objectInfo.PositionOriginal.X
: Math.Clamp(previousPosition.X, possibleMovementBounds.Left, possibleMovementBounds.Right);
float newY = possibleMovementBounds.Height < 0
? objectInfo.PositionOriginal.Y
: Math.Clamp(previousPosition.Y, possibleMovementBounds.Top, possibleMovementBounds.Bottom);
slider.Position = objectInfo.PositionRandomised = new Vector2(newX, newY);
objectInfo.EndPositionRandomised = slider.EndPosition;
shiftNestedObjects(slider, objectInfo.PositionRandomised - objectInfo.PositionOriginal);
return objectInfo.PositionRandomised - previousPosition;
}
/// <summary>
/// Decreasingly shift a list of <see cref="OsuHitObject"/>s by a specified amount.
/// The first item in the list is shifted by the largest amount, while the last item is shifted by the smallest amount.
/// </summary>
/// <param name="hitObjects">The list of hit objects to be shifted.</param>
/// <param name="shift">The amount to be shifted.</param>
private void applyDecreasingShift(IList<OsuHitObject> hitObjects, Vector2 shift)
{
for (int i = 0; i < hitObjects.Count; i++)
{
var hitObject = hitObjects[i];
// The first object is shifted by a vector slightly smaller than shift
// The last object is shifted by a vector slightly larger than zero
Vector2 position = hitObject.Position + shift * ((hitObjects.Count - i) / (float)(hitObjects.Count + 1));
hitObject.Position = clampToPlayfieldWithPadding(position, (float)hitObject.Radius);
}
}
/// <summary>
/// Calculates a <see cref="RectangleF"/> which contains all of the possible movements of the slider (in relative X/Y coordinates)
/// such that the entire slider is inside the playfield.
/// </summary>
/// <remarks>
/// If the slider is larger than the playfield, the returned <see cref="RectangleF"/> may have negative width/height.
/// </remarks>
private RectangleF calculatePossibleMovementBounds(Slider slider)
{
var pathPositions = new List<Vector2>();
slider.Path.GetPathToProgress(pathPositions, 0, 1);
float minX = float.PositiveInfinity;
float maxX = float.NegativeInfinity;
float minY = float.PositiveInfinity;
float maxY = float.NegativeInfinity;
// Compute the bounding box of the slider.
foreach (var pos in pathPositions)
{
minX = MathF.Min(minX, pos.X);
maxX = MathF.Max(maxX, pos.X);
minY = MathF.Min(minY, pos.Y);
maxY = MathF.Max(maxY, pos.Y);
}
// Take the circle radius into account.
float radius = (float)slider.Radius;
minX -= radius;
minY -= radius;
maxX += radius;
maxY += radius;
// Given the bounding box of the slider (via min/max X/Y),
// the amount that the slider can move to the left is minX (with the sign flipped, since positive X is to the right),
// and the amount that it can move to the right is WIDTH - maxX.
// Same calculation applies for the Y axis.
float left = -minX;
float right = OsuPlayfield.BASE_SIZE.X - maxX;
float top = -minY;
float bottom = OsuPlayfield.BASE_SIZE.Y - maxY;
return new RectangleF(left, top, right - left, bottom - top);
}
/// <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 += shift;
}
}
/// <summary>
/// Clamp a position to playfield, keeping a specified distance from the edges.
/// </summary>
/// <param name="position">The position to be clamped.</param>
/// <param name="padding">The minimum distance allowed from playfield edges.</param>
/// <returns>The clamped position.</returns>
private Vector2 clampToPlayfieldWithPadding(Vector2 position, float padding)
{
return new Vector2(
Math.Clamp(position.X, padding, OsuPlayfield.BASE_SIZE.X - padding),
Math.Clamp(position.Y, padding, OsuPlayfield.BASE_SIZE.Y - padding)
);
}
private class RandomObjectInfo
{
/// <summary>
/// The jump angle from the previous hit object to this one, relative to the previous hit object's jump angle.
/// </summary>
/// <remarks>
/// <see cref="RelativeAngle"/> of the first hit object in a beatmap represents the absolute angle from playfield center to the object.
/// </remarks>
/// <example>
/// If <see cref="RelativeAngle"/> is 0, the player's cursor doesn't need to change its direction of movement when passing
/// the previous object to reach this one.
/// </example>
public float RelativeAngle { get; set; }
/// <summary>
/// The jump distance from the previous hit object to this one.
/// </summary>
/// <remarks>
/// <see cref="DistanceFromPrevious"/> of the first hit object in a beatmap is relative to the playfield center.
/// </remarks>
public float DistanceFromPrevious { get; set; }
public Vector2 PositionOriginal { get; }
public Vector2 PositionRandomised { get; set; }
public Vector2 EndPositionOriginal { get; }
public Vector2 EndPositionRandomised { get; set; }
public OsuHitObject HitObject { get; }
public RandomObjectInfo(OsuHitObject hitObject)
{
PositionRandomised = PositionOriginal = hitObject.Position;
EndPositionRandomised = EndPositionOriginal = hitObject.EndPosition;
HitObject = hitObject;
}
}
}
}