osu/osu.Game.Rulesets.Osu/Utils/OsuHitObjectGenerationUtils...

451 lines
20 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.Collections.Generic;
using System.Linq;
using osu.Framework.Graphics.Primitives;
using osu.Framework.Utils;
using osu.Game.Rulesets.Osu.Objects;
using osu.Game.Rulesets.Osu.UI;
using osuTK;
namespace osu.Game.Rulesets.Osu.Utils
{
public static partial class OsuHitObjectGenerationUtils
{
/// <summary>
/// Number of previous hitobjects to be shifted together when an object is being moved.
/// </summary>
private const int preceding_hitobjects_to_shift = 10;
private static readonly Vector2 playfield_centre = OsuPlayfield.BASE_SIZE / 2;
/// <summary>
/// Generate a list of <see cref="ObjectPositionInfo"/>s containing information for how the given list of
/// <see cref="OsuHitObject"/>s are positioned.
/// </summary>
/// <param name="hitObjects">A list of <see cref="OsuHitObject"/>s to process.</param>
/// <returns>A list of <see cref="ObjectPositionInfo"/>s describing how each hit object is positioned relative to the previous one.</returns>
public static List<ObjectPositionInfo> GeneratePositionInfos(IEnumerable<OsuHitObject> hitObjects)
{
var positionInfos = new List<ObjectPositionInfo>();
Vector2 previousPosition = playfield_centre;
float previousAngle = 0;
foreach (OsuHitObject hitObject in hitObjects)
{
Vector2 relativePosition = hitObject.Position - previousPosition;
float absoluteAngle = MathF.Atan2(relativePosition.Y, relativePosition.X);
float relativeAngle = absoluteAngle - previousAngle;
ObjectPositionInfo positionInfo;
positionInfos.Add(positionInfo = new ObjectPositionInfo(hitObject)
{
RelativeAngle = relativeAngle,
DistanceFromPrevious = relativePosition.Length
});
if (hitObject is Slider slider)
{
float absoluteRotation = getSliderRotation(slider);
positionInfo.Rotation = absoluteRotation - absoluteAngle;
absoluteAngle = absoluteRotation;
}
previousPosition = hitObject.EndPosition;
previousAngle = absoluteAngle;
}
return positionInfos;
}
/// <summary>
/// Reposition the hit objects according to the information in <paramref name="objectPositionInfos"/>.
/// </summary>
/// <param name="objectPositionInfos">Position information for each hit object.</param>
/// <returns>The repositioned hit objects.</returns>
public static List<OsuHitObject> RepositionHitObjects(IEnumerable<ObjectPositionInfo> objectPositionInfos)
{
List<WorkingObject> workingObjects = objectPositionInfos.Select(o => new WorkingObject(o)).ToList();
WorkingObject? previous = null;
for (int i = 0; i < workingObjects.Count; i++)
{
var current = workingObjects[i];
var hitObject = current.HitObject;
if (hitObject is Spinner)
{
previous = current;
continue;
}
computeModifiedPosition(current, previous, i > 1 ? workingObjects[i - 2] : null);
// Move hit objects back into the playfield if they are outside of it
Vector2 shift = Vector2.Zero;
switch (hitObject)
{
case HitCircle:
shift = clampHitCircleToPlayfield(current);
break;
case Slider:
shift = clampSliderToPlayfield(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 (!(workingObjects[j].HitObject is HitCircle)) break;
toBeShifted.Add(workingObjects[j].HitObject);
}
if (toBeShifted.Count > 0)
applyDecreasingShift(toBeShifted, shift);
}
previous = current;
}
return workingObjects.Select(p => p.HitObject).ToList();
}
/// <summary>
/// Compute the modified position of a hit object while attempting to keep it inside the playfield.
/// </summary>
/// <param name="current">The <see cref="WorkingObject"/> representing the hit object to have the modified position computed for.</param>
/// <param name="previous">The <see cref="WorkingObject"/> representing the hit object immediately preceding the current one.</param>
/// <param name="beforePrevious">The <see cref="WorkingObject"/> representing the hit object immediately preceding the <paramref name="previous"/> one.</param>
private static void computeModifiedPosition(WorkingObject current, WorkingObject? previous, WorkingObject? beforePrevious)
{
float previousAbsoluteAngle = 0f;
if (previous != null)
{
if (previous.HitObject is Slider s)
{
previousAbsoluteAngle = getSliderRotation(s);
}
else
{
Vector2 earliestPosition = beforePrevious?.HitObject.EndPosition ?? playfield_centre;
Vector2 relativePosition = previous.HitObject.Position - earliestPosition;
previousAbsoluteAngle = MathF.Atan2(relativePosition.Y, relativePosition.X);
}
}
float absoluteAngle = previousAbsoluteAngle + current.PositionInfo.RelativeAngle;
var posRelativeToPrev = new Vector2(
current.PositionInfo.DistanceFromPrevious * MathF.Cos(absoluteAngle),
current.PositionInfo.DistanceFromPrevious * MathF.Sin(absoluteAngle)
);
Vector2 lastEndPosition = previous?.EndPositionModified ?? playfield_centre;
posRelativeToPrev = RotateAwayFromEdge(lastEndPosition, posRelativeToPrev);
current.PositionModified = lastEndPosition + posRelativeToPrev;
if (!(current.HitObject is Slider slider))
return;
absoluteAngle = MathF.Atan2(posRelativeToPrev.Y, posRelativeToPrev.X);
Vector2 centreOfMassOriginal = calculateCentreOfMass(slider);
Vector2 centreOfMassModified = rotateVector(centreOfMassOriginal, current.PositionInfo.Rotation + absoluteAngle - getSliderRotation(slider));
centreOfMassModified = RotateAwayFromEdge(current.PositionModified, centreOfMassModified);
float relativeRotation = MathF.Atan2(centreOfMassModified.Y, centreOfMassModified.X) - MathF.Atan2(centreOfMassOriginal.Y, centreOfMassOriginal.X);
if (!Precision.AlmostEquals(relativeRotation, 0))
RotateSlider(slider, relativeRotation);
}
/// <summary>
/// Move the modified position of a <see cref="HitCircle"/> so that it fits inside the playfield.
/// </summary>
/// <returns>The deviation from the original modified position in order to fit within the playfield.</returns>
private static Vector2 clampHitCircleToPlayfield(WorkingObject workingObject)
{
var previousPosition = workingObject.PositionModified;
workingObject.EndPositionModified = workingObject.PositionModified = clampToPlayfieldWithPadding(
workingObject.PositionModified,
(float)workingObject.HitObject.Radius
);
workingObject.HitObject.Position = workingObject.PositionModified;
return workingObject.PositionModified - 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 modified position in order to fit within the playfield.</returns>
private static Vector2 clampSliderToPlayfield(WorkingObject workingObject)
{
var slider = (Slider)workingObject.HitObject;
var possibleMovementBounds = CalculatePossibleMovementBounds(slider);
// The slider rotation applied in computeModifiedPosition might make it impossible to fit the slider into the playfield
// For example, a long horizontal slider will be off-screen when rotated by 90 degrees
// In this case, limit the rotation to either 0 or 180 degrees
if (possibleMovementBounds.Width < 0 || possibleMovementBounds.Height < 0)
{
float currentRotation = getSliderRotation(slider);
float diff1 = getAngleDifference(workingObject.RotationOriginal, currentRotation);
float diff2 = getAngleDifference(workingObject.RotationOriginal + MathF.PI, currentRotation);
if (diff1 < diff2)
{
RotateSlider(slider, workingObject.RotationOriginal - getSliderRotation(slider));
}
else
{
RotateSlider(slider, workingObject.RotationOriginal + MathF.PI - getSliderRotation(slider));
}
possibleMovementBounds = CalculatePossibleMovementBounds(slider);
}
var previousPosition = workingObject.PositionModified;
// Clamp slider position to the placement area
// If the slider is larger than the playfield, at least make sure that the head circle is inside the playfield
float newX = possibleMovementBounds.Width < 0
? Math.Clamp(possibleMovementBounds.Left, 0, OsuPlayfield.BASE_SIZE.X)
: Math.Clamp(previousPosition.X, possibleMovementBounds.Left, possibleMovementBounds.Right);
float newY = possibleMovementBounds.Height < 0
? Math.Clamp(possibleMovementBounds.Top, 0, OsuPlayfield.BASE_SIZE.Y)
: Math.Clamp(previousPosition.Y, possibleMovementBounds.Top, possibleMovementBounds.Bottom);
slider.Position = workingObject.PositionModified = new Vector2(newX, newY);
workingObject.EndPositionModified = slider.EndPosition;
shiftNestedObjects(slider, workingObject.PositionModified - workingObject.PositionOriginal);
return workingObject.PositionModified - 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 static 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>
/// <param name="slider">The <see cref="Slider"/> for which to calculate a movement bounding box.</param>
/// <returns>A <see cref="RectangleF"/> which contains all of the possible movements of the slider such that the entire slider is inside the playfield.</returns>
/// <remarks>
/// If the slider is larger than the playfield, the returned <see cref="RectangleF"/> may have negative width/height.
/// </remarks>
public static 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 static 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 static 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)
);
}
/// <summary>
/// Estimate the centre of mass of a slider relative to its start position.
/// </summary>
/// <param name="slider">The slider to process.</param>
/// <returns>The centre of mass of the slider.</returns>
private static Vector2 calculateCentreOfMass(Slider slider)
{
const double sample_step = 50;
// just sample the start and end positions if the slider is too short
if (slider.Distance <= sample_step)
{
return Vector2.Divide(slider.Path.PositionAt(1), 2);
}
int count = 0;
Vector2 sum = Vector2.Zero;
double pathDistance = slider.Distance;
for (double i = 0; i < pathDistance; i += sample_step)
{
sum += slider.Path.PositionAt(i / pathDistance);
count++;
}
return sum / count;
}
/// <summary>
/// Get the absolute rotation of a slider, defined as the angle from its start position to the end of its path.
/// </summary>
/// <param name="slider">The slider to process.</param>
/// <returns>The angle in radians.</returns>
private static float getSliderRotation(Slider slider)
{
var endPositionVector = slider.Path.PositionAt(1);
return MathF.Atan2(endPositionVector.Y, endPositionVector.X);
}
/// <summary>
/// Get the absolute difference between 2 angles measured in Radians.
/// </summary>
/// <param name="angle1">The first angle</param>
/// <param name="angle2">The second angle</param>
/// <returns>The absolute difference with interval <c>[0, MathF.PI)</c></returns>
private static float getAngleDifference(float angle1, float angle2)
{
float diff = MathF.Abs(angle1 - angle2) % (MathF.PI * 2);
return MathF.Min(diff, MathF.PI * 2 - diff);
}
public class ObjectPositionInfo
{
/// <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; }
/// <summary>
/// The rotation of the hit object, relative to its jump angle.
/// For sliders, this is defined as the angle from the slider's start position to the end of its path, relative to its jump angle.
/// For hit circles and spinners, this property is ignored.
/// </summary>
public float Rotation { get; set; }
/// <summary>
/// The hit object associated with this <see cref="ObjectPositionInfo"/>.
/// </summary>
public OsuHitObject HitObject { get; }
public ObjectPositionInfo(OsuHitObject hitObject)
{
HitObject = hitObject;
}
}
private class WorkingObject
{
public float RotationOriginal { get; }
public Vector2 PositionOriginal { get; }
public Vector2 PositionModified { get; set; }
public Vector2 EndPositionModified { get; set; }
public ObjectPositionInfo PositionInfo { get; }
public OsuHitObject HitObject => PositionInfo.HitObject;
public WorkingObject(ObjectPositionInfo positionInfo)
{
PositionInfo = positionInfo;
RotationOriginal = HitObject is Slider slider ? getSliderRotation(slider) : 0;
PositionModified = PositionOriginal = HitObject.Position;
EndPositionModified = HitObject.EndPosition;
}
}
}
}