Merge pull request #26309 from OliBomby/grids-1

Add ability to change position, spacing, and rotation of the positional snap grid in the editor

osu.Game.Rulesets.Osu.Tests/Editor/TestSceneOsuEditorGrids.cs

@@ -8,7 +8,9 @@ using osu.Framework.Utils;
 using osu.Game.Rulesets.Edit;
 using osu.Game.Rulesets.Osu.Edit;
 using osu.Game.Rulesets.Osu.Edit.Blueprints.HitCircles;
+using osu.Game.Screens.Edit.Compose.Components;
 using osu.Game.Tests.Visual;
+using osu.Game.Utils;
 using osuTK;
 using osuTK.Input;
 
@@ -25,22 +27,22 @@ namespace osu.Game.Rulesets.Osu.Tests.Editor
             AddStep("select second object", () => EditorBeatmap.SelectedHitObjects.Add(EditorBeatmap.HitObjects.ElementAt(1)));
 
             AddUntilStep("distance snap grid visible", () => this.ChildrenOfType<OsuDistanceSnapGrid>().Any());
-            rectangularGridActive(false);
+            gridActive<RectangularPositionSnapGrid>(false);
 
             AddStep("enable rectangular grid", () => InputManager.Key(Key.Y));
 
             AddStep("select second object", () => EditorBeatmap.SelectedHitObjects.Add(EditorBeatmap.HitObjects.ElementAt(1)));
             AddUntilStep("distance snap grid still visible", () => this.ChildrenOfType<OsuDistanceSnapGrid>().Any());
-            rectangularGridActive(true);
+            gridActive<RectangularPositionSnapGrid>(true);
 
             AddStep("disable distance snap grid", () => InputManager.Key(Key.T));
             AddUntilStep("distance snap grid hidden", () => !this.ChildrenOfType<OsuDistanceSnapGrid>().Any());
             AddStep("select second object", () => EditorBeatmap.SelectedHitObjects.Add(EditorBeatmap.HitObjects.ElementAt(1)));
-            rectangularGridActive(true);
+            gridActive<RectangularPositionSnapGrid>(true);
 
             AddStep("disable rectangular grid", () => InputManager.Key(Key.Y));
             AddUntilStep("distance snap grid still hidden", () => !this.ChildrenOfType<OsuDistanceSnapGrid>().Any());
-            rectangularGridActive(false);
+            gridActive<RectangularPositionSnapGrid>(false);
         }
 
         [Test]
@@ -117,33 +119,56 @@ namespace osu.Game.Rulesets.Osu.Tests.Editor
         [Test]
         public void TestGridSnapMomentaryToggle()
         {
-            rectangularGridActive(false);
+            gridActive<RectangularPositionSnapGrid>(false);
             AddStep("hold shift", () => InputManager.PressKey(Key.ShiftLeft));
-            rectangularGridActive(true);
+            gridActive<RectangularPositionSnapGrid>(true);
             AddStep("release shift", () => InputManager.ReleaseKey(Key.ShiftLeft));
-            rectangularGridActive(false);
+            gridActive<RectangularPositionSnapGrid>(false);
         }
 
-        private void rectangularGridActive(bool active)
+        private void gridActive<T>(bool active) where T : PositionSnapGrid
         {
             AddStep("choose placement tool", () => InputManager.Key(Key.Number2));
-            AddStep("move cursor to (1, 1)", () =>
+            AddStep("move cursor to spacing + (1, 1)", () =>
             {
-                var composer = Editor.ChildrenOfType<OsuRectangularPositionSnapGrid>().Single();
-                InputManager.MoveMouseTo(composer.ToScreenSpace(new Vector2(1, 1)));
+                var composer = Editor.ChildrenOfType<T>().Single();
+                InputManager.MoveMouseTo(composer.ToScreenSpace(uniqueSnappingPosition(composer) + new Vector2(1, 1)));
             });
 
             if (active)
-                AddAssert("placement blueprint at (0, 0)", () => Precision.AlmostEquals(Editor.ChildrenOfType<HitCirclePlacementBlueprint>().Single().HitObject.Position, new Vector2(0, 0)));
+            {
+                AddAssert("placement blueprint at spacing + (0, 0)", () =>
+                {
+                    var composer = Editor.ChildrenOfType<T>().Single();
+                    return Precision.AlmostEquals(Editor.ChildrenOfType<HitCirclePlacementBlueprint>().Single().HitObject.Position,
+                        uniqueSnappingPosition(composer));
+                });
+            }
             else
-                AddAssert("placement blueprint at (1, 1)", () => Precision.AlmostEquals(Editor.ChildrenOfType<HitCirclePlacementBlueprint>().Single().HitObject.Position, new Vector2(1, 1)));
+            {
+                AddAssert("placement blueprint at spacing + (1, 1)", () =>
+                {
+                    var composer = Editor.ChildrenOfType<T>().Single();
+                    return Precision.AlmostEquals(Editor.ChildrenOfType<HitCirclePlacementBlueprint>().Single().HitObject.Position,
+                        uniqueSnappingPosition(composer) + new Vector2(1, 1));
+                });
+            }
+        }
+
+        private Vector2 uniqueSnappingPosition(PositionSnapGrid grid)
+        {
+            return grid switch
+            {
+                RectangularPositionSnapGrid rectangular => rectangular.StartPosition.Value + GeometryUtils.RotateVector(rectangular.Spacing.Value, -rectangular.GridLineRotation.Value),
+                _ => Vector2.Zero
+            };
         }
 
         [Test]
         public void TestGridSizeToggling()
         {
             AddStep("enable rectangular grid", () => InputManager.Key(Key.Y));
-            AddUntilStep("rectangular grid visible", () => this.ChildrenOfType<OsuRectangularPositionSnapGrid>().Any());
+            AddUntilStep("rectangular grid visible", () => this.ChildrenOfType<RectangularPositionSnapGrid>().Any());
             gridSizeIs(4);
 
             nextGridSizeIs(8);
@@ -159,7 +184,7 @@ namespace osu.Game.Rulesets.Osu.Tests.Editor
         }
 
         private void gridSizeIs(int size)
-            => AddAssert($"grid size is {size}", () => this.ChildrenOfType<OsuRectangularPositionSnapGrid>().Single().Spacing == new Vector2(size)
+            => AddAssert($"grid size is {size}", () => this.ChildrenOfType<RectangularPositionSnapGrid>().Single().Spacing.Value == new Vector2(size)
                                                        && EditorBeatmap.BeatmapInfo.GridSize == size);
     }
 }

osu.Game.Rulesets.Osu/Edit/OsuGridToolboxGroup.cs

@@ -0,0 +1,171 @@
+// 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 osu.Framework.Allocation;
+using osu.Framework.Bindables;
+using osu.Framework.Graphics;
+using osu.Framework.Input.Bindings;
+using osu.Framework.Input.Events;
+using osu.Game.Graphics.UserInterface;
+using osu.Game.Input.Bindings;
+using osu.Game.Rulesets.Edit;
+using osu.Game.Rulesets.Osu.UI;
+using osu.Game.Screens.Edit;
+using osuTK;
+
+namespace osu.Game.Rulesets.Osu.Edit
+{
+    public partial class OsuGridToolboxGroup : EditorToolboxGroup, IKeyBindingHandler<GlobalAction>
+    {
+        [Resolved]
+        private EditorBeatmap editorBeatmap { get; set; } = null!;
+
+        /// <summary>
+        /// X position of the grid's origin.
+        /// </summary>
+        public BindableFloat StartPositionX { get; } = new BindableFloat(OsuPlayfield.BASE_SIZE.X / 2)
+        {
+            MinValue = 0f,
+            MaxValue = OsuPlayfield.BASE_SIZE.X,
+            Precision = 1f
+        };
+
+        /// <summary>
+        /// Y position of the grid's origin.
+        /// </summary>
+        public BindableFloat StartPositionY { get; } = new BindableFloat(OsuPlayfield.BASE_SIZE.Y / 2)
+        {
+            MinValue = 0f,
+            MaxValue = OsuPlayfield.BASE_SIZE.Y,
+            Precision = 1f
+        };
+
+        /// <summary>
+        /// The spacing between grid lines.
+        /// </summary>
+        public BindableFloat Spacing { get; } = new BindableFloat(4f)
+        {
+            MinValue = 4f,
+            MaxValue = 128f,
+            Precision = 1f
+        };
+
+        /// <summary>
+        /// Rotation of the grid lines in degrees.
+        /// </summary>
+        public BindableFloat GridLinesRotation { get; } = new BindableFloat(0f)
+        {
+            MinValue = -45f,
+            MaxValue = 45f,
+            Precision = 1f
+        };
+
+        /// <summary>
+        /// Read-only bindable representing the grid's origin.
+        /// Equivalent to <code>new Vector2(StartPositionX, StartPositionY)</code>
+        /// </summary>
+        public Bindable<Vector2> StartPosition { get; } = new Bindable<Vector2>();
+
+        /// <summary>
+        /// Read-only bindable representing the grid's spacing in both the X and Y dimension.
+        /// Equivalent to <code>new Vector2(Spacing)</code>
+        /// </summary>
+        public Bindable<Vector2> SpacingVector { get; } = new Bindable<Vector2>();
+
+        private ExpandableSlider<float> startPositionXSlider = null!;
+        private ExpandableSlider<float> startPositionYSlider = null!;
+        private ExpandableSlider<float> spacingSlider = null!;
+        private ExpandableSlider<float> gridLinesRotationSlider = null!;
+
+        public OsuGridToolboxGroup()
+            : base("grid")
+        {
+        }
+
+        private const float max_automatic_spacing = 64;
+
+        [BackgroundDependencyLoader]
+        private void load()
+        {
+            Children = new Drawable[]
+            {
+                startPositionXSlider = new ExpandableSlider<float>
+                {
+                    Current = StartPositionX,
+                    KeyboardStep = 1,
+                },
+                startPositionYSlider = new ExpandableSlider<float>
+                {
+                    Current = StartPositionY,
+                    KeyboardStep = 1,
+                },
+                spacingSlider = new ExpandableSlider<float>
+                {
+                    Current = Spacing,
+                    KeyboardStep = 1,
+                },
+                gridLinesRotationSlider = new ExpandableSlider<float>
+                {
+                    Current = GridLinesRotation,
+                    KeyboardStep = 1,
+                },
+            };
+
+            Spacing.Value = editorBeatmap.BeatmapInfo.GridSize;
+        }
+
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+
+            StartPositionX.BindValueChanged(x =>
+            {
+                startPositionXSlider.ContractedLabelText = $"X: {x.NewValue:N0}";
+                startPositionXSlider.ExpandedLabelText = $"X Offset: {x.NewValue:N0}";
+                StartPosition.Value = new Vector2(x.NewValue, StartPosition.Value.Y);
+            }, true);
+
+            StartPositionY.BindValueChanged(y =>
+            {
+                startPositionYSlider.ContractedLabelText = $"Y: {y.NewValue:N0}";
+                startPositionYSlider.ExpandedLabelText = $"Y Offset: {y.NewValue:N0}";
+                StartPosition.Value = new Vector2(StartPosition.Value.X, y.NewValue);
+            }, true);
+
+            Spacing.BindValueChanged(spacing =>
+            {
+                spacingSlider.ContractedLabelText = $"S: {spacing.NewValue:N0}";
+                spacingSlider.ExpandedLabelText = $"Spacing: {spacing.NewValue:N0}";
+                SpacingVector.Value = new Vector2(spacing.NewValue);
+                editorBeatmap.BeatmapInfo.GridSize = (int)spacing.NewValue;
+            }, true);
+
+            GridLinesRotation.BindValueChanged(rotation =>
+            {
+                gridLinesRotationSlider.ContractedLabelText = $"R: {rotation.NewValue:#,0.##}";
+                gridLinesRotationSlider.ExpandedLabelText = $"Rotation: {rotation.NewValue:#,0.##}";
+            }, true);
+        }
+
+        private void nextGridSize()
+        {
+            Spacing.Value = Spacing.Value * 2 >= max_automatic_spacing ? Spacing.Value / 8 : Spacing.Value * 2;
+        }
+
+        public bool OnPressed(KeyBindingPressEvent<GlobalAction> e)
+        {
+            switch (e.Action)
+            {
+                case GlobalAction.EditorCycleGridDisplayMode:
+                    nextGridSize();
+                    return true;
+            }
+
+            return false;
+        }
+
+        public void OnReleased(KeyBindingReleaseEvent<GlobalAction> e)
+        {
+        }
+    }
+}

osu.Game.Rulesets.Osu/Edit/OsuHitObjectComposer.cs

@@ -24,6 +24,7 @@ using osu.Game.Rulesets.Edit.Tools;
 using osu.Game.Rulesets.Mods;
 using osu.Game.Rulesets.Objects;
 using osu.Game.Rulesets.Osu.Objects;
+using osu.Game.Rulesets.Osu.UI;
 using osu.Game.Rulesets.UI;
 using osu.Game.Screens.Edit.Components.TernaryButtons;
 using osu.Game.Screens.Edit.Compose.Components;
@@ -65,6 +66,9 @@ namespace osu.Game.Rulesets.Osu.Edit
         [Cached(typeof(IDistanceSnapProvider))]
         protected readonly OsuDistanceSnapProvider DistanceSnapProvider = new OsuDistanceSnapProvider();
 
+        [Cached]
+        protected readonly OsuGridToolboxGroup OsuGridToolboxGroup = new OsuGridToolboxGroup();
+
         [Cached]
         protected readonly FreehandSliderToolboxGroup FreehandlSliderToolboxGroup = new FreehandSliderToolboxGroup();
 
@@ -80,10 +84,6 @@ namespace osu.Game.Rulesets.Osu.Edit
             LayerBelowRuleset.AddRange(new Drawable[]
             {
                 distanceSnapGridContainer = new Container
-                {
-                    RelativeSizeAxes = Axes.Both
-                },
-                rectangularPositionSnapGrid = new OsuRectangularPositionSnapGrid
                 {
                     RelativeSizeAxes = Axes.Both
                 }
@@ -99,8 +99,11 @@ namespace osu.Game.Rulesets.Osu.Edit
             // we may be entering the screen with a selection already active
             updateDistanceSnapGrid();
 
+            updatePositionSnapGrid();
+
             RightToolbox.AddRange(new EditorToolboxGroup[]
                 {
+                    OsuGridToolboxGroup,
                     new TransformToolboxGroup
                     {
                         RotationHandler = BlueprintContainer.SelectionHandler.RotationHandler,
@@ -111,6 +114,23 @@ namespace osu.Game.Rulesets.Osu.Edit
             );
         }
 
+        private void updatePositionSnapGrid()
+        {
+            if (positionSnapGrid != null)
+                LayerBelowRuleset.Remove(positionSnapGrid, true);
+
+            var rectangularPositionSnapGrid = new RectangularPositionSnapGrid();
+
+            rectangularPositionSnapGrid.StartPosition.BindTo(OsuGridToolboxGroup.StartPosition);
+            rectangularPositionSnapGrid.Spacing.BindTo(OsuGridToolboxGroup.SpacingVector);
+            rectangularPositionSnapGrid.GridLineRotation.BindTo(OsuGridToolboxGroup.GridLinesRotation);
+
+            positionSnapGrid = rectangularPositionSnapGrid;
+
+            positionSnapGrid.RelativeSizeAxes = Axes.Both;
+            LayerBelowRuleset.Add(positionSnapGrid);
+        }
+
         protected override ComposeBlueprintContainer CreateBlueprintContainer()
             => new OsuBlueprintContainer(this);
 
@@ -151,7 +171,7 @@ namespace osu.Game.Rulesets.Osu.Edit
         private readonly Cached distanceSnapGridCache = new Cached();
         private double? lastDistanceSnapGridTime;
 
-        private RectangularPositionSnapGrid rectangularPositionSnapGrid;
+        private PositionSnapGrid positionSnapGrid;
 
         protected override void Update()
         {
@@ -209,9 +229,13 @@ namespace osu.Game.Rulesets.Osu.Edit
             {
                 if (rectangularGridSnapToggle.Value == TernaryState.True)
                 {
-                    Vector2 pos = rectangularPositionSnapGrid.GetSnappedPosition(rectangularPositionSnapGrid.ToLocalSpace(result.ScreenSpacePosition));
+                    Vector2 pos = positionSnapGrid.GetSnappedPosition(positionSnapGrid.ToLocalSpace(result.ScreenSpacePosition));
 
-                    result.ScreenSpacePosition = rectangularPositionSnapGrid.ToScreenSpace(pos);
+                    // A grid which doesn't perfectly fit the playfield can produce a position that is outside of the playfield.
+                    // We need to clamp the position to the playfield bounds to ensure that the snapped position is always in bounds.
+                    pos = Vector2.Clamp(pos, Vector2.Zero, OsuPlayfield.BASE_SIZE);
+
+                    result.ScreenSpacePosition = positionSnapGrid.ToScreenSpace(pos);
                 }
             }
 

osu.Game.Rulesets.Osu/Edit/OsuRectangularPositionSnapGrid.cs

@@ -1,69 +0,0 @@
-// 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.Framework.Allocation;
-using osu.Framework.Input.Bindings;
-using osu.Framework.Input.Events;
-using osu.Game.Input.Bindings;
-using osu.Game.Rulesets.Osu.UI;
-using osu.Game.Screens.Edit;
-using osu.Game.Screens.Edit.Compose.Components;
-using osuTK;
-
-namespace osu.Game.Rulesets.Osu.Edit
-{
-    public partial class OsuRectangularPositionSnapGrid : RectangularPositionSnapGrid, IKeyBindingHandler<GlobalAction>
-    {
-        private static readonly int[] grid_sizes = { 4, 8, 16, 32 };
-
-        private int currentGridSizeIndex = grid_sizes.Length - 1;
-
-        [Resolved]
-        private EditorBeatmap editorBeatmap { get; set; } = null!;
-
-        public OsuRectangularPositionSnapGrid()
-            : base(OsuPlayfield.BASE_SIZE / 2)
-        {
-        }
-
-        [BackgroundDependencyLoader]
-        private void load()
-        {
-            int gridSizeIndex = Array.IndexOf(grid_sizes, editorBeatmap.BeatmapInfo.GridSize);
-            if (gridSizeIndex >= 0)
-                currentGridSizeIndex = gridSizeIndex;
-            updateSpacing();
-        }
-
-        private void nextGridSize()
-        {
-            currentGridSizeIndex = (currentGridSizeIndex + 1) % grid_sizes.Length;
-            updateSpacing();
-        }
-
-        private void updateSpacing()
-        {
-            int gridSize = grid_sizes[currentGridSizeIndex];
-
-            editorBeatmap.BeatmapInfo.GridSize = gridSize;
-            Spacing = new Vector2(gridSize);
-        }
-
-        public bool OnPressed(KeyBindingPressEvent<GlobalAction> e)
-        {
-            switch (e.Action)
-            {
-                case GlobalAction.EditorCycleGridDisplayMode:
-                    nextGridSize();
-                    return true;
-            }
-
-            return false;
-        }
-
-        public void OnReleased(KeyBindingReleaseEvent<GlobalAction> e)
-        {
-        }
-    }
-}

osu.Game.Tests/Visual/Editing/TestScenePositionSnapGrid.cs

@@ -16,7 +16,7 @@ using osuTK.Graphics;
 
 namespace osu.Game.Tests.Visual.Editing
 {
-    public partial class TestSceneRectangularPositionSnapGrid : OsuManualInputManagerTestScene
+    public partial class TestScenePositionSnapGrid : OsuManualInputManagerTestScene
     {
         private Container content;
         protected override Container<Drawable> Content => content;
@@ -33,28 +33,34 @@ namespace osu.Game.Tests.Visual.Editing
                 },
                 content = new Container
                 {
-                    RelativeSizeAxes = Axes.Both
+                    RelativeSizeAxes = Axes.Both,
+                    Padding = new MarginPadding(10),
                 }
             });
         }
 
         private static readonly object[][] test_cases =
         {
-            new object[] { new Vector2(0, 0), new Vector2(10, 10) },
-            new object[] { new Vector2(240, 180), new Vector2(10, 15) },
-            new object[] { new Vector2(160, 120), new Vector2(30, 20) },
-            new object[] { new Vector2(480, 360), new Vector2(100, 100) },
+            new object[] { new Vector2(0, 0), new Vector2(10, 10), 0f },
+            new object[] { new Vector2(240, 180), new Vector2(10, 15), 10f },
+            new object[] { new Vector2(160, 120), new Vector2(30, 20), -10f },
+            new object[] { new Vector2(480, 360), new Vector2(100, 100), 0f },
         };
 
         [TestCaseSource(nameof(test_cases))]
-        public void TestRectangularGrid(Vector2 position, Vector2 spacing)
+        public void TestRectangularGrid(Vector2 position, Vector2 spacing, float rotation)
         {
             RectangularPositionSnapGrid grid = null;
 
-            AddStep("create grid", () => Child = grid = new RectangularPositionSnapGrid(position)
+            AddStep("create grid", () =>
             {
-                RelativeSizeAxes = Axes.Both,
-                Spacing = spacing
+                Child = grid = new RectangularPositionSnapGrid
+                {
+                    RelativeSizeAxes = Axes.Both,
+                };
+                grid.StartPosition.Value = position;
+                grid.Spacing.Value = spacing;
+                grid.GridLineRotation.Value = rotation;
             });
 
             AddStep("add snapping cursor", () => Add(new SnappingCursorContainer

osu.Game.Tournament/Screens/Editors/LadderEditorScreen.cs

@@ -51,15 +51,16 @@ namespace osu.Game.Tournament.Screens.Editors
 
             AddInternal(rightClickMessage = new WarningBox("Right click to place and link matches"));
 
-            ScrollContent.Add(grid = new RectangularPositionSnapGrid(Vector2.Zero)
+            ScrollContent.Add(grid = new RectangularPositionSnapGrid
             {
-                Spacing = new Vector2(GRID_SPACING),
                 Anchor = Anchor.Centre,
                 Origin = Anchor.Centre,
                 BypassAutoSizeAxes = Axes.Both,
                 Depth = float.MaxValue
             });
 
+            grid.Spacing.Value = new Vector2(GRID_SPACING);
+
             LadderInfo.Matches.CollectionChanged += (_, _) => updateMessage();
             updateMessage();
         }

osu.Game/Screens/Edit/Compose/Components/LinedPositionSnapGrid.cs

@@ -0,0 +1,166 @@
+// 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;
+using osu.Framework.Graphics.Shapes;
+using osu.Framework.Utils;
+using osuTK;
+
+namespace osu.Game.Screens.Edit.Compose.Components
+{
+    public abstract partial class LinedPositionSnapGrid : PositionSnapGrid
+    {
+        protected void GenerateGridLines(Vector2 step, Vector2 drawSize)
+        {
+            if (Precision.AlmostEquals(step, Vector2.Zero))
+                return;
+
+            int index = 0;
+
+            // Make lines the same width independent of display resolution.
+            float lineWidth = DrawWidth / ScreenSpaceDrawQuad.Width;
+            float rotation = MathHelper.RadiansToDegrees(MathF.Atan2(step.Y, step.X));
+
+            List<Box> generatedLines = new List<Box>();
+
+            while (true)
+            {
+                Vector2 currentPosition = StartPosition.Value + index * step;
+                index++;
+
+                if (!lineDefinitelyIntersectsBox(currentPosition, step.PerpendicularLeft, drawSize, out var p1, out var p2))
+                {
+                    if (!isMovingTowardsBox(currentPosition, step, drawSize))
+                        break;
+
+                    continue;
+                }
+
+                var gridLine = new Box
+                {
+                    Colour = Colour4.White,
+                    Alpha = 0.1f,
+                    Origin = Anchor.Centre,
+                    RelativeSizeAxes = Axes.None,
+                    Width = lineWidth,
+                    Height = Vector2.Distance(p1, p2),
+                    Position = (p1 + p2) / 2,
+                    Rotation = rotation,
+                };
+
+                generatedLines.Add(gridLine);
+            }
+
+            if (generatedLines.Count == 0)
+                return;
+
+            generatedLines.First().Alpha = 0.2f;
+
+            AddRangeInternal(generatedLines);
+        }
+
+        private bool isMovingTowardsBox(Vector2 currentPosition, Vector2 step, Vector2 box)
+        {
+            return (currentPosition + step).LengthSquared < currentPosition.LengthSquared ||
+                   (currentPosition + step - box).LengthSquared < (currentPosition - box).LengthSquared;
+        }
+
+        /// <summary>
+        /// Determines if the line starting at <paramref name="lineStart"/> and going in the direction of <paramref name="lineDir"/>
+        /// definitely intersects the box on (0, 0) with the given width and height and returns the intersection points if it does.
+        /// </summary>
+        /// <param name="lineStart">The start point of the line.</param>
+        /// <param name="lineDir">The direction of the line.</param>
+        /// <param name="box">The width and height of the box.</param>
+        /// <param name="p1">The first intersection point.</param>
+        /// <param name="p2">The second intersection point.</param>
+        /// <returns>Whether the line definitely intersects the box.</returns>
+        private bool lineDefinitelyIntersectsBox(Vector2 lineStart, Vector2 lineDir, Vector2 box, out Vector2 p1, out Vector2 p2)
+        {
+            p1 = Vector2.Zero;
+            p2 = Vector2.Zero;
+
+            if (Precision.AlmostEquals(lineDir.X, 0))
+            {
+                // If the line is vertical, we only need to check if the X coordinate of the line is within the box.
+                if (!Precision.DefinitelyBigger(lineStart.X, 0) || !Precision.DefinitelyBigger(box.X, lineStart.X))
+                    return false;
+
+                p1 = new Vector2(lineStart.X, 0);
+                p2 = new Vector2(lineStart.X, box.Y);
+                return true;
+            }
+
+            if (Precision.AlmostEquals(lineDir.Y, 0))
+            {
+                // If the line is horizontal, we only need to check if the Y coordinate of the line is within the box.
+                if (!Precision.DefinitelyBigger(lineStart.Y, 0) || !Precision.DefinitelyBigger(box.Y, lineStart.Y))
+                    return false;
+
+                p1 = new Vector2(0, lineStart.Y);
+                p2 = new Vector2(box.X, lineStart.Y);
+                return true;
+            }
+
+            float m = lineDir.Y / lineDir.X;
+            float mInv = lineDir.X / lineDir.Y; // Use this to improve numerical stability if X is close to zero.
+            float b = lineStart.Y - m * lineStart.X;
+
+            // Calculate intersection points with the sides of the box.
+            var p = new List<Vector2>(4);
+
+            if (0 <= b && b <= box.Y)
+                p.Add(new Vector2(0, b));
+            if (0 <= (box.Y - b) * mInv && (box.Y - b) * mInv <= box.X)
+                p.Add(new Vector2((box.Y - b) * mInv, box.Y));
+            if (0 <= m * box.X + b && m * box.X + b <= box.Y)
+                p.Add(new Vector2(box.X, m * box.X + b));
+            if (0 <= -b * mInv && -b * mInv <= box.X)
+                p.Add(new Vector2(-b * mInv, 0));
+
+            switch (p.Count)
+            {
+                case 4:
+                    // If there are 4 intersection points, the line is a diagonal of the box.
+                    if (m > 0)
+                    {
+                        p1 = Vector2.Zero;
+                        p2 = box;
+                    }
+                    else
+                    {
+                        p1 = new Vector2(0, box.Y);
+                        p2 = new Vector2(box.X, 0);
+                    }
+
+                    break;
+
+                case 3:
+                    // If there are 3 intersection points, the line goes through a corner of the box.
+                    if (p[0] == p[1])
+                    {
+                        p1 = p[0];
+                        p2 = p[2];
+                    }
+                    else
+                    {
+                        p1 = p[0];
+                        p2 = p[1];
+                    }
+
+                    break;
+
+                case 2:
+                    p1 = p[0];
+                    p2 = p[1];
+
+                    break;
+            }
+
+            return !Precision.AlmostEquals(p1, p2);
+        }
+    }
+}

osu.Game/Screens/Edit/Compose/Components/PositionSnapGrid.cs

@@ -0,0 +1,93 @@
+// 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 osu.Framework.Bindables;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Shapes;
+using osu.Framework.Layout;
+using osuTK;
+
+namespace osu.Game.Screens.Edit.Compose.Components
+{
+    public abstract partial class PositionSnapGrid : CompositeDrawable
+    {
+        /// <summary>
+        /// The position of the origin of this <see cref="PositionSnapGrid"/> in local coordinates.
+        /// </summary>
+        public Bindable<Vector2> StartPosition { get; } = new Bindable<Vector2>(Vector2.Zero);
+
+        protected readonly LayoutValue GridCache = new LayoutValue(Invalidation.RequiredParentSizeToFit);
+
+        protected PositionSnapGrid()
+        {
+            StartPosition.BindValueChanged(_ => GridCache.Invalidate());
+
+            AddLayout(GridCache);
+        }
+
+        protected override void Update()
+        {
+            base.Update();
+
+            if (GridCache.IsValid) return;
+
+            ClearInternal();
+
+            if (DrawWidth > 0 && DrawHeight > 0)
+                CreateContent();
+
+            GridCache.Validate();
+        }
+
+        protected abstract void CreateContent();
+
+        protected void GenerateOutline(Vector2 drawSize)
+        {
+            // Make lines the same width independent of display resolution.
+            float lineWidth = DrawWidth / ScreenSpaceDrawQuad.Width;
+
+            AddRangeInternal(new[]
+            {
+                new Box
+                {
+                    Colour = Colour4.White,
+                    Alpha = 0.3f,
+                    Origin = Anchor.CentreLeft,
+                    RelativeSizeAxes = Axes.X,
+                    Height = lineWidth,
+                    Y = 0,
+                },
+                new Box
+                {
+                    Colour = Colour4.White,
+                    Alpha = 0.3f,
+                    Origin = Anchor.CentreLeft,
+                    RelativeSizeAxes = Axes.X,
+                    Height = lineWidth,
+                    Y = drawSize.Y,
+                },
+                new Box
+                {
+                    Colour = Colour4.White,
+                    Alpha = 0.3f,
+                    Origin = Anchor.TopCentre,
+                    RelativeSizeAxes = Axes.Y,
+                    Width = lineWidth,
+                    X = 0,
+                },
+                new Box
+                {
+                    Colour = Colour4.White,
+                    Alpha = 0.3f,
+                    Origin = Anchor.TopCentre,
+                    RelativeSizeAxes = Axes.Y,
+                    Width = lineWidth,
+                    X = drawSize.X,
+                },
+            });
+        }
+
+        public abstract Vector2 GetSnappedPosition(Vector2 original);
+    }
+}

osu.Game/Screens/Edit/Compose/Components/RectangularPositionSnapGrid.cs

@@ -2,132 +2,51 @@
 // 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;
-using osu.Framework.Graphics.Containers;
-using osu.Framework.Graphics.Shapes;
-using osu.Framework.Layout;
-using osu.Framework.Utils;
+using osu.Framework.Bindables;
+using osu.Game.Utils;
 using osuTK;
 
 namespace osu.Game.Screens.Edit.Compose.Components
 {
-    public partial class RectangularPositionSnapGrid : CompositeDrawable
+    public partial class RectangularPositionSnapGrid : LinedPositionSnapGrid
     {
-        /// <summary>
-        /// The position of the origin of this <see cref="RectangularPositionSnapGrid"/> in local coordinates.
-        /// </summary>
-        public Vector2 StartPosition { get; }
-
-        private Vector2 spacing = Vector2.One;
-
         /// <summary>
         /// The spacing between grid lines of this <see cref="RectangularPositionSnapGrid"/>.
         /// </summary>
-        public Vector2 Spacing
-        {
-            get => spacing;
-            set
-            {
-                if (spacing.X <= 0 || spacing.Y <= 0)
-                    throw new ArgumentException("Grid spacing must be positive.");
+        public Bindable<Vector2> Spacing { get; } = new Bindable<Vector2>(Vector2.One);
 
-                spacing = value;
-                gridCache.Invalidate();
-            }
+        /// <summary>
+        /// The rotation in degrees of the grid lines of this <see cref="RectangularPositionSnapGrid"/>.
+        /// </summary>
+        public BindableFloat GridLineRotation { get; } = new BindableFloat();
+
+        public RectangularPositionSnapGrid()
+        {
+            Spacing.BindValueChanged(_ => GridCache.Invalidate());
+            GridLineRotation.BindValueChanged(_ => GridCache.Invalidate());
         }
 
-        private readonly LayoutValue gridCache = new LayoutValue(Invalidation.RequiredParentSizeToFit);
-
-        public RectangularPositionSnapGrid(Vector2 startPosition)
-        {
-            StartPosition = startPosition;
-
-            AddLayout(gridCache);
-        }
-
-        protected override void Update()
-        {
-            base.Update();
-
-            if (!gridCache.IsValid)
-            {
-                ClearInternal();
-
-                if (DrawWidth > 0 && DrawHeight > 0)
-                    createContent();
-
-                gridCache.Validate();
-            }
-        }
-
-        private void createContent()
+        protected override void CreateContent()
         {
             var drawSize = DrawSize;
+            var rot = Quaternion.FromAxisAngle(Vector3.UnitZ, MathHelper.DegreesToRadians(GridLineRotation.Value));
 
-            generateGridLines(Direction.Horizontal, StartPosition.Y, 0, -Spacing.Y);
-            generateGridLines(Direction.Horizontal, StartPosition.Y, drawSize.Y, Spacing.Y);
+            GenerateGridLines(Vector2.Transform(new Vector2(0, -Spacing.Value.Y), rot), drawSize);
+            GenerateGridLines(Vector2.Transform(new Vector2(0, Spacing.Value.Y), rot), drawSize);
 
-            generateGridLines(Direction.Vertical, StartPosition.X, 0, -Spacing.X);
-            generateGridLines(Direction.Vertical, StartPosition.X, drawSize.X, Spacing.X);
+            GenerateGridLines(Vector2.Transform(new Vector2(-Spacing.Value.X, 0), rot), drawSize);
+            GenerateGridLines(Vector2.Transform(new Vector2(Spacing.Value.X, 0), rot), drawSize);
+
+            GenerateOutline(drawSize);
         }
 
-        private void generateGridLines(Direction direction, float startPosition, float endPosition, float step)
+        public override Vector2 GetSnappedPosition(Vector2 original)
         {
-            int index = 0;
-            float currentPosition = startPosition;
-
-            // Make lines the same width independent of display resolution.
-            float lineWidth = DrawWidth / ScreenSpaceDrawQuad.Width;
-
-            List<Box> generatedLines = new List<Box>();
-
-            while (Precision.AlmostBigger((endPosition - currentPosition) * Math.Sign(step), 0))
-            {
-                var gridLine = new Box
-                {
-                    Colour = Colour4.White,
-                    Alpha = 0.1f,
-                };
-
-                if (direction == Direction.Horizontal)
-                {
-                    gridLine.Origin = Anchor.CentreLeft;
-                    gridLine.RelativeSizeAxes = Axes.X;
-                    gridLine.Height = lineWidth;
-                    gridLine.Y = currentPosition;
-                }
-                else
-                {
-                    gridLine.Origin = Anchor.TopCentre;
-                    gridLine.RelativeSizeAxes = Axes.Y;
-                    gridLine.Width = lineWidth;
-                    gridLine.X = currentPosition;
-                }
-
-                generatedLines.Add(gridLine);
-
-                index += 1;
-                currentPosition = startPosition + index * step;
-            }
-
-            if (generatedLines.Count == 0)
-                return;
-
-            generatedLines.First().Alpha = 0.3f;
-            generatedLines.Last().Alpha = 0.3f;
-
-            AddRangeInternal(generatedLines);
-        }
-
-        public Vector2 GetSnappedPosition(Vector2 original)
-        {
-            Vector2 relativeToStart = original - StartPosition;
-            Vector2 offset = Vector2.Divide(relativeToStart, Spacing);
+            Vector2 relativeToStart = GeometryUtils.RotateVector(original - StartPosition.Value, GridLineRotation.Value);
+            Vector2 offset = Vector2.Divide(relativeToStart, Spacing.Value);
             Vector2 roundedOffset = new Vector2(MathF.Round(offset.X), MathF.Round(offset.Y));
 
-            return StartPosition + Vector2.Multiply(roundedOffset, Spacing);
+            return StartPosition.Value + GeometryUtils.RotateVector(Vector2.Multiply(roundedOffset, Spacing.Value), -GridLineRotation.Value);
         }
     }
 }

osu.Game/Utils/GeometryUtils.cs

@@ -26,9 +26,7 @@ namespace osu.Game.Utils
             point.X -= origin.X;
             point.Y -= origin.Y;
 
-            Vector2 ret;
-            ret.X = point.X * MathF.Cos(float.DegreesToRadians(angle)) + point.Y * MathF.Sin(float.DegreesToRadians(angle));
-            ret.Y = point.X * -MathF.Sin(float.DegreesToRadians(angle)) + point.Y * MathF.Cos(float.DegreesToRadians(angle));
+            Vector2 ret = RotateVector(point, angle);
 
             ret.X += origin.X;
             ret.Y += origin.Y;
@@ -36,6 +34,19 @@ namespace osu.Game.Utils
             return ret;
         }
 
+        /// <summary>
+        /// Rotate a vector around the origin.
+        /// </summary>
+        /// <param name="vector">The vector.</param>
+        /// <param name="angle">The angle to rotate (in degrees).</param>
+        public static Vector2 RotateVector(Vector2 vector, float angle)
+        {
+            return new Vector2(
+                vector.X * MathF.Cos(float.DegreesToRadians(angle)) + vector.Y * MathF.Sin(float.DegreesToRadians(angle)),
+                vector.X * -MathF.Sin(float.DegreesToRadians(angle)) + vector.Y * MathF.Cos(float.DegreesToRadians(angle))
+            );
+        }
+
         /// <summary>
         /// Given a flip direction, a surrounding quad for all selected objects, and a position,
         /// will return the flipped position in screen space coordinates.