From f45f17339c9d6c4d4c7d61020cbcfdd8ad090ac3 Mon Sep 17 00:00:00 2001
From: smoogipoo <smoogipoo@smgi.me>
Date: Thu, 24 Oct 2019 18:09:20 +0900
Subject: [PATCH] Implement slider path distance snapping

---
 .../Blueprints/Sliders/SliderPlacementBlueprint.cs    | 11 +++++++++--
 osu.Game/Rulesets/Edit/HitObjectComposer.cs           |  4 ++++
 .../Edit/Compose/Components/DistanceSnapGrid.cs       |  7 +++++++
 3 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/osu.Game.Rulesets.Osu/Edit/Blueprints/Sliders/SliderPlacementBlueprint.cs b/osu.Game.Rulesets.Osu/Edit/Blueprints/Sliders/SliderPlacementBlueprint.cs
index b7b8d0af88..e1478a062c 100644
--- a/osu.Game.Rulesets.Osu/Edit/Blueprints/Sliders/SliderPlacementBlueprint.cs
+++ b/osu.Game.Rulesets.Osu/Edit/Blueprints/Sliders/SliderPlacementBlueprint.cs
@@ -33,6 +33,9 @@ namespace osu.Game.Rulesets.Osu.Edit.Blueprints.Sliders
 
         private PlacementState state;
 
+        [Resolved]
+        private HitObjectComposer composer { get; set; }
+
         public SliderPlacementBlueprint()
             : base(new Objects.Slider())
         {
@@ -131,8 +134,12 @@ namespace osu.Game.Rulesets.Osu.Edit.Blueprints.Sliders
 
         private void updateSlider()
         {
-            var newControlPoints = segments.SelectMany(s => s.ControlPoints).Concat(cursor.Yield()).ToArray();
-            HitObject.Path = new SliderPath(newControlPoints.Length > 2 ? PathType.Bezier : PathType.Linear, newControlPoints);
+            Vector2[] newControlPoints = segments.SelectMany(s => s.ControlPoints).Concat(cursor.Yield()).ToArray();
+
+            var unsnappedPath = new SliderPath(newControlPoints.Length > 2 ? PathType.Bezier : PathType.Linear, newControlPoints);
+            var snappedDistance = composer.GetSnappedDistance((float)unsnappedPath.Distance);
+
+            HitObject.Path = new SliderPath(newControlPoints.Length > 2 ? PathType.Bezier : PathType.Linear, newControlPoints, snappedDistance);
 
             bodyPiece.UpdateFrom(HitObject);
             headCirclePiece.UpdateFrom(HitObject.HeadCircle);
diff --git a/osu.Game/Rulesets/Edit/HitObjectComposer.cs b/osu.Game/Rulesets/Edit/HitObjectComposer.cs
index 6396301add..f9d2734e80 100644
--- a/osu.Game/Rulesets/Edit/HitObjectComposer.cs
+++ b/osu.Game/Rulesets/Edit/HitObjectComposer.cs
@@ -261,6 +261,8 @@ namespace osu.Game.Rulesets.Edit
 
         public override double GetSnappedTime(double startTime, Vector2 position) => distanceSnapGrid?.GetSnapTime(position) ?? startTime;
 
+        public override float GetSnappedDistance(float distance) => distanceSnapGrid?.GetSnapDistance(distance) ?? distance;
+
         protected override void Dispose(bool isDisposing)
         {
             base.Dispose(isDisposing);
@@ -313,5 +315,7 @@ namespace osu.Game.Rulesets.Edit
         public abstract Vector2 GetSnappedPosition(Vector2 position);
 
         public abstract double GetSnappedTime(double startTime, Vector2 screenSpacePosition);
+
+        public abstract float GetSnappedDistance(float distance);
     }
 }
diff --git a/osu.Game/Screens/Edit/Compose/Components/DistanceSnapGrid.cs b/osu.Game/Screens/Edit/Compose/Components/DistanceSnapGrid.cs
index 096ff0a6dd..3bedff79f5 100644
--- a/osu.Game/Screens/Edit/Compose/Components/DistanceSnapGrid.cs
+++ b/osu.Game/Screens/Edit/Compose/Components/DistanceSnapGrid.cs
@@ -128,6 +128,13 @@ namespace osu.Game.Screens.Edit.Compose.Components
         /// <returns>The time at the snapped position.</returns>
         public double GetSnapTime(Vector2 position) => startTime + (position - CentrePosition).Length / Velocity;
 
+        /// <summary>
+        /// Snaps a distance by the snap distance of this grid.
+        /// </summary>
+        /// <param name="distance">The distance to snap.</param>
+        /// <returns>The snapped distance.</returns>
+        public float GetSnapDistance(float distance) => (int)(distance / DistanceSpacing) * DistanceSpacing;
+
         /// <summary>
         /// Retrieves the applicable colour for a beat index.
         /// </summary>