Make RandomSeed a property, not a bindable

osu.Game.Rulesets.Catch.Tests/TestSceneFruitRandomness.cs

@@ -2,7 +2,6 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using NUnit.Framework;
-using osu.Framework.Bindables;
 using osu.Game.Rulesets.Catch.Objects;
 using osu.Game.Rulesets.Catch.Objects.Drawables;
 using osu.Game.Tests.Visual;
@@ -12,7 +11,6 @@ namespace osu.Game.Rulesets.Catch.Tests
 {
     public class TestSceneFruitRandomness : OsuTestScene
     {
-        private readonly Bindable<int> randomSeed = new Bindable<int>();
         private readonly TestDrawableFruit drawableFruit;
         private readonly TestDrawableBanana drawableBanana;
 
@@ -21,27 +19,30 @@ namespace osu.Game.Rulesets.Catch.Tests
             drawableFruit = new TestDrawableFruit(new Fruit());
             drawableBanana = new TestDrawableBanana(new Banana());
 
-            drawableFruit.RandomSeed.BindTo(randomSeed);
-            drawableBanana.RandomSeed.BindTo(randomSeed);
-
             Add(new TestDrawableCatchHitObjectSpecimen(drawableFruit) { X = -200 });
             Add(new TestDrawableCatchHitObjectSpecimen(drawableBanana));
 
-            AddSliderStep("random seed", 0, 100, 0, x => randomSeed.Value = x);
+            AddSliderStep("start time", 500, 600, 0, x =>
+            {
+                drawableFruit.HitObject.StartTime = drawableBanana.HitObject.StartTime = x;
+            });
         }
 
         [Test]
         public void TestFruitRandomness()
         {
+            // Use values such that the banana colour changes (2/3 of the integers are okay)
+            const int initial_start_time = 500;
+            const int another_start_time = 501;
+
             float fruitRotation = 0;
             float bananaRotation = 0;
             float bananaScale = 0;
             Color4 bananaColour = new Color4();
 
-            AddStep("set random seed to 0", () =>
+            AddStep("Initialize start time", () =>
             {
-                drawableFruit.HitObject.StartTime = 500;
+                drawableFruit.HitObject.StartTime = drawableBanana.HitObject.StartTime = initial_start_time;
-                randomSeed.Value = 0;
 
                 fruitRotation = drawableFruit.InnerRotation;
                 bananaRotation = drawableBanana.InnerRotation;
@@ -49,10 +50,9 @@ namespace osu.Game.Rulesets.Catch.Tests
                 bananaColour = drawableBanana.AccentColour.Value;
             });
 
-            AddStep("change random seed", () =>
+            AddStep("change start time", () =>
             {
-                // Use a seed value such that the banana colour is different (2/3 of the seed values are okay).
+                drawableFruit.HitObject.StartTime = drawableBanana.HitObject.StartTime = another_start_time;
-                randomSeed.Value = 10;
             });
 
             AddAssert("fruit rotation is changed", () => drawableFruit.InnerRotation != fruitRotation);
@@ -60,9 +60,9 @@ namespace osu.Game.Rulesets.Catch.Tests
             AddAssert("banana scale is changed", () => drawableBanana.InnerScale != bananaScale);
             AddAssert("banana colour is changed", () => drawableBanana.AccentColour.Value != bananaColour);
 
-            AddStep("reset random seed", () =>
+            AddStep("reset start time", () =>
             {
-                randomSeed.Value = 0;
+                drawableFruit.HitObject.StartTime = drawableBanana.HitObject.StartTime = initial_start_time;
             });
 
             AddAssert("rotation and scale restored", () =>
@@ -70,13 +70,6 @@ namespace osu.Game.Rulesets.Catch.Tests
                 drawableBanana.InnerRotation == bananaRotation &&
                 drawableBanana.InnerScale == bananaScale &&
                 drawableBanana.AccentColour.Value == bananaColour);
-
-            AddStep("change start time", () =>
-            {
-                drawableFruit.HitObject.StartTime = 1000;
-            });
-
-            AddAssert("random seed is changed", () => randomSeed.Value == 1000);
         }
 
         private class TestDrawableFruit : DrawableFruit

osu.Game.Rulesets.Catch/Objects/Banana.cs

@@ -33,7 +33,7 @@ namespace osu.Game.Rulesets.Catch.Objects
 
         private Color4 getBananaColour()
         {
-            switch (StatelessRNG.NextInt(3, RandomSeed.Value))
+            switch (StatelessRNG.NextInt(3, RandomSeed))
             {
                 default:
                     return new Color4(255, 240, 0, 255);

osu.Game.Rulesets.Catch/Objects/CatchHitObject.cs

@@ -99,9 +99,9 @@ namespace osu.Game.Rulesets.Catch.Objects
 
         /// <summary>
         /// The seed value used for visual randomness such as fruit rotation.
-        /// By default, <see cref="HitObject.StartTime"/> truncated to an integer is used.
+        /// The value is <see cref="HitObject.StartTime"/> truncated to an integer.
         /// </summary>
-        public Bindable<int> RandomSeed = new Bindable<int>();
+        public int RandomSeed => (int)StartTime;
 
         protected override void ApplyDefaultsToSelf(ControlPointInfo controlPointInfo, BeatmapDifficulty difficulty)
         {
@@ -117,10 +117,6 @@ namespace osu.Game.Rulesets.Catch.Objects
         protected CatchHitObject()
         {
             XBindable.BindValueChanged(x => originalX = x.NewValue - xOffset);
-            StartTimeBindable.BindValueChanged(change =>
-            {
-                RandomSeed.Value = (int)change.NewValue;
-            }, true);
         }
     }
 }

osu.Game.Rulesets.Catch/Objects/Drawables/DrawableBanana.cs

@@ -24,11 +24,8 @@ namespace osu.Game.Rulesets.Catch.Objects.Drawables
         {
             base.LoadComplete();
 
-            RandomSeed.BindValueChanged(_ =>
+            // start time affects the random seed which is used to determine the banana colour
-            {
+            StartTimeBindable.BindValueChanged(_ => UpdateComboColour());
-                UpdateComboColour();
-                UpdateInitialTransforms();
-            });
         }
 
         protected override void UpdateInitialTransforms()

osu.Game.Rulesets.Catch/Objects/Drawables/DrawableCatchHitObject.cs

@@ -21,7 +21,7 @@ namespace osu.Game.Rulesets.Catch.Objects.Drawables
 
         protected override float SamplePlaybackPosition => HitObject.X / CatchPlayfield.WIDTH;
 
-        public Bindable<int> RandomSeed = new Bindable<int>();
+        public int RandomSeed => HitObject?.RandomSeed ?? 0;
 
         protected DrawableCatchHitObject([CanBeNull] CatchHitObject hitObject)
             : base(hitObject)
@@ -32,14 +32,13 @@ namespace osu.Game.Rulesets.Catch.Objects.Drawables
         /// <summary>
         /// Get a random number in range [0,1) based on seed <see cref="RandomSeed"/>.
         /// </summary>
-        public float RandomSingle(int series) => StatelessRNG.NextSingle(RandomSeed.Value, series);
+        public float RandomSingle(int series) => StatelessRNG.NextSingle(RandomSeed, series);
 
         protected override void OnApply()
         {
             base.OnApply();
 
             XBindable.BindTo(HitObject.XBindable);
-            RandomSeed.BindTo(HitObject.RandomSeed);
         }
 
         protected override void OnFree()
@@ -47,7 +46,6 @@ namespace osu.Game.Rulesets.Catch.Objects.Drawables
             base.OnFree();
 
             XBindable.UnbindFrom(HitObject.XBindable);
-            RandomSeed.UnbindFrom(HitObject.RandomSeed);
         }
 
         public Func<CatchHitObject, bool> CheckPosition;

osu.Game.Rulesets.Catch/Objects/Drawables/DrawableFruit.cs

@@ -36,11 +36,13 @@ namespace osu.Game.Rulesets.Catch.Objects.Drawables
 
             VisualRepresentation.BindValueChanged(_ => updatePiece());
             HyperDash.BindValueChanged(_ => updatePiece(), true);
+        }
 
-            RandomSeed.BindValueChanged(_ =>
+        protected override void UpdateInitialTransforms()
-            {
+        {
-                ScaleContainer.Rotation = (RandomSingle(1) - 0.5f) * 40;
+            base.UpdateInitialTransforms();
-            }, true);
+
+            ScaleContainer.Rotation = (RandomSingle(1) - 0.5f) * 40;
         }
 
         private void updatePiece()