Combine triangle system implementations.

osu.Game.Modes.Osu/Objects/Drawables/Pieces/CirclePiece.cs

@@ -14,9 +14,8 @@ namespace osu.Game.Modes.Osu.Objects.Drawables.Pieces
 {
     public class CirclePiece : Container
     {
-
         private Sprite disc;
-        private Triangles triangles;
+
 
         public Func<bool> Hit;
 
@@ -36,10 +35,11 @@ namespace osu.Game.Modes.Osu.Objects.Drawables.Pieces
                     Anchor = Anchor.Centre,
                     Origin = Anchor.Centre
                 },
-                triangles = new Triangles
+                new TrianglesPiece
                 {
+                    RelativeSizeAxes = Axes.Both,
                     BlendingMode = BlendingMode.Additive,
-                    RelativeSizeAxes = Axes.Both
+                    Alpha = 0.5f,
                 }
             };
         }

osu.Game.Modes.Osu/Objects/Drawables/Pieces/ExplodePiece.cs

@@ -21,10 +21,11 @@ namespace osu.Game.Modes.Osu.Objects.Drawables.Pieces
 
             Children = new Drawable[]
             {
-                new Triangles
+                new TrianglesPiece
                 {
                     BlendingMode = BlendingMode.Additive,
-                    RelativeSizeAxes = Axes.Both
+                    RelativeSizeAxes = Axes.Both,
+                    Alpha = 0.1f,
                 }
             };
         }

osu.Game.Modes.Osu/Objects/Drawables/Pieces/Triangles.cs

@@ -1,46 +0,0 @@
-// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
-// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
-
-using osu.Framework.Allocation;
-using osu.Framework.Graphics;
-using osu.Framework.Graphics.Containers;
-using osu.Framework.Graphics.Sprites;
-using osu.Framework.Graphics.Textures;
-using osu.Framework.MathUtils;
-using OpenTK;
-
-namespace osu.Game.Modes.Osu.Objects.Drawables.Pieces
-{
-    public class Triangles : Container<Triangle>
-    {
-        public override bool HandleInput => false;
-
-        protected override void LoadComplete()
-        {
-            base.LoadComplete();
-
-            const float size = 100;
-            for (int i = 0; i < 10; i++)
-            {
-                Add(new Triangle
-                {
-                    Origin = Anchor.Centre,
-                    RelativePositionAxes = Axes.Both,
-                    Position = new Vector2(RNG.NextSingle(), RNG.NextSingle()),
-                    Scale = new Vector2(RNG.NextSingle() * 0.4f + 0.2f),
-                    // Scaling height by 0.866 results in equiangular triangles (== 60° and equal side length)
-                    Size = new Vector2(size, 0.866f * size),
-                    Alpha = RNG.NextSingle() * 0.3f,
-                });
-            }
-        }
-
-        protected override void Update()
-        {
-            base.Update();
-
-            foreach (Drawable d in Children)
-                d.Position -= new Vector2(0, (float)(d.Scale.X * (Time.Elapsed / 2880)));
-        }
-    }
-}

osu.Game.Modes.Osu/Objects/Drawables/Pieces/TrianglesPiece.cs

@@ -0,0 +1,26 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using System;
+using osu.Game.Graphics.Backgrounds;
+
+namespace osu.Game.Modes.Osu.Objects.Drawables.Pieces
+{
+    public class TrianglesPiece : Triangles
+    {
+        protected override bool ExpireOffScreenTriangles => false;
+        protected override bool CreateNewTriangles => false;
+        protected override float SpawnRatio => 0.5f;
+
+        public TrianglesPiece()
+        {
+            TriangleScale = 1.2f;
+        }
+
+        protected override void Update()
+        {
+            if (IsPresent)
+                base.Update();
+        }
+    }
+}

osu.Game.Modes.Osu/osu.Game.Modes.Osu.csproj

@@ -62,7 +62,7 @@
     <Compile Include="Objects\Drawables\Pieces\RingPiece.cs" />
     <Compile Include="Objects\Drawables\Pieces\SliderBouncer.cs" />
     <Compile Include="Objects\Drawables\Pieces\SpinnerDisc.cs" />
-    <Compile Include="Objects\Drawables\Pieces\Triangles.cs" />
+    <Compile Include="Objects\Drawables\Pieces\TrianglesPiece.cs" />
     <Compile Include="Objects\Drawables\Pieces\SliderBall.cs" />
     <Compile Include="Objects\Drawables\Pieces\SliderBody.cs" />
     <Compile Include="Objects\OsuHitObjectParser.cs" />

osu.Game/Graphics/Backgrounds/Triangles.cs

@@ -2,12 +2,10 @@
 // Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
 using System.Linq;
-using osu.Framework.Allocation;
 using osu.Framework.Extensions.IEnumerableExtensions;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Sprites;
-using osu.Framework.Graphics.Textures;
 using osu.Framework.MathUtils;
 using OpenTK;
 using OpenTK.Graphics;
@@ -22,6 +20,21 @@ namespace osu.Game.Graphics.Backgrounds
         public Color4 ColourLight = Color4.White;
         public Color4 ColourDark = Color4.Black;
 
+        /// <summary>
+        /// Whether we want to expire triangles as they exit our draw area completely.
+        /// </summary>
+        protected virtual bool ExpireOffScreenTriangles => true;
+
+        /// <summary>
+        /// Whether we should create new triangles as others expire.
+        /// </summary>
+        protected virtual bool CreateNewTriangles => true;
+
+        /// <summary>
+        /// The amount of triangles we want compared to the default distribution.
+        /// </summary>
+        protected virtual float SpawnRatio => 1;
+
         private float triangleScale = 1;
 
         public float TriangleScale
@@ -29,9 +42,11 @@ namespace osu.Game.Graphics.Backgrounds
             get { return triangleScale; }
             set
             {
+                float change = value / triangleScale;
                 triangleScale = value;
 
-                Children.ForEach(t => t.ScaleTo(triangleScale));
+                if (change != 1)
+                    Children.ForEach(t => t.Scale *= change);
             }
         }
 
@@ -42,20 +57,20 @@ namespace osu.Game.Graphics.Backgrounds
                 addTriangle(true);
         }
 
-        private int aimTriangleCount => (int)(DrawWidth * DrawHeight * 0.002f / (triangleScale * triangleScale));
+        private int aimTriangleCount => (int)(DrawWidth * DrawHeight * 0.002f / (triangleScale * triangleScale) * SpawnRatio);
 
         protected override void Update()
         {
             base.Update();
 
-            foreach (Drawable d in Children)
+            foreach (var t in Children)
             {
-                d.Position -= new Vector2(0, (float)(d.Scale.X * (50 / DrawHeight) * (Time.Elapsed / 950)) / triangleScale);
+                t.Position -= new Vector2(0, (float)(t.Scale.X * (50 / DrawHeight) * (Time.Elapsed / 950)) / triangleScale);
-                if (d.DrawPosition.Y + d.DrawSize.Y * d.Scale.Y < 0)
+                if (ExpireOffScreenTriangles && t.DrawPosition.Y + t.DrawSize.Y * t.Scale.Y < 0)
-                    d.Expire();
+                    t.Expire();
             }
 
-            while (Children.Count() < aimTriangleCount)
+            while (CreateNewTriangles && Children.Count() < aimTriangleCount)
                 addTriangle(false);
         }
 
@@ -77,8 +92,8 @@ namespace osu.Game.Graphics.Backgrounds
                 RelativePositionAxes = Axes.Both,
                 Scale = new Vector2(scale),
                 EdgeSmoothness = new Vector2(1),
-                // Scaling height by 0.866 results in equiangular triangles (== 60° and equal side length)
                 Colour = GetTriangleShade(),
+                // Scaling height by 0.866 results in equiangular triangles (== 60° and equal side length)
                 Size = new Vector2(size, 0.866f * size),
                 Depth = scale,
             };
@@ -89,8 +104,8 @@ namespace osu.Game.Graphics.Backgrounds
         private void addTriangle(bool randomY)
         {
             var sprite = CreateTriangle();
-            var triangleHeight = sprite.DrawHeight / DrawHeight;
+            float triangleHeight = (sprite.DrawHeight / DrawHeight);
-            sprite.Position = new Vector2(RNG.NextSingle(), randomY ? (RNG.NextSingle() * (1 + triangleHeight) - triangleHeight) : 1);
+            sprite.Position = new Vector2(RNG.NextSingle(), randomY ? RNG.NextSingle() * (1 + triangleHeight) - triangleHeight : 1);
             Add(sprite);
         }
     }