Move WaveformDisplay into separate class and add some commenting

osu.Game/Screens/Edit/Screens/Compose/WaveformDisplay.cs

@@ -0,0 +1,168 @@
+// 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 System.Collections.Generic;
+using OpenTK;
+using osu.Framework.Allocation;
+using osu.Framework.Audio.Track;
+using osu.Framework.Configuration;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Batches;
+using osu.Framework.Graphics.Colour;
+using osu.Framework.Graphics.OpenGL.Vertices;
+using osu.Framework.Graphics.Primitives;
+using osu.Framework.Graphics.Shaders;
+using osu.Framework.Graphics.Textures;
+using osu.Game.Beatmaps;
+
+namespace osu.Game.Screens.Edit.Screens.Compose
+{
+    public class WaveformDisplay : Drawable
+    {
+        /// <summary>
+        /// The beatmap which the audio waveform should be displayed for.
+        /// </summary>
+        /// <returns></returns>
+        public readonly Bindable<WorkingBeatmap> Beatmap = new Bindable<WorkingBeatmap>();
+
+        private Shader shader;
+        private readonly Texture texture;
+
+        public WaveformDisplay()
+        {
+            texture = Texture.WhitePixel;
+            Beatmap.ValueChanged += generateWaveform;
+        }
+
+        [BackgroundDependencyLoader]
+        private void load(ShaderManager shaders)
+        {
+            shader = shaders?.Load(VertexShaderDescriptor.TEXTURE_2, FragmentShaderDescriptor.TEXTURE_ROUNDED);
+        }
+
+        private float resolution = 1;
+        /// <summary>
+        /// Controls the amount of interpolation of the waveform into the width of this <see cref="WaveformDisplay"/>.
+        /// Points in the waveform are interpolated between 1 / <see cref="Resolution"/> pixels of this <see cref="WaveformDisplay"/>.
+        /// </summary>
+        /// <returns></returns>
+        public float Resolution
+        {
+            get { return resolution; }
+            set
+            {
+                if (value < 0 || value > 1)
+                    throw new ArgumentOutOfRangeException(nameof(value));
+
+                if (resolution == value)
+                    return;
+                resolution = value;
+
+                Invalidate(Invalidation.DrawNode);
+            }
+        }
+
+        private Waveform waveform;
+        private Track lastQueriedTrack;
+        private void generateWaveform(WorkingBeatmap beatmap)
+        {
+            // Cancel the old query so we don't saturate the audio thread
+            lastQueriedTrack?.CancelWaveformQuery();
+
+            beatmap.Track.QueryWaveform(w =>
+            {
+                if (Beatmap.Value == beatmap)
+                {
+                    waveform = w;
+                    Invalidate(Invalidation.DrawNode);
+                }
+            });
+
+            lastQueriedTrack = beatmap.Track;
+        }
+
+        private readonly WaveformDrawNodeSharedData sharedData = new WaveformDrawNodeSharedData();
+        protected override DrawNode CreateDrawNode() => new WaveformDrawNode();
+        protected override void ApplyDrawNode(DrawNode node)
+        {
+            var n = (WaveformDrawNode)node;
+
+            n.Shader = shader;
+            n.Texture = texture;
+            n.Size = DrawSize;
+            n.Shared = sharedData;
+            n.Points = waveform.Generate((int)(MathHelper.Clamp(Math.Ceiling(DrawWidth), 0, waveform.TotalPoints) * resolution));
+            n.Channels = waveform.Channels;
+
+            base.ApplyDrawNode(node);
+        }
+
+        private class WaveformDrawNodeSharedData
+        {
+            public readonly QuadBatch<TexturedVertex2D> VertexBatch = new QuadBatch<TexturedVertex2D>(1000, 10);
+        }
+
+        private class WaveformDrawNode : DrawNode
+        {
+            public Shader Shader;
+            public Texture Texture;
+
+            public WaveformDrawNodeSharedData Shared;
+
+            public List<WaveformPoint> Points;
+            public Vector2 Size;
+            public int Channels;
+
+            public override void Draw(Action<TexturedVertex2D> vertexAction)
+            {
+                base.Draw(vertexAction);
+
+                if (Points == null || Points.Count == 0)
+                    return;
+
+                Shader.Bind();
+                Texture.TextureGL.Bind();
+
+                float separation = Size.X / (Points.Count - 1);
+                Vector2 localInflationAmount = new Vector2(0, 1) * DrawInfo.MatrixInverse.ExtractScale().Xy;
+
+                for (int i = 0; i < Points.Count - 1; i++)
+                {
+                    ColourInfo colour = DrawInfo.Colour;
+                    Quad quadToDraw;
+
+                    switch (Channels)
+                    {
+                        default:
+                        case 2:
+                            {
+                                float height = Size.Y / 2;
+                                quadToDraw = new Quad(
+                                    new Vector2(i * separation, height - Points[i].Amplitude[0] * height),
+                                    new Vector2((i + 1) * separation, height - Points[i + 1].Amplitude[0] * height),
+                                    new Vector2(i * separation, height + Points[i].Amplitude[1] * height),
+                                    new Vector2((i + 1) * separation, height + Points[i + 1].Amplitude[1] * height)
+                                );
+                            }
+                            break;
+                        case 1:
+                            {
+                                quadToDraw = new Quad(
+                                    new Vector2(i * separation, Size.Y - Points[i].Amplitude[0] * Size.Y),
+                                    new Vector2((i + 1) * separation, Size.Y - Points[i + 1].Amplitude[0] * Size.Y),
+                                    new Vector2(i * separation, Size.Y),
+                                    new Vector2((i + 1) * separation, Size.Y)
+                                );
+                                break;
+                            }
+                    }
+
+                    Texture.DrawQuad(quadToDraw * DrawInfo.Matrix, colour, null, Shared.VertexBatch.Add, Vector2.Divide(localInflationAmount, quadToDraw.Size));
+                }
+
+                Shader.Unbind();
+            }
+        }
+    }
+}

osu.Game/Tests/Visual/TestCaseWaveform.cs

@@ -1,26 +1,17 @@
 // 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 System.Collections.Generic;
 using OpenTK;
 using OpenTK.Graphics;
-using OpenTK.Graphics.ES30;
 using osu.Framework.Allocation;
-using osu.Framework.Audio.Track;
 using osu.Framework.Configuration;
 using osu.Framework.Graphics;
-using osu.Framework.Graphics.Batches;
-using osu.Framework.Graphics.Colour;
 using osu.Framework.Graphics.Containers;
-using osu.Framework.Graphics.OpenGL.Vertices;
-using osu.Framework.Graphics.Primitives;
-using osu.Framework.Graphics.Shaders;
 using osu.Framework.Graphics.Shapes;
-using osu.Framework.Graphics.Textures;
 using osu.Game.Beatmaps;
 using osu.Game.Graphics.Sprites;
 using osu.Game.Overlays;
+using osu.Game.Screens.Edit.Screens.Compose;
 
 namespace osu.Game.Tests.Visual
 {
@@ -94,143 +85,5 @@ namespace osu.Game.Tests.Visual
 
         [BackgroundDependencyLoader]
         private void load(OsuGameBase osuGame) => beatmapBacking.BindTo(osuGame.Beatmap);
-
-        private class WaveformDisplay : Drawable
-        {
-            public readonly Bindable<WorkingBeatmap> Beatmap = new Bindable<WorkingBeatmap>();
-
-            private Waveform waveform;
-
-            private Shader shader;
-            private readonly Texture texture;
-
-            public WaveformDisplay()
-            {
-                texture = Texture.WhitePixel;
-                Beatmap.ValueChanged += generateWaveform;
-            }
-
-            [BackgroundDependencyLoader]
-            private void load(ShaderManager shaders)
-            {
-                shader = shaders?.Load(VertexShaderDescriptor.TEXTURE_2, FragmentShaderDescriptor.TEXTURE_ROUNDED);
-            }
-
-            private float resolution = 1;
-            public float Resolution
-            {
-                get { return resolution; }
-                set
-                {
-                    if (resolution == value)
-                        return;
-                    resolution = value;
-
-                    Invalidate(Invalidation.DrawNode);
-                }
-            }
-
-            private Track lastQueriedTrack;
-
-            private void generateWaveform(WorkingBeatmap beatmap)
-            {
-                // Cancel the old query so we don't saturate the audio thread
-                lastQueriedTrack?.CancelWaveformQuery();
-
-                beatmap.Track.QueryWaveform(w =>
-                {
-                    if (Beatmap.Value == beatmap)
-                    {
-                        waveform = w;
-                        Invalidate(Invalidation.DrawNode);
-                    }
-                });
-
-                lastQueriedTrack = beatmap.Track;
-            }
-
-            private readonly WaveformDrawNodeSharedData sharedData = new WaveformDrawNodeSharedData();
-            protected override DrawNode CreateDrawNode() => new WaveformDrawNode();
-            protected override void ApplyDrawNode(DrawNode node)
-            {
-                var n = (WaveformDrawNode)node;
-
-                n.Shader = shader;
-                n.Texture = texture;
-                n.Size = DrawSize;
-                n.Shared = sharedData;
-                n.Points = waveform.Generate((int)(MathHelper.Clamp(Math.Ceiling(DrawWidth), 0, waveform.TotalPoints) * resolution));
-                n.Channels = waveform.Channels;
-
-                base.ApplyDrawNode(node);
-            }
-
-            private class WaveformDrawNodeSharedData
-            {
-                public readonly QuadBatch<TexturedVertex2D> VertexBatch = new QuadBatch<TexturedVertex2D>(1000, 10);
-            }
-
-            private class WaveformDrawNode : DrawNode
-            {
-                public Shader Shader;
-                public Texture Texture;
-
-                public WaveformDrawNodeSharedData Shared;
-
-                public List<WaveformPoint> Points;
-                public Vector2 Size;
-                public int Channels;
-
-                public override void Draw(Action<TexturedVertex2D> vertexAction)
-                {
-                    base.Draw(vertexAction);
-
-                    if (Points == null || Points.Count == 0)
-                        return;
-
-                    Shader.Bind();
-                    Texture.TextureGL.Bind();
-
-                    float separation = Size.X / (Points.Count - 1);
-                    Vector2 localInflationAmount = new Vector2(0, 1) * DrawInfo.MatrixInverse.ExtractScale().Xy;
-
-                    for (int i = 0; i < Points.Count - 1; i++)
-                    {
-                        ColourInfo colour = DrawInfo.Colour;
-                        Quad quadToDraw;
-
-                        switch (Channels)
-                        {
-                            default:
-                            case 2:
-                                {
-                                    float height = Size.Y / 2;
-                                    quadToDraw = new Quad(
-                                        new Vector2(i * separation, height - Points[i].Amplitude[0] * height),
-                                        new Vector2((i + 1) * separation, height - Points[i + 1].Amplitude[0] * height),
-                                        new Vector2(i * separation, height + Points[i].Amplitude[1] * height),
-                                        new Vector2((i + 1) * separation, height + Points[i + 1].Amplitude[1] * height)
-                                    );
-                                }
-                                break;
-                            case 1:
-                                {
-                                    quadToDraw = new Quad(
-                                        new Vector2(i * separation, Size.Y - Points[i].Amplitude[0] * Size.Y),
-                                        new Vector2((i + 1) * separation, Size.Y - Points[i + 1].Amplitude[0] * Size.Y),
-                                        new Vector2(i * separation, Size.Y),
-                                        new Vector2((i + 1) * separation, Size.Y)
-                                    );
-                                    break;
-                                }
-                        }
-
-                        Texture.DrawQuad(quadToDraw * DrawInfo.Matrix, colour, null, Shared.VertexBatch.Add, Vector2.Divide(localInflationAmount, quadToDraw.Size));
-                    }
-
-                    Shader.Unbind();
-                }
-            }
-        }
     }
 }

osu.Game/osu.Game.csproj

@@ -620,6 +620,7 @@
     <Compile Include="Screens\Edit\Menus\ScreenSelectionTabControl.cs" />
     <Compile Include="Screens\Edit\Screens\EditorScreen.cs" />
     <Compile Include="Screens\Edit\Screens\Compose\Compose.cs" />
+    <Compile Include="Screens\Edit\Screens\Compose\WaveformDisplay.cs" />
     <Compile Include="Screens\Loader.cs" />
     <Compile Include="Screens\Menu\Button.cs" />
     <Compile Include="Screens\Menu\ButtonSystem.cs" />