Limit minimum brightness of combo colours

osu.Game/Configuration/OsuConfigManager.cs

@@ -175,6 +175,7 @@ namespace osu.Game.Configuration
             SetDefault(OsuSetting.EditorWaveformOpacity, 0.25f);
 
             SetDefault(OsuSetting.LastProcessedMetadataId, -1);
+            SetDefault(OsuSetting.ComboColourBrightness, 0.7f, 0f, 1f);
         }
 
         protected override bool CheckLookupContainsPrivateInformation(OsuSetting lookup)
@@ -370,6 +371,7 @@ namespace osu.Game.Configuration
         DiscordRichPresence,
         AutomaticallyDownloadWhenSpectating,
         ShowOnlineExplicitContent,
-        LastProcessedMetadataId
+        LastProcessedMetadataId,
+        ComboColourBrightness
     }
 }

osu.Game/Graphics/OsuColour.cs

@@ -229,6 +229,173 @@ namespace osu.Game.Graphics
             return Gray(brightness > 0.5f ? 0.2f : 0.9f);
         }
 
+        /// <summary>
+        /// Converts RGBA to HSPA.
+        /// </summary>
+        public static Color4 ToHSPA(Color4 colour)
+        {
+            const float p_r = 0.299f;
+            const float p_g = 0.587f;
+            const float p_b = 0.114f;
+
+            Color4 result = new Color4
+            {
+                A = colour.A,
+                B = MathF.Sqrt(colour.R * colour.R * p_r + colour.G * colour.G * p_g + colour.B + colour.B * p_b)
+            };
+
+            if (colour.R == colour.G && colour.R == colour.B)
+                return result;
+
+            if (colour.R >= colour.G && colour.R >= colour.B)
+            {
+                if (colour.B >= colour.G)
+                {
+                    result.R = 6f / 6f - 1f / 6f * (colour.B - colour.G) / (colour.R - colour.G);
+                    result.G = 1f - colour.G / colour.R;
+                }
+                else
+                {
+                    result.R = 0f / 6f + 1f / 6f * (colour.G - colour.B) / (colour.R - colour.B);
+                    result.G = 1f - colour.B / colour.R;
+                }
+            }
+            else if (colour.G >= colour.R && colour.G >= colour.B)
+            {
+                if (colour.R >= colour.B)
+                {
+                    result.R = 2f / 6f - 1f / 6f * (colour.R - colour.B) / (colour.G - colour.B);
+                    result.G = 1f - colour.B / colour.G;
+                }
+                else
+                {
+                    result.R = 2f / 6f + 1f / 6f * (colour.B - colour.R) / (colour.G - colour.R);
+                    result.G = 1f - colour.R / colour.G;
+                }
+            }
+            else
+            {
+                if (colour.G >= colour.R)
+                {
+                    result.R = 4f / 6f - 1f / 6f * (colour.G - colour.R) / (colour.B - colour.R);
+                    result.G = 1f - colour.R / colour.B;
+                }
+                else
+                {
+                    result.R = 4f / 6f + 1f / 6f * (colour.R - colour.G) / (colour.B - colour.G);
+                    result.G = 1f - colour.G / colour.B;
+                }
+            }
+
+            return result;
+        }
+
+        public static Color4 FromHSPA(Color4 colour)
+        {
+            const float p_r = 0.299f;
+            const float p_g = 0.587f;
+            const float p_b = 0.114f;
+
+            float minOverMax = 1f - colour.G;
+
+            Color4 result = new Color4 { A = colour.A };
+
+            if (minOverMax > 0f)
+            {
+                float part = 1f + colour.R * (1f / minOverMax - 1f);
+
+                if (colour.R < 1f / 6f)
+                {
+                    colour.R = 6f * (colour.R - 0f / 6f);
+                    result.B = colour.B / MathF.Sqrt(p_r / minOverMax / minOverMax + p_g * part * part + p_b);
+                    result.R = result.B / minOverMax;
+                    result.G = result.B + colour.R * (result.R - result.B);
+                }
+                else if (colour.R < 2f / 6f)
+                {
+                    colour.R = 6f * (-colour.R + 2f / 6f);
+                    result.B = colour.B / MathF.Sqrt(p_g / minOverMax / minOverMax + p_r * part * part + p_b);
+                    result.G = result.B / minOverMax;
+                    result.R = result.B + colour.R * (result.R - result.B);
+                }
+                else if (colour.R < 3f / 6f)
+                {
+                    colour.R = 6f * (colour.R - 2f / 6f);
+                    result.R = colour.B / MathF.Sqrt(p_g / minOverMax / minOverMax + p_b * part * part + p_r);
+                    result.G = result.R / minOverMax;
+                    result.B = result.R + colour.R * (result.G - result.R);
+                }
+                else if (colour.R < 4f / 6f)
+                {
+                    colour.R = 6f * (-colour.R + 4f / 6f);
+                    result.R = colour.B / MathF.Sqrt(p_b / minOverMax / minOverMax + p_g * part * part + p_r);
+                    result.B = result.R / minOverMax;
+                    result.G = result.R + colour.R * (result.B - result.R);
+                }
+                else if (colour.R < 5f / 6f)
+                {
+                    colour.R = 6f * (colour.R - 4f / 6f);
+                    result.G = colour.B / MathF.Sqrt(p_b / minOverMax / minOverMax + p_r * part * part + p_g);
+                    result.B = result.G / minOverMax;
+                    result.R = result.G + colour.R * (result.B - result.G);
+                }
+                else
+                {
+                    colour.R = 6f * (-colour.R + 6f / 6f);
+                    result.G = colour.B / MathF.Sqrt(p_r / minOverMax / minOverMax + p_b * part * part + p_g);
+                    result.R = result.G / minOverMax;
+                    result.B = result.G + colour.R * (result.R - result.G);
+                }
+            }
+            else
+            {
+                if (colour.R < 1f / 6f)
+                {
+                    colour.R = 6f * (colour.R - 0f / 6f);
+                    result.R = MathF.Sqrt(colour.B * colour.B / (p_r + p_g * colour.R * colour.R));
+                    result.G = result.R * colour.R;
+                    result.B = 0f;
+                }
+                else if (colour.R < 2f / 6f)
+                {
+                    colour.R = 6f * (-colour.R + 2f / 6f);
+                    result.G = MathF.Sqrt(colour.B * colour.B / (p_g + p_r * colour.R * colour.R));
+                    result.R = result.G * colour.R;
+                    result.B = 0f;
+                }
+                else if (colour.R < 3f / 6f)
+                {
+                    colour.R = 6f * (colour.R - 2f / 6f);
+                    result.G = MathF.Sqrt(colour.B * colour.B / (p_g + p_b * colour.R * colour.R));
+                    result.B = result.G * colour.R;
+                    result.R = 0f;
+                }
+                else if (colour.R < 4f / 6f)
+                {
+                    colour.R = 6f * (-colour.R + 4f / 6f);
+                    result.B = MathF.Sqrt(colour.B * colour.B / (p_b + p_g * colour.R * colour.R));
+                    result.G = result.B * colour.R;
+                    result.R = 0f;
+                }
+                else if (colour.R < 5f / 6f)
+                {
+                    colour.R = 6f * (colour.R - 4f / 6f);
+                    result.B = MathF.Sqrt(colour.B * colour.B / (p_b + p_r * colour.R * colour.R));
+                    result.R = result.B * colour.R;
+                    result.G = 0f;
+                }
+                else
+                {
+                    colour.R = 6f * (-colour.R + 6f / 6f);
+                    result.R = MathF.Sqrt(colour.B * colour.B / (p_r + p_b * colour.R * colour.R));
+                    result.B = result.R * colour.R;
+                    result.G = 0f;
+                }
+            }
+
+            return result;
+        }
+
         public readonly Color4 TeamColourRed = Color4Extensions.FromHex("#AA1414");
         public readonly Color4 TeamColourBlue = Color4Extensions.FromHex("#1462AA");
 

osu.Game/Overlays/Settings/Sections/Gameplay/BeatmapSettings.cs

@@ -40,6 +40,12 @@ namespace osu.Game.Overlays.Settings.Sections.Gameplay
                     LabelText = GraphicsSettingsStrings.StoryboardVideo,
                     Current = config.GetBindable<bool>(OsuSetting.ShowStoryboard)
                 },
+                new SettingsSlider<float>
+                {
+                    LabelText = "Combo colour brightness",
+                    Current = config.GetBindable<float>(OsuSetting.ComboColourBrightness),
+                    DisplayAsPercentage = true
+                }
             };
         }
     }

osu.Game/Rulesets/Objects/Drawables/DrawableHitObject.cs

@@ -17,6 +17,7 @@ using osu.Framework.Graphics.Primitives;
 using osu.Framework.Threading;
 using osu.Game.Audio;
 using osu.Game.Configuration;
+using osu.Game.Graphics;
 using osu.Game.Rulesets.Judgements;
 using osu.Game.Rulesets.Objects.Pooling;
 using osu.Game.Rulesets.Objects.Types;
@@ -128,6 +129,7 @@ namespace osu.Game.Rulesets.Objects.Drawables
         private readonly Bindable<int> comboIndexBindable = new Bindable<int>();
 
         private readonly Bindable<float> positionalHitsoundsLevel = new Bindable<float>();
+        private readonly Bindable<float> comboColourBrightness = new Bindable<float>();
         private readonly Bindable<int> comboIndexWithOffsetsBindable = new Bindable<int>();
 
         protected override bool RequiresChildrenUpdate => true;
@@ -171,6 +173,7 @@ namespace osu.Game.Rulesets.Objects.Drawables
         private void load(OsuConfigManager config, ISkinSource skinSource)
         {
             config.BindWith(OsuSetting.PositionalHitsoundsLevel, positionalHitsoundsLevel);
+            config.BindWith(OsuSetting.ComboColourBrightness, comboColourBrightness);
 
             // Explicit non-virtual function call in case a DrawableHitObject overrides AddInternal.
             base.AddInternal(Samples = new PausableSkinnableSound());
@@ -192,6 +195,8 @@ namespace osu.Game.Rulesets.Objects.Drawables
             comboIndexBindable.BindValueChanged(_ => UpdateComboColour());
             comboIndexWithOffsetsBindable.BindValueChanged(_ => UpdateComboColour(), true);
 
+            comboColourBrightness.BindValueChanged(_ => UpdateComboColour());
+
             // Apply transforms
             updateState(State.Value, true);
         }
@@ -519,7 +524,14 @@ namespace osu.Game.Rulesets.Objects.Drawables
         {
             if (!(HitObject is IHasComboInformation combo)) return;
 
-            AccentColour.Value = combo.GetComboColour(CurrentSkin);
+            Color4 colour = combo.GetComboColour(CurrentSkin);
+
+            // Normalise the combo colour to the given brightness level.
+            colour = OsuColour.ToHSPA(colour);
+            colour.B = comboColourBrightness.Value;
+            colour = OsuColour.FromHSPA(colour);
+
+            AccentColour.Value = colour;
         }
 
         /// <summary>