From cc4f05f3d3ce98a33f3c51a2779d42930f4cc480 Mon Sep 17 00:00:00 2001
From: Andrei Zavatski <megaman9919@gmail.com>
Date: Wed, 16 Nov 2022 15:12:57 +0300
Subject: [PATCH] Replace Scale with SpeedMultiplier

---
 osu.Game/Graphics/Backgrounds/TrianglesV2.cs | 35 +++++++-------------
 1 file changed, 12 insertions(+), 23 deletions(-)

diff --git a/osu.Game/Graphics/Backgrounds/TrianglesV2.cs b/osu.Game/Graphics/Backgrounds/TrianglesV2.cs
index 01e4a39431..da31c6112b 100644
--- a/osu.Game/Graphics/Backgrounds/TrianglesV2.cs
+++ b/osu.Game/Graphics/Backgrounds/TrianglesV2.cs
@@ -57,14 +57,6 @@ namespace osu.Game.Graphics.Backgrounds
         /// </summary>
         protected virtual float SpawnRatio => 1;
 
-        private readonly BindableFloat triangleScale = new BindableFloat(1f);
-
-        public float TriangleScale
-        {
-            get => triangleScale.Value;
-            set => triangleScale.Value = value;
-        }
-
         /// <summary>
         /// The relative velocity of the triangles. Default is 1.
         /// </summary>
@@ -102,7 +94,7 @@ namespace osu.Game.Graphics.Backgrounds
             colourTop.BindValueChanged(_ => updateTexture());
             colourBottom.BindValueChanged(_ => updateTexture(), true);
 
-            triangleScale.BindValueChanged(_ => Reset(), true);
+            addTriangles(true);
         }
 
         private void updateTexture()
@@ -138,20 +130,17 @@ namespace osu.Game.Graphics.Backgrounds
 
             float elapsedSeconds = (float)Time.Elapsed / 1000;
             // Since position is relative, the velocity needs to scale inversely with DrawHeight.
-            // Since we will later multiply by the scale of individual triangles we normalize by
-            // dividing by triangleScale.
-            float movedDistance = -elapsedSeconds * Velocity * base_velocity / (DrawHeight * TriangleScale);
+            float movedDistance = -elapsedSeconds * Velocity * base_velocity / DrawHeight;
 
             for (int i = 0; i < parts.Count; i++)
             {
                 TriangleParticle newParticle = parts[i];
 
-                // Scale moved distance by the size of the triangle. Smaller triangles should move more slowly.
-                newParticle.Position.Y += Math.Max(0.5f, parts[i].Scale) * movedDistance;
+                newParticle.Position.Y += Math.Max(0.5f, parts[i].SpeedMultiplier) * movedDistance;
 
                 parts[i] = newParticle;
 
-                float bottomPos = parts[i].Position.Y + triangle_size * parts[i].Scale * equilateral_triangle_ratio / DrawHeight;
+                float bottomPos = parts[i].Position.Y + triangle_size * equilateral_triangle_ratio / DrawHeight;
                 if (bottomPos < 0)
                     parts.RemoveAt(i);
             }
@@ -177,7 +166,7 @@ namespace osu.Game.Graphics.Backgrounds
             // Limited by the maximum size of QuadVertexBuffer for safety.
             const int max_triangles = ushort.MaxValue / (IRenderer.VERTICES_PER_QUAD + 2);
 
-            AimCount = (int)Math.Min(max_triangles, DrawWidth * DrawHeight * 0.002f / (TriangleScale * TriangleScale) * SpawnRatio);
+            AimCount = (int)Math.Min(max_triangles, DrawWidth * DrawHeight * 0.001f * SpawnRatio);
 
             int currentCount = parts.Count;
 
@@ -194,7 +183,7 @@ namespace osu.Game.Graphics.Backgrounds
             if (randomY)
             {
                 // since triangles are drawn from the top - allow them to be positioned a bit above the screen
-                float maxOffset = triangle_size * particle.Scale * equilateral_triangle_ratio / DrawHeight;
+                float maxOffset = triangle_size * equilateral_triangle_ratio / DrawHeight;
                 y = Interpolation.ValueAt(nextRandom(), -maxOffset, 1f, 0f, 1f);
             }
 
@@ -204,7 +193,7 @@ namespace osu.Game.Graphics.Backgrounds
         }
 
         /// <summary>
-        /// Creates a triangle particle with a random scale.
+        /// Creates a triangle particle with a random speed multiplier.
         /// </summary>
         /// <returns>The triangle particle.</returns>
         protected virtual TriangleParticle CreateTriangle()
@@ -215,9 +204,9 @@ namespace osu.Game.Graphics.Backgrounds
             float u1 = 1 - nextRandom(); //uniform(0,1] random floats
             float u2 = 1 - nextRandom();
             float randStdNormal = (float)(Math.Sqrt(-2.0 * Math.Log(u1)) * Math.Sin(2.0 * Math.PI * u2)); // random normal(0,1)
-            float scale = Math.Max(TriangleScale * (mean + std_dev * randStdNormal), 0.1f); // random normal(mean,stdDev^2)
+            float speedMultiplier = Math.Max(mean + std_dev * randStdNormal, 0.1f); // random normal(mean,stdDev^2)
 
-            return new TriangleParticle { Scale = scale };
+            return new TriangleParticle { SpeedMultiplier = speedMultiplier };
         }
 
         private float nextRandom() => (float)(stableRandom?.NextDouble() ?? RNG.NextSingle());
@@ -267,7 +256,7 @@ namespace osu.Game.Graphics.Backgrounds
 
                 foreach (TriangleParticle particle in parts)
                 {
-                    var offset = triangle_size * new Vector2(particle.Scale * 0.5f, particle.Scale * equilateral_triangle_ratio);
+                    var offset = triangle_size * new Vector2(0.5f, equilateral_triangle_ratio);
 
                     Vector2 topLeft = particle.Position * size + new Vector2(-offset.X, 0f);
                     Vector2 topRight = particle.Position * size + new Vector2(offset.X, 0);
@@ -310,9 +299,9 @@ namespace osu.Game.Graphics.Backgrounds
             public Vector2 Position;
 
             /// <summary>
-            /// The scale of the triangle.
+            /// The speed multiplier of the triangle.
             /// </summary>
-            public float Scale;
+            public float SpeedMultiplier;
         }
     }
 }