From 5f19081db69efe63a0f96a52771d3cefbffb661e Mon Sep 17 00:00:00 2001 From: smoogipoo Date: Fri, 9 Oct 2020 21:20:00 +0900 Subject: [PATCH] Fix incorrect probability calculation for hitobject conversion --- .../Legacy/HitObjectPatternGenerator.cs | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) diff --git a/osu.Game.Rulesets.Mania/Beatmaps/Patterns/Legacy/HitObjectPatternGenerator.cs b/osu.Game.Rulesets.Mania/Beatmaps/Patterns/Legacy/HitObjectPatternGenerator.cs index 84f950997d..bc4ab55767 100644 --- a/osu.Game.Rulesets.Mania/Beatmaps/Patterns/Legacy/HitObjectPatternGenerator.cs +++ b/osu.Game.Rulesets.Mania/Beatmaps/Patterns/Legacy/HitObjectPatternGenerator.cs @@ -397,7 +397,11 @@ namespace osu.Game.Rulesets.Mania.Beatmaps.Patterns.Legacy case 4: centreProbability = 0; - p2 = Math.Min(p2 * 2, 0.2); + + // Stable requires rngValue > x, which is an inverse-probability. Lazer uses true probability (1 - x). + // But multiplying this value by 2 (stable) is not the same operation as dividing it by 2 (lazer), + // so it needs to be converted to from a probability and then back after the multiplication. + p2 = 1 - Math.Max((1 - p2) * 2, 0.8); p3 = 0; break; @@ -408,11 +412,20 @@ namespace osu.Game.Rulesets.Mania.Beatmaps.Patterns.Legacy case 6: centreProbability = 0; - p2 = Math.Min(p2 * 2, 0.5); - p3 = Math.Min(p3 * 2, 0.15); + + // Stable requires rngValue > x, which is an inverse-probability. Lazer uses true probability (1 - x). + // But multiplying this value by 2 (stable) is not the same operation as dividing it by 2 (lazer), + // so it needs to be converted to from a probability and then back after the multiplication. + p2 = 1 - Math.Max((1 - p2) * 2, 0.5); + p3 = 1 - Math.Max((1 - p3) * 2, 0.85); break; } + // The stable values were allowed to exceed 1, which indicate <0% probability. + // These values needs to be clamped otherwise GetRandomNoteCount() will throw an exception. + p2 = Math.Clamp(p2, 0, 1); + p3 = Math.Clamp(p3, 0, 1); + double centreVal = Random.NextDouble(); int noteCount = GetRandomNoteCount(p2, p3);