diff --git a/osu.Game/Storyboards/StoryboardSprite.cs b/osu.Game/Storyboards/StoryboardSprite.cs index a759482b5d..249be39b65 100644 --- a/osu.Game/Storyboards/StoryboardSprite.cs +++ b/osu.Game/Storyboards/StoryboardSprite.cs @@ -30,24 +30,52 @@ namespace osu.Game.Storyboards { get { - // check for presence affecting commands as an initial pass. - double earliestStartTime = TimelineGroup.EarliestDisplayedTime ?? double.MaxValue; + // To get the initial start time, we need to check whether the first alpha command to exist has an initial value of zero. + // A start value of zero on an alpha governs, above all else, the first valid display time of a sprite. + // + // To make this valid, we need to aggregate all alpha commands across all loops before checking for the first, time-wise, else we could run into a scenario where: + // L,1000,1 + // F,0,0,,1 # this NEEDS TO BE considered the StartTime... but has a StartValue greater than zero so won't in the initial pass. + // F,0,2000,,0 # ..this will be treated as earliest start due to a StartValue of zero. - foreach (var l in loops) + double zeroAlphaStartTimeOverride = double.MaxValue; + + var topLevelFirstAlphaCommand = TimelineGroup.Alpha.Commands.FirstOrDefault(); + if (topLevelFirstAlphaCommand?.StartValue == 0) + zeroAlphaStartTimeOverride = topLevelFirstAlphaCommand.StartTime; + + foreach (var loop in loops) { - if (l.EarliestDisplayedTime is double loopEarliestDisplayTime) - earliestStartTime = Math.Min(earliestStartTime, l.LoopStartTime + loopEarliestDisplayTime); + var loopFirstAlphaCommand = loop.Alpha.Commands.FirstOrDefault(); + + if (loopFirstAlphaCommand == null) + continue; + + double loopFirstAlphaStartTime = loopFirstAlphaCommand.StartTime + loop.LoopStartTime; + + if (loopFirstAlphaCommand.StartValue == 0) + { + // Found a loop containing a zero StartValue earlier than previous. + zeroAlphaStartTimeOverride = loopFirstAlphaStartTime; + } + else if (loopFirstAlphaStartTime < zeroAlphaStartTimeOverride) + { + // If a loop's first alpha command's StartValue is non-zero, we need to check whether the command's StartTime is less than any previously found zero alpha command. + // If this is the case, we want to abort zero alpha override logic and use the earliest command time instead. + // This is because if the first alpha command is non-zero, the sprite will be shown at that alpha from the time of the first command (of any type, not just alpha). + zeroAlphaStartTimeOverride = double.MaxValue; + break; + } } - if (earliestStartTime < double.MaxValue) - return earliestStartTime; - - // if an alpha-affecting command was not found, use the earliest of any command. - earliestStartTime = TimelineGroup.StartTime; + if (zeroAlphaStartTimeOverride < double.MaxValue) + return zeroAlphaStartTimeOverride; + // if we got to this point, either no alpha commands were present, or the earliest had a non-zero start value. + // the sprite's StartTime will be determined by the earliest command, of any type. + double earliestStartTime = TimelineGroup.StartTime; foreach (var l in loops) earliestStartTime = Math.Min(earliestStartTime, l.StartTime); - return earliestStartTime; } }