public override IEnumerable <Issue> GetIssues(Beatmap beatmap)
{
List <ObservedDistance> observedDistances = new List <ObservedDistance>();
double ratioProblemThreshold = 15.0;
double ratioWarningThreshold = 4.0;
double ratioMinorThreshold = 2.0;
double snapLeniencyMs = 5;
double deltaTime;
double distance;
foreach (HitObject hitObject in beatmap.hitObjects)
{
HitObject nextObject = hitObject.Next();
// Ignore spinners, since they have no clear start or end.
if (hitObject is Spinner || nextObject is Spinner || nextObject == null)
{
continue;
}
deltaTime = nextObject.GetPrevDeltaTime();
// Ignore objects ~1/2 or more beats apart (assuming 160 bpm), since they're unlikely to be an issue.
if (deltaTime > 180)
{
continue;
}
distance = nextObject.GetPrevDistance();
if (distance < 20)
{
distance = 20;
}
List <ObservedDistance> sameSnappedDistances =
observedDistances
.FindAll(observedDistance =>
deltaTime <= observedDistance.deltaTime + snapLeniencyMs &&
deltaTime >= observedDistance.deltaTime - snapLeniencyMs &&
// Count the distances of sliders separately, as these have leniency unlike circles.
observedDistance.hitObject is Slider == hitObject is Slider);
ObservedDistance observedDistance = new ObservedDistance(deltaTime, distance, hitObject);
observedDistances.Add(observedDistance);
if (!sameSnappedDistances.Any() ||
distance / deltaTime < sameSnappedDistances.Max(obvDist => obvDist.distance / obvDist.deltaTime * Decay(hitObject, obvDist)))
{
continue;
}
if (distance <= beatmap.difficultySettings.GetCircleRadius() * 4)
{
continue;
}
if (sameSnappedDistances.Count < 3)
{
// Too few samples, probably going to get inaccurate readings.
continue;
}
double expectedDistance = sameSnappedDistances.Sum(obvDist => obvDist.distance * Decay(hitObject, obvDist)) / sameSnappedDistances.Count();
double expectedDeltaTime = sameSnappedDistances.Sum(obvDist => obvDist.deltaTime * Decay(hitObject, obvDist)) / sameSnappedDistances.Count();
if (hitObject is Slider)
{
// Account for slider follow circle leniency.
distance -= Math.Min(beatmap.difficultySettings.GetCircleRadius() * 3, distance);
}
double actualExpectedRatio = (distance / deltaTime) / (expectedDistance / expectedDeltaTime);
if (actualExpectedRatio <= ratioMinorThreshold)
{
continue;
}
IEnumerable <string> comparisonTimestamps = sameSnappedDistances.Select(obvDist =>
Timestamp.Get(obvDist.hitObject, obvDist.hitObject.Next())
).TakeLast(3);
string templateName = "Minor";
if (actualExpectedRatio > ratioProblemThreshold)
{
templateName = "Problem";
}
else if (actualExpectedRatio > ratioWarningThreshold)
{
templateName = "Warning";
}
yield return(new Issue(GetTemplate(templateName), beatmap,
Timestamp.Get(hitObject, nextObject), Math.Round(actualExpectedRatio * 10) / 10,
string.Join("", comparisonTimestamps)));
}
}
