internal void CalcStrain(CatchDifficultyHitObject lastHitObject, double timeRate)
{
var time = (HitObject.Offset - lastHitObject.HitObject.Offset) / timeRate;
var decay = Math.Pow(Constants.DecayBase, time / 1000d);
Offset = MathUtlity.Clamp(
lastHitObject.ScaledPosition + lastHitObject.Offset,
ScaledPosition - (Constants.NormalizedHitobjectRadius - _errorMargin),
ScaledPosition + (Constants.NormalizedHitobjectRadius - _errorMargin)) - ScaledPosition;
LastMovement = Math.Abs(ScaledPosition - lastHitObject.ScaledPosition + Offset - lastHitObject.Offset);
var addition = Math.Pow(LastMovement, 1.3) / 500;
if (ScaledPosition < lastHitObject.ScaledPosition)
{
LastMovement *= -1;
}
var additionBonus = 0d;
var sqrtTime = Math.Sqrt(Math.Max(time, 25));
if (Math.Abs(LastMovement) > 0.1)
{
if (Math.Abs(lastHitObject.LastMovement) > 0.1 &&
MathUtlity.Sign(LastMovement) != MathUtlity.Sign(lastHitObject.LastMovement))
{
var bonus = Constants.DirectionChangeBonus / sqrtTime;
var bonusFactor = Math.Min(_errorMargin, Math.Abs(LastMovement)) / _errorMargin;
addition += bonus * bonusFactor;
if (lastHitObject.HyperdashDistance <= 10)
{
additionBonus += 0.3 * bonusFactor;
}
}
addition += 7.5 * Math.Min(Math.Abs(LastMovement), Constants.NormalizedHitobjectRadius * 2) / (Constants.NormalizedHitobjectRadius * 6) / sqrtTime;
}
if (lastHitObject.HyperdashDistance <= 10)
{
if (!lastHitObject.HyperDash)
{
additionBonus += 1;
}
else
{
Offset = 0;
}
addition *= 1 + additionBonus * ((10 - lastHitObject.HyperdashDistance) / 10);
}
addition *= 850.0 / Math.Max(time, 25);
Strain = lastHitObject.Strain * decay + addition;
}
double CalcDifficulty()
{
double strainStep = Constants.StrainStep * TimeRate;
List <double> highestStrain = new List <double>();
double interval = strainStep;
double maxStrain = 0;
CatchDifficultyHitObject last = null;
foreach (var difficultyHitObject in DifficultyHitObjects)
{
while (difficultyHitObject.HitObject.Offset > interval)
{
highestStrain.Add(maxStrain);
if (last is null)
{
maxStrain = 0;
}
else
{
double decay = Math.Pow(Constants.DecayBase, (interval - last.HitObject.Offset) / 1000);
maxStrain = last.Strain * decay;
}
interval += strainStep;
}
if (difficultyHitObject.Strain > maxStrain)
{
maxStrain = difficultyHitObject.Strain;
}
last = difficultyHitObject;
}
double difficulty = 0, weight = 1;
var revserSortedList = from l in highestStrain orderby(int) l descending select l;
foreach (var strain in revserSortedList)
{
difficulty += weight * strain;
weight *= Constants.DecayWeight;
}
return(difficulty);
}
