float FRichCurve::Eval(float InTime, float DefaultValue) const
{
// Remap time if extrapolation is present and compute offset value to use if cycling
float CycleValueOffset = 0;
RemapTimeValue(InTime, CycleValueOffset);
const int32 NumKeys = Keys.Num();
float InterpVal = DefaultValue;
if (NumKeys == 0)
{
// If no keys in curve, return the Default value we passed in.
InterpVal = DefaultValue;
}
else if (NumKeys < 2 || (InTime <= Keys[0].Time))
{
if (PreInfinityExtrap == RCCE_Linear && NumKeys > 1)
{
float DT = Keys[1].Time - Keys[0].Time;
if (FMath::IsNearlyZero(DT))
{
InterpVal = Keys[0].Value;
}
else
{
float DV = Keys[1].Value - Keys[0].Value;
float Slope = DV / DT;
InterpVal = Slope * (InTime - Keys[0].Time) + Keys[0].Value;
}
}
else
{
// Otherwise if constant or in a cycle or oscillate, always use the first key value
InterpVal = Keys[0].Value;
}
}
else if (InTime < Keys[NumKeys - 1].Time)
{
// perform a lower bound to get the second of the interpolation nodes
int32 first = 1;
int32 last = NumKeys - 1;
int32 count = last - first;
while (count > 0)
{
int32 step = count / 2;
int32 middle = first + step;
if (InTime > Keys[middle].Time)
{
first = middle + 1;
count -= step + 1;
}
else
{
count = step;
}
}
int32 InterpNode = first;
const float Diff = Keys[InterpNode].Time - Keys[InterpNode - 1].Time;
if (Diff > 0.f && Keys[InterpNode - 1].InterpMode != RCIM_Constant)
{
const float Alpha = (InTime - Keys[InterpNode - 1].Time) / Diff;
const float P0 = Keys[InterpNode - 1].Value;
const float P3 = Keys[InterpNode].Value;
if (Keys[InterpNode - 1].InterpMode == RCIM_Linear)
{
InterpVal = FMath::Lerp(P0, P3, Alpha);
}
else
{
const float OneThird = 1.0f / 3.0f;
const float P1 = P0 + (Keys[InterpNode - 1].LeaveTangent * Diff*OneThird);
const float P2 = P3 - (Keys[InterpNode].ArriveTangent * Diff*OneThird);
InterpVal = BezierInterp(P0, P1, P2, P3, Alpha);
}
}
else
{
InterpVal = Keys[InterpNode - 1].Value;
}
}
else
{
if (PostInfinityExtrap == RCCE_Linear)
{
float DT = Keys[NumKeys - 2].Time - Keys[NumKeys - 1].Time;
if (FMath::IsNearlyZero(DT))
{
InterpVal = Keys[NumKeys - 1].Value;
}
else
{
float DV = Keys[NumKeys - 2].Value - Keys[NumKeys - 1].Value;
float Slope = DV / DT;
InterpVal = Slope * (InTime - Keys[NumKeys - 1].Time) + Keys[NumKeys - 1].Value;
}
}
else
{
// Otherwise if constant or in a cycle or oscillate, always use the last key value
InterpVal = Keys[NumKeys - 1].Value;
}
}
return InterpVal+CycleValueOffset;
}
float FRichCurve::Eval(const float InTime, float DefaultValue) const
{
const int32 NumKeys = Keys.Num();
float InterpVal = DefaultValue;
if (NumKeys == 0)
{
// If no keys in curve, return the Default value we passed in.
InterpVal = DefaultValue;
}
else if (NumKeys < 2 || (InTime <= Keys[0].Time))
{
// If only one point, or before the first point in the curve, return the first points value.
InterpVal = Keys[0].Value;
}
else if (InTime < Keys[NumKeys - 1].Time)
{
// perform a lower bound to get the second of the interpolation nodes
int32 first = 1;
int32 last = NumKeys - 1;
int32 count = last - first;
while (count > 0)
{
int32 step = count / 2;
int32 middle = first + step;
if (InTime > Keys[middle].Time)
{
first = middle + 1;
count -= step + 1;
}
else
{
count = step;
}
}
int32 InterpNode = first;
const float Diff = Keys[InterpNode].Time - Keys[InterpNode - 1].Time;
if (Diff > 0.f && Keys[InterpNode - 1].InterpMode != RCIM_Constant)
{
const float Alpha = (InTime - Keys[InterpNode - 1].Time) / Diff;
const float P0 = Keys[InterpNode - 1].Value;
const float P3 = Keys[InterpNode].Value;
if (Keys[InterpNode - 1].InterpMode == RCIM_Linear)
{
InterpVal = FMath::Lerp(P0, P3, Alpha);
}
else
{
const float OneThird = 1.0f / 3.0f;
const float P1 = P0 + (Keys[InterpNode - 1].LeaveTangent * Diff*OneThird);
const float P2 = P3 - (Keys[InterpNode].ArriveTangent * Diff*OneThird);
InterpVal = BezierInterp(P0, P1, P2, P3, Alpha);
}
}
else
{
InterpVal = Keys[InterpNode - 1].Value;
}
}
else
{
// If beyond the last point in the curve, return its value.
InterpVal = Keys[NumKeys - 1].Value;
}
return InterpVal;
}
