getTangent method
t
- A position on the curve. Must be in the range 0, 1
.
optionalTarget
— (optional) If specified, the result will be
copied into this Vector, otherwise a new Vector will be created.
Returns a unit vector tangent at t. If the derived curve does not implement its tangent derivation, two points a small delta apart will be used to find its gradient which seems to give a reasonable approximation.
Implementation
@override
Vector getTangent(double t, [Vector? optionalTarget]) {
final tangent = optionalTarget ?? Vector2();
tangent.setFrom(v2).sub(v1).normalize();
return tangent;
}