std::lerp (3) - Linux Manuals

std::lerp: std::lerp


std::lerp - std::lerp


Defined in header <cmath>
constexpr float lerp( float a, float b, float t ); (1) (since C++20)
constexpr double lerp( double a, double b, double t ); (2) (since C++20)
constexpr long double lerp( long double a, long double b, long double t ); (3) (since C++20)
constexpr Promoted lerp( Arithmetic1 a, Arithmetic2 b, Arithmetic3 t ); (4) (since C++20)

1-3) Computes a+t*(b−a), i.e. the linear interpolation between a and b for the parameter t (or extrapolation, when t is outside the range [0,1]).
4) A set of overloads or a function template for all combinations of arguments of arithmetic_type not covered by 1-3). If any argument has integral_type, it is cast to double. If any other argument is long double, then the return type is long double, otherwise it is double.


a, b, t - values of floating-point or integral_types

Return value

When isfinite(a) && isfinite(b), the following properties are guaranteed:

* If t == 0, the result is equal to a.
* If t == 1, the result is equal to b.
* If t >= 0 && t <= 1, the result is finite.
* If isfinite(t) && a == b, the result is equal to a.
* If isfinite(t) || (!isnan(t) && b-a != 0), the result is not NaN.

Let CMP(x,y) be 1 if x > y, -1 if x < y, and 0 otherwise. For any t1 and t2, the product of CMP(lerp(a, b, t2), lerp(a, b, t1)), CMP(t2, t1), and CMP(b, a) is non-negative. (That is, lerp is monotonic.)


 This section is incomplete
 Reason: no example