std::lerp
From cppreference.com
Defined in header <cmath>
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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.
Parameters
a, b, t | - | values of floating-point or integral types |
Return value
a+t*(b−a)
When isfinite(a) && isfinite(b)
, the following properties are guaranteed:
- If
t == 0
, the result is equal toa
. - If
t == 1
, the result is equal tob
. - If
t >= 0 && t <= 1
, the result is finite. - If
isfinite(t) && a == b
, the result is equal toa
. - If
isfinite(t) || (!isnan(t) && b-a != 0)
, the result is notNaN
.
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.)
Examples
This section is incomplete Reason: no example |