# lerp proc

Source: https://ref.dm-lang.org/proc/lerp
Added in BYOND 516.

### Format
> `lerp(A, B, factor)`

### Returns
> An interpolated value between A and B

### Args
- `A`: A number, matrix, vector, or turf/pixloc.
- `B`: Another number, matrix, vector, or turf/pixloc.
- `factor`: Interpolation factor, usually 0 to 1


Returns an interpolation or extrapolation from A to B. If factor is 0, A is returned; if factor is 1, B is returned. Otherwise an interpolated value between A and B is returned, based on the value of factor. The types of A and B must match, with few exceptions.

This is basically equivalent to returning `A + (B-A) * factor` for most things. When interpolating objects such as vectors, the returned value is always a new value, never a direct copy of A or B.

```dm /lerp/
usr << lerp(1, 5, 0.25)   // outputs 2
```

Turfs can be treated like pixlocs in `lerp()`, so you can interpolate between turfs. Note that they must have the same Z coordinate.

Matrix interpolation behaves according to the rules in the matrix [Interpolate()](https://ref.dm-lang.org/matrix/proc/Interpolate.md) proc. For linear interpolation you need to use `A + (B-A) * factor` instead.

### See also
- [vector](https://ref.dm-lang.org/vector/index.md)
- [pixloc](https://ref.dm-lang.org/pixloc/index.md)
- [Interpolate proc (matrix)](https://ref.dm-lang.org/matrix/proc/Interpolate.md)