WEAPON SWAYING?(Does anyone know how to use "linear_interpolation" in 3D?)

Question

Does anyone know how to use "linearinterpolation" in 3D? I would make a weapon swaying, like PlanetSide2 or Battlefield. I think I had tried everything, but without some success. Here I've found the description of "linearinterpolate": https://docs.godotengine.org/en/3.1/tutorials/math/interpolation.html

Can somebody help me, please?

Answer 1

For something to sway you need to lerp using an amount that ping-pongs similar to Unity's Mathf.PingPong.

Here's a script that has a custom ping pong method.

export var number : float
export var pingpong_amount : float

func _process(delta):
    translation.lerp(start, end, ping_pong(number, pingpong_amount))
    number += delta

func ping_pong(number, pingpong):
    var length = 2*pingpong
    var value = number
    while value > length:
        value -= length
    if value > pingpong:
        return pingpong-(value-pingpong)
    else:
        return value