Up to date

This page is up to date for Godot 4.0. If you still find outdated information, please open an issue.

Interpolation

Interpolation is a very basic operation in graphics programming. It's good to become familiar with it in order to expand your horizons as a graphics developer.

The basic idea is that you want to transition from A to B. A value t, represents the states in-between.

For example, if t is 0, then the state is A. If t is 1, then the state is B. Anything in-between is an interpolation.

Between two real (floating-point) numbers, an interpolation can be described as:

interpolation = A * (1 - t) + B * t

And often simplified to:

interpolation = A + (B - A) * t

The name of this type of interpolation, which transforms a value into another at constant speed is "linear". So, when you hear about Linear Interpolation, you know they are referring to this formula.

There are other types of interpolations, which will not be covered here. A recommended read afterwards is the Bezier page.

Vector interpolation

Vector types (Vector2 and Vector3) can also be interpolated, they come with handy functions to do it Vector2.lerp() and Vector3.lerp().

For cubic interpolation, there are also Vector2.cubic_interpolate() and Vector3.cubic_interpolate(), which do a Bezier style interpolation.

Here is example pseudo-code for going from point A to B using interpolation:

var t = 0.0

func _physics_process(delta):
    t += delta * 0.4

    $Sprite2D.position = $A.position.lerp($B.position, t)