lerp

With this function you can find the value that equates to the position between two other values for a given percentage. So if you do, for example:

lerp(0, 10, 0.5)

you would get the return value of 5, which is 50% of the input values. You can extrapolate using this function too, by supplying a positive or negative value for the interpolation amount so that doing something like:

lerp(0, 10, 2)

will return a value of 20.

Syntax:

lerp(a, b, amt)

Returns:

Real

Example:

var _gamespeed = game_get_speed(gamespeed_fps);
xx = lerp(x, x + hspeed, _gamespeed);
yy = lerp(y, y + vspeed, _gamespeed);

The above code uses the linear interpolation function to predict where an instance would have moved to after one second of game time.