Help with Vector2.Lerp() [SOLVED]

1

Hi there,

So I’m trying to move a sprite to a specified position using Lerp, however, when I run my game the sprite just moves to one location between the two points and doesn’t constantly move and I can’t figure out why… I’m pretty sure its my ‘amount’ value but I have tried putting in a non-changing value and a value that changes with time.

In my code, the ‘sprite1’ is part of the components list. Here is my code:

`
public override void Update(GameTime gameTime)
{

        sprite1.pos = Vector2.Lerp(new Vector2(destionion.pos.X - 40, destionion.pos.Y - 40), gridclass.cord[7,3].nodepos, 0.4f);

        foreach (Components component in gamecomps)
            component.Update(gameTime);
    }`

Thanks for any help in advance!

2

The last parameter is a value from 0 to 1 that acts as a percentage for interpolating. If you put a value of 0.5, it will return a vector halfway between the start and the end (Ex. (0, 0) and (3, 1) will return (1.5, .5)); likewise, 0 will return the start vector and 1 will return the end vector.

You’ll need to update that value over time. Also make sure that your start and end vectors aren’t changing, or the lerp may be off.

1 Like
3

Hi thanks for your help, just got my sprite moving correctly! Thank you.
However, have one more question…
My sprite now moves beyond the second position and doesn’t stop there, I thought that with lerp the sprite would stop when reaching its destination?
Thanks for all the help

4

Lerp doesn’t do this by itself; to stop it, you’ll have to clamp the time value or stop calling lerp once the time has exceeded.

5

Lerp(a, b, t) just does a + (b - a) * t, which is a for t = 0 and b for t = 1. MG’s Lerp doesn’t clamp or check if t is in the [0 1] range. If you don’t want to overshoot you can clamp t yourself using t = MathHelper.Clamp(t, 0, 1).

1 Like
6

Thank a lot for your help! Much appreciated.