Can't add gravity vector on to velocity without vanishing far away

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Can't add gravity vector on to velocity without vanishing far away

elvisish

I have a direction, I get as dir = -get_transform().basis.z and a velocity which is set as dir * speed * delta and then I move it with: global_translate(). This works fine, but then I have gravity as grav = Vector3(0,-8,0) which when I add on via dir * speed + grav * delta makes it vanish into the distance. Strangely it also does it when I set grav = Vector3(0,0,0). Is this somehow translating everything to global coordinates? I tried translating the gravity with transform.basis.xform() and even transform.basis.xform_inv() but nothing works. Even if i try dir + grav and gravity is Vector3(0,0,0) it fires off into the distance?

elvisish

Okay, so this seems to be the correct way of doing it?

var velocity = dir * (speed * delta) + (gravity * delta)
global_translate(velocity )

Each part has to be separated up so as not to confuse things when multiplied by delta? It isn't really working that well though, should I be translating the velocity some other, better way?

cybereality

Yes, that is one way to do it. The issue with your first version was that speed was not getting multiplied by delta (only gravity) so that would make it insanely fast (probably like 1000x the normal speed).

elvisish

@cybereality said: Yes, that is one way to do it. The issue with your first version was that speed was not getting multiplied by delta (only gravity) so that would make it insanely fast (probably like 1000x the normal speed).

So, I had dir * speed * delta which worked okay, but dir * speed + grav * delta should also work? I'm not sure why speed wouldn't be multiplied by delta here?

cybereality

You have to multiply both. Here is one way to do it:

var velocity = (dir * speed + gravity) * delta
global_translate(velocity )