Sprite Kit - Apply static impulse

Question

I have a simple example where I'm applying an impulse to a node on touch like so :

[_bird.physicsBody applyImpulse:CGVectorMake(0, 15)];

What I want is to apply a "static" impulse.

Let me explain : When my node is in a falling phase, due to gravity, applying an impulse will be harder and the impulse will apply a dy of 5 instead of 15 (for example).

In another case, when my node is not falling (i.e is on the ground), if I tapped multiple time quickly, my impulse seems to be multiplied and not being added, causing my node to reach the "roof" way too fast.

I want to apply the same number of dy, whenever the case.

Is there anyway to do that ?

Thanks in advance for your help.

Answer 1

In order to make the impulse have the same effect on the sprite node regardless of it's state, you could try setting it's velocity property to zero. Like so:

_bird.physicsBody.velocity = CGVectorMake(0,0);
[_bird.physicsBody applyImpulse:CGVectorMake(0, 15)];

This should make the 'bird' (Flappy Bird?) behave the same way in the any situation.