SpriteKit simulation speed / applyImpluse speed

Question

I'm in the process of learning sprite kit and decided a catapult style game would be a good project to start with.

I am launching a projectile by using physicsBody?.applyImpulse(CGVector(dx: strength * dx, dy: strength * dy)) and this all works fine.

I'm currently trying to predict the trajectory of the projectile. I am doing this by applying the same impulse to a hidden SKNode and plotting the path it takes.

The problem is that the user has to wait until the impulse/physics has finished until they can see the full path. (see image below)

Path Image

(from the image above) I want the green path to either appear instantly or appear a lot faster.

I've tried to adjust the speed of the SKNode but it doesn't seem to have any effect on the simulation (it always runs at the same speed). I've also tried using SKAction.applyImpulse with the speed property being adjusted but it didn't have any effect either.

The only thing that has worked is setting physicsWorld.speed but I don't want to change the speed of the whole physics world, only the hidden trajectory node.

I was wondering if there was a way to run the physics simulation on a specific node instantly, or at least speed it up so it runs quicker?

Thanks in advance.

Answer 1

You can massively increase the gravity, and then factor this increase into the increase in the force used to project your object. This will result in the same arc of flight, but rising and falling much faster.