Rotate SKSpriteNode along arc using SpriteKit

3
votes

I'm trying to figure out a method for rotating a SKSpriteNode object while it is in-flight (being affected by gravity) along an arc path. I'm using SpriteKit and throw the object using applyImpulse. The problem is that the object, despite traveling in an arc path in the air, stays in the same position.

Imagine an archer shooting an arrow. The arrow is shot upwards and should point upwards in that direction. Once the arrow starts falling along the arc, it should begin to rotate downwards.

Is there some way to automate this using the SpriteKit physics? Should I throw the arrow a different way instead of using applyImpulse? Do I need to come up with some algorithm by myself for the rotation based on the objects velocity?

1
iosanimationrotationsprite-kitskspritenode

1 Answers

5
votes

In your didSimulatePhysics or your update you can rotate your sprite towards its vector. Not sure theres a way to automatically make this happen. 

let angle = atan2(mySprite.physicsBody!.velocity.dy, mySprite.physicsBody!.velocity.dx)
mySprite.zRotation = angle