I'm trying to use two points on a spaceship to create a "tank like movement" were the space ship will move forward when both points get an impulse on the
applyImpulse(CGVector, atPoint: CGPoint)
CGPoint(x: 0, y: 0) and CGPoint(x: 1, y: 0)
CGPoint(x: 0, y: 0) and CGPoint(x: spaceship.size.width, y: 0)
Reviewing the documentation, the points you apply the impulses at must be in scene coordinates. What that means, is you need to determine the points in the coordinates of your sprite (probably coordinates like
CGPoint(x: 0, y: 1) and
CGPoint(x: 0, y: -1), but you may need to play with those), then convert those to scene coordinates using
convertPoint(point, fromNode: ship).