Simple pin joint in SpriteKit doesn't work as expected - ios

Question

I'd like to make a pendulum. Starting with an SKScene and everything defaulted, I do the following...
- (void)createSceneContents {
self.physicsBody = [SKPhysicsBody bodyWithEdgeLoopFromRect:self.view.bounds];
// object 1 is the fulcrum
SKSpriteNode *object1 = [SKSpriteNode spriteNodeWithColor:[UIColor redColor] size:CGSizeMake(5, 5)];
[self addChild:object1];
object1.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:object1.frame.size];
object1.physicsBody.dynamic = NO;
object1.position = self.view.center;
// object2 is like a broomstick, which I will pin to the fulcrum
SKSpriteNode *object2 = [SKSpriteNode spriteNodeWithColor:[UIColor greenColor] size:CGSizeMake(90, 2)];
[self addChild:object2];
object2.anchorPoint = CGPointMake(0.0, 0.5);
object2.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:object2.frame.size];
object2.position = self.view.center;
// pin the physics bodies
SKPhysicsJointPin *pinJoint = [SKPhysicsJointPin jointWithBodyA:object1.physicsBody bodyB:object2.physicsBody anchor:object1.position];
[self.physicsWorld addJoint:pinJoint];
}
If I don't add the pin logic, as expected the fulcrum stays in the middle of the scene and the broomstick falls to the floor, so I know the broomstick is subject to gravity. After adding the pin, I get this:
No motion. Why? This causes no motion either...
[object2.physicsBody applyForce:CGVectorMake(0, -5)];
I expect the broomstick to swing and oscillate because it's pinned to the fulcrum. I've seen articles about positioning the nodes first, before joints, but I've done that. Am I wrong to expect the broom to swing? How can I get it to do so?

Answer 1

Node 2 have bad defined anchorPoint, here an upload an example:
Full code of example
Image:
Swift 3 code:
let nodeSize = CGSize(width: 10, height: 10)
let node = SKSpriteNode(color: .red, size: nodeSize)
node.physicsBody = SKPhysicsBody(rectangleOf: nodeSize)
node.physicsBody?.isDynamic = false
self.addChild(node)
let node2Size = CGSize(width: 60, height: 8)
let node2 = SKSpriteNode(color: .green, size: node2Size)
node2.position = CGPoint(x: 30, y: 0)
node2.physicsBody = SKPhysicsBody(rectangleOf: node2Size)
node2.physicsBody?.mass = 1.0
self.addChild(node2)
let a = SKPhysicsJointPin.joint(withBodyA: node.physicsBody! , bodyB: node2.physicsBody!, anchor: CGPoint(x: 0.0, y: 0.0))
self.physicsWorld.add(a)
Objective-C:
SKSpriteNode *object1 = [SKSpriteNode spriteNodeWithColor:[UIColor redColor] size:CGSizeMake(5, 5)];
[self addChild:object1];
object1.position = self.view.center;
object1.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:object1.frame.size];
object1.physicsBody.dynamic = NO;
SKSpriteNode *object2 = [SKSpriteNode spriteNodeWithColor:[UIColor greenColor] size:CGSizeMake(90, 2)];
[self addChild:object2];
object2.position = CGPointMake(self.view.center.x+45, self.view.center.y);
object2.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:object2.frame.size];
SKPhysicsJointPin *pinJoint = [SKPhysicsJointPin jointWithBodyA:object1.physicsBody bodyB:object2.physicsBody anchor:self.view.center];
[self.physicsWorld addJoint:pinJoint];

Answer 2

Thanks to #Maetschl, I was able to make it work in Objective-c as follows (removing the anchor point and just positioning the swinging node to one edge)...
SKSpriteNode *object1 = [SKSpriteNode spriteNodeWithColor:[UIColor redColor] size:CGSizeMake(5, 5)];
[self addChild:object1];
object1.position = self.view.center;
object1.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:object1.frame.size];
object1.physicsBody.dynamic = NO;
SKSpriteNode *object2 = [SKSpriteNode spriteNodeWithColor:[UIColor greenColor] size:CGSizeMake(90, 2)];
[self addChild:object2];
object2.position = CGPointMake(self.view.center.x+45, self.view.center.y);
object2.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:object2.frame.size];
SKPhysicsJointPin *pinJoint = [SKPhysicsJointPin jointWithBodyA:object1.physicsBody bodyB:object2.physicsBody anchor:self.view.center];
[self.physicsWorld addJoint:pinJoint];