SpriteKit - Detect if node hits another nodes children and perform action - ios

Question

I have a Cat node, and a Bird node. The bird nodes are nested together in a container node called a birdBlock. Everything is contained in a WorldNode. If I add a bird to the WorldNode, the Cat can interact with it appropriately, but when the birds are in the birdBlock, the Cat just shoves them out of the way and they go flying.
I am using the following to find my birds:
[worldNode enumerateChildNodesWithName:kBirdName usingBlock:^(SKNode *node, BOOL *stop)
{
SKSpriteNode *newBird = (SKSpriteNode *)node;
if (CGRectIntersectsRect(newBird.frame,cat.frame))
{
//Do Something
//This is never reached when the birds are in the SKSpriteNode birdBlock.
//They just get shoved all over the screen.
}
}];
The birds in the block have the correct name.
They are now being enumerated, but still do not interact with the cat other than flying around the screen.
Now I am doing this:
[[worldNode children] enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop)
{
SKSpriteNode *blockNode = (SKSpriteNode *)obj;
if ([blockNode.name isEqualToString:kBirdBlockName])
{
[blockNode enumerateChildNodesWithName:kBirdName usingBlock:^(SKNode *node, BOOL *stop)
{
SKSpriteNode *nbird = (SKSpriteNode *)node;
NSLog(#"FOUND BIRDS HERE");
//THIS IS FOUND! But below still does not work
if (CGRectIntersectsRect(nbird.frame, cat.frame))
{
NSLog(#"Hit BIRD");
[nbird removeFromParent];
}
}
}
}];
So this does not work either. How do you change the coordinate system of a sprite?

Answer 1

You can search the node tree in many ways. The SKNode documentation explains it clearly under the section Searching the Node Tree.
If you have a node named #"node" then you can search through all descendants by putting a // before the name. So you would search for #"//node".
Try changing your constant kBirdName to equal #"//my_bird_name"
An example using a string literal would be -
[worldNode enumerateChildNodesWithName:#"//nodeName" usingBlock:^(SKNode *node, BOOL *stop)
{ // Do stuff here... }

Answer 2

I could not get this to work, so I just gave all the birds a physicsBody, and moved the detection to didBeginContact
Now it does not matter what their parent is and I don't need to worry about changing coordinates.
- (void)didBeginContact:(SKPhysicsContact *)contact
{
SKSpriteNode *firstNode = (SKSpriteNode *)contact.bodyA.node;
SKSpriteNode *secondNode = (SKSpriteNode *) contact.bodyB.node;
if ((firstNode.physicsBody.categoryBitMask == catCategory && secondNode.physicsBody.categoryBitMask == birdCategory) || (firstNode.physicsBody.categoryBitMask == birdCategory && secondNode.physicsBody.categoryBitMask == catCategory))
{
NSLog(#"DID HIT BIRD");
if (firstNode.physicsBody.categoryBitMask == catCategory) {
//do something to secondNode.
}
if (firstNode.physicsBody.categoryBitMask == birdCategory) {
//do something to firstNode.
}
}
}