Sprite Kit Physics - Wrong behaviour on collision

Question

I'm working a on retro arcade game in Sprite Kit. I'm new to this framework so I discover new things every minute but having a hard time to solve this issue i've tried to solve for the past hours.

First a screendump of the game and the physics bodies outlined by red.

http://i.imgur.com/KcbMVn4.png?1

When you hit the boxing glove button the big guy performs a punch by this method

-(void)performPunch {
SKTexture *punch1 = [SKTexture textureWithImageNamed:@"punch1"];
SKTexture *punch2 = [SKTexture textureWithImageNamed:@"punch2"];
SKTexture *punch3 = [SKTexture textureWithImageNamed:@"punch3"];
SKTexture *punch4 = [SKTexture textureWithImageNamed:@"punch4"];
SKTexture *punch5 = [SKTexture textureWithImageNamed:@"punch5"];

NSArray *animationObjects = [NSArray arrayWithObjects:punch1, punch2, punch3, punch4, punch5, nil];

SKAction *punch = [SKAction animateWithTextures:animationObjects timePerFrame:0.1];
[_tusk runAction:punch withKey:@"punch"];

}

My collision delegate looks like this

    - (void)didBeginContact:(SKPhysicsContact *)contact
{
if([_tusk actionForKey:@"punch"]) {
    NSLog(@"DAT HIT");
}
}

My issue here is the only way to make didBeginContact to log the hit is when the punch is being made upon the first contact with the other units. I know it's pretty easy to understand as the method name says "didBeginContact" but I need something between this and the other "didEndContact" as I want to be able to punch the guys when I stand next to them :)

I need to better understand what you are trying to do. Do you want the punches to count only when the the physics bodies of the two characters are contacting each other? And during this contact, all punches count? Or do you want punches to count any time the character's fist appears to touch another character even though their physics bodies may not be in contact? — ninefifteen

meisenman meisenman · Accepted Answer · 2014-03-24T02:26:52

If your Glove and (thing that gets punched) are both sprites with physics bodies, you must set their collision categories and your didBeginContact would look more like:

- (void)didBeginContact:(SKPhysicsContact *)contact{

SKPhysicsBody *firstBody, *secondBody;

if (contact.bodyA.categoryBitMask < contact.bodyB.categoryBitMask)
{
    firstBody = contact.bodyA;
    secondBody = contact.bodyB;
}
else
{
    firstBody = contact.bodyB;
    secondBody = contact.bodyA;
}
if (firstBody.categoryBitMask==gloveCategory && secondBody.categoryBitMask == monsterCategory)
{
   NSLog(@"DAT HIT");
}

}

Sprite Kit Physics - Wrong behaviour on collision

1 Answers