Sprite Collision With Three Different Sprites? - objective-c

Question

I've created three sprites that works as walls in my scene. Then I have a sprite and a score. I want the sprite to set the score to 0 only when it touches the floor(one of the three sprites). So that's what I have for the contact.
- (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 & shipCategory) != 0 &&
(secondBody.categoryBitMask & obstacleCategory) != 0)
{
score = 0;
myLabel.text = [NSString stringWithFormat:#"%i", score];
}
}
Here are the categoryBitMask
static const uint32_t shipCategory = 0x1 << 1;
static const uint32_t obstacleCategory = 0x1 << 1;
static const uint32_t wallCategory = 0x1 << 1;
Theese are the codes for the sprite, the floor and the walls
-(SKSpriteNode *)floorNode
{
floorNode = [SKSpriteNode spriteNodeWithImageNamed:#"rectangle.png"];
floorNode.position = CGPointMake(160,100);
floorNode.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:floorNode.size];
floorNode.physicsBody.categoryBitMask = obstacleCategory;
floorNode.physicsBody.contactTestBitMask = shipCategory;
fireNode.physicsBody.usesPreciseCollisionDetection = YES;
fireNode.physicsBody.collisionBitMask = 2;
floorNode.physicsBody.dynamic = NO;
floorNode.zPosition = 1.0;
return floorNode;
}
-(SKSpriteNode *)walldxNode
{
walldxNode = [SKSpriteNode spriteNodeWithImageNamed:#"wall.png"];
walldxNode.position = CGPointMake(30, 568);
walldxNode.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:walldxNode.size];
walldxNode.physicsBody.categoryBitMask = wallCategory;
walldxNode.physicsBody.dynamic = NO;
return walldxNode;
}
-(SKSpriteNode *)wallsxNode
{
wallsxNode = [SKSpriteNode spriteNodeWithImageNamed:#"wall.png"];
wallsxNode.position = CGPointMake(290, 568);
wallsxNode.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:wallsxNode.size];
wallsxNode.physicsBody.categoryBitMask = wallCategory;
wallsxNode.physicsBody.dynamic = NO;
return wallsxNode;
}
-(SKSpriteNode *)fireButtonNode
{
fireNode = [SKSpriteNode spriteNodeWithImageNamed:#"Spaceship.png"];
fireNode.position = CGPointMake(160,450);
fireNode.xScale = 0.32;
fireNode.yScale = 0.32;
fireNode.physicsBody = [SKPhysicsBody bodyWithCircleOfRadius: fireNode.size.height/2];
fireNode.physicsBody.categoryBitMask = shipCategory;
fireNode.physicsBody.dynamic = YES;
fireNode.physicsBody.contactTestBitMask = obstacleCategory;
fireNode.physicsBody.collisionBitMask = 2;
fireNode.physicsBody.usesPreciseCollisionDetection = YES;
fireNode.name = #"fireButtonNode";//how the node is identified later
fireNode.zPosition = 2.0;
return fireNode;
}
The problem is that the sprite sets the score to 0 also when collides with the others two walls, which have differents categoryBitMask. I don't know what to do.

Answer 1

Your category bitmasks all have the same values. Make them differ like this:
static const uint32_t shipCategory = 0x1 << 1; // this equals 2
static const uint32_t obstacleCategory = 0x1 << 2; // this equals 4
static const uint32_t wallCategory = 0x1 << 3; // this equals 8

Answer 2

Batalia is correct, but these days you should probably use an enum rather than some crusty old static const. I did it in some code like this and then filed a bug against the sample code for not using Apple's own current best practices:
// These constans are used to define the physics interactions between physics bodies in the scene.
typedef NS_OPTIONS(NSUInteger, RockBusterCollionsMask) {
RBCmissileCategory = 1 << 0,
RBCasteroidCategory = 1 << 1,
RBCshipCategory = 1 << 2
};