Loss of Contact - ios

Question

I'm sorry to post this, I know it has been asked before but I have tried the previous solutions and nothing has seemed to work.
The problem that I'm having is that I use both didBeginContact and didEndContact to establish whether or not my sprite is touching the ground.
The sprite has a BOOL named grounded that determines this state. Basically I want to know if its on the ground when its touching a platform. The results that I am getting are a constant battle between establishing contact with the platform and then losing contact immediately, its very frustrating. Here's what I have so far:
-(Player *)createPlayer
{
...
sprite.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:player.size];
sprite.physicsBody.mass = 0.02;
sprite.physicsBody.restitution = 0;
sprite.physicsBody.categoryBitMask = playerCategory;
sprite.physicsBody.collisionBitMask = platformCategory;
sprite.physicsBody.contactTestBitMask = platformCategory;
sprite.physicsBody.usesPreciseCollisionDetection = YES;
return sprite;
}
-(SKSpriteNode *)createPlatform
{
SKSpriteNode *platform = [[SKSpriteNode alloc] initWithColor:[SKColor grayColor] size:CGSizeMake(100,25)];
platform.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:player.size];
platform.dynamic = NO;
platform.physicsBody.categoryBitMask = platformCategory;
platform.physicsBody.collisionBitMask = playerCategory;
platform.physicsBody.contactTestBitMask = playerCategory;
return platform;
}
-(void)didBeginContact:(SKPhysicsContact *)contact
{
SKPhysicsBody *firstBody, *secondBody;
if(contact.bodyA.categoryBitMask < contact.B.categoryBitMask)
{
firstBody = contact.bodyA;
secondBody = contact.bodyB;
}
else
{
firstBody = contact.bodyB;
secondBody = contact.bodyA;
}
if((firstBody.categoryBitMask & playerCategory) != 0)
{
Player *player = firstBody.node;
if((secondBody.categoyBitMask & platformCategoy) != 0)
{
NSLog(#"Connection Established");
player.grounded = YES;
}
}
}
-(void)didEndContact:(SKPhysicsContact *)contact
{
SKPhysicsBody *firstBody, *secondBody;
if(contact.bodyA.categoryBitMask < contact.B.categoryBitMask)
{
firstBody = contact.bodyA;
secondBody = contact.bodyB;
}
else
{
firstBody = contact.bodyB;
secondBody = contact.bodyA;
}
if((firstBody.categoryBitMask & playerCategory) != 0)
{
Player *player = firstBody.node;
if((secondBody.categoyBitMask & platformCategoy) != 0)
{
NSLog(#"Connection Lost");
player.grounded = NO;
}
}
}
Basically the end result of this looks like this when I examine the log:
Contact Established
Contact Lost
Contact Established
Contact Lost
Thank you in advance for any help you offer, I am completely stumped.

Answer 1

-(void)didEndContact:(SKPhysicsContact *)contact
{
uint32_t collision = (contact.bodyA.categoryBitMask | contact.bodyB.categoryBitMask);
if (collision != (playerCategory | platformCategory)) {
SKNode *node = contact.bodyA.node;
if (contact.bodyB.categoryBitMask == platformCategory) {
node = contact.bodyB.node;
}
NSLog(#"Connection Lost");
player.grounded = NO;
}