Scrolling the background and blocks

To simulate that the Yeti is running for its life, we will scroll the background, the floors, and the platforms independently.

To do this, let's start by defining a constant that we will use to control the speed of the blocks:

// Value for the blocks speed
const float kBLOCKS_SPEED = 220.0f;

Now we call the method that will start everything by adding the following lines at the end of the init method just before return self;:

    // Make the yeti run
    [self makeYetiRun];

We implement it by adding the following block of code:

-(void) makeYetiRun{
    // Run action
    [_yeti.yetiSprite runAction:_yeti.actionRun];
    // Update state
    _yeti.yetiState = yetiRunning;
    
    // Move platforms
    [self movePlatforms];
    // Move floors
    [self moveFloors];
    
    // Run the scrolling action
    if ([_backGroundScrollingNode numberOfRunningActions] == 0) {
        [_backGroundScrollingNode runAction:_loop];
    }
}

In this method, we start the previously...