Guarding the ground - adding the Blade

The Blade class will keep Pierre from flying too low. This enemy class will be similar to the others we have created, with one exception: we will generate a physics body based on the texture. The physics body circles that we have been using are much faster computationally and are usually sufficient to describe the shapes of our enemies; the Blade class requires a more complicated physics body, given its half-circle shape and bumpy edges:

Adding the Blade class

To add the Blade class, create a new file named Blade.swift and add the following code:

import SpriteKit 
 
class Blade: SKSpriteNode, GameSprite { 
    var initialSize = CGSize(width: 185, height: 92) 
    var textureAtlas:SKTextureAtlas = 
        SKTextureAtlas(named: "Enemies") 
    var spinAnimation = SKAction() 
 
    init() { 
        super.init(texture: nil, color: .clear, 
            size: initialSize) 
        let startTexture =...