Simulating physics

.swift

// If you do not want to create your own shapes, you can use SpriteKit to create a shape for you based on the sprite’s texture.

//objc
SKSpriteNode *sprite = [SKSpriteNode spriteNodeWithImageNamed:@"Spaceship"];
sprite.physicsBody = [SKPhysicsBody bodyWithTexture:sprite.texture size:sprite.texture.size];

//swift
let sprite = SKSpriteNode(imageNamed:"Spaceship")
sprite.physicsBody = SKPhysicsBody(texture: sprite.texture!, size: sprite.size)