Prevent two SKSpriteNodes from overlapping - ios

Question

I want to reproduce Super-Mario for iOS using Swift and SpriteKit. I use SKPhysics-bodies to simulate collisions between the player and the environment. The player and all objects have their own SKPhysicsBody (rectangle of their size). But when the player jumps against a brick (from top left or top right) like this, the player stucks in the air.
My assumption is that when the two SKSpriteNodes collide, they overlap a tiny bit. And the SKPhysics-Engine thinks that the player is on top of the middle brick because the player is a tiny bit inside the brick above and falls down on the middle brick.
So my question is: How can i prevent SKSPriteNodes from overlapping? Or how can i fix this?
P.S. If you need more information to answer, please tell me!
EDIT: Some Code of the Brick Class:
import SpriteKit
class Brick: SKSpriteNode {
let imgBrick = SKTexture(imageNamed: "Brick")
init(let xCoor: Float, let yCoor: Float) {
// position is a global variable wich is 1334/3840
super.init(texture: imgBrick, color: UIColor.clearColor(), size: CGSize(width: 80*proportion, height: 80*proportion))
position = CGPoint(x:Int(xCoor*667)+Int(40*proportion), y:Int(375-(yCoor*375))-Int(40*proportion))
name = "Brick"
physicsBody = SKPhysicsBody(rectangleOfSize: self.size)
physicsBody?.affectedByGravity = false
physicsBody?.dynamic = false
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
and my Player Class
import SpriteKit
class Mario: SKSpriteNode {
let atlas = SKTextureAtlas(named: "Mario")
var imgMario = [SKTexture]()
var action = SKAction()
init(let xCoor: Float, let yCoor: Float) {
for(var i = 1; i < 24; i++) {
imgMario.append(atlas.textureNamed("X\(i)"))
}
super.init(texture: imgMario[0], color: UIColor.clearColor(), size: CGSize(width: 120*proportion, height: 160*proportion))
position = CGPoint(x:Int(xCoor)+Int(60*proportion), y:Int(yCoor)-Int(90*proportion))
name = "Mario"
physicsBody = SKPhysicsBody(rectangleOfSize: self.size)
physicsBody?.allowsRotation = false
action = SKAction.repeatActionForever(SKAction.animateWithTextures(imgMario, timePerFrame: 0.03, resize: false, restore: true))
runAction(action, withKey: "walking")
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
and SOME PART of my Level Class
class Level: SKScene, SKPhysicsContactDelegate {
var motionManager = CMMotionManager()
var mario = Mario(xCoor: 100, yCoor: 90)
var world = SKSpriteNode()
let MarioCategory: UInt32 = 0x1 << 0
let BrickCategory: UInt32 = 0x1 << 1
/*
Some more code...
*/
func setUpPhysics() {
physicsWorld.contactDelegate = self
mario.physicsBody!.categoryBitMask = marioCategory
mario.physicsBody?.collisionBitMask = brickCategory
mario.physicsBody?.contactTestBitMask = brickCategory
for(var i = 0; i < world.children.count; i++) {
if(world.children[i].name == "Brick") {
world.children[i].physicsBody?.categoryBitMask = brickCategory
world.children[i].physicsBody?.collisionBitMask = marioCategory
world.children[i].physicsBody?.contactTestBitMask = marioCategory
world.children[i].physicsBody?.friction = 0
}
}
}
}

Answer 1

Try setting UsePreciseCollisionDetection to true on your physicsbody.
mario.physicsBody?.usesPreciseCollisionDetection = true
https://developer.apple.com/reference/spritekit/skphysicsbody has some examples.
By setting this property to true could cause it to detect collisions more accurately so only when you mean to. I'd also rethink giving each block its own physics body. You only really care about the edge of a group of blocks rather than the edges of each individual block.
Another suggestion is that you can create a physics body based on a texture. So if your SKSpriteNode has a complex texture with transparent bits you can create another texture that is just a simple black block or similar this will help the engine detect more accurate collisions.