So I'm trying to work with two SKPhysicsBody objects. I was looking at some tutorials to help work with the collision mechanics and dealing with that.
I pulled this code out of one of the tutorials:
func didBeginContact(contact: SKPhysicsContact) {
var firstBody: SKPhysicsBody
var secondBody: SKPhysicsBody
if contact.bodyA.categoryBitMask < contact.bodyB.categoryBitMask {
firstBody = contact.bodyA
secondBody = contact.bodyB
} else {
firstBody = contact.bodyB
secondBody = contact.bodyA
}
if ((firstBody.categoryBitMask & ColliderType.Bird != 0) &&
(secondBody.categoryBitMask & ColliderType.Edge != 0)) {
birdCollideWithEdge(firstBody.node as SKSpriteNode)
}
}
My ColliderType is set up like this:
enum ColliderType:UInt32 {
case Bird = 1
case Edge = 3
}
The error I'm getting comes from this line:
if ((firstBody.categoryBitMask & ColliderType.Bird != 0) &&
(secondBody.categoryBitMask & ColliderType.Edge != 0))
The error is
Could not find an overload for '&&' that accepts the supplied
arguments
I've tried casting the 0 as UInt32 and also casting the firstBody.categoryBitMask & ColliderType.Bird as Int but that didn't help.
I also tried bringing the firstBody.categoryBitMask & ColliderType.Bird out of that and setting it as it's own variable thinking that maybe there was just too much going on in that if statement but that didn't fix anything either.
Can anyone help push me toward the right documentation that might help or let me know if this won't work under its current setup.
Thanks in advance
EDIT: Adding rawValue to the end of ColliderType.Bird fixed my errors.
You can use rawValue of your enum this way:
if ((firstBody.categoryBitMask & ColliderType.Bird.rawValue != 0) && (secondBody.categoryBitMask & ColliderType.Edge.rawValue != 0)) {
}
Related
Okay I've searched around and I cannot find an answer to this problem.
I have 3 different node types that I want to handle collisions with. A meteor, a shot, and a station. I have the code for the collision handling between the shots and the meteors working perfectly, but I cannot for the life of me figure out how to respond to collisions (yes the collision is being detected but the response code isn't executing) between the station and a meteor. Here's my didBegin func:
func didBegin(_ contact: SKPhysicsContact){
print("contact")
let shot = (contact.bodyA.categoryBitMask == shotCategory) ? contact.bodyA : contact.bodyB
let stationBody = (contact.bodyA.categoryBitMask == stationCategory) ? contact.bodyA : contact.bodyB
let otherObject = (shot == contact.bodyA) ? contact.bodyB : contact.bodyA
if ((contact.bodyA == stationBody) && (contact.bodyB == otherObject)) {
print("collision!")
}
}
"contact" is being printed when a meteor collides with the station, but "collision!" is not being printed. I know its got something to do with the way the code is worded but i can't seem to get it to work no matter how I write/rewrite it
Try considering the order...
if (contact.bodyA == stationBody && contact.bodyB == otherObject) || (contact.bodyB == stationBody && contact.bodyA == otherObject)
Also you are setting the other object according to shot, so if shot is not one of the objects in the collision it might be a problem
if bodyA is the other object and bodyB the station for example, shot would be set to bodyB (because the categoryBitMask != shotCategory) and then the otherObject would be set to bodyA. Therefore contact.bodyB won't equal otherObject.
In my game, I use SKSprite. Some collisions are not detected. I did 10 tries, collisions are working well but about 25% of collisions that are supposed to be detected are not detected. I have NO idea why, I tried many things. Collisions are only with nodes of the same category.
I have no idea why randomly some collisions are not made when I can obviously see them, do you have any idea? Thanks for your help.
Here is the code of didBeginContact:
func didBeginContact(contact: SKPhysicsContact) {
var firstBody: SKPhysicsBody = contact.bodyA
var secondBody: SKPhysicsBody = contact.bodyB
if firstBody.categoryBitMask == secondBody.categoryBitMask {
listContacts.append([firstBody.node!,secondBody.node!])
}
}
}
Here is the code of didEndContact:
func didEndContact(contact: SKPhysicsContact) {
var firstBody: SKPhysicsBody = contact.bodyA
var secondBody: SKPhysicsBody = contact.bodyB
if contact.bodyA.categoryBitMask == contact.bodyB.categoryBitMask {
for i in listContacts{
if (i.contains(firstBody.node!) && i.contains(secondBody.node!)){
let findIndex = listContacts.indexOf { $0 == i }
listContacts.removeFirst(findIndex!)
}
}
}
Finally when I declare a new SKSpriteNode I set this:
rectangle.physicsBody = SKPhysicsBody(rectangleOfSize: rectangle.size)
rectangle.physicsBody?.dynamic = true
rectangle.physicsBody?.collisionBitMask = PhysicsCategory.None
usesPreciseCollisionDetection = true doesn't change anything so I don't use usePrecisionCollisionDetection
Every SKSpriteNode has his categoryBitmask and contactTestBitmask equal because only same SKSpriteNodes are supposed to collide.
Also:
physicsWorld.gravity = CGVectorMake(0, 0)
physicsWorld.contactDelegate = self
Finally here is a short video of my game if you want to understand easily what happens (problem of collisions are between rectangles) https://www.youtube.com/watch?v=-pbmKwQiE9U
You seem to be checking if the categoryBitMask of body A equals body B.
if firstBody.categoryBitMask == secondBody.categoryBitMask {
listContacts.append([firstBody.node!,secondBody.node!])
}
}
This will only run an action if a node hits a node with the same categoryBitMask
You should be checking the collisionBitMasks to see if you have a collision, or you can check the name.
For an example using categoryBitMask you can do something like this:
func didBeginContact(contact: SKPhysicsContact) {
var sprite: SKSpriteNode!
if contact.bodyA.categoryBitMask == <your category bitmask> {
sprite = contact.bodyA.node! as! SKSpriteNode
}
else if contact.bodyB.categoryBitMask == <your category bitmask> {
sprite = contact.bodyB.node! as! SKSpriteNode
}
// Do something with sprite....
// You can also create another sprite, and assign it to the other body, and perform functions on it, or both A and B.
// It is good to have different functions you send can send the nodes to once you find out which ones they are.
}
You can do these checks to see which sprites are hitting each other.
I just fixed it! The reason was that in the function "touchesEnded", I had a recursive function that was deleting bad connections in the listContacts!
struct PhysicsCategory {
static let None : UInt32 = 0
static let All : UInt32 = UInt32.max
static let planet : UInt32 = 0b1
static let rocket : UInt32 = 0b10 }
planet.physicsBody = SKPhysicsBody(circleOfRadius: planet.size.width / 2)
planet.physicsBody?.dynamic = true planet.physicsBody?.categoryBitMask = PhysicsCategory.planet
planet.physicsBody?.contactTestBitMask = PhysicsCategory.rocket
planet.physicsBody?.collisionBitMask = PhysicsCategory.None
func planetCollidedWithRocket(rocket: SKSpriteNode, planet: SKSpriteNode) {
println("collision planet") }
func didBeginContact(contact: SKPhysicsContact) {
var firstBody: SKPhysicsBody
var secondBody: SKPhysicsBody
if contact.bodyA.categoryBitMask < contact.bodyB.categoryBitMask {
firstBody = contact.bodyA
secondBody = contact.bodyB
} else {
firstBody = contact.bodyB
secondBody = contact.bodyA }
if ((firstBody.categoryBitMask & PhysicsCategory.planet != 0) &&
(secondBody.categoryBitMask & PhysicsCategory.rocket != 0)) {
planetCollidedWithRocket(firstBody.node as! SKSpriteNode, planet: secondBody.node as! SKSpriteNode)}
I'm currently using this to add collision detection to my game (I've taken only taken out the bits of code I think are relevant). The first time I ran the game on the simulator it worked fine, and I added a game over scene to the planetCollidedWithRocket method. But I tested it again today and for some reason the game is detecting a collision between the rocket and the planet when they aren't colliding! Can anyone see what Ive done wrong??
Your contact isn't set up correctly. This is what you have, and what it translates to:
if((firstBody.categoryBitMask & PhysicsCategory.planet !=0)
// This is checking if the firstBody *has* a categoryBitMask, but it is not evaluating what it is.
// In addition to that, it is requiring that the PhysicsCategory.planet does not equal zero, which it doesn't.
// This would evaluate to true every time, no matter what.
// It is also requiring that...
&& (secondBody.categoryBitMask & PhysicsCategory.rocket != 0))
// This is checking if the secondBody *has* a categoryBitMask, but it is not evaluating what it is.
// In addition to that, it is requiring that the PhysicsCategory.planet does not equal zero, which it doesn't.
// This would evaluate to true every time, no matter what.
What you need to do is check that you categoryBitMask equals one of your PhysicsCategory variables, such that when a planet and a rocket contact, something evaluates to true. Try this:
if ((firstBody.categoryBitMask == PhysicsCategory.planet) &&
(secondBody.categoryBitMask == PhysicsCategory.rocket)){
// Code Here
}
Alternatively, since you know the hard-coded numbers in your PhysicsCategory struct, you can evaluate to hard numbers:
if ((firstBody.categoryBitMask == 1) &&
(secondBody.categoryBitMask == 2)){
// Code Here
}
What this will do is check to see if the physicsBody's categoryBitMask equals certain numbers when they contact. If they do, something happens, if not, nothing happens.
I have been trying to do this for ages, what I would like to do is, I have a rocket and missiles coming down in my Scene and I want a very very simple explanation on how to do this so when the missiles collide with the rocket it will run a function in your code just call the function "func" and
I am not very familiar with SKPhysicsBody and enums so please explain those as well please (This is in swift spriteKit).
Thanks in Advance.
I would comment but i don't have enough reputation XD. I have watched a tutorial on youtube that explains you how to remove with collision. https://www.youtube.com/watch?v=ylIIy5EbsWQ
func didBeginContact(contact: SKPhysicsContact!){
// Body1 and 2 depend on the categoryBitMask << 0 und << 1
var firstBody:SKPhysicsBody
var secondBody:SKPhysicsBody
if (contact.bodyA.categoryBitMask < contact.bodyB.categoryBitMask){
firstBody = contact.bodyA
secondBody = contact.bodyB
}else{
firstBody = contact.bodyB
secondBody = contact.bodyA
}
torpedoDidCollideWithAlien(contact.bodyA.node as SKSpriteNode, alien: contact.bodyB.node as SKSpriteNode)
}
func torpedoDidCollideWithAlien(torpedo:SKSpriteNode, alien:SKSpriteNode){
println("HIT")
torpedo.removeFromParent()
alien.removeFromParent()
aliensDestroyed++
if (aliensDestroyed > 30){
var transition:SKTransition = SKTransition.flipHorizontalWithDuration(0.5)
var gameOverScene:SKScene = GameOverScene(size: self.size, won: true)
self.view.presentScene(gameOverScene, transition: transition)
}
}
I want a sprite to delete itself when touching another sprite. Right now when they touch, they just push each other.
I have this:
let alphaCategory: UInt32 = 0x1 << 0
let betaCategory: UInt32 = 0x1 << 1
I made the sprites dynamic and not affected by gravity
self.physicsworld.contactDelegate = self
alpha.physicsBody?.categoryBitMask = alphaCategory
alpha.physicsBody?.contactTestBitmask = betaCategory
and
beta.physicsBody?.categoryBitMask = betaCategory
beta.physicsBody?.contactTestBitmask = alphaCategory
I couldn't find anything in swift that made sense to me, but I think the problem is here
func didBeginContact(contact: SKPhysicsContact) {
var firstBody: SKPhysicsBody
var secondBody: SKPhysicsBody
if contact.bodyA.categoryBitMask < contact.bodyB.categoryBitMask {
firstBody = contact.bodyA
secondBody = contact.BodyB
beta.removeFromParent()
}
}
First you should set your firstBody & secondBody to the order of their collisionBitMask:
if contact.bodyA.categoryBitMask < contact.bodyB.categoryBitMask
{
firstBody = contact.bodyA
secondBody = contact.bodyB
}
else {
firstBody = contact.bodyB
secondBody = contact.bodyA
}
if firstBody.categoryBitMask=0 && secondBody.categoryBitMask=1 {
secondBody.removeFromParent()
}
This will prevent your sprites from colliding with anything (including each other). Set this where you set the other BitMask properties:
alpha.physicsBody.collisionBitMask = 0
beta.physicsBody.collisionBitMask = 0
This will actually cause problems as I found out last summer when working on a SpritKit game. If you modify the scene's node structure during any of the SKPhysicsContact callbacks the results are undefined according to Apple. What I was told after filing a bug on this was that you should never modify the scene Node structure from inside any of those callbacks. Instead, Apple says to simply set a flag and then deal with the scene modification in your update loop where it's safe.
Try:
secondBody = contact.bodyB