I'm a beginner with Swift and SpriteKit and I am working on a basic game. I have created a Sprite game character (Sapceman) using 2 SKTexture images. When the screen is touched the Sprite image changes from one texture image to another(Jet Pack Fires) and the Sprite is moved around the screen. I want to set up a collision detection (with an Alien Spite) that removes them from the screen but only when the screen is touched and second texture image is displayed and only for the bottom part of the sprite (i.e. when the person touches the screen and the JetPack is fired I want the fire part to "kill" the alien). Appreciate if anyone can offer any suggestions on this
Try this code
static const uint32_t fireBallCategory = 0x1;
static const uint32_t alienCategory = 0x1 << 1;
In adding fire ball and alien method add this,
fireBall.physicsBody.categoryBitMask = fireBallCategory;
alien.physicsBody.categoryBitMask = alienCategory;
fireBall.physicsBody.contactTestBitMask = alienCategory;
By doing this you will get notified when fireball and aliens meet each other. So after this you have to add logic to hide alien in delegate method. So first set self as contact delegate. Add this line in -(id)initWithSize:(CGSize)size method.
self.physicsWorld.contactDelegate = self;
Implement the contact delegate as follows,
-(void)didBeginContact:(SKPhysicsContact *)contact
{
SKPhysicsBody *notFireBall;
if (contact.bodyA.categoryBitMask < contact.bodyB.categoryBitMask){
notFireBall = contact.bodyB;
} else {
notFireBall = contact.bodyA;
}
[notFireBall removeFromParent];
}
Related
I am creating a game where I do not want the player to be able to move out of the screen. The node follows the players moving touch. The code I have "under construction" so the player can't move out on the top or right side, but I do not want the player to be able to move out on any of the sides.
- (void)movementPlayer {
SKAction * actionMoveX = [SKAction moveToX:MIN(location2.x - playerPositionX, self.size.width - (_player.size.width/2)) duration:0];
SKAction * actionMoveY = [SKAction moveToY:MIN(location2.y - playerPositionY, self.size.height - (_player.size.height/2)) duration:0];
[_player runAction:[SKAction sequence:#[actionMoveX, actionMoveY]]];
}
You should create a physics world and add a border rectangle around the screen. This border must have a physics body that is set to collide with the physics body collision category given to your player node. If the player node starts inside the border, the player cannot leave the screen and no additional coding is required (besides properly setting up collision categories for each physics body)
RayWenderlich.com has easy to understand game tutorials that show how to handle collisions following the sprite kit manual.
In your SKScene:
self.physicsBody=[SKPhysicsBody bodyWithEdgeLoopFromRect:self.frame];
self.physicsWorld.gravity=CGVectorMake=(0,0);
_player.physicsBody=[SKPhysicsBody bodyWithRectangleOfSize:CGSizeMake(10,10)];//example; use bodyWithPolygonFromPath:yourCGPath if player has more complex form, or bodyWithCircleOfRadius:radius if its shape is circle
_player.physicsBody.velocity=CGVectorMake(10,10); //or more then 10,10
Good luck!
just add the bottom code to your method that is called it should stop all physical bodies from leaving the screen!! veryuseful!
SKPhysicsBody* gameborderBody = [SKPhysicsBody bodyWithEdgeLoopFromRect:self.frame];
// 2 Set physicsBody of scene to borderBody
self.physicsBody = gameborderBody;
// 3 Set the friction of that physicsBody to 0
self.physicsBody.friction = 1.0f;
I want to make two sprites disappear when they hit each other in sprite kit. The example in apple's documentation doesn't really help me that much so if you could explain it it would be good. :)
OK, so you need to do several things.
I'm going to assume that you have two sprites...
SKSpriteNode *sprite1;
SKSpriteNode *sprite2;
These are currently flying around your scene and may or may not come into contact with each other.
So, you need to set everything up to enable hit testing and call backs.
First, add physics bodies to the sprites...
sprite1.physicsBody = [SKPhysicsBody bodyWithCircleOfRadius:10];
sprite2.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:CGSizeMake(10, 10)];
// this is a couple of examples, you'll have to set yours up to match the sprite size, shapes
Next you need to add categories to the sprites. This gives the physics engine some information about what type of body it is...
sprite1.physicsBody.categoryBitMask = 1 << 0;
sprite2.physicsBody.categoryBitMask = 1 << 1;
// again this is an example. You probably want to put these in an NS_OPTIONS typedef.
Then you need to tell the physics engine which contact you want to be told about. In the is case you want to be told when sprite1 (1 << 0) comes into contact with sprite2 (1 << 1).
So...
sprite1.physicsBody.contactTestBitMask = 1 << 1; // it will test for contact against sprite 2
sprite2.physicsBody.contactTestBitMask = 1 << 0; // test against sprite 1.
Now in you scene you need to adopt <SKPhysicsContactDelegate> and set the scene to be the physics delegate...
self.physicsWorld.contactDelegate = self;
And then create the method...
- (void)didBeginContact:(SKPhysicsContact *)contact
{
// these two physics bodies have come into contact!
SKSpriteNode *firstContactNode = contact.bodyA.node;
SKSpriteNode *secondContactNode = contact.bodyB.node;
// now remove them...
[firstContactNode removeFromParent];
[secondContactNode removeFromParent];
}
SKAction* _vanishAction =[SKAction fadeOutWithDuration: 1];
[sprite runAction:_vanishAction completion:^(void){
[sprite removeFromParent];
}];
Hi I am trying to setup collision detection in my game and I want to add collision detection so when the balloons hit the spikes they pop. I have looked at Ray Wenderliches tutorial but I couldn't figure it out because it didn't apply to my case. Any ideas how to set it up for my case?
The spikes are at the top of the screen and the balloons spawn at the bottom.
The basics for setting upp collision between 2 objects is to first setting upp constant that represent the different objects that can collide. I usually make a constants.h file where i keep all the variables that will be used thru out the game/application.
Declare following in either a constants.h file or just declare them as global variables in the class:
static const int balloonHitCategory = 1;
static const int spikeHitCategory = 2;
What you want to do now is set up the physics for both your balloon and spikes
SKSpriteNode *ballooon = [SKSpriteNode spriteNodeWithImageNamed:#"yourimagefilename"];
ballooon.physicsBody = [SKPhysicsBody bodyWithCircleOfRadius:yourSize];
ballooon.physicsBody.categoryBitMask = balloonHitCategory;
ballooon.physicsBody.contactTestBitMask = spikeHitCategory;
ballooon.physicsBody.collisionBitMask = spikeHitCategory;
you should set your size and set your images for both of the spritenodes
SKSpriteNode *spikes = [SKSpriteNode spriteNodeWithImageNamed:#"yourimagefilename"];
spikes.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:CGSizeMake(yourSizeX, yourSizeY)];
spikes.physicsBody.categoryBitMask = spikeHitCategory;
spikes.physicsBody.contactTestBitMask = balloonHitCategory;
spikes.physicsBody.collisionBitMask = balloonHitCategory;
for collision set up the following method:
-(void)didBeginContact:(SKPhysicsContact *)contact
{
SKPhysicsBody *firstBody, *secondBody;
firstBody = contact.bodyA;
secondBody = contact.bodyB;
if(firstBody.categoryBitMask == spikeHitCategory || secondBody.categoryBitMask == spikeHitCategory)
{
NSLog(#"balloon hit the spikes");
//setup your methods and other things here
}
}
Before the collision will work you should also add the . In your scenes .h file add .
#interface myScene : SKScene <SKPhysicsContactDelegate>
#end
and in the .m file in the init function add:
-(id)initWithSize:(CGSize)size {
if (self = [super initWithSize:size]) {
self.physicsWorld.contactDelegate = self;
}
return self;
}
For more about collision handling check out apple documentation and adventure game example:
https://developer.apple.com/library/ios/documentation/GraphicsAnimation/Conceptual/CodeExplainedAdventure/HandlingCollisions/HandlingCollisions.html#//apple_ref/doc/uid/TP40013140-CH5-SW1
I have just released a plug-in 2D collision engine for Sprite Kit. It's still in its early stages but could be of some help to you: https://github.com/henryeverett/ToastCollisions2D
I am working on an iOS game using Sprite Kit.
I recently added an SKSpriteNode into my scene and did NOT create a physics body for it. However, when I build and run, when the player's character(which does have a physics body) moves into the SKSpriteNode, it spins and moves away, like it has a physics body -but I didn't create one for the SKSpriteNode.
Even if I type
sprite.physicsBody = nil;
it still behaves like it's part of the simulation.
I wondered if a physics body is created automatically when you make an SKSpriteNode, but I looked at the documentation and searched it on Google and couldn't find anything to suggest that is the case.
Any help or suggestions would be much appreciated.
This is the code I used to create the sprite (the one that should not be affected by the simulation)
-(void)addSprite
{
SKSpriteNode *sprite = [SKSpriteNode spriteNodeWithImageNamed:#"image"];
sprite.position = CGPointMake(40, 30);
sprite.zPosition = 30;
sprite.name = #"spriteName";
[self addChild:sprite];
}
In another part of the project I have
[self addSprite];
to call the method.
Yes every SKSpriteNode comes with a physics body. Its best to change the physics body's properties instead of getting rid of it altogether. If you want your sprite to be on screen and not interact with any other sprite nodes, do the following:
sprite.physicsBody.dynamic = NO;
sprite.physicsBody.collisionBitMask = 0x0;
sprite.physicsBody.contactTestBitMask = 0x0;
I'm using collision detection in Sprite Kit. It is working and preventing my sprites from crossing paths. However, I'm not getting notifications in didBeginContact: and I don't seem to have any control over how the physics engine responds when a collision occurs.
I have various cars (SKSpriteNodes) moving around following paths using the SKAction followPath:asOffset:orientToPath:duration:
Previously, if two cars crossed paths they would both just continue as normal with one driving over the other. To implement collision detection I have made the following changes...
Added this to my #interface:
<SKPhysicsContactDelegate>
Added this to my #implementation:
static const uint32_t carCategory = 0x1 << 0;
Added this in my init method:
self.physicsWorld.contactDelegate = self;
self.physicsWorld.gravity = CGVectorMake(0.0, 0.0);
I create my blue car:
- (void)addBlueCar
{
_blueCar = [SKSpriteNode spriteNodeWithImageNamed:#"Blue Car.png"];
_blueCar.position = CGPointMake(818.0, -50.0);
_blueCar.name = #"car";
[self addChild:_blueCar];
CGSize contactSize = CGSizeMake(_blueCar.size.width - 5.0, _blueCar.size.height - 5.0);
_blueCar.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:contactSize];
_blueCar.physicsBody.categoryBitMask = carCategory;
_blueCar.physicsBody.collisionBitMask = carCategory;
_blueCar.physicsBody.contactTestBitMask = carCategory;
}
And I also create a red car:
- (void)addRedCar
{
_redCar = [SKSpriteNode spriteNodeWithImageNamed:#"Red Car.png"];
_redCar = CGPointMake(818.0, -50.0);
_redCar = #"car";
[self addChild: _redCar];
CGSize contactSize = CGSizeMake(_blueCar.size.width - 5.0, _blueCar.size.height - 5.0);
_redCar.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:contactSize];
_redCar.physicsBody.categoryBitMask = carCategory;
_redCar.physicsBody.collisionBitMask = carCategory;
_redCar.physicsBody.contactTestBitMask = carCategory;
}
There are other cars as well, but I'm just using these two until I figure out what the problem is. I want to be notified of any collision between any two cars. That's why I'm just using a single category, carCategory.
The first problem is that I get no notifications. I have this yet it never logs anything to the console:
- (void)didBeginContact:(SKPhysicsContact *)contact
{
NSLog(#"Contact");
}
The second problem is that when two cars cross paths they start nudging each other off course. This is ok, but I don't seem to able to manage any aspects of how the collision is handled. The bizarre thing is that nothing changes when I do this to both of my car creation methods:
- (void)addBlueCar
{
_blueCar = [SKSpriteNode spriteNodeWithImageNamed:#"Blue Car.png"];
_blueCar.position = CGPointMake(818.0, -50.0);
_blueCar.name = #"car";
[self addChild:_blueCar];
CGSize contactSize = CGSizeMake(_blueCar.size.width - 5.0, _blueCar.size.height - 5.0);
_blueCar.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:contactSize];
// _blueCar.physicsBody.categoryBitMask = carCategory;
// _blueCar.physicsBody.collisionBitMask = carCategory;
// _blueCar.physicsBody.contactTestBitMask = carCategory;
}
Collision detection still works the same with those three lines commented out for both cars. This just doesn't seem right to me. Collision detection only ceases when I also comment out this line:
_blueCar.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:contactSize];
So my main question is: why is the contactTest not reporting anything? My second question is: why is collision detection happening when I don't assign a categoryBitMask, collisionBitMask or contactTestBitMask to any car?
collisionBitMask's default value is 0xFFFFFFFF (all bits set). Therefore the node will collide with each physicBody on the scene.
Just a small observation, perhaps you should setup your nodes and set the contact delegate in the scene's didMoveToView method.
If that doesn't solve it, any chance you can post some working code to github for debugging?
Something that helped me with this: Collisions and contacts are different things.
Collision is handled by the physics engine and setting collisionBitMask will determine which bodies collide and interact with each other in the physics world. By default, all your bodies will collide with each other, which kinda makes sense.
Contacts are events- when bodies make contact, will they create a notification that you can use in the delegate method to do more interesting things. If you have a ball you want to hit with a paddle, you want them to collide at a minimum. But if you have a ball moving through a cloud, you probably don't want them to collide in the physics world, but you might want to register the contact.