Can a child have multiple parents in Sprite Kit? - ios

I'm working on a Sprite-Kit game and I have a menu that displays all the levels. I've created a locked image that I want to display on levels that are locked, below is the code:
SKSpriteNode *locked = [SKSpriteNode spriteNodeWithImageNamed:#"Locked.png"];
locked.position = CGPointMake(0, 0);
locked.zPosition = 2.0;
locked.size = CGSizeMake(20, 20);
Then I want to display it on all the levels until they are unlocked. This is the code:
SKSpriteNode *level2 = [SKSpriteNode spriteNodeWithColor:[SKColor redColor] size:CGSizeMake(40, 40)];
level2.position = CGPointMake(CGRectGetMidX(self.frame)-75, CGRectGetMidY(self.frame)+100);
[level2 addChild:locked];
[_levels addObject:level2];
[self addChild:level2];
But when I tried to display it on the third level:
SKSpriteNode *level3 = [SKSpriteNode spriteNodeWithColor:[SKColor redColor] size:CGSizeMake(40, 40)];
level3.position = CGPointMake(CGRectGetMidX(self.frame)-30, CGRectGetMidY(self.frame)+100);
[level3 addChild:locked];
[_levels addObject:level3];
[self addChild:level3];
I ran into an error because locked already had a parent.
Can a child have multiple parents?
If so where am I going wrong?

A SKNode can only have one parent. (Its parent method can only return one thing, after all.)
It also conforms to NSCopying, which means you can copy a node if you need more than one with the copy method. So, you might try something like [level3 addChild:[locked copy]];

Related

Check if SKShapeNode which is a Line contains Point

I'm programming a little Game. For this I need some Walls. Therefor I have used:
Wall[w] = [[SKShapeNode alloc] init];
Wall[w].path = WallPos[w];
Wall[w].lineWidth = 4;
Wall[w].strokeColor = [UIColor whiteColor];
Wall[w].zPosition = 3;
[self addChild: Wall[w]];
Wall is an Array of SKShapeNodes and is set in #interface, so I can use it in every method. WallPos contains CGMutablePathRefs.
In TouchesBegan and TouchesMoved I'm calling a method which should check if you have touched one of the walls.
I have also some SKShapeNodes which are Rectangles, and to check if they are touched, I have used
if ([SomeShape containsPoint: Position] {
//Do some stuff
}
But with a line it's not working. Sometimes I'm touching on the line and nothing happens. Then I've seen this: Detecting Touch on SKShapeNode that is a Line and I have tried to do it on that way:
for (int i = 0; i < NrWalls; i++) {
if (CGRectContainsPoint(Wall[i].frame, Position)) {
[self GameOver];
}
}
But now every Point I touch sets a "Game Over" to me!!
Has anyone an Idea, how could I check if the line is touched?
Thanks for your help!
DXXL
Not sure why you want to use SKShapeNodes for walls and rectangles. To answer your question, you can attach a physics body to your shape node and use the contact methods to check for possible contacts. However, assigning a physics body to a shape node could be a tricky undertaking due to the anchor points and getting a desired alignment.
Seeing that you are really only drawing rectangles for your walls, I suggest you use a SKSpriteNode with a physics body instead. Something like this:
SKSpriteNode *myNode = [SKSpriteNode spriteNodeWithColor:[SKColor redColor] size:CGSizeMake(5, 100)];
myNode.position = CGPointMake(100, 100);
myNode.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:myNode.size];
myNode.physicsBody.dynamic = NO;
myNode.physicsBody.categoryBitMask = CategoryWall;
[self addObject:myNode];
If you need, you can read up on SKPhysicsBody here.

Sprite Kit: One node with two physics body

It's possible for one node to have two physics body paths? I want to create a node that has two (circle) physics bodies on the sides of the node.
If it's not possible, is there are any workaround to achieve that? thank you
You want to use [SKPhysicsBody bodyWithBodies:...]. From the docs :
The shapes of the physics bodies passed into this method are used to
create a new physics body whose covered area is the union of the areas
of its children. These areas do not need to be contiguous. If there is
space between two parts, other bodies may be able to pass between
these parts. However, the physics body is treated as a single
connected body, meaning that a force or impulse applied to the body
affects all of the pieces as if they were held together with an
indestructible frame.
It would look something like this :
SKPhysicsBody *leftCircle = [SKPhysicsBody bodyWithCircleOfRadius:leftCircleRadius center:leftCircleCenter];
SKPhysicsBody *rightCircle = [SKPhysicsBody bodyWithCircleOfRadius:rightCircleRadius center:rightCircleCenter];
node.physicsBody = [SKPhysicsBody bodyWithBodies:#[leftCircle, rightCircle]];
Here's an example of how to connect to sprite nodes using SKPhysicsJointFixed. First, create two sprites:
SKSpriteNode *sprite1 = [SKSpriteNode spriteNodeWithColor:[SKColor blueColor] size:CGSizeMake(64, 64)];
// position must be set before creating physics body to avoid bug in iOS 7.0.x
sprite1.position = CGPointMake(CGRectGetMidX(self.frame),
CGRectGetMidY(self.frame));
sprite1.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:sprite1.size];
sprite1.physicsBody.restitution = 1.0;
[self addChild:sprite1];
SKSpriteNode *sprite2 = [SKSpriteNode spriteNodeWithColor:[SKColor blueColor] size:CGSizeMake(64, 64)];
sprite2.position = CGPointMake(CGRectGetMidX(self.frame)-sprite2.size.width*2,
CGRectGetMidY(self.frame));
sprite2.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:sprite2.size];
sprite2.physicsBody.restitution = 1.0;
[self addChild:sprite2];
then connect the nodes by calling this method:
[self connectNode1:sprite1 toNode2:sprite2];
This method joins two nodes at their midpoint. Note that both physic bodies must be in the scene prior to calling this method.
- (void) connectNode1:(SKSpriteNode *)node1 toNode2:(SKSpriteNode *)node2
{
CGPoint midPoint = CGPointMake((node1.position.x + node2.position.x)/2,
(node1.position.y + node2.position.y)/2);
SKPhysicsJointFixed *joint = [SKPhysicsJointFixed jointWithBodyA:node1.physicsBody
bodyB:node2.physicsBody
anchor:midPoint];
[self.physicsWorld addJoint:joint];
}
Here is an easy way to achieve the behavior you are looking for:
How to detect contact on different areas of a physicsbody
//Create SpriteNode1 & physicsBody
//Create SpriteNode2 & physicsBody
[SpriteNode1 addChild: SpriteNode2]
You can position SpriteNode2 relative to SpriteNode1. Any movement, etc. performed on SpriteNode1 will also move SpriteNode2.
Set: SpriteNode2.PhysicsBody.Dynamic=NO;
You could also create a SpriteNode that acts as the main object and add both SN1 and SN2 as children if you find that easier.

How to remove a specific child from a sprite node?

I'm working on a sprite kit game that displays 25 levels in world 1. What I'm trying to do is lock each level so I've added a locked.png image over top of the level icons. When the user reaches that level, I want to remove the locked icon so that the user can access the level.
The problem is that I've added BOTH the lock and level number as children, so when I go to removeAllChildren from _level2's icon, it also removes the level number.
Is there a way to remove a single child from a spriteNode??
This is the code:
//Lock
SKSpriteNode *locked = [SKSpriteNode spriteNodeWithImageNamed:#"Locked.png"];
locked.position = CGPointMake(0, 0);
locked.zPosition = 2.0;
locked.size = CGSizeMake(20*DoubleIfIpad, 20*DoubleIfIpad);
locked.color = [UIColor colorWithRed:255/255. green:156/255. blue:0/255. alpha:1.0];
locked.colorBlendFactor = 1.0;
_level2 = [SKSpriteNode spriteNodeWithTexture:[SKTexture textureWithImageNamed:#"crate.png"] size:CGSizeMake(40*DoubleIfIpad, 40*DoubleIfIpad)];
_level2.position = CGPointMake(CGRectGetMidX(self.frame)-50*DoubleIfIpad, CGRectGetMidY(self.frame)+50*DoubleIfIpad);
_level2.name = #"level2";
SKLabelNode *level2txt = [SKLabelNode labelNodeWithFontNamed:#"DIN Condensed"];
level2txt.position = CGPointMake(0, -8*DoubleIfIpad);
level2txt.fontColor = [SKColor whiteColor];
level2txt.fontSize = 20*DoubleIfIpad;
level2txt.text = #"2";
level2txt.name = #"level2";
[_level2 addChild:locked];
[_level2 addChild:level2txt];
[_levels addObject:_level2];
[self addChild:_level2];
What I've set up to unlock a level in a separate method:
if (highLevel >= 2) {
[_level2 removeAllChildren];
}
Where highLevel is an NSInteger.
Where node is the node you want to delete and scene is the parent node of node.
// when you create it
node.name = #"RemoveThisGuy"
[scene addChild:node];
// when you want to delete it
[[scene childNodeWithName:#"RemoveThisGuy"] removeFromParent];

Changing SpriteKit Game Background At A Certain Score

I'm having a little trouble implementing a background change when the player hits a certain score.
I'm using the if(self.score>=10) line to tell my game to change the background but it doesn't seem to be working. I have no errors with this line but no results either.
What I have:
#implementation Scene{
SKScrollingNode * floor;
SKScrollingNode * back;
SKLabelNode * scoreLabel;
}
- (void) createBackground
{
back = [SKScrollingNode scrollingNodeWithImageNamed:#"back" inContainerWidth:WIDTH(self)];
if(self.score>=10){
back = [SKScrollingNode scrollingNodeWithImageNamed:#"image2" inContainerWidth:WIDTH(self)];
[back setAnchorPoint:CGPointZero];
[back setPhysicsBody:[SKPhysicsBody bodyWithEdgeLoopFromRect:self.frame]];
back.physicsBody.categoryBitMask = backBitMask;
back.physicsBody.contactTestBitMask = birdBitMask;
[self addChild:back];
}
there are certain points you have to keep in your mind i think your both background contains physics body
1)may be and the time of transition they first background colliding with second background and they preventing each other to swap
change your collisionBitMask for both background ->prevent them for colliding
for eg
bg.physicsBody.categoryBitMask=bg1;
bg.physicsBody.collisionBitMask=0;
bg.physicsBody.contactTestBitMask=bg2;
bg.physicsBody.categoryBitMask=bg2;
bg.physicsBody.collisionBitMask=0;
bg.physicsBody.contactTestBitMask=bg1;
or use skaction to swap backgrounds
The way i would do this would be to create a brand new SKScene entirely with a new background.
Or if you want them to scroll to the next background. I would create two backgrounds.
Ex.
//this syntax is wrong (dont remember)
//initializing
SKSpriteNode *bg1 = [SKSpritenode spritenodefromImage:#"bg1"];
SKSpriteNode *bg1 = [SKSpritenode spritenodefromImage:#"bg1"];
bg1.position = CGPointMake(self.size.width/2, self.size.height/2);
bg2.position = CGPointMake(self.size.width/2 + bg1.size.width, self.size.height/2);
//////////////////////////////
//then when you want to scroll them
-(void)scrollBackgrounds
{
bg1.position = CGPointMake(bg1.position.x - 5, self.size.height/2);
bg2.position = CGPointMake(bg2.position.x -5 , self.size.height/2);
}

iOS SpriteKit - Creating physics for a bobblehead?

I am trying to create a realistic bobblehead app, and want to use physics for the bobble animation. I have seen other apps out there that do it, and from what I gather I need to use SpriteKit.
I have created a SKScene and used a SKPhysicsJointPin to pin the head to the body, but it doesnt move around at all. Any ideas or suggestions?
UPDATED CODE (5/28):
Now using 2 spring joints on the head and it moves left to right, but not up and down. Also, tapping quickly causes the head to eventually go far enough right to "fall of" and out of view. Weird.
Have any ideas on what the proper setting would be to allow it to bobble up, down, left, and right whil staying remotely centered on it's starting position and staying within a specified region so it doesnt come off the body and look all funny?
BobbleheadView is a subclassed SKView
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
// Initialization code
self.backgroundColor =[UIColor clearColor];
self.showsFPS = YES;
self.showsNodeCount = YES;
UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc]
initWithTarget:self
action:#selector(animateBobble)];
[self addGestureRecognizer:tap];
SKScene *bobbleheadScene = [SKScene sceneWithSize:self.bounds.size];
[self presentScene:bobbleheadScene];
// 1. Body
self.body = [SKSpriteNode spriteNodeWithImageNamed:#"Bobble-Body"];
self.body.position = CGPointMake(self.frame.size.width/2, self.body.frame.size.height/2);
self.body.physicsBody = [SKPhysicsBody bodyWithEdgeLoopFromRect:self.frame];
[bobbleheadScene addChild:self.body];
// 2. Head
self.head = [SKSpriteNode spriteNodeWithImageNamed:#"Bobble-Head"];
self.head.position = CGPointMake(self.center.x, self.body.frame.size.height);
//self.head.physicsBody.affectedByGravity = YES;
// self.head.physicsBody.dynamic = NO;
//This bobbles head great, but head falls off body and out of view
self.head.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:self.head.size center:self.head.position];
//End
//self.head.physicsBody = [SKPhysicsBody bodyWithEdgeLoopFromRect:self.head.frame];
//self.head.physicsBody = [SKPhysicsBody bodyWithCircleOfRadius:self.head.size.height/2];
[bobbleheadScene addChild:self.head];
// 3. Ceiling
self.ceiling = [SKSpriteNode spriteNodeWithColor:[UIColor whiteColor] size:CGSizeMake(32, 32)];
self.ceiling.position = CGPointMake(self.frame.origin.x+self.frame.size.width/2, self.frame.size.height);
self.ceiling.physicsBody = [SKPhysicsBody bodyWithEdgeLoopFromRect:self.frame];
[bobbleheadScene addChild:self.ceiling];
//Spring Joint for Ceiling to Head
SKPhysicsJointSpring *spring1 = [SKPhysicsJointSpring jointWithBodyA:self.ceiling.physicsBody bodyB:self.head.physicsBody anchorA:self.ceiling.position anchorB:CGPointMake(self.head.frame.origin.x+self.head.frame.size.width/2, 0)];
spring1.frequency = 20.0; //gives the spring some elasticity.
spring1.damping = 5.0; //Will remove damping to create the 'pendulum'
[bobbleheadScene.physicsWorld addJoint:spring1];
//Spring Joint for Head to Body
SKPhysicsJointSpring *spring = [SKPhysicsJointSpring jointWithBodyA:self.body.physicsBody bodyB:self.head.physicsBody anchorA:CGPointMake(self.body.position.x+self.body.size.width/2, self.body.position.y) anchorB:CGPointMake(self.head.position.x+self.head.size.width/2, self.body.position.y-self.body.size.height/2)];
spring.frequency = 10.0; //gives the spring some elasticity.
spring.damping = 1.0;
[bobbleheadScene.physicsWorld addJoint:spring];
}
return self;
}
-(void)animateBobble{
NSLog(#"Did Tap Bobblehead!");
[self.head.physicsBody applyImpulse:CGVectorMake(100, -200)];
//[self.body.physicsBody applyImpulse:CGVectorMake(20, 10)];
}
The only way you'll get this to work is to make a "sled".
So: make an app where, on screen there are (say) six sliders.
TBC I mean, when the app is actually running, you'll see six sliders.
TBC, this is only a sled, it's only for you as a developer, it's not for the consumer app.
(I believe the term "sled" comes from the automotive industry; when they make the first version of a chassis/engine to test it out.)
Make it so that some sliders control spring power/damp (or whatever factors you have available in cocos) and that other sliders nudge the position of the connections/spring lengths.
it's the only way to get a result! Be sure to show the values on screen, or at least print them out on the console as they change.
This is the everyday thing in game development. Typically the sled is more work than the actual consumer scene or feature. You won't be able to achieve it without a "sled". I hope it helps!

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