How to remove a specific child from a sprite node? - ios

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];

Related

Change Physical body frame in spritekit

I develop an iOS game using SpriteKit (such a helpful framework to quickly make a game). I add texture and configure a physical body for a main character as image
The green rectangle is the frame of the physical body. I'm using the following code to create it
#interface MainCharacter : SKSpriteNode
#end
#implementation MainCharacter
+ (instancetype)mainCharacterAtPosition:(CGPoint)pos {
MainCharacter* mainChar = [[MainCharacter alloc] initWithTexture:[SKTexture textureWithImageNamed:#"stand_up"]];
mainChar.position = pos;
mainChar.xScale = 0.5f;
mainChar.yScale = 0.5f;
return mainChar;
}
- (instancetype)initWithTexture:(SKTexture *)texture {
if (self = [super initWithTexture:texture]) {
self.name = kCharacterName;
self.anchorPoint = CGPointMake(0.5f, 0.0f);
[self standup];
CGSize spriteSize = self.size;
CGPoint center = CGPointMake(spriteSize.width*(self.anchorPoint.x-0.5f), spriteSize.height*(0.5f-self.anchorPoint.y));
self.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:spriteSize center:center];
self.physicsBody.dynamic = NO;
self.physicsBody.categoryBitMask = kCharacterCategory;
self.physicsBody.contactTestBitMask = 0x0;
self.physicsBody.collisionBitMask = 0x0;
}
return self;
}
- (void)standup {
SKAction* standupAction = [SKAction setTexture:self.standupTexture resize:YES];
[self runAction:standupAction];
}
- (void)standdown {
SKAction* standownAction = [SKAction setTexture:self.standdownTexture resize:YES];
[self runAction:standownAction completion:^{
}];
[self performSelector:#selector(standup) withObject:nil afterDelay:1.0f];
}
MainCharacter is a class that inherits from SKSPriteNode, just an convienient class to manage a main character. Stand Up is a first state of the character. I have another state, temporarily called stand down (demonstrate as following image)
I add a swipe down gesture to make character stand down.
The green rectangle also the physical body but it's too large for the character. I want to make a physical body frame as the red rectangle.
Can anyone help me how to make the physical body smaller when my character stand down and enlarge the physical body after it stands up
You can destroy the current physics body self.physicsBody = nil; and then simply create a new one with the new size requirements.
I solve this problem by using 2 nodes for 2 states (as a suggestion): stand up state and stand down state. I named it
standupNode and standdownNode
First, add the standupNode to the game scene. If swipe donw gesture recognize, I remove the standupNode from game scene and add the standdownNode instead. On contrary, removing the standdownNode from the game scene then add the standupNode if character stands up

How can one make only one side of a physics body active in SpriteKit?

I have a hero, ground and a table. I want to make a table-top active for collision and contact with hero. But hero should be able not to jump on the top and just run "through" and jump on it, if player wants it, wherever he wants. For better example of what i'm trying to achieve - think about Mario. When you are running on ground, some sky platforms appearing. You could jump on it in the middle of a platform and stay there. So I need physics body to not stop hero when he is contacting it from the bottom, but hold him if he is on top of it.
By now i'm using body with texture for table:
self.table.physicsBody = SKPhysicsBody(texture:table.texture, size:self.table.size)
self.table.physicsBody?.dynamic = false
self.table.physicsBody?.categoryBitMask = ColliderType.Table.rawValue
self.table.physicsBody?.contactTestBitMask = ColliderType.Hero.rawValue
self.table.physicsBody?.collisionBitMask = ColliderType.Hero.rawValue
It obviously, is not working. How can I implement such a thing?
The answer to this question is actually not too difficult but the implementation into a full fledged game will be much more difficult for you. This is not something for a novice programmer to start out with.
First the same code project (tap/click on screen to jump up):
#import "GameScene.h"
typedef NS_OPTIONS(uint32_t, Level1PhysicsCategory) {
CategoryPlayer = 1 << 0,
CategoryFloor0 = 1 << 1,
CategoryFloor1 = 1 << 2,
};
#implementation GameScene {
int playerFloorLevel;
SKSpriteNode *node0;
SKSpriteNode *node1;
SKSpriteNode *node2;
}
-(void)didMoveToView:(SKView *)view {
self.backgroundColor = [SKColor whiteColor];
node0 = [SKSpriteNode spriteNodeWithColor:[SKColor grayColor] size:CGSizeMake(400, 10)];
node0.position = CGPointMake(300, 200);
node0.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:node0.size];
node0.physicsBody.dynamic = NO;
node0.physicsBody.categoryBitMask = CategoryFloor0;
node0.physicsBody.collisionBitMask = CategoryPlayer;
[self addChild:node0];
node1 = [SKSpriteNode spriteNodeWithColor:[SKColor grayColor] size:CGSizeMake(400, 10)];
node1.position = CGPointMake(300, 300);
node1.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:node1.size];
node1.physicsBody.dynamic = NO;
node1.physicsBody.categoryBitMask = CategoryFloor1;
node1.physicsBody.collisionBitMask = CategoryPlayer;
[self addChild:node1];
node2 = [SKSpriteNode spriteNodeWithColor:[SKColor redColor] size:CGSizeMake(50, 50)];
node2.position = CGPointMake(300, 250);
node2.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:node2.size];
node2.physicsBody.categoryBitMask = CategoryPlayer;
node2.physicsBody.collisionBitMask = CategoryFloor0;
[self addChild:node2];
playerFloorLevel = 0;
}
-(void)update:(CFTimeInterval)currentTime {
if(((node2.position.y-25) > (node1.position.y+10)) && (playerFloorLevel == 0)) {
node2.physicsBody.collisionBitMask = CategoryFloor0 | CategoryFloor1;
playerFloorLevel = 1;
}
}
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
for (UITouch *touch in touches) {
CGPoint touchLocation = [touch locationInNode:self];
//SKNode *node = [self nodeAtPoint:touchLocation];
// change 75 value to 50 to see player jump half way up through floor 1
[node2.physicsBody applyImpulse:CGVectorMake(0, 75)];
}
}
The gist of the code is the player node (node2) has to keep checking its y position (update method) in relation to the other floors. In the example, the player jumps up through floor1. Once the player is higher than floor1, the player node's physics body modifies its collision bit mask to include floor1.
Sounds easy enough. However, in a real game you will have a large number of floors and all floors might not be evenly spaced y distances. You have to keep all that in mind when coding.
I am not sure how your platforms looks like (edge based or volume based bodies) but you can consider some of these:
1. Checking positions
Check if the hero's position.y is beneath/above the platform and ignore/handle the collision.
2. Checking velocity
Or to check if player node if falling, which is indicated by a negative velocity.dy value.
I can't say if any of these can fully help you with your game or is it possible with your setup, but you can get some basic idea on where to start.
Enabling/disabling collisions can be done by changing player's and platform's collision bitmasks. If possible try to avoid tracking states like isInTheAir, isOnPlatform, isFaling, isJumping and similar because it can become messy as number of states grows. For example, instead of adding custom boolean variable called "isFalling" and constantly maintaining its state, you can check if velocity.dy is negative to see if player is falling.
I tried changing the platforms collision bitmask but wasn't working fine. I found a different solution.
Inside the update() function you can check the following
if player.physicsBody?.velocity.dy <= 0 {
player.physicsBody?.collisionBitMask = PhysicsCategory.Platform
} else {
player.physicsBody?.collisionBitMask = PhysicsCategory.None
}
In this way, every time the player is going up, it can pass through rocks, and every time it is falling, it can stand.
Using swift you can create a sprite node subclass like this:
class TableNode: SKSpriteNode {
var isBodyActivated: Bool = false {
didSet {
physicsBody = isBodyActivated ? activatedBody : nil
}
}
private var activatedBody: SKPhysicsBody?
init(texture: SKTexture) {
super.init(texture: texture, color: SKColor.clearColor(), size: texture.size())
// physics body setup. Assuming anchorPoint = (0.5, 0.5)
let bodyInitialPoint = CGPoint(x: -size.width/2, y: +size.height/2)
let bodyEndPoint = CGPoint(x: +size.width/2, y: +size.height/2)
activatedBody = SKPhysicsBody(edgeFromPoint: bodyInitialPoint, toPoint: bodyEndPoint)
activatedBody!.categoryBitMask = ColliderType.Table.rawValue
activatedBody!.collisionBitMask = ColliderType.Hero.rawValue
physicsBody = isBodyActivated ? activatedBody : nil
name = "tableNode"
}
}
Then, update all tableNodes in the gameScene:
override func didSimulatePhysics() {
self.enumerateChildNodesWithName("tableNode") {
node, stop in
if let tableNode = node as? TableNode {
// Assuming anchorPoint = (0.5, 0.5) for table and hero
let tableY = tableNode.position.y + tableNode.size.height/2
let heroY = hero.position.y - hero.size.height/2
tableNode.isBodyActivated = heroY > tableY
}
}
}

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!

Can a child have multiple parents in Sprite Kit?

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]];

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