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
We have been using enums to organize the zPositions of our sprites. As we started to add SKNodes with several subsprites to our game, the structure quickly began to break down. Some child sprites that were placed on the screen had to have negative values in order to be beneath other nodes with children. These negative values are hard to keep track of in relation to other sprites in separate enums.
Is there a better way to organize the zPosition of sprites (especially those with sub-sprites) than using enums?
Upon reading more into your issue, it looks like you are using multiple enums to organize your z order. I suggest using a single enum for the z - ordering of your game.
Use layers to organize your scene:
- (instancetype)initWithSize:(CGSize)size {
if (self = [super initWithSize:size]) {
self.view.ignoresSiblingOrder = YES;
[self addLayers];
}
return self;
}
- (void)addLayers {
self.backgroundLayer = [SKNode node];
self.backgroundLayer.zPosition = 100;
[self addChild:self.backgroundLayer];
self.playerLayer = [SKNode node];
self.playerLayer.zPosition = 300;
[self addChild:self.playerLayer];
self.enemyLayer = [SKNode node];
self.enemyLayer.zPosition = 400;
[self addChild:self.enemyLayer];
// UI elements must be on top of all nodes on the scene
self.uiLayer = [SKNode node];
self.uiLayer.zPosition = 1000;
}
- (void)addBackgrounds {
SKSpriteNode *backgroundNode1 = [SKSpriteNode spriteNodeWithTexture:[self backgroundTexture1]];
backgroundNode1.zPosition = 10;
[self.backgroundLayer addChild:backgroundNode1];
SKSpriteNode *backgroundNode2 = [SKSpriteNode spriteNodeWithTexture:[self backgroundTexture2]];
backgroundNode2.zPosition = 20;
[self.backgroundLayer addChild:backgroundNode2];
}
.... etc
I want to apply the same effect to a number of different sprites in my iOS game so am looking in to a general approach rather than an animation created in another program and using its images to create a UIImageView animation.
This effect is an ‘explosion’ type animation where my sprite’s image gets chopped in to different pieces, then, using the physics engine, those pieces get exploded out in different directions before falling down.
I’m new to SpriteKit, but am assuming I have to do this in Quartz? Then re-add the new images as sprites and apply the animation?
I don’t really know where to start, let alone how to continue with the rest of the steps.
Does anyone have any ideas?
Thanks.
1) Upon initialization of said exploding object, first we create a SKTextureAtlas which holds all of the images being animated. You must have the texture atlas resources available.
2) Load all of the relevant SKTextures into an array. This array should be private to the object to which the explosion is happening.
A safe way to do this:
- (void)loadContactImages {
NSMutableArray *frames = [NSMutableArray array];
SKTextureAtlas *explosionFrames = [SKTextureAtlas atlasNamed:#"explosionFrames"];
for(int i = 0; i < explosionFrames.textureNames.count; i++) {
NSString *textureName = [NSString stringWithFormat:#"explosionFrame_%d" , i];
SKTexture *texture = [explosionFrames textureNamed:textureName];
if(texture) {
[frames addObject:texture];
}
}
self.contactFrames = frames;
}
3) You will then define a method which will animate the explosion. Look into the SKAction header for more info. Plug in time per frame that makes sense to your explosion
- (SKAction *)runExplosion {
return [SKAction animateWithTextures:self.contactFrames timePerFrame:0.1];
}
4) As for the exploding pieces, you should preload them, so to limit the overhead of sending the pieces into random directions (with this we won't have the extra overhead of creating all those new sprites at the time of the explosion). Don't forget to give them physics bodies (SKPhysicsBody) and set the isAffectedByGravity property to YES!
- (SKAction *)explosionOfPieces {
return [SKAction runBlock:^ {
for(SKSpriteNode *piece in self.explodingPieces) {
piece.hidden = NO;
piece.position = self.position;
[self addChild:piece];
[piece.physicsBody applyImpulse:CGVectorMake(dx , dy)]; //specify the direction here
}
}];
}
5) Bringing it all together, expose a method to return a sequence of these actions. If you would like to have these two actions occur together, there is also a class method on SKAction called [SKAction group: (NSArray *)]
- (void)explosionSequence {
[self runAction: [SKAction sequence:#[ [self runExplosion] , [self explosionOfPieces]]]];
}
Note: Physics reactions occur in SKScene's. We expose this action so the scene can run it on your object within the scene. You will also want to conform to a protocol called SKPhysicsContactDelegate within your scene and call:
[myExplodingObject explosionSequence];
within the delegate method:
- (void)didBeginContact:(SKPhysicsContact *)contact
Within this SKPhysicsContact object lie two colliding bodies. Both of these bodies ("exploding object" and "explosion trigger") must have their SKPhysicsBody property initialized and their contactTestBitMask property set (so this object knows what it can collide with). I would also set the categoryBitMask property so we can directly introspect the bodies' type. We reference these colliding bodies like this:
- (void)didBeginContact:(SKPhysicsContact *)contact {
if(contact.bodyA.categoryBitMask == explodingObjectCategory && contact.bodyB.categoryBitMask == explodingTriggerCategory) {
[self.myExplodingObject explosionSequence];
}
}
Please look into Apple's docs for more info.
I am having a little trouble doing something that is supposed to be very simple.
I cannot get the floor of my tiles to display above a background picture. However I can get all my other game objects to show from my control pad, to my HUD to even coins and monsters set up in the same tile map. Basically everything appears in front the background like I expect the floor of my tilemap so it looks like im walking on air. I have tried many things like changing which layer i add the background picture or the tilemap floor too, or even tried setting it the same way i set my characters but same results. Tilemap floor is always at the back.
Adding my Set up code, Hope it is helpful too solving the problem.
I created this BG sprite since, I wanted my tilemap to scroll vertically or horzi. automatically. So the easiest way I found to do that was to make the tilemap the child of the "bg" and scroll the "bg" hence scrolling the tile map. However, I have tried setting the background as the child of the bg and setting the Z for both of them but that didnt seem to help.
Thanks in advance for any help in solving this
#implementation GameLevelScene
{
SKNode *_worldNode;
SKSpriteNode *bg;
SKSpriteNode *bkg;
}
Init
-(id)initWithSize:(CGSize)size level:(int)level {
if (self = [super initWithSize:size]) {
// [self showBackground];
NSDictionary *levelData = config[#"levels"][level];
//[show background];
if (levelData[#"tmxFile"]) {
[self showBackground];
_tileMap = [ JSTileMap mapNamed:levelData[#"tmxFile"]];
}
//self.backgroundColor = [SKColor colorWithRed:.4 green:.4 blue:.95 alpha:1.0];
// UIImage *bkgb =[UIImage imageNamed:#"land.jpg"];
// self.position=CGPointZero;
// self.anchorPoint=CGPointZero;
// self.backgroundColor=[UIColor colorWithPatternImage:bkgb];
//Above code shows no picture but it changes the color
[self setUpWorld];
[self createChar];
[self controlPadNode];
//[show background];
}
return self;
}
setUpWorld
- (void)setUpWorld
{
bg = [SKSpriteNode spriteNodeWithImageNamed:#"bg3"];
bg.userInteractionEnabled=NO;
bg.anchorPoint = CGPointZero;
bg.zPosition=0;
bg.position = CGPointZero;
bg.name = #"bg";
[self addChild:bg];
_worldNode = [SKNode node];
if (_tileMap) {
[bg addChild:_tileMap];
}
[bg addChild:_worldNode];
self.physicsWorld.contactDelegate = self;
}
create char
- (void)createChar
{
_Layer = [[TmxTileMapLayer alloc]
initWithTmxObjectGroup:[_tileMap
groupNamed:#"LevelOneObjects"]
tileSize:_tileMap.tileSize
gridSize:_bgLayer.gridSize];
[self addChild:_Layer];
}
Create Control
- (SKSpriteNode *)controlPadNode
//-(void)controlPad
{
SKSpriteNode *controlPadNode = [SKSpriteNode spriteNodeWithImageNamed:#"controller.png"];
controlPadNode.position = CGPointMake(100,50);
controlPadNode.name = #"controlPadNode";
controlPadNode.zPosition = 1.0;
[self addChild:controlPadNode];
}
background
-(void)showBackground
{
bkg = [SKSpriteNode spriteNodeWithImageNamed:#"desert_land.jpg"];
bkg.userInteractionEnabled=NO;
bkg.anchorPoint = CGPointZero;
bkg.position = CGPointZero;
bkg.zPosition=-1;
bkg.name = #"bkg";
// [self addChild:bkg];
//[_tileMap addChild:bkg];
// [_worldNode addChild:bkg];
[bg addChild:bkg];
}
Set your bkg.zposition to 1 and set your bg.zPosition to 2.
Also, the whole point of having a tile map is NOT to use a gigantic background picture but to instead use tiles.
** Update **
I just tested your code and ran a sample project myself. I assume you are using the Tiled app for your tiles. I ran variations on parents (self, worldNode, etc...) and zPositions. The bottom line is you cannot do it. Tiled does not have an alpha channel for its background color options. So either the background image is covered by the tile map or, in your case, the background image covers the tile map.
Your possible solutions are to either not use Tiled and place your tiles manually or to look for another tile app which has an alpha channel.
I noticed that where you define the wall properties of the tile if you say
SKSpriteNode* wall =
[SKSpriteNode spriteNodeWithColor:[SKColor greenColor]
size:CGSizeMake(w, h)];
the green color will be uptop of the background. Bit of a dirty fix than an answer
I need to add a rain particle effect to my app, I have been having a tough time finding ways to actually execute this idea.
I tried following this CALayer approach tutorial : Link but I am not quite sure if this is the best approach, considering the new iOS 7 SpriteKit Particle Emitter available in Xcode 5.
I have already created the .sks file and it's in my Hierarchy, but I am still unable to add it to my storyboard / project.
With that being said, How exactly do I add a SpriteKit Particle (sks) to my view? I am not at all familiar with scenes, layering , etc in the SpriteKit framework as I am not a game developer.
I need the most details and sample code possible so that I can figure this out please
UPDATE:
I have followed the direction provided in an answer by fellow SO member: AyatollahAndy, please see his answer below. Although I was able to display the SKScene in my view the app crashes when any touch event is received. I get the following:
Thanks
Create a SKScene in your UIView to add a SKEmitterNode particle effect.
One way of doing this:
1.In storyboard (or programatically if you prefer) add a View object on top of the existing View and resize it to your needs.
2.Change the class of the new view to SKView
3.In your view controller .h file create a property for the SKView:
#property IBOutlet SKView *skView;
4.Link the SKView on your storyboard to the skView property.
5.Create a new class, subclassing SKScene. MyScene.h will look like:
#import <SpriteKit/SpriteKit.h>
#interface MyScene : SKScene
#end
MyScene.m below contains code to create a particle effect whenever and wherever the SKView is touched.
#import "MyScene.h"
#implementation MyScene
-(id)initWithSize:(CGSize)size {
if (self = [super initWithSize:size]) {
/* Setup your scene here */
self.backgroundColor = [SKColor colorWithRed:0.15 green:0.15 blue:0.3 alpha:1.0];
SKLabelNode *myLabel = [SKLabelNode labelNodeWithFontNamed:#"Chalkduster"];
myLabel.text = #"Hello, World!";
myLabel.fontSize = 30;
myLabel.position = CGPointMake(CGRectGetMidX(self.frame),
CGRectGetMidY(self.frame));
[self addChild:myLabel];
}
return self;
}
//particle explosion - uses MyParticle.sks
- (SKEmitterNode *) newExplosion: (float)posX : (float) posy
{
SKEmitterNode *emitter = [NSKeyedUnarchiver unarchiveObjectWithFile:[[NSBundle mainBundle] pathForResource:#"MyParticle" ofType:#"sks"]];
emitter.position = CGPointMake(posX,posy);
emitter.name = #"explosion";
emitter.targetNode = self.scene;
emitter.numParticlesToEmit = 1000;
emitter.zPosition=2.0;
return emitter;
}
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
/* Called when a touch begins */
for (UITouch *touch in touches) {
CGPoint location = [touch locationInNode:self];
//add effect at touch location
[self addChild:[self newExplosion:location.x : location.y]];
}
}
-(void)update:(CFTimeInterval)currentTime {
/* Called before each frame is rendered */
}
#end
6.In your main view controller, include your scene class:
#import "MyScene.h"
and add code to viewDidLoad to initialise the SKView:
- (void)viewDidLoad
{
[super viewDidLoad];
// Configure the SKView
SKView * skView = _skView;
skView.showsFPS = YES;
skView.showsNodeCount = YES;
// Create and configure the scene.
SKScene * scene = [MyScene sceneWithSize:skView.bounds.size];
scene.scaleMode = SKSceneScaleModeAspectFill;
// Present the scene.
[skView presentScene:scene];
}
You should then have a working SKScene within your main UIView.
In modern Xcode:
This is now very easy.
1. In Xcode, click to create a new
"SpriteKit Particle File"
it will be a single .sks file.
(NOTE: Do NOT choose "SceneKit Particle System File". Choose "SpriteKit Particle File".)
Click once on the .sks file. Notice the many controls on the right.
The particles will actually be moving, it is a living preview. Anything that can be done with particles, you can do it. It is like using particles in a game engine, except performance is 18 billion times better.
2. Have any ordinary UIView, anywhere you want:
#IBOutlet weak var teste: UIView! // totally ordinary UIView
3. Just use the following code to link:
The following slab of code will put your new particle system, inside, the ordinary UIView "teste":
import SpriteKit ...
let sk: SKView = SKView()
sk.frame = teste.bounds
sk.backgroundColor = .clear
teste.addSubview(sk)
let scene: SKScene = SKScene(size: teste.bounds.size)
scene.scaleMode = .aspectFit
scene.backgroundColor = .clear
let en = SKEmitterNode(fileNamed: "SimpleSpark.sks")
en?.position = sk.center
scene.addChild(en!)
sk.presentScene(scene)
Add this to anything you want.
If you want a sparkling button, add it to a button.
If you want the whole screen to shower rainbows, add it to a full-screen view.
It's that easy.
Example of how to use the SpriteKit Particle File controls:
Say you want a burst of sparks, which ends.
Set the max to 50...
Tip - if your effect "finishes" (ie, it is not a loop), it seems you can simply get rid of the SKScene when finished. Like this:
...
scene.addChild(en!)
sk.presentScene(scene)
delay(1.5) { sk.removeFromSuperview() }
That one line of code at the end seems to clean-up everything.
BTW if you want fantastic ideas for particle systems, a great idea is click to the Unity "asset store", where various particle artists buy and sell particle systems. Their work will give you great ideas.
Just click "particles" in the list on the right; watch the videos. (Innovative examples .)
Note! Apple are going to make it so that you can very simply make a SKView in storyboard, and select the .sks scene. However ..
... it does not work yet! It's still broken as of the last edit to this post (2020). So you need the code fragment above.
You can add SKView as a subview within your UIKit hierarchy. A function like the following would work, allowing you to create a UIImageView with the effect as a subview, and then you can add this to your main view. Be sure to link against SpriteKit.
UIImageView *NewEffectUIImageViewWithFrame(CGRect frame)
{
UIImageView *tempView = [[UIImageView alloc] initWithFrame:frame];
SKView *skView = [[SKView alloc] initWithFrame:CGRectMake(0.0, 0.0, frame.size.width, frame.size.height)];
[tempView addSubview:skView];
SKScene *skScene = [SKScene sceneWithSize:skView.frame.size];
skScene.scaleMode = SKSceneScaleModeAspectFill;
skScene.backgroundColor = [UIColor clearColor];
SKEmitterNode *emitter = [NSKeyedUnarchiver unarchiveObjectWithFile:[[NSBundle mainBundle] pathForResource:#"SparkParticle" ofType:#"sks"]];
emitter.position = CGPointMake(frame.size.width*0.5,0.0);
[skScene addChild:emitter];
[skView presentScene:skScene];
return tempView;
}
In the end, if all you need is an emitter, it may be easier to create a CAEmitterLayer and add that as a sublayer to your UIView instead. Of course, that means you have to programmatically create the CAEmitterLayer and can't use the cool Xcode particle editor...
Here's approach totally different approach to try. My buddy gave me this cool way to go. Using CAEmitterCell. All in code! Looks like you need a spark.png image.
extension UIView {
final public func ignite() {
let emitter = CAEmitterLayer()
emitter.frame = self.bounds
emitter.renderMode = kCAEmitterLayerAdditive
emitter.emitterPosition = self.center
self.layer.addSublayer(emitter)
let cell = CAEmitterCell()
let bundle = Bundle.init(for: UIColor.self)
let image = UIImage(named: "spark", in: bundle, compatibleWith: traitCollection)
cell.contents = image?.cgImage
cell.birthRate = 1500
cell.lifetime = 5.0
cell.color = UIColor(red: 1.0, green: 0.5, blue: 0.1, alpha: 1).cgColor
cell.alphaSpeed = -0.4
cell.velocity = 50
cell.velocityRange = 250
cell.emissionRange = CGFloat.pi * 2.0
emitter.emitterCells = [cell]
}
}
Enjoy.
Actually there is a way to add particles without SpriteKit - CoreAnimation's CAEmitterCells.
This way you can add particles in your UIView easily. If you want to play around with the parameters and get the code easily, get this app (Particle X).
It also supports SpriteKit so if you want to play around or design particles on the go and immediately get the code for it, this app is the solution.
PS. If you haven't noticed it, I am the developer of the app - made it to use it myself when designing app and games. :)
Putting this here for visibility reasons.
The answers regarding the user of a .clear backgroundColor are correct, except that you must also set the allowsTransparency property on SKView to 'true'.
skView.allowsTransparency = true
skView.backgroundColor = .clear // (not nil)
scene.backgroundColor = .clear
If you don't set allowsTransparency to true, and you layout your SKView over, say, a UIImageView, the composition engine will have a fit, and will send your GPU red-lining, even if only a single particle is drawn. (In the Simulator, the CPU will spike instead.)
You cannot use particle effects within UIView directly.
SKEmitterNode must be in a node tree defined with a node scene (SKScene). The scene node runs an animation loop that renders the contents of the node tree for display. UIView is static, won't work for it.
However, you probably able to create a scene inside your UIView, but I've never tried to do that.