Sprite Kit - Objective c, move multiple SKNode at the same time - ios

i have this method that makes the Lines
lineaGuida_Img = [SKTexture textureWithImageNamed:#"LineaGuida copia.jpeg"];
_Linea = [SKNode node];
_Linea.position = CGPointMake((self.frame.size.width / 7 ) * 2, self.frame.size.height / 2 );
_Linea.zPosition = -10;
SKSpriteNode * linea = [SKSpriteNode spriteNodeWithTexture:lineaGuida_Img];
linea.position = CGPointMake(0,0);
linea.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:linea.size];
linea.physicsBody.dynamic = FALSE;
linea.physicsBody.collisionBitMask = 0;
linea.physicsBody.categoryBitMask = CollisionEnemy;
[_Linea addChild:linea];
[self addChild:_Linea];
In the touchesBegan method when i touch the screen, the player is always on the center of screen, and those lines behind him have to move by -x.
[_Linea runAction:[SKAction moveByX: -(self.size.width/8) y:0 duration:0.1]];
[self spawn_Lines];
But this action is only executed by the last SKNode. I need to apply this to all Lines simultaneously. After that, when the line's position is less then the player's position, the line must be deleted.

SpriteKit uses a tree based model, so whatever the parent node does, the children fall suit. Create an SKNode to house all of your lines, add all of your lines to this SKNode, then apply the actions to the SKNode, not the lines.

Add them to NSMutableArray to keep the reference and use for each loop to make each one run the action. I would recommend you to use NSTimer to provide [SKAction moveByX: -1 y:0 duration:0]] with constant speed which will result in the same motion as you already used. Each time this NSTimer execute you will check all positions of object from your NSMutableArray and than delete it if it fits your conditions. Be careful when you want to lose the reference completely use [object removeFromParent]; and remove it also from your NSMutableArray to avoid lose of performance later on. For this I use rather forLoop with continue method

Related

How to get correct zRotation during [SKAction rotateBy:duration:]

I'm running a rotateBy action that's repeated forever for a node, and occasionally I want to get the node's current rotation. But zRotation always return 0. How can I get the correct zRotation for this node?
Edit: so finally what I'm doing is creating a custom rotation action instead of using Sprite Kit's default action. A lot more complicated and hard to extend but it does what I want and can be encapsulated in each node's own class.
I believe the reason why you are getting 0 is because you are using animation. The properties of nodes undergoing animation are not updated at each step in the simulation. You will need to manually rotate the node in the update method or create a physics body and set the angular velocity. Using real-time motion will allow you to constantly monitor the properties of you nodes at each step in the simulation.
You can see an example of simulating rotation using real-time motion (albeit more complex) in my answer here.
If you paste the following into a new project, you should see the zRotation property change over time. With an 180 degree/second rotational rate and 60 FPS, the zRotation changes by ~3 degrees per update.
#implementation GameScene {
SKSpriteNode *sprite;
}
-(void)didMoveToView:(SKView *)view {
self.scaleMode = SKSceneScaleModeResizeFill;
sprite = [SKSpriteNode spriteNodeWithImageNamed:#"Spaceship"];
sprite.xScale = 0.5;
sprite.yScale = 0.5;
sprite.position = CGPointMake (CGRectGetMidX(view.frame),CGRectGetMidY(view.frame));
SKAction *action = [SKAction rotateByAngle:M_PI duration:1];
[sprite runAction:[SKAction repeatActionForever:action]];
[self addChild:sprite];
}
-(void)didEvaluateActions {
// Wrap at 360 degrees
CGFloat angle = fmod(sprite.zRotation*180/M_PI, 360.0);
NSLog(#"%g",angle);
}
#end

SKAction to Change AnchorPoint?

I am creating a relatively complicated animation sequence. In it, a certain SKSpriteNode (shark) does two rotations. At the beginning of the animation, it rotates around a certain anchor point ap1, then later rotates around a different anchor point ap2. How should I change anchor points midway through an animation sequence?
Some initial thoughts:
I could change the anchor point outside of SKActions, in the update: loop perhaps.
I could use multiple SKSpriteNodes for the same shark sprite (with their respective anchor points), switching (hiding/showing) the sprite nodes when I need to change the anchor point.
Since changing a sprite's anchor point affects where it's rendered, you will likely need to make some sort of adjustment to prevent the sprite from appearing to suddenly move to a new location. Here's one way to do that:
Create action that changes the anchor point
SKAction *changeAnchorPoint = [SKAction runBlock:^{
[self updatePosition:sprite withAnchorPoint:CGPointMake(0, 0)];
}];
SKAction *rotate = [SKAction rotateByAngle:2*M_PI duration: 2];
Run action to rotate, change the anchor point, and rotate
[sprite runAction:[SKAction sequence:#[rotate,changeAnchorPoint,rotate]] completion:^{
// Restore the anchor point
[self updatePosition:sprite withAnchorPoint:CGPointMake(0.5, 0.5)];
}];
This method adjusts a sprite's position to compensate for the anchor point change
- (void) updatePosition:(SKSpriteNode *)node withAnchorPoint:(CGPoint)anchorPoint
{
CGFloat dx = (anchorPoint.x - node.anchorPoint.x) * node.size.width;
CGFloat dy = (anchorPoint.y - node.anchorPoint.y) * node.size.height;
node.position = CGPointMake(node.position.x+dx, node.position.y+dy);
node.anchorPoint = anchorPoint;
}
As Julio Montoya said, the easiest way to do this is to just "translate" code into an SKAction with the method [SKAction runBlock:myBlock].

Sprites are removed by themselfs as soon as they pass the screen height

I'm currently trying SpriteKit for first time and using some actions. I was under the impression that every node/sprite you create you would need to remove it but for some reason they are removed by themselfs as soon as they pass the screen height. Is this a normal behavior in SpriteKit?
Here is the code.
I'm basically using an action to animate a sprite across the screen (from bottom to top in protrait-mode), the funny thing is that the node count stays at 0 no matter how many sprites I create, it actually counts them but it subtracts them as soon as they pass the screen height.
-(void) shoot
{
bullet = [SKSpriteNode spriteNodeWithImageNamed:#"bullet"];
bullet.position = CGPointMake(airPlane.position.x, airPlane.position.y + 50);
[self addChild:bullet];
SKAction *moveBullet = [SKAction moveTo:CGPointMake(airPlane.position.x, self.size.height + 20) duration:0.5];
[bullet runAction:moveBullet];
}
If I change my action to where the sprite doesn't cross the screen height then the node count keeps the count.
Change this line...
SKAction *moveBullet = [SKAction moveTo:CGPointMake(airPlane.position.x, self.size.height + 20) duration:0.5];
... to this
SKAction *moveBullet = [SKAction moveTo:CGPointMake(airPlane.position.x, self.size.height) duration:0.5];
Again Is this a normal behavior in SpriteKit?
Thanks a lot
The node count displayed on the lower right corner is just an indication of the nodes which are being rendered on the screen. They are not an indication of the total nodes in the scene.
Use the following code
[skView setValue:#(YES) forKey:#"_showsCulledNodesInNodeCount"];
At the same place where you call
skView.showsFPS = YES;
skView.showsNodeCount = YES;
Also, please have a look at this answer.
that can be a memory leak because sprite kit holds textures in the memory for further use for better result remove it from the screen when its passing out of the screen and set it manually to nil
for eg
[self enumerateChildNodesWithName:name usingBlock:^(SKNode *node, BOOL *stop) {
if(node.x>900)
{
//remove all the action
[node removeAllActions];
//remove node from parent
[node removeFromParent];
//set nil//not required set automatically to nil when node is remove from parent
node=nil;
}
}];

Transform a physics body using Sprite Kit

I am making a 2D game where a character stands stationary at the left hand side of the screen and objects fly towards him from the right. He needs to be able to slap these flying enemies down. I have a sprite animation that contains the "slap" animation frames. During the slap, his body moves slightly and his arm rotates from resting on the ground, to fully extended above his head and then slaps down to the ground. Here is what it looks like:
SumoSmash Animation GIF
For these purposes I have a class called SumoWarrior which is a SKSpriteNode subclass. The SumoWarrior sprite node has a child sprite node called warriorArm. My idea was to have the main sumo warrior sprite node display the animation, and to use this warriorArm sprite node only for the purposes of a physics body in the shape of the warriors arm. I need to somehow rotate this arm body to follow the sprite animation, in order to detect collisions with the flying objects.
Here is how the arm is created:
sumoWarrior.warriorArm = [SKSpriteNode spriteNodeWithTexture:[SKTexture textureWithImageNamed:#"warriorArm"]];
sumoWarrior.warriorArm.position = CGPointMake(15, 25);
sumoWarrior.warriorArm.anchorPoint = CGPointMake(0.16, 0.7);
sumoWarrior.warriorArm.texture = nil;
sumoWarrior.warriorArm.physicsBody = [SKPhysicsBody bodyWithPolygonFromPath:[sumoWarrior createArmBody]];
sumoWarrior.warriorArm.physicsBody.mass = 9999;
sumoWarrior.warriorArm.physicsBody.categoryBitMask = CollisionPlayer;
sumoWarrior.warriorArm.physicsBody.collisionBitMask = CollisionEnemy;
sumoWarrior.warriorArm.physicsBody.contactTestBitMask = CollisionEnemy | CollisionAlly;
sumoWarrior.warriorArm.physicsBody.allowsRotation = YES;
sumoWarrior.warriorArm.physicsBody.dynamic = YES;
Is it possible to rotate and extend this arm somehow, in order for it to follow the animation precisely? Is it also possible to alter the main physics body of the warrior (which is just a polygon around the body, without the arm) so that IT also follow the animation? Or am I completely missing the way that this should be done?
I used Texture Packer for the texture and animation. I created an Texture Atlas called sumoAnimations and Texture Packer created a .h file for me which I then imported into the project.
You can get a free copy if you do not already have it.
Before I launch into the code, you might want to reconsider using the animation you have. Going by your previous comments the only relevant frames in the animation are frame 15, 16 and 17. I am not even sure about frame 17 because the sumo already has his hand down. That only give you 3 frames which by the animation you provided is equal to 0.1 seconds as each frame has a time of 0.05 seconds.
Take a look at the 3 pics I included to see what I mean. You might want to consider getting a new animation or allowing for greater time in between frames. I used 0.25 seconds per frame so you can see it more clearly. You can change it to anything you like.
As for the player being missing and being hit, you can create a clearColor sprite rect around the player (behind the arm of course) to detect contact of a missed object.
#import "MyScene.h"
#import "sumoAnimation.h"
#interface MyScene()<SKPhysicsContactDelegate>
#end
#implementation MyScene
{
SKSpriteNode *sumo;
SKSpriteNode *arm;
SKAction *block0;
SKAction *block1;
SKAction *block2;
SKAction *block3;
SKAction *block4;
SKAction *slapHappy;
SKAction *wait0;
SKAction *wait1;
}
-(id)initWithSize:(CGSize)size
{
if (self = [super initWithSize:size])
{
sumo = [SKSpriteNode spriteNodeWithTexture:SUMOANIMATION_TEX_SUMO_001];
sumo.anchorPoint = CGPointMake(0, 0);
sumo.position = CGPointMake(0, 0);
[self addChild:sumo];
arm = [SKSpriteNode spriteNodeWithColor:[SKColor clearColor] size:CGSizeMake(34, 14)];
arm.anchorPoint = CGPointMake(0, 0);
arm.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:CGSizeMake(34,14) center:CGPointMake(17, 7)];
arm.physicsBody.dynamic = NO;
slapHappy = [SKAction animateWithTextures:SUMOANIMATION_ANIM_SUMO timePerFrame:0.25];
// start the animation
block0 = [SKAction runBlock:^{
[sumo runAction:slapHappy];
}];
// time until frame 15 is reached
wait0 = [SKAction waitForDuration:3.50];
// add arm at frame 15 positon
block1 = [SKAction runBlock:^{
arm.position = CGPointMake(205, 125);
arm.zRotation = 1.3;
[self addChild:arm];
}];
// wait until next frame
wait1 = [SKAction waitForDuration:0.25]; // time in between frames
// move arm and rotate to frame 16 position
block2 = [SKAction runBlock:^{
arm.position = CGPointMake(224, 105);
arm.zRotation = 0.4;
}];
// move arm and rotate to frame 17 position
block3 = [SKAction runBlock:^{
arm.position = CGPointMake(215, 68);
arm.zRotation = -0.65;
}];
// remove arm from view
block4 = [SKAction runBlock:^{
[arm removeFromParent];
}];
}
return self;
}
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
[sumo runAction:[SKAction sequence:#[block0, wait0, block1, wait1, block2, wait1, block3, wait1, block4]]];
}
-(void)update:(CFTimeInterval)currentTime
{
//
}
#end
Updated based on additional comments
The pic below outlines my suggestion. Add a physics body rect for the frames the sumo is swatting. This will allow you to not have to deal with adding a body for every frame in the precise position. It will also make the swatting more effective.
Your object can still fall to the ground and have the crushed animation play. Remember that your sumo animation moves very fast and the player will not see precise locations for each frame.
Your idea of having the arm "push" the object would take a much more precise animation. Something like the arm's position changing by a single increment. Then you would have to precisely position a body on the hand. I am not saying its impossible but its certainly A LOT of work and difficult to do.

how to display an x.position in my sprite?

i have a method to create sprites with an initial position, final position, height, image of the sprite and a name property to the sprite (to access the sprite later)
The problem is when i need to debug, because i can't display, for example, a number (of a position in this case...)
In this case, i want to know what sprite is disapearing sooner than expected, so i want to set a new parameter in my method which would be an NSString number(1,2,3..)so i could localize what sprite is making troubles... but i cant display this number or i don't know how. The other debugging technique i thought to do were to put an if(x.position> 600)callAMethod with a label, but... the coordinates are CGPoint and not float. So i'm a bit lost... Do anybody know a technique to do this??
here is my method to create sprites:
-(void)crearMontanaconLaPosicionFinal:(CGFloat)xFinal inicial:(CGFloat)xInicial altura:(CGFloat)altura imagen:(NSString*)imagen nombre:(NSString*)nombre
{
CGPoint posicionFinal = CGPointMake(xFinal, altura);
SKSpriteNode *montaña = [SKSpriteNode spriteNodeWithImageNamed:imagen];
montaña.name = nombre;
SKAction* parallaxMoveAction3 = [SKAction sequence:#[[SKAction moveTo:posicionFinal duration:20],[SKAction customActionWithDuration:0 actionBlock:^(SKNode* montaña, CGFloat elapsedTime){
[montaña setPosition:CGPointMake(xInicial,altura)];
}]]];
montaña.position = CGPointMake(xInicial, altura);
SKAction *repetir=[SKAction repeatActionForever:parallaxMoveAction3];
[montaña runAction:repetir];
[self addChild:montaña];
}

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