SKSpriteNode vibrating when physics body is attached and impulse is applied - sprite-kit

I've noticed something very odd with my subclassed SKSpriteNode with physicsBody attached and responding to impulses.
It has a SKPhysicsBody attached, but when applying impulses to the sprite it vibrates during movement. It's highly annoying and looks awful.
What could be causing this?
Here's the setup code:
self.texture = [[SKTextureAtlas atlasNamed:#"karl"]textureNamed:#"karlidle-1"];
self.size = CGSizeMake(69.0, 93.0);
self.userInteractionEnabled = NO;
self.name = #"karl";
self.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:CGSizeMake(69.0, 93.0)];
self.physicsBody.dynamic = YES;
self.physicsBody.allowsRotation = NO;
self.physicsBody.affectedByGravity = YES;
self.physicsBody.usesPreciseCollisionDetection = YES;
self.physicsBody.mass = 1.0;
self.physicsBody.linearDamping = 0.0;
self.physicsBody.angularDamping = 0.0;
self.physicsBody.restitution = 0.3;
self.physicsBody.categoryBitMask = karlCategory;
self.physicsBody.collisionBitMask = obstaclesCategory|floorCategory|wallCategory;
self.physicsBody.contactTestBitMask = obstaclesCategory|floorCategory|wallCategory;
and applying the impulse:
if (self.physicsBody.velocity.dy >= kKarlMaxVelocity) {
self.physicsBody.velocity = CGVectorMake(0, kKarlMaxVelocity);
}
else if (self.physicsBody.velocity.dy <= kKarlLowVelocityBoostThreshold){
self.physicsBody.velocity = CGVectorMake(0, kKarlVelocityImpulseIncrement*kKarlVelocityBoost);
}
else{
[self.physicsBody applyImpulse:CGVectorMake(0, kKarlVelocityImpulseIncrement)];
//[self.physicsBody applyForce:CGVectorMake(0, 3000) atPoint:self.frame.origin];
//self.physicsBody.velocity = CGVectorMake([self returnNormalisedXVelocity], self.physicsBody.velocity.dy);
}
One thing to note is I clamp the velocity so it doesn't go nuts, but turning this off doesn't seem to fix the issue.

Related

Stop node rotation in Sprite Kit

I can't figure out how to stop node from rotating.
Why allowsRotation isn't disabling it?
Here's how I describe my node:
SKSpriteNode *badguy = [SKSpriteNode spriteNodeWithTexture:[self.spriteAtlas textureNamed:#"test"]];
badguy.texture.filteringMode = SKTextureFilteringNearest;
badguy.physicsBody.angularVelocity = 0;
badguy.physicsBody.allowsRotation = NO;
badguy.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:CGSizeMake(32, 32)];
badguy.physicsBody.velocity = CGVectorMake(0, 0);
badguy.physicsBody.categoryBitMask = CollisionTypeEnemy;
badguy.physicsBody.contactTestBitMask = CollisionTypePlayer | CollisionTypeWall | CollisionTypeEnemy;
badguy.physicsBody.collisionBitMask = CollisionTypeWall | CollisionTypePlayer | CollisionTypeEnemy;
badguy.physicsBody.mass = 10000;
badguy.physicsBody.restitution = 0;
badguy.physicsBody.dynamic = YES;
badguy.zPosition = 10;
On Update I call this method:
-(void)enemiesFollow
{
[self.world enumerateChildNodesWithName:#"badGuy" usingBlock:^(SKNode * _Nonnull badGuyNode, BOOL * _Nonnull stop) {
if((SDistanceBetweenPoints(self.player.position, badGuyNode.position) < 100)&&
(SDistanceBetweenPoints(self.player.position, badGuyNode.position) > 32))
{
SKAction * actionMove = [SKAction moveTo:self.player.position duration:2.0];
[badGuyNode runAction:actionMove];
}else{
[badGuyNode removeAllActions];
}
}];
}
Thanks to Skyler Lauren's suggestion, I am pretty much sure that the problem is in these lines:
SKSpriteNode *badguy = [SKSpriteNode spriteNodeWithTexture:[self.spriteAtlas textureNamed:#"test"]];
badguy.texture.filteringMode = SKTextureFilteringNearest;
badguy.physicsBody.angularVelocity = 0;
badguy.physicsBody.allowsRotation = NO;
badguy.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:CGSizeMake(32, 32)];
The point is that you can't set properties of a physics body before you create an actual body. So, just move those lines after you create a physics body and you will be good, like this:
SKSpriteNode *badguy = [SKSpriteNode spriteNodeWithColor:[SKColor greenColor] size:CGSizeMake(32,32)];
badguy.texture.filteringMode = SKTextureFilteringNearest;
badguy.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:CGSizeMake(32, 32)];
badguy.physicsBody.angularVelocity = 0;
badguy.physicsBody.allowsRotation = YES;

precise collision error with sprite kit

I have created a hero node and enemy node, when they collide,game over.But I have problem with precise collision. Sometimes there is overlap.Sometimes collision happens when one node doesn't reach the other's frame. can anybody give me some advise? appreciate your help~
my hero is affected by gravity, when tap, it will change the direction of gravity.
following is some of my code:
-(void)addRectHero {
rectHero = [SKSpriteNode spriteNodeWithImageNamed:#“hero.png”];
rectHero.scale = 0.2;
rectHero.position = CGPointMake(self.size.width/2, self.size.height*0.3);
rectHero.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:rectHero.size];
rectHero.physicsBody.restitution = 0.0;
rectHero.physicsBody.allowsRotation = NO;
rectHero.physicsBody.dynamic = YES;
rectHero.physicsBody.affectedByGravity=NO;
rectHero.physicsBody.categoryBitMask = heroCategory;
rectHero.physicsBody.contactTestBitMask = enemyCategory;
rectHero.zPosition = 100;
rectHero.physicsBody.collisionBitMask = enemyCategory;
rectHero.physicsBody.usesPreciseCollisionDetection = YES;
[self addChild:rectHero];
}
-(void)createEnemy{
randomStartPoint =(float)((random()%(int)(self.size.height/3))+self.size.height/3);
startPoint = CGPointMake(self.size.width + 50, randomStartPoint);
enemyNode = [SKSpriteNode spriteNodeWithImageNamed:#"enemy_4.png"];
enemyNode.scale =0.5;
enemyNode.position = startPoint;
enemyNode.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:enemyNode.size];
enemyNode.physicsBody.dynamic = NO;
enemyNode.physicsBody.categoryBitMask = enemyCategory;
enemyNode.physicsBody.contactTestBitMask = heroCategory;
enemyNode.physicsBody.collisionBitMask = heroCategory;
enemyNode.physicsBody.usesPreciseCollisionDetection = YES;
enemyNode.physicsBody.allowsRotation = NO;
enemyNode.physicsBody.restitution = 0.0;
enemyNode.name = #"enemy";
[self addChild:enemyNode];
}
-(void)didBeginContact:(SKPhysicsContact *)contact{
if (!_gameIsOn) {
return;
}
SKPhysicsBody *firstBody, *secondBody;
if (contact.bodyA.categoryBitMask<contact.bodyB.categoryBitMask) {
firstBody = contact.bodyA;
secondBody = contact.bodyB;
}
else
{
firstBody=contact.bodyB;
secondBody=contact.bodyA;
}
if (firstBody.categoryBitMask == heroCategory && secondBody.categoryBitMask == enemyCategory) {
[self runAction:sound_play completion:^{
[self gameOver];
}];
[self stopTimer];
}
}
I create a lot of enemies in update method: (I also tried self repeatActionForever method to create enemy but the problem still exists)
-(void)update:(CFTimeInterval)currentTime {
if (_lastTime)
{
_dt = currentTime - _lastTime;
}
else
{
_dt = 0;
}
_lastTime = currentTime;
if( currentTime - _lastEnemyAdded > 1 && _gameIsOn)
{
_lastEnemyAdded = currentTime + 1;
[self createEnemy];
}
}
In your ViewController make sure you have skView.showsPhysics = YES; Run your game again and look if your physics bodies are what you expect them to be. It sounds like you are creating a larger physics body than what you want.
If the issue ends up being a larger than desired physics body, try creating a physics body like this:
// to create a circular physics body
self.physicsBody = [SKPhysicsBody bodyWithCircleOfRadius:10 center:CGPointMake(0, 0)];
// to create a rect physics body
self.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:CGSizeMake(20, 20) center:CGPointMake(0, 0)];
Use the center coordinates to properly center the body.
To create a physics body made up of more than one shape, you can do something like this:
SKPhysicsBody *firstBody = [SKPhysicsBody bodyWithCircleOfRadius:20 center:CGPointMake(0, 0)];
SKPhysicsBody *secondBody = [SKPhysicsBody bodyWithRectangleOfSize:CGSizeMake(20, 20) center:CGPointMake(0, 20)];
self.physicsBody = [SKPhysicsBody bodyWithBodies:#[firstBody, secondBody]];

Prevent SKSpriteNode from bouncing off other SKSpriteNode

I have a SKSpriteNode that collides and bounces off another SKSpriteNode. What I want is to be able to detect the collision, but not have it bounce off. I want it to bounce off other nodes, but not this one. Is that possible?
self.physicsWorld.contactDelegate = self;
self.physicsBody = [SKPhysicsBody bodyWithEdgeLoopFromRect:self.frame];
self.physicsWorld.gravity = CGVectorMake(0.0f, 0.0f);
self.zone = [SKSpriteNode spriteNodeWithImageNamed:#"Oval.png"];
self.zone.position = CGPointMake(CGRectGetMidX(self.frame),CGRectGetMidY(self.frame)); self.zone.xScale = 0.3;
self.zone.yScale = 0.3;
self.zone.physicsBody = [SKPhysicsBody bodyWithCircleOfRadius:self.zone.frame.size.width/2];
self.zone.physicsBody.restitution = 0.0f;
self.zone.physicsBody.density = 0;
self.zone.physicsBody.friction = 0.4f;
self.zone.physicsBody.categoryBitMask = zoneCategory;
self.zone.physicsBody.dynamic = NO;
self.ball = [SKSpriteNode spriteNodeWithImageNamed:#"Ball.png"];
self.ball.position = CGPointMake(80,0);
self.ball.name = #"BallNode";//how the node is identified later
self.ball.physicsBody = [SKPhysicsBody bodyWithCircleOfRadius:self.ball.frame.size.width/2];
self.ball.physicsBody.restitution = 0.1f;
self.ball.physicsBody.friction = 0.4f;
self.ball.physicsBody.categoryBitMask = ballCategory;
self.ball.physicsBody.dynamic = NO;
I don't want ball and zone to bounce. Any ideas?
set collisionBitMask and contactTestBitMask of those two bodies
like:
self.zone.collisionBitMask = 0xFFFFFFFF & (~ballCategory);
self.ball.collisionBitMask = 0xFFFFFFFF & (~zoneCategory);
self.zone.contactTestBitMask = ballCategory;
then when contact occurs expect call of didBeginContact: in your SKPhysicsContactDelegate.
There will be no collsion.

Spritekit - Spawn waves of monsters

I'm making a simple racing game in which the monsters are spawned (randomly) from 3 out of the 5 lanes in the portrait mode.
-(void)addEnemy
{
SKSpriteNode *Enemy;
Enemy = [SKSpriteNode spriteNodeWithImageNamed:#"Enemy1"];
[Enemy setScale:.65];
Enemy.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:Enemy.size];
Enemy.physicsBody.categoryBitMask = obstacleCategory;
Enemy.physicsBody.dynamic = YES;
Enemy.zPosition = 2;
Enemy.physicsBody.contactTestBitMask = TurtleCategory;
Enemy.physicsBody.collisionBitMask = 0;
Enemy.physicsBody.usesPreciseCollisionDetection = YES;
Enemy.name = #"Enemy";
//selecting random y position for Enemy
int r = (arc4random() % 5) ;
Enemy.position = CGPointMake(48+r*56,self.frame.size.height);
[self addChild:Enemy];
SKAction *actionMove =
[SKAction moveTo:CGPointMake(Enemy.position.x,-80)
duration:1.43];
[Enemy runAction:actionMove];
SKSpriteNode *Enemy2;
Enemy2 = [SKSpriteNode spriteNodeWithImageNamed:#"Enemy1"];
[Enemy2 setScale:.65];
//Adding SpriteKit physicsBody for collision detection
Enemy2.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:Enemy.size];
Enemy2.physicsBody.categoryBitMask = obstacleCategory;
Enemy2.physicsBody.dynamic = YES;
Enemy2.zPosition = 2;
Enemy2.physicsBody.contactTestBitMask = TurtleCategory;
Enemy2.physicsBody.collisionBitMask = 0;
Enemy2.physicsBody.usesPreciseCollisionDetection = YES;
Enemy2.name = #"Enemy2";
//selecting random y position for Enemy
int r2 = (arc4random() % 5) ;
Enemy2.position = CGPointMake(48+r2*56,self.frame.size.height);
[self addChild:Enemy2];
SKAction *actionMove2 =
[SKAction moveTo:CGPointMake(Enemy2.position.x,-80)
duration:1.43];
[Enemy2 runAction:actionMove2];
SKSpriteNode *Enemy1;
Enemy1 = [SKSpriteNode spriteNodeWithImageNamed:#"boss1"];
[Enemy1 setScale:.65];
//Adding SpriteKit physicsBody for collision detection
Enemy1.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:Enemy1.size];
Enemy1.physicsBody.categoryBitMask = obstacleCategory;
Enemy1.physicsBody.dynamic = YES;
Enemy1.zPosition =2;
Enemy1.physicsBody.contactTestBitMask = TurtleCategory;
Enemy1.physicsBody.collisionBitMask = 0;
Enemy1.physicsBody.usesPreciseCollisionDetection = YES;
Enemy1.name = #"Enemy1";
int r1 = (arc4random() % 5) ;
Enemy1.position = CGPointMake(48+r1*56,self.frame.size.height);
[self addChild:Enemy1];
SKAction *actionMove1 =
[SKAction moveTo:CGPointMake(Enemy1.position.x,-80)
duration:1.43];
[Enemy1 runAction:actionMove1];
However, one of problem of this code is that monsters are sometimes spawned on top of each other. Is there a better way to do this?
Thanks
- (CGFloat)randomValueBetween:(CGFloat)low andValue:(CGFloat)high {
return (((CGFloat) arc4random() / 0xFFFFFFFFu) * (high - low)) + low;
}
I found this piece of code from a raywenderlich tutorial I think.
What u can do is call,
CGFloat r1 = [self randomValueBetween:0 andValue:3];
CGFloat r2 = [self randomValueBetween:3 andValue:6]; etc
that might give you different values that u can use as offset.

Not able to apply impulse to SKSpriteNode physics body

I am new to xcode's sprite kit and I'm an trying to apply an impulse to a SKSpriteNode's physics body.
Here is how I create the scene:
self.backgroundColor = [SKColor colorWithRed:0 green:0 blue:0 alpha:1.0];
self.physicsBody = [SKPhysicsBody bodyWithEdgeLoopFromRect:self.frame];
self.physicsBody.friction = 0.0f;
self.physicsWorld.gravity = CGVectorMake(0.0f, 0.0f);
ballCategory = 1;
wallCategory = 2;
self.physicsBody.categoryBitMask = wallCategory;
Here is how I create the player AND give it its impulse:
player = [SKSpriteNode spriteNodeWithImageNamed:filePath];
player.size = CGSizeMake(100, 100);
player.position = CGPointMake(150, 250);
player.physicsBody = [SKPhysicsBody bodyWithEdgeLoopFromRect:player.frame];
player.physicsBody.categoryBitMask = ballCategory;
player.physicsBody.collisionBitMask = wallCategory;
player.physicsBody.friction = 0.0f;
player.physicsBody.restitution = 1.0f;
player.physicsBody.linearDamping = 0.0f;
player.physicsBody.allowsRotation = NO;
[self addChild:player];
CGVector impulse = CGVectorMake(100,100);
[player.physicsBody applyImpulse:impulse];
Is there anything obvious that I am missing because I've been following the iOS Developer Library Sprite Kit Programming Guide perfectly? Thanks in advance for the help!
You are creating the player's physicsBody as an edge body - these are always static (immovable by forces/impulses). You should change that line to:
player.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:player.frame.size];
This example makes it a dynamic volume based on a rectangle which will be affected by physics forces. You can read up on the types of physics bodies here.