Sprite Kit - Player going of screen with accelerometer - c++

Question

Im programming a game using sprite kit and i have written the accelerometer code and it works. But the problem is it doesn't stop when hitting the edge of the screen, can anyone help me out with this?
Here is the code for the player:
-(void)addShip
{
//initalizing spaceship node
ship = [SKSpriteNode spriteNodeWithImageNamed:#"Spaceship"];
[ship setScale:0.5];
ship.zRotation = - M_PI / 2;
//Adding SpriteKit physicsBody for collision detection
ship.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:ship.frame.size];
ship.physicsBody.mass = 0.02;
ship.physicsBody.categoryBitMask = shipCategory;
ship.physicsBody.dynamic = YES;
ship.physicsBody.affectedByGravity = NO;
ship.physicsBody.contactTestBitMask = DonutCategory | PizzaCategory | ChocolateCategory | SoftCategory | AppleCategory | GrapeCategory | OrangeCategory | BananaCategory;
ship.physicsBody.collisionBitMask = 0;
ship.physicsBody.usesPreciseCollisionDetection = YES;
ship.name = #"ship";
ship.position = CGPointMake(260,30);
[self addChild:ship];
motionManager = [[CMMotionManager alloc] init];
if ([motionManager isAccelerometerAvailable] == YES) {
[motionManager startAccelerometerUpdatesToQueue:[[NSOperationQueue alloc] init]
withHandler:^(CMAccelerometerData *data, NSError *error)
{
float destX, destY;
float currentX = ship.position.x;
float currentY = ship.position.y;
BOOL shouldMove = NO;
if(data.acceleration.x < -0.25) { // tilting the device to the right
destX = currentX + (data.acceleration.x * kPlayerSpeed);
destY = currentY;
shouldMove = YES;
} else if (data.acceleration.x > 0.25) { // tilting the device to the left
destX = currentX + (data.acceleration.x * kPlayerSpeed);
destY = currentY;
shouldMove = YES;
}
if(shouldMove) {
SKAction *action = [SKAction moveTo:CGPointMake(destX, destY) duration:1];
[ship runAction:action];
}
}];
}
}

Answer 1

You can add edges to your screen so the physics will stop the ship when it hits the edge (do it in init method):
self.physicsBody = [SKPhysicsBody bodyWithEdgeLoopFromRect:self.frame];
//Add this to change some behaviour when ship will collide with the screen
//self.physicsBody.friction = 0.0f;
The other way is check in update method when ship is touching edge of the screen and change the ship position.
//Extended
I believe moveTo:duration: method mess up your phasic, to fix it just mate sure your destX and destX to go more that screen size width (height) - ship size width (height) and less that origin x and origin y.
You shouldn't use moveTo:duration: method, instead you should apply force to your ship.
Try this code, it's a little bit different that yours but this is much better way to move your ship (ignore the code above):
//Your ship setting
_ship.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:_ship.frame.size];
_ship.physicsBody.mass = 0.02;
_ship.physicsBody.categoryBitMask = shipCategory;
_ship.physicsBody.dynamic = YES;
_ship.physicsBody.affectedByGravity = NO;
// Edge around the screen
self.physicsBody = [SKPhysicsBody bodyWithEdgeLoopFromRect:self.frame];
//Apply movement (instead of moveTo:duration:)
//Get the accelerometer value
CMAccelerometerData* accelData = _motionManager.accelerometerData;
if (fabs(accelData.acceleration.x) > 0.2) {
// 35 is the value you can play with to make your ship movement feel more natural
[_ship.physicsBody applyForce:CGVectorMake(0.0, 35.0 * data.acceleration.x)];
}