Speed of touch varies with number of objects on Scene - ios

Question

I am creating game in which user can hit the object falling from the top of the screen with the racket. user can continuously move the racket but if it is at minimal speed or is at rest it should not hit the object, but if it above the minimal speed user should hit them. I have achieved that but the issue is when user start touching the racket which continously move with the user touch, the speed varition is their it does not start with the same speed and while touch is moving at that time also some times speed is very less even though the movement is fast. Here is my piece of code
-(void)didMoveToView:(SKView *)view {
self.physicsWorld.contactDelegate = (id)self;
racketNode = [SKSpriteNode spriteNodeWithImageNamed:#"racket"];
racketNode.size = CGSizeMake(50,50);
racketNode.position = CGPointMake(self.frame.origin.x + self.frame.size.width - 50,50);
racketNode.name = #"racket";
[self addChild:racketNode];
}
-(void) didBeginContact:(SKPhysicsContact *)contact {
SKSpriteNode *nodeA = (SKSpriteNode *)contact.bodyA.node ;
SKSpriteNode *nodeB = (SKSpriteNode *) contact.bodyB.node;
if (([nodeA.name isEqualToString:#"racket"] && [nodeB.name isEqualToString:#"fallingObject"])) {
if (racketNode.speed > kMinSpeed)
[nodeB removeFromParent];
else {
nodeB.physicsBody.contactTestBitMask = 0;
[self performSelector:#selector(providingCollsion:) withObject:nodeB afterDelay:0.1];
}
}
}
-(void) providingCollsion:(SKSpriteNode *) node {
node.physicsBody.contactTestBitMask = racketHit;
}
-(void) touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
for (UITouch *touch in touches) {
CGPoint location = [touch locationInNode:self];
start = location;
startTime = touch.timestamp;
racketNode.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:racketNode.frame.size];
racketNode.physicsBody.categoryBitMask = racket;
racketNode.physicsBody.contactTestBitMask = HitIt;
racketNode.physicsBody.dynamic = NO;
racketNode.physicsBody.affectedByGravity = NO;
[racketNode runAction:[SKAction moveTo:location duration:0.01]];
}
}
- (void) touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
racketNode.physicsBody = nil;
racketNode.speed = 0;
}
-(void) touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
UITouch *touch = [touches anyObject];
CGPoint location = [touch locationInNode:self];
CGFloat dx = location.x - start.x;
CGFloat dy = location.y - start.y;
CGFloat magnitude = sqrt(dx*dx+dy*dy);
// Determine time difference from start of the gesture
CGFloat dt = touch.timestamp - startTime;
// Determine gesture speed in points/sec
CGFloat speed = magnitude/dt;
racketNode.speed = speed;
[handNode runAction:[SKAction moveTo:[touch locationInNode:self] duration:0.01]];
}
Please tell me which part my code is wrong so as to make same object collide with high speed only not on slow speed and also no collision on stable state.

Answer 1

Instead of doing it manually, use UIPanGestureRecognizer to handle your swipes. With it, there is a velocity property that you can use to check if the speed is greater than a given value.
Here is a great tutorial to do it:
https://www.raywenderlich.com/76020/using-uigesturerecognizer-with-swift-tutorial