Single point several times and more naturally

Question

so my current version is as follows: Animated film

I am new to core animation, so I try to achieve that there are several points, such as the current one, moving from the left field at different angles, heights and speeds from it, like in a tennis ball machine.

the first problem is that my "ball" does not look like it is caught from gravity, and also the speed is not high enough at first.

as well as making this animation several times with variable distances between the start.

If something is unclear, PLEASE leave a comment.

my current code is:

- (void)loadView {
    [super loadView];

    self.view.backgroundColor = [UIColor lightGrayColor];   

    CGPoint startPoint = CGPointMake(20, 300);
    CGPoint endPoint = CGPointMake(300, 500);

    UIBezierPath *trackPath = [UIBezierPath bezierPath];
    [trackPath moveToPoint:startPoint];
    [trackPath addQuadCurveToPoint:endPoint controlPoint:CGPointMake(endPoint.x, startPoint.y)];

    CALayer *point = [CALayer layer];
    point.bounds = CGRectMake(0, 0, 20.0, 20.0);
    point.position = startPoint;
    point.contents = (id)([UIImage imageNamed:@"point.png"].CGImage);
    [self.view.layer addSublayer:point];

    CAKeyframeAnimation *anim = [CAKeyframeAnimation animationWithKeyPath:@"position"];
    anim.path = trackPath.CGPath;
    anim.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut];
    anim.repeatCount = HUGE_VALF;
    anim.duration = 2.0;
    [point addAnimation:anim forKey:@"movepoint"];

    CALayer *caseLayer = [CALayer layer];
    caseLayer.bounds = CGRectMake(0, 0, 140.0, 150.0);
    caseLayer.position = startPoint;
    caseLayer.contents = (id)([UIImage imageNamed:@"case.png"].CGImage);
    [self.view.layer addSublayer:caseLayer];

}

Answer 1

- , . , , (IN RADIANS, 0 ). CALayer .

CADisplayLink ( , ), . , , . , (`vy - = 0,5f;). / , 0.5f.

- (id)initWithFrame:(CGRect)frame {

    self = [super initWithFrame:frame];
    if (self) {
      point = [[CALayer alloc] init];
      point.bounds = CGRectMake(0.0f, 0.0f, 10.0f, 10.0f);
      point.backgroundColor = [UIColor redColor].CGColor;
      point.position = CGPointMake(-10.0f, -10.0f);
      [self.layer addSublayer:point];
      [point release];
    }
    return self;
}

-(void)animateBallFrom:(CGPoint)start withSpeed:(CGFloat)speed andAngle:(CGFloat)angle       
  vx = speed*cos(angle);
  vy = speed*sin(angle);


  [CATransaction begin];
  [CATransaction setDisableActions:YES];
  point.position = start;
  [CATransaction commit];

  displayLink = [CADisplayLink displayLinkWithTarget:self selector:@selector(animate)];
  [displayLink setFrameInterval:2];
  [displayLink addToRunLoop:[NSRunLoop currentRunLoop] forMode:NSRunLoopCommonModes];
}

-(void)animate {
  if (point.position.x + point.bounds.size.width/2.0f < 0.0f || point.position.x > self.bounds.size.width + point.bounds.size.width/2.0f ||
    point.position.y + point.bounds.size.height/2.0f < 0.0f || point.position.y > self.bounds.size.height + point.bounds.size.height/2.0f) {
    [displayLink invalidate];
  } else {
    [CATransaction begin];
    [CATransaction setDisableActions:YES];
    point.position = CGPointMake(point.position.x+vx, point.position.y-vy);
    vy -= 0.5f;
    [CATransaction commit];
  }
}

:

@interface Bounce : UIView {
  CALayer *point;
  CADisplayLink *displayLink;
  CGFloat vx, vy;
}

-(void)animateBallFrom:(CGPoint)start withSpeed:(CGFloat)speed andAngle:(CGFloat)angle;

@end

Answer 2

, . - - kCAMediaTimingFunctionLinear kCAMediaTimingFunctionEaseOut.
- - , . :

CGPoint startPoint = CGPointMake(20, 300);
CGPoint controlPoint = CGPointMake(160, 400);
CGPoint endPoint = CGPointMake(300, 500);

UIBezierPath *trackPath = [UIBezierPath bezierPath];
[trackPath moveToPoint:startPoint];
[trackPath addQuadCurveToPoint:endPoint controlPoint:controlPoint];

CALayer *point = [CALayer layer];
point.bounds = CGRectMake(0, 0, 20.0, 20.0);
point.position = startPoint;
point.contents = (id)([UIImage imageNamed:@"point.png"].CGImage);
[self.view.layer addSublayer:point];

CAKeyframeAnimation *anim = [CAKeyframeAnimation animationWithKeyPath:@"position"];
anim.path = trackPath.CGPath;
anim.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear];
anim.repeatCount = HUGE_VALF;
anim.duration = 2.0;
[point addAnimation:anim forKey:@"movepoint"];

.