05-UIDynamic

//
//  ViewController.m
//  06-UIDynamic


#import "ViewController.h"

@interface ViewController ()
@property (weak, nonatomic) IBOutlet UIView *blueView;
/** 物理仿真器 */
@property (nonatomic, strong) UIDynamicAnimator *animator;
@property (weak, nonatomic) IBOutlet UISegmentedControl *segmentControl;
@end

@implementation ViewController

- (UIDynamicAnimator *)animator
{
    if (!_animator) {
        // 创建物理仿真器(ReferenceView, 参照视图, 其实就是设置仿真范围)
        _animator = [[UIDynamicAnimator alloc] initWithReferenceView:self.view];
    }
    return _animator;
}

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    
    self.blueView.transform = CGAffineTransformMakeRotation(M_PI_4);
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    // 获得触摸点
    UITouch *touch = [touches anyObject];
    CGPoint point = [touch locationInView:self.view];
    
    // 创建吸附捕捉行为
    UISnapBehavior *snap = [[UISnapBehavior alloc] initWithItem:self.blueView snapToPoint:point];
    // 防抖系数(值越小, 越抖)
    snap.damping = 1.0;
    
    // 添加行为
    [self.animator removeAllBehaviors];
    [self.animator addBehavior:snap];
}

- (void)testCollision2
{
    // 1.创建 碰撞行为
    UICollisionBehavior *collision = [[UICollisionBehavior alloc] init];
    [collision addItem:self.blueView];
    //    [collision addItem:self.segmentControl];
    
    // 添加边界
    //    CGFloat startX = 0;
    //    CGFloat startY = self.view.frame.size.height * 0.5;
    //    CGFloat endX = self.view.frame.size.width;
    //    CGFloat endY = self.view.frame.size.height;
    //    [collision addBoundaryWithIdentifier:@"line1" fromPoint:CGPointMake(startX, startY) toPoint:CGPointMake(endX, endY)];
    //    [collision addBoundaryWithIdentifier:@"line2" fromPoint:CGPointMake(endX, 0) toPoint:CGPointMake(endX, endY)];
    
    CGFloat width = self.view.frame.size.width;
    UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(0, 0, width, width)];
    [collision addBoundaryWithIdentifier:@"circle" forPath:path];
    
    // 2.创建物理仿真行为 - 重力行为
    UIGravityBehavior *gravity = [[UIGravityBehavior alloc] init];
    gravity.magnitude = 10;
    [gravity addItem:self.blueView];
    
    // 3.添加行为
    [self.animator addBehavior:collision];
    [self.animator addBehavior:gravity];
}

- (void)testCollision
{
    // 1.创建 碰撞行为
    UICollisionBehavior *collision = [[UICollisionBehavior alloc] init];
    // 让参照视图的bounds变为碰撞检测的边框
    collision.translatesReferenceBoundsIntoBoundary = YES;
    [collision addItem:self.blueView];
    [collision addItem:self.segmentControl];
    
    // 2.创建物理仿真行为 - 重力行为
    UIGravityBehavior *gravity = [[UIGravityBehavior alloc] init];
    gravity.magnitude = 100;
    [gravity addItem:self.blueView];
    
    // 3.添加行为
    [self.animator addBehavior:collision];
    [self.animator addBehavior:gravity];
}

- (void)testGravity
{
    // 1.创建物理仿真行为 - 重力行为
    UIGravityBehavior *gravity = [[UIGravityBehavior alloc] init];
    [gravity addItem:self.blueView];
    // 重力方向
    //    gravity.gravityDirection = CGVectorMake(100, 100);
    // 重力加速度()
    gravity.magnitude = 10;
    // 100 point/s²
    // 移动的距离 = 1/2 * magnitude * 时间²
    
    // 2.添加 物理仿真行为 到 物理仿真器 中, 开始物理仿真
    [self.animator addBehavior:gravity];
}
@end