我有两个UIView,其中的一个使用以下代码每0.01秒旋转一次:
self.rectView.transform = CGAffineTransformRotate(self.rectView.transform, .05);
现在,我想知道另一个UIView(称为view)是否与rectView相交。我使用了以下代码:
if(CGRectIntersectsRect(self.rectView.frame, view.frame)) {
//Intersection
}
如您所知,这是有问题的。这是屏幕截图:
在这种情况下,即使很明显它们没有接触,也会检测到碰撞。我环顾四周,但似乎找不到真正的代码来检测此冲突。如何才能做到这一点?在这种情况下,用于检测碰撞的工作代码将不胜感激!或者,也许还有比UIView更好的类可以使用?
旋转视图时,其范围不会改变 but its frame changes.
因此,对于我使用backgroundColor blue的视图,
我设置为的初始帧是
框架=(30,150,150,35);
bounds = {{0,0},{150,35}};
但旋转45度后,框架变为
框架=(39.5926 102.093; 130.815 130.815);
bounds = {{0,0},{150,35}};
因为框架始终返回该视图的最小封闭矩形。
因此,就您而言,即使看起来两个视图都不相交,它们的框架也相交。
为了解决这个问题,您可以使用分离轴测试。如果您想学习,请在这里链接
我试图解决它,最后得到了解决方案。如果您想检查,下面是代码。复制以下代码,将其粘贴到一个空项目中以将其签出。
在.m文件中
@implementation ViewController{
UIView *nonRotatedView;
UIView *rotatedView;
}
- (void)viewDidLoad
{
[super viewDidLoad];
nonRotatedView =[[UIView alloc] initWithFrame:CGRectMake(120, 80, 150, 40)];
nonRotatedView.backgroundColor =[UIColor blackColor];
[self.view addSubview:nonRotatedView];
rotatedView =[[UIView alloc] initWithFrame:CGRectMake(30, 150, 150, 35)];
rotatedView.backgroundColor =[UIColor blueColor];
[self.view addSubview:rotatedView];
CGAffineTransform t=CGAffineTransformMakeRotation(M_PI_4);
rotatedView.transform=t;
CAShapeLayer *layer =[CAShapeLayer layer];
[layer setFrame:rotatedView.frame];
[self.view.layer addSublayer:layer];
[layer setBorderColor:[UIColor blackColor].CGColor];
[layer setBorderWidth:1];
CGPoint p=CGPointMake(rotatedView.bounds.size.width/2, rotatedView.bounds.size.height/2);
p.x = -p.x;p.y=-p.y;
CGPoint tL =CGPointApplyAffineTransform(p, t);
tL.x +=rotatedView.center.x;
tL.y +=rotatedView.center.y;
p.x = -p.x;
CGPoint tR =CGPointApplyAffineTransform(p, t);
tR.x +=rotatedView.center.x;
tR.y +=rotatedView.center.y;
p.y=-p.y;
CGPoint bR =CGPointApplyAffineTransform(p, t);
bR.x +=rotatedView.center.x;
bR.y +=rotatedView.center.y;
p.x = -p.x;
CGPoint bL =CGPointApplyAffineTransform(p, t);
bL.x +=rotatedView.center.x;
bL.y +=rotatedView.center.y;
//check for edges of nonRotated Rect's edges
BOOL contains=YES;
CGFloat value=nonRotatedView.frame.origin.x;
if(tL.x<value && tR.x<value && bR.x<value && bL.x<value)
contains=NO;
value=nonRotatedView.frame.origin.y;
if(tL.y<value && tR.y<value && bR.y<value && bL.y<value)
contains=NO;
value=nonRotatedView.frame.origin.x+nonRotatedView.frame.size.width;
if(tL.x>value && tR.x>value && bR.x>value && bL.x>value)
contains=NO;
value=nonRotatedView.frame.origin.y+nonRotatedView.frame.size.height;
if(tL.y>value && tR.y>value && bR.y>value && bL.y>value)
contains=NO;
if(contains==NO){
NSLog(@"no intersection 1");
return;
}
//check for roatedView's edges
CGPoint rotatedVertexArray[]={tL,tR,bR,bL,tL,tR};
CGPoint nonRotatedVertexArray[4];
nonRotatedVertexArray[0]=CGPointMake(nonRotatedView.frame.origin.x,nonRotatedView.frame.origin.y);
nonRotatedVertexArray[1]=CGPointMake(nonRotatedView.frame.origin.x+nonRotatedView.frame.size.width,nonRotatedView.frame.origin.y);
nonRotatedVertexArray[2]=CGPointMake(nonRotatedView.frame.origin.x+nonRotatedView.frame.size.width,nonRotatedView.frame.origin.y+nonRotatedView.frame.size.height);
nonRotatedVertexArray[3]=CGPointMake(nonRotatedView.frame.origin.x,nonRotatedView.frame.origin.y+nonRotatedView.frame.size.height);
NSInteger i,j;
for (i=0; i<4; i++) {
CGPoint first=rotatedVertexArray[i];
CGPoint second=rotatedVertexArray[i+1];
CGPoint third=rotatedVertexArray[i+2];
CGPoint mainVector =CGPointMake(second.x-first.x, second.y-first.y);
CGPoint selfVector =CGPointMake(third.x-first.x, third.y-first.y);
BOOL sign;
sign=[self crossProductOf:mainVector withPoint:selfVector];
for (j=0; j<4; j++) {
CGPoint otherPoint=nonRotatedVertexArray[j];
CGPoint otherVector = CGPointMake(otherPoint.x-first.x, otherPoint.y-first.y);
BOOL checkSign=[self crossProductOf:mainVector withPoint:otherVector];
if(checkSign==sign)
break;
else if (j==3)
contains=NO;
}
if(contains==NO){
NSLog(@"no intersection 2");
return;
}
}
NSLog(@"intersection");
}
-(BOOL)crossProductOf:(CGPoint)point1 withPoint:(CGPoint)point2{
if((point1.x*point2.y-point1.y*point2.x)>=0)
return YES;
else
return NO;
}
希望这可以帮助。
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