ios – 线条图线与自身的交点,也可以检测绘制线内的CCSprites

http://www.merowing.info/2012/04/drawing-smooth-lines-with-cocos2d-ios-inspired-by-paper/

现在我要…..

1 GT;检测线是否与自身相交.
2)检测CCSprite是否在该闭合线内.

在搜索时遇到了LineIntersection的许多逻辑,但都没有准确.我给其中一个检测到一个十字路口,但是当没有相交线时也会检测到.

>第一种方法

- (BOOL) lineIntersectOccured:(CGPoint)t1 pointEnd:(CGPoint)t2
{
    BOOL result = NO;
    int pointsCount = [arrlinePoints count];

    CGPoint cp1;
    CGPoint cp2;

    for(int i = 0,j = 1; j < pointsCount; i++,j++)
    {
        [[arrlinePoints objectAtIndex:i] getValue:&cp1];
        [[arrlinePoints objectAtIndex:j] getValue:&cp2];

        // lines connected do not need to be included.
        if((cp2.x == t1.x && cp2.y == t1.y) || (cp1.x == t2.x && cp1.y == t2.y))
        {
            continue;
        }

        CGPoint diffLA = CGPointMake(cp2.x - cp1.x,cp2.y - cp1.y);
        CGPoint diffLB = CGPointMake(t2.x - t1.x,t2.y - t1.y);

        float compA = diffLA.x*cp1.y - diffLA.y * cp1.x;
        float compB = diffLB.x*t1.y - diffLB.y*t1.x;

        BOOL compA1 = (diffLA.x*t1.y - diffLA.y*t1.x) < compA;
        BOOL compA2 = (diffLA.x*t2.y - diffLA.y*t2.x) < compA;
        BOOL compB1 = (diffLB.x*cp1.y - diffLB.y*cp1.x) < compB;
        BOOL compB2 = (diffLB.x*cp2.y - diffLB.y*cp2.x) < compB;

        if(((!compA1 && compA2) || (compA1 && !compA2)) && ((!compB1 && compB2) || (compB1 && !compB2)))
        {
            result = YES;
        }
    }
    return result;
}

这就是我所说的这个方法,
我已经把我的分数存储在arrLinePoints中,从pangesture识别方法

if ([self lineIntersectOccured:[[arrlinePoints objectAtIndex:0] CGPointValue] pointEnd:[[arrlinePoints objectAtIndex:[arrlinePoints count] - 1] CGPointValue]] )
  {
      NSLog(@"Line Intersected");
  }

即使在以下情况下,这也使我成真

我也用不同的方法尝试了相同的功能,通过添加视图到CCDirector的视图

UIBezierPath intersect

但是这是提供性能问题,我的fps降低到近3到6.而且交叉路口的问题依然如此.

交点的完美情况是

请尽快帮忙！
感谢所有支持.