检测SKSpriteNode何时完全低于另一个SKSpriteNode

For a game I'm creating, an SKSpriteNode gradually makes its way down the user's screen. There's another SKSpriteNode (position is static) near the bottom of the screen, leaving only a little bit of space for the original SKSpriteNode to fit in. I need to detect when the first SKSpriteNode is COMPLETELY below the second SKSpriteNode, which I'm having a bit of trouble with. Here's the code I'm currently using:

对于我正在创建的游戏,SKSpriteNode逐渐沿着用户的屏幕向下移动。在屏幕底部附近还有另一个SKSpriteNode(位置是静态的),只留下一点空间让原始SKSpriteNode适合。我需要检测第一个SKSpriteNode何时完全低于第二个SKSpriteNode,我有有点麻烦。这是我目前使用的代码:

if (pos.y > barPosY) //pos.y = 1st SKSpriteNode, barPosY = 2nd SKSpriteNode
{
    touchedTooEarly = true
}

For some reason, when the first SKSpriteNode goes just a little bit over the 2nd SKSpriteNode (not all the way), it still detects it as being completely over. Is there a coordinate space issue I'm missing?

出于某种原因,当第一个SKSpriteNode稍微超过第二个SKSpriteNode(不是一直)时,它仍然会检测到它完全结束。是否存在我缺少的坐标空间问题?

Thanks

1 个解决方案

#1

The logic

A sprite a covers a sprite b if

一个精灵a覆盖一个精灵b if

1. b.frame is inside a.frame

b.frame在a.frame内

2. b.zPosition is below a.zPosition

b.zPosition低于a.zPosition

The extension

Now let's build an extension

现在让我们构建一个扩展

extension SKSpriteNode {
    func isCoveredBy(otherSprite: SKSpriteNode) -> Bool {
        let otherFrame = CGRect(
            origin: convertPoint(otherSprite.position, fromNode: otherSprite),
            size: otherSprite.frame.size
        )
        return zPosition < otherSprite.zPosition && CGRectContainsRect(frame, otherFrame)
    }
}

Problem #1: transparency

This mechanism totally ignores transparency.

这种机制完全忽略了透明度。

Problem #2: same sprite

If you compare 2 sprites of the same type the function CGRectContainsRect will return true only when they are exactly aligned. Althoug you can solve this problem creating a smaller rectangle when you compare the sprites.

如果比较相同类型的2个精灵,则函数CGRectContainsRect仅在精确对齐时才返回true。虽然你可以解决这个问题,比较精灵时创建一个较小的矩形。