swift - Swift 4 中的特定头部碰撞

Question

我是 iOS 开发的新手，我制作了一款无限跑酷游戏。正如您在下面的函数中看到的，玩家在与障碍物碰撞时死亡。但是，只要玩家与障碍物的任何一侧发生碰撞，玩家就会死亡。如何将此碰撞检测限制在障碍物框架的特定一侧？

func didBegin(_ contact: SKPhysicsContact) { //so the player can't jump while in the air
    var firstBody = SKPhysicsBody()
    var secondBody = SKPhysicsBody()

    if contact.bodyA.node?.name == "Player" {
        firstBody = contact.bodyA
        secondBody = contact.bodyB
    } else {
        firstBody = contact.bodyB
        secondBody = contact.bodyA
    }

    if firstBody.node?.name == "Player" && secondBody.node?.name == "Ground" { //if colliding with ground
        canJump = true //can jump when on ground
    }

    if firstBody.node?.name == "Player" && secondBody.node?.name == "Bus" || firstBody.node?.name == "Player" && secondBody.node?.name == "Obstacle" {
        // kill player and prompt buttons
        playerDied()
    }
}

Answer 1

您可以尝试计算两个碰撞节点之间的交点，然后只需检查结果帧的宽度和高度就足以检测碰撞侧，粗略的解释:

1. 左/右碰撞

1. 上/下碰撞

对于无限跑酷游戏，这个检查应该足够了:

if firstBody.node?.name == "Player" && secondBody.node?.name == "Obstacle" {
    let intersection = firstBody.node!.frame.intersection(secondBody.node!.frame)
    if intersection.height > intersection.width { // collision left/right
        playerDied()
    } else { // collision top/down
       //...//
    }
}