从 SKNode 楼层类中移除重力

Posted 2023-03-16

【中文标题】从 SKNode 楼层类中移除重力

【英文标题】：Remove Gravity From SKNode Floor Class

【发布时间】：2017-12-22 00:34:00

【问题描述】：

我的游戏开始时出现了两个矩形，但一旦开始，重力就会将它们拉下来。我在一个单独的“Floor.swift”类中有下面的代码。我还有一个“BitMaskCategories.swift”文件，其中包含以下信息。

let ballCategory : UInt32 = 0x1 << 1
let avoidCategory : UInt32 = 0x1 << 2
let floorCategory : UInt32 = 0x1 << 3
let pointCategory : UInt32 = 0x1 << 4
let lifeCategory : UInt32 = 0x1 << 5 

这是我的“Floor.swift”类

import Foundation
import SpriteKit

class Floor: SKNode 
    override init() 
        super.init()

        let leftWall = SKSpriteNode(color: UIColor.brown, size: CGSize(width: 50, height: 300))
        leftWall.position = CGPoint(x: 0, y: 100)
        leftWall.physicsBody!.isDynamic = false
        leftWall.physicsBody = SKPhysicsBody(rectangleOf: leftWall.size)
        self.addChild(leftWall)

        let rightWall = SKSpriteNode(color: UIColor.brown, size: CGSize(width: 50, height: 300))
        rightWall.position = CGPoint(x: 100, y: 200)
       rightWall.physicsBody!.isDynamic = false
        rightWall.physicsBody = SKPhysicsBody(rectangleOf: rightWall.size)
        self.addChild(rightWall)

        // self.physicsBody?.affectedByGravity = false
        // self.physicsBody?.isDynamic = false

        // Set the bit mask properties
        self.physicsBody?.categoryBitMask = balloonCategory
        self.physicsBody?.contactTestBitMask = nailDropCategory | pointCategory | lifeCategory
        //self.physicsBody?.collisionBitMask = balloonCategory
    

    required init?(coder aDecoder: NSCoder) 
        fatalError("init(coder:) has not been implemted")
    

为什么我得到错误，“线程 1：致命错误：在展开可选值时意外发现 nil”但是当我使用“？”代替 ”！”该应用程序有效，但矩形下降。我需要那条线才能让他们不这样做，我什至不明白这有什么意义。

【参考方案1】：

您正在尝试分配：.isDynamic = false 在对象初始化之前，

你应该移动leftWall.physicsBody!.isDynamic = false

之后 leftWall.physicsBody = SKPhysicsBody(rectangleOf: leftWall.size)

同样：rightWall.physicsBody!.isDynamic = false，移动它

之后：rightWall.physicsBody = SKPhysicsBody(rectangleOf: rightWall.size)

所以你的代码可能是：

let leftWall = SKSpriteNode(color: UIColor.brown, size: CGSize(width: 50, height: 300))
leftWall.position = CGPoint(x: 0, y: 100)
leftWall.physicsBody = SKPhysicsBody(rectangleOf: leftWall.size)
leftWall.physicsBody!.isDynamic = false
self.addChild(leftWall)

let rightWall = SKSpriteNode(color: UIColor.brown, size: CGSize(width: 50, height: 300))
rightWall.position = CGPoint(x: 100, y: 200)
rightWall.physicsBody = SKPhysicsBody(rectangleOf: rightWall.size)
rightWall.physicsBody!.isDynamic = false
self.addChild(rightWall)

【讨论】：

非常感谢你！

很高兴您发现它很有用。是的！ :)

所以一件事导致了另一个问题，我觉得您很快就会知道解决方案。如果您有机会，请查看我的新帖子***.com/questions/47946410/…