显示上限 SKRange

Question

所以这是我的代码：

import SpriteKit
import GameplayKit

class GameScene: SKScene {

    var ship1 = [2,1]
    var ship2 = [1,2]

    let jonahSpriteNode = SKSpriteNode(imageNamed: "jonah_spaceship")
    let georgeSpriteNode = SKSpriteNode(imageNamed: "george_spaceship")

    override func didMove(to view: SKView) {
        //var jonahFrames = [SKTexture]()
        jonahSpriteNode.position = CGPoint(x: 30, y: frame.midY)
        jonahSpriteNode.size = CGSize(width: 100.0, height: 100.0)
        addChild(jonahSpriteNode)

        georgeSpriteNode.position = CGPoint(x: 628, y: frame.midY)
        georgeSpriteNode.size = CGSize(width: 100.0, height: 100.0)
        addChild(georgeSpriteNode)
    }

    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        for touch in touches{
            var touchLocation = touch.location(in: self)
            var angle1 = atan2(jonahSpriteNode.position.y - touchLocation.y , jonahSpriteNode.position.x - touchLocation.x)
            var angle = angle1 - CGFloat(Double.pi / 1)

            makeCircularRange(to: jonahSpriteNode)

            let rotate = SKAction.rotate(toAngle: angle, duration: 1.0)
            let move = SKAction.move(to: CGPoint(x: touchLocation.x, y: touchLocation.y), duration: 2.5)
            let sequence = SKAction.sequence([rotate, move])
            jonahSpriteNode.run(sequence)
        }
    }

    func makeCircularRange(to node: SKNode) {
        let range = SKRange(lowerLimit: 0, upperLimit: 400)
        let constraint = SKConstraint.distance(range, to: .zero)
        node.constraints = [constraint]
    }

}

我想通过以某种颜色显示 upperLimit 来显示 SKRange。我试着在极限附近制作节点，然后给节点上色，但它只显示了一堆错误。如果您有任何想法，请回答。

像这样：

精灵节点将位于中心，圆圈将显示它可以移动的位置。

Answer 1

您可以使用 range.upperLimit 作为半径创建一个圆形并添加到场景中。

func drawCircularRangeBy(range: SKRange) {
    let radius = range.upperLimit
    let node = SKShapeNode(circleOfRadius: radius)
    node.strokeColor = .white
    addChild(node)
}

看看这个例子：https://github.com/Maetschl/SpriteKitExamples/blob/master/CircularRange/CircularRange/GameScene.swift

如果你真的需要点而不是线，请看这个答案：

显示上限 SKRange

Display upperLimit SKRange

sprite

sprite-kit

swift

swift5