ios - 引入障碍物时 GKObstacleGraph 找不到路径

我正在研究 Gameplaykit 寻路概念验证，但我无法让 GKObstacleGraph 正确找到路径。

在以下代码片段中(它应该在 Xcode 7.2 Playground 上工作)，如果在创建图形时提供了障碍物，则 path2 始终是一个空数组。如果我使用空的障碍物数组创建 obGraph 对象，则 findPathFromNode 返回正确的路径。

创建的障碍物应该是一个简单的 U 形多边形，端点在 U 内。

import UIKit

import GameplayKit

let pts = [vector_float2(2,2),
    vector_float2(3,2),
    vector_float2(3,6),
    vector_float2(7,6),
    vector_float2(7,2),
    vector_float2(8,3),
    vector_float2(8,7),
    vector_float2(2,7),
    vector_float2(2,2)]
let obstacle1 = GKPolygonObstacle(points: UnsafeMutablePointer(pts) ,
    count: pts.count)

let obGraph = GKObstacleGraph(obstacles: [obstacle1], bufferRadius: 0)

let startPt = GKGraphNode2D(point: vector_float2(5,9))
let endPt = GKGraphNode2D(point: vector_float2(5,5))
let pt3 = GKGraphNode2D(point: vector_float2(0,0))
let pt4 = GKGraphNode2D(point: vector_float2(0,9))
let pt5 = GKGraphNode2D(point: vector_float2(5,0))
let pt6 = GKGraphNode2D(point: vector_float2(10,0))

obGraph.connectNodeUsingObstacles(startPt)
obGraph.connectNodeUsingObstacles(endPt)
obGraph.connectNodeUsingObstacles(pt3)
obGraph.connectNodeUsingObstacles(pt4)
obGraph.connectNodeUsingObstacles(pt5)
obGraph.connectNodeUsingObstacles(pt6)
startPt.connectedNodes
endPt.connectedNodes
pt3.connectedNodes

let path2 = obGraph.findPathFromNode(startPt, toNode: endPt)
print(path2)

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Best Answer-推荐答案

我和 jack 有同样的问题。我从 Will 的代码示例开始，并在 Xcode 10.3 中将其翻译为 Swift 5.0。我将它添加到 Xcode 的 Game 项目模板中。我仍然得到了相同的结果:来自 findPath(from:to 的空数组。

在玩弄了代码之后，我意识到任何与物理相关的东西都会影响路径。显示适用于所有人的代码的唯一方法是包括创建 SKScene 和所有 SKNode 实例。请注意，我在 SKPhysicsWorld 中将 gravity 设置为 0，并且没有向任何内容添加 SKPhysicsBody。

在 Playground 上运行它。您可以通过点击场景中的任意位置来激事件画。

import PlaygroundSupport
import SpriteKit
import GameKit

class GameScene: SKScene {

    let nodeToMove:SKShapeNode = {
        let n = SKShapeNode(circleOfRadius: 10)
        n.lineWidth = 2
        n.strokeColor = UIColor.orange
        n.position = CGPoint(x: -200, y: 150)
        return n
    }()

    override func sceneDidLoad() {
        addChild(nodeToMove)

        let nodeToFind = SKShapeNode(circleOfRadius: 5)
        nodeToFind.lineWidth = 2
        nodeToFind.strokeColor = UIColor.red
        addChild(nodeToFind)
        nodeToFind.position = CGPoint(x: 200, y: -150)

        let nodeToAvoid = SKShapeNode(rectOf: CGSize(width: 100, height: 100))
        nodeToAvoid.lineWidth = 4
        nodeToAvoid.strokeColor = UIColor.blue
        addChild(nodeToAvoid)
        nodeToAvoid.position = CGPoint.zero

        let polygonObstacles = SKNode.obstacles(fromNodeBounds: [nodeToAvoid])
        let graph = GKObstacleGraph(obstacles: polygonObstacles, bufferRadius: 10.0)
        let end = GKGraphNode2D(point: vector2(Float(nodeToMove.position.x), Float(nodeToMove.position.y)))
        let start = GKGraphNode2D(point: vector2(Float(nodeToFind.position.x), Float(nodeToFind.position.y)))
        graph.connectUsingObstacles(node: end)
        graph.connectUsingObstacles(node: start)

        graphNodes = graph.findPath(from: end, to: start) as!  [GKGraphNode2D]
        print("graphNodes = \(graphNodes)")
    }

    var graphNodes = [GKGraphNode2D]()

    override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
        touches.first.flatMap {_ in
            let newActions: [SKAction] = graphNodes.map { n in
                return SKAction.move(to: CGPoint(x: CGFloat(n.position.x), y: CGFloat(n.position.y)), duration: 2)
            }
            nodeToMove.run(SKAction.sequence(newActions))
        }
    }
}

let sceneView = SKView(frame: CGRect(x:0 , y:0, width: 640, height: 480))
let scene = GameScene(size: CGSize(width: 640, height: 480))
scene.scaleMode = .aspectFill
scene.anchorPoint = CGPoint(x: 0.5, y: 0.5)
scene.backgroundColor = UIColor.purple
scene.physicsWorld.gravity = CGVector(dx: 0.0, dy: 0.0)
sceneView.presentScene(scene)

PlaygroundSupport.PlaygroundPage.current.liveView = sceneView

控制台的输出是:

graphNodes = [GKGraphNode2D: {-200.00, 150.00}, GKGraphNode2D: {62.85, 62.85}, GKGraphNode2D: {200.00, -150.00}]

开始状态:

结束状态:

警告:我不知道为什么用户点击和动画开始之间需要一整秒。性能调优是一个单独的主题。

关于ios - 引入障碍物时 GKObstacleGraph 找不到路径，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/34901988/