【发布时间】：2017-06-23 21:55:20
【问题描述】：
大家！首先，我知道这个问题与Draw images evenly spaced along a path in iOS 非常相似。但是，这是在 Objective-C 中（我看不懂）并且它在使用 CGImageRefs 的普通 ViewController 中。我需要它迅速并使用 SKSpriteNodes（不是 CGImageRefs）。这是我的问题：
我正在尝试制作一个程序，让用户绘制一个简单的形状（如圆形）并沿着用户绘制的路径以固定间隔放置 SKSpriteNodes。我已经让它以缓慢的速度正常工作，但是如果用户绘制得太快，那么节点就会被放置得太远。下面是我慢慢画的例子：
用户绘制的路径，其中节点彼此相距大约 60 像素。蓝色是开始节点，紫色是结束节点。
目标是每个节点都有一个 PhysicsBody 来防止实体越过用户绘制的线（这些实体将无法挤入均匀间隔的节点之间）。但是，如果用户画得太快，就会出现我无法修复的防御缺口。例如：
请注意第 7 和第 8 个节点之间明显更大的间隙。这是因为我画得太快了。许多人的问题有些相似，但对我的任务没有帮助（例如，沿路径均匀分布特定数量的节点，而不是放置尽可能多的节点以使它们沿路径相距 60 像素）。
最后，这又是我的主要问题：如何将节点放置在沿用户绘制的任意形状路径完美间隔的位置？预先感谢您的帮助！这是我的 GameScene.swift 文件：
import SpriteKit
导入 GameplayKit
类 GameScene：SKScene {
let minDist: CGFloat = 60 //The minimum distance between one point and the next
var points: [CGPoint] = []
var circleNodes: [SKShapeNode] = []
override func didMove(to view: SKView) {
}
func getDistance (fromPoint: CGPoint, toPoint: CGPoint) -> CGFloat {
let deltaX = fromPoint.x - toPoint.x
let deltaY = fromPoint.y - toPoint.y
let deltaXSquared = deltaX*deltaX
let deltaYSquared = deltaY*deltaY
return sqrt(deltaXSquared + deltaYSquared) //Return the distance
}
func touchDown(atPoint pos : CGPoint) {
self.removeAllChildren()
//The first time the user touches, we need to place a point and mark that as the firstCircleNode
print(pos)
points.append(pos)
//allPoints.append(pos)
let firstCircleNode = SKShapeNode(circleOfRadius: 5.0)
firstCircleNode.fillColor = UIColor.blue
firstCircleNode.strokeColor = UIColor.blue
firstCircleNode.position = pos
circleNodes.append(firstCircleNode)
self.addChild(firstCircleNode)
}
func touchMoved(toPoint pos : CGPoint) {
let lastIndex = points.count - 1 //The index of the last recorded point
let distance = getDistance(fromPoint: points[lastIndex], toPoint: pos)
//vector_distance(vector_double2(Double(points[lastIndex].x), Double(points[lastIndex].y)), vector_double2(Double(pos.x), Double(pos.y))) //The distance between the user's finger and the last placed circleNode
if distance >= minDist {
points.append(pos)
//Add a box to that point
let newCircleNode = SKShapeNode(circleOfRadius: 5.0)
newCircleNode.fillColor = UIColor.red
newCircleNode.strokeColor = UIColor.red
newCircleNode.position = pos
circleNodes.append(newCircleNode)
self.addChild(newCircleNode)
}
}
func touchUp(atPoint pos : CGPoint) {
//When the user has finished drawing a circle:
circleNodes[circleNodes.count-1].fillColor = UIColor.purple //Make the last node purple
circleNodes[circleNodes.count-1].strokeColor = UIColor.purple
//Calculate the distance between the first placed node and the last placed node:
let distance = getDistance(fromPoint: points[0], toPoint: points[points.count-1])
//vector_distance(vector_double2(Double(points[0].x), Double(points[0].y)), vector_double2(Double(points[points.count - 1].x), Double(points[points.count - 1].y)))
if distance <= minDist { //If the distance is closer than the minimum distance
print("Successful circle")
} else { //If the distance is too far
print("Failed circle")
}
points = []
circleNodes = []
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
for t in touches { self.touchDown(atPoint: t.location(in: self)) }
}
override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
for t in touches { self.touchMoved(toPoint: t.location(in: self)) }
}
override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
for t in touches { self.touchUp(atPoint: t.location(in: self)) }
}
override func touchesCancelled(_ touches: Set<UITouch>, with event: UIEvent?) {
for t in touches { self.touchUp(atPoint: t.location(in: self)) }
}
override func update(_ currentTime: TimeInterval) {
// Called before each frame is rendered
}
}
【问题讨论】：
标签： ios swift swift3 skspritenode cgpath