在一段时间内手动移动节点

问题描述

我目前已声明以下函数，这些函数将节点移动到场景的更新函数中调用的目标位置(在这种情况下，我不能使用SKAction.moveTo)

I currently have the following functions declared which moves a node to a target location which is called in the update function of the scene (In this situation, I can't use SKAction.moveTo)

func moveTowardsPosition(targetPosition: CGPoint, withTimeInterval timeInterval: NSTimeInterval) {
    let currentPosition = self.position
    var deltaX = targetPosition.x - currentPosition.x
    var deltaY = targetPosition.y - currentPosition.y
    var maximumDistance = 3 * CGFloat(timeInterval)
    moveFromCurrentPosition(currentPosition, byDeltaX: deltaX, deltaY: deltaY, maximumDistance: maximumDistance)
}

func moveFromCurrentPosition(currentPosition: CGPoint, byDeltaX dx: CGFloat, deltaY dy: CGFloat, maximumDistance: CGFloat) {
    let targetPosition = CGPointMake(currentPosition.x + dx, currentPosition.y + dy)
    var distRemaining = hypot(dx, dy)
    if distRemaining < maximumDistance {
        position = targetPosition
    } else {
        let x = currentPosition.x * maximumDistance
        let y = currentPosition.y * maximumDistance
        position = CGPointMake(x, y)
    }
}

(这些是从Apple的冒险"游戏中稍作修改的)

(These are slightly modified from Apples "Adventure" game)

我的问题是 moveCurrentPosition 函数中的这些行.

My problem is these lines in the moveCurrentPosition function.

let x = currentPosition.x * maximumDistance
let y = currentPosition.y * maximumDistance
position = CGPointMake(x, y)

基本上，我不知道将x和y设置为什么值，以便该位置代表正确的位置.在Apple的示例中，他们将其乘以maximumDistance-angle.角度var是一个仅影响资产旋转的值，但是我的资产是静态"的，并且没有多个位置-仅为1.

Basically, I have no idea what values to set x and y to so that position represents the correct position.In Apple's example, they are multiplying it by maximumDistance - angle. The angle var is a value that just affects the assets rotation, however my asset is 'static' and doesn't have multiple positions -- just 1.

考虑到这一点，我将 x 和 y 设置为什么，以便它们代表正确的位置?

With that in mind, what would I set x and y to so they are representative of the correct position?

(您可以在此处看到Apple的示例: https://developer.apple.com/library/prerelease/ios/samplecode/Adventure-Swift/Listings/Swift_Adventure_Adventure_Shared_Sprites_Character_swift.html )

(You can see Apple's example here: https://developer.apple.com/library/prerelease/ios/samplecode/Adventure-Swift/Listings/Swift_Adventure_Adventure_Shared_Sprites_Character_swift.html)

推荐答案

您正确的在这种情况下不要使用SKActions.我看到您正在尝试将node移到某个位置而不使用SKActions.我不太了解您发布的代码所遇到的问题.但是，我编写了一个小示例项目，演示了在没有SKActions的情况下将节点移动到更新功能中的某个位置.在这个示例项目中，我有一个精灵可以移动到当前的触摸位置.您可以设置节点移动的速度以及应用速度的速率.您可以尝试改变速率以获得正确的游戏感觉.当节点到达目标位置时，您还需要处理这种情况(同样，这取决于您的游戏).

You are correct not to use the SKActions in a scenario like this. I see you are trying to move a node to a position without using SKActions. I don't really understand the problem you are having with the code you posted. However I have written a small sample project that demonstrates moving a node to a position in the update function without SKActions. In this sample project, I have a sprite that moves to the current touch position. You can set the speed at which the node travels as well as the rate at which the velocity is applied. You can try messing with the rate to get the correct feel for your game. You will also need to handle the case when the node arrives at the target location (again, this will depend on your game).

让我知道这是否有帮助和/或您有任何疑问.

Let me know if this helps at all and/or if you have any questions.

import SpriteKit
class GameScene: SKScene {
    var sprite: SKSpriteNode!
    var travelPoint: CGPoint = CGPoint() //The point to travel to.
    let travelSpeed = CGVector(dx: 200, dy: 200) //The speed at which to travel.
    let rate:CGFloat = 0.1 //1.0 Completely responsive. 0.0 Completely unresponsive. I set this value to < 1 to smooth the application of motion.
    override func didMoveToView(view: SKView) {
        self.physicsBody = SKPhysicsBody(edgeLoopFromRect: self.frame)
        sprite = SKSpriteNode(color: UIColor.redColor(), size: CGSize(width: 50, height: 50))
        sprite.physicsBody = SKPhysicsBody(rectangleOfSize: sprite.size)
        sprite.position = CGPoint(x: self.size.width/2.0, y: self.size.height/2.0)
        sprite.physicsBody?.affectedByGravity = false
        self.addChild(sprite)
    }
    override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
        let touch = touches.first as! UITouch
        let location = touch.locationInNode(self)
            travelPoint = location
    }
    override func touchesMoved(touches: Set<NSObject>, withEvent event: UIEvent) {
        let touch = touches.first as! UITouch
        let location = touch.locationInNode(self)
        travelPoint = location
    }
    override func update(currentTime: CFTimeInterval) {
        let disp = CGVector(dx: travelPoint.x-sprite.position.x, dy: travelPoint.y-sprite.position.y)
        let angle = atan2(disp.dy, disp.dx)
        let vel = CGVector(dx: cos(angle)*travelSpeed.dx, dy: sin(angle)*travelSpeed.dy)
        let relVel = CGVector(dx: vel.dx-sprite.physicsBody!.velocity.dx, dy: vel.dy-sprite.physicsBody!.velocity.dy)
        sprite.physicsBody!.velocity = CGVector(dx: sprite.physicsBody!.velocity.dx+relVel.dx*rate, dy: sprite.physicsBody!.velocity.dy+relVel.dy*rate)
    }
}

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