Question

在提供的屏幕截图中，红色箭头和十字架仅用于演示目的，不在游戏中。我希望太空飞船的精灵能够面对射击球的方向。

这是我当前的触摸位置代码

override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
   /* Called when a touch begins */

    for touch in touches {
        let location = touch.locationInNode(self)

        var bullet = SKSpriteNode(imageNamed: "bullet")
        bullet.position = cannon.position
        bullet.size = CGSize(width: 35, height: 35)

        //physics
        bullet.physicsBody = SKPhysicsBody(circleOfRadius: bullet.size.width/2)
        bullet.physicsBody?.categoryBitMask = PhysicsCategory.bullet
        bullet.physicsBody?.collisionBitMask = PhysicsCategory.enemy
        bullet.physicsBody?.contactTestBitMask = PhysicsCategory.enemy
        bullet.name = "bullet"
        bullet.physicsBody?.affectedByGravity = false

        self.addChild(bullet)

        var dx = CGFloat(location.x - cannon.position.x)
        var dy = CGFloat(location.y - cannon.position.y)

        let magnitude = sqrt(dx * dx + dy * dy)

        dx /= magnitude
        dy /= magnitude

        let vector = CGVector(dx: 120.0 * dx, dy: 120.0 * dy) //adjust constant to increase impluse.

        bullet.physicsBody?.applyImpulse(vector)

        // I found this code bellow this comment, but it just moves the cannon's y position

        let direction = SKAction.moveTo(
            CGPointMake(
                400 * -cos(bullet.zRotation - CGFloat(M_PI_2)) + bullet.position.x,
                400 * -sin(bullet.zRotation - CGFloat(M_PI_2)) + bullet.position.y
            ),
            duration: 0.8)

        cannon.runAction(direction)
    }
}

Answer 1

前段时间我曾经按照你想要的方式工作，这是我的结果

首先你需要使用Nick Lockwood创建的VectorMath.swift，这是我的代码让我的蜘蛛向用户触摸移动

import SpriteKit
import SceneKit

class GameScene: SKScene {
    let sprite = SKSpriteNode(imageNamed:"Aranna")
    var velocity = Vector2(x: 0, y: 0)
    var positionV2D = Vector2(x: 0, y: 0)
    var headingVector = Vector2(x: 0, y: 1)

    override func didMoveToView(view: SKView) {
        /* Setup your scene here */
        let myLabel = SKLabelNode(fontNamed:"Chalkduster")
        myLabel.text = "Hello, World!";
        myLabel.fontSize = 45;
        myLabel.position = CGPoint(x:CGRectGetMidX(self.frame), y:CGRectGetMidY(self.frame));

        sprite.position = CGPoint(x:CGRectGetMidX(self.frame), y:CGRectGetMidY(self.frame));
        positionV2D = Vector2(point:sprite.position);

        let testVector = Vector2(x: 10, y: 14);
        velocity += testVector;
        print(velocity.toString());
        velocity += Vector2(x: 1, y: 1);
        //velocity = velocity + testVector;
        print(velocity.toString());
        velocity *= 0.5;
        velocity.printVector2D();

        velocity = Vector2(x: 2, y: 2);
        velocity.normalized();
        velocity.printVector2D();

        self.addChild(sprite)
    }


    func ToRad(grados:CGFloat) ->CGFloat
    {
        return ((CGFloat(M_PI) * grados) / 180.0)
    }

    func ToDeg(rad:CGFloat) ->CGFloat
    {
        return (180.0 * rad / CGFloat(M_PI))
    }

    override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
       /* Called when a touch begins */

        for touch in touches {
            let location = touch.locationInNode(self)

            let toTarget = Vec2DNormalize(Vector2(point:location) - positionV2D);


            let angle2 = headingVector.angleWith(toTarget);

            print(ToDeg(CGFloat(angle2)));

            headingVector.printVector2D();

            self.sprite.runAction(SKAction.rotateToAngle(CGFloat(angle2), duration: 0.1))
            self.sprite.runAction(SKAction.moveTo(location, duration: 0.5))
            positionV2D = Vector2(point: location);

        }
    }

    override func update(currentTime: CFTimeInterval) {
        /* Called before each frame is rendered */
    }
}

我希望这有助于你

Answer 2

以下是我发现的完美无瑕的代码。

Rotate a sprite to sprite position not exact in SpriteKit with Swift

 let angle = atan2(location.y - cannon.position.y , location.x - cannon.position.x)
 cannon.zRotation = angle - CGFloat(M_PI_2)

Answer 3

如果您只想旋转，则不应调用moveTo操作。计算触摸位置和大炮位置之间的角度，并调用动作rotateToAngel

这是代码

        let angle = atan2(dy, dx) - CGFloat(M_PI_2)
        let direction = SKAction.rotateToAngle(angle, duration: 0.4, shortestUnitArc: true)
        cannon.runAction(direction)

Answer 4

我发现，詹姆斯提交的答案导致它以错误的方式旋转，如果你有类似canonball的东西，但是因为它在我的游戏中使用了它有一个法师和一个带有踪迹的火球它很好造成问题，可以通过

轻松解决

 let angle = atan2(touchlocation.x - cannon.position.x , touchlocation.y - 
 cannon.position.y)
 cannon.zRotation = -(angle - CGFloat(Double.pi/2))

使用Double.pi / 2并且M_PI_2现在被摧毁

（Swift SpriteKit）沿触摸方向旋转精灵

4 个答案: