(Swift SpriteKit) 沿触摸方向旋转精灵

Posted 2023-03-10

【中文标题】(Swift SpriteKit) 沿触摸方向旋转精灵

【英文标题】：(Swift SpriteKit) Rotate sprite in the direction of touch

【发布时间】：2016-06-24 15:16:26

【问题描述】：

在提供的屏幕截图中，红色箭头和十字仅用于演示目的，不在游戏中。我希望飞船的精灵朝向它射出的球的方向。

Link to image

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)
    

【问题讨论】：

请提供您的触摸处理和拍摄代码

【参考方案1】：

这是我找到的完美运行的代码。

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)

【参考方案2】：

我前段时间一直在做你想要的事情，这是我的结果

首先你需要使用由 Nick Lockwood 创建的VectorMath.swift，这是我的代码，可以让我的蜘蛛移向用户触摸

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 */
    

希望对你有帮助

【讨论】：

嗨，我发现另一段代码在两行中完美运行，我将添加答案。

【参考方案3】：

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

这里是代码

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

【参考方案4】：

我发现根据詹姆斯提交的答案，这会导致它以错误的方式旋转，如果你有类似炮弹的东西，那很好，但因为它被用于我的游戏中，它有一个法师和一个带有轨迹的火球引起了问题，这可以很容易地解决

 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 现在已贬值