Question

我正在尝试创建两条锚定在某个点（精灵）并旋转以在它们之间形成30度角的线。下面是我想要实现的图像。

这是我到目前为止所做的：

extension Int {
  var degreesToRadians: Double { return Double(self) * .pi / 180 }
}
extension FloatingPoint {
  var degreesToRadians: Self { return self * .pi / 180 }
  var radiansToDegrees: Self { return self * 180 / .pi }
}

class GameScene: SKScene, SKPhysicsContactDelegate {

var anchorSprite = SKSpriteNode(imageNamed: "anchorSprite")
var armLeft = SKSpriteNode(imageNamed: "lineSprite")
var armRight = SKSpriteNode(imageNamed: "lineSprite")

override func didMove(to view: SKView) {

    self.physicsWorld.gravity = CGVector(dx: 0, dy: -1.8)
    self.physicsWorld.contactDelegate = self

    var tealBg = SKSpriteNode(imageNamed: "tealBg")
    tealBg.position = CGPoint(x: frame.midX, y: frame.midY)
    tealBg.zPosition = 10
    addChild(tealBg)

    anchorSprite.position = CGPoint(x: frame.midX, y: frame.midY + frame.midY/2)
    anchorSprite.zPosition = 20

    anchorSprite.physicsBody = SKPhysicsBody(rectangleOf: anchorSprite.frame.size)
    anchorSprite.physicsBody?.categoryBitMask = pinCategory
    anchorSprite.physicsBody?.isDynamic = false

    addChild(anchorSprite)

    armRight.anchorPoint = CGPoint(x: 0.5, y: 1)
    armRight.position = anchorSprite.position
    armRight.zPosition = 20
    armRight.physicsBody = SKPhysicsBody(rectangleOf: armRight.frame.size)
    armRight.zRotation = CGFloat(Double(15).degreesToRadians)//CGFloat(Double.pi/6)
    armRight.physicsBody!.isDynamic = true
    addChild(armRight)

    armLeft.anchorPoint = CGPoint(x: 0.5, y: 1)
    armLeft.position = anchorSprite.position
    armLeft.zPosition = 20
    armLeft.physicsBody = SKPhysicsBody(rectangleOf: armRight.frame.size)
    armLeft.zRotation = CGFloat(Double(-15).degreesToRadians)//CGFloat(-Double.pi/6)
    armLeft.physicsBody!.isDynamic = true
    addChild(armLeft)

    //Pin joints
    var pinAndRightArmJoint = SKPhysicsJointPin.joint(withBodyA: anchorSprite.physicsBody!, bodyB: armRight.physicsBody!, anchor: CGPoint(x: anchorSprite.position.x, y: self.armRight.frame.maxY))
    self.physicsWorld.add(pinAndRightArmJoint)

    var pinAndLeftArmJoint = SKPhysicsJointPin.joint(withBodyA: anchorSprite.physicsBody!, bodyB: armLeft.physicsBody!, anchor: CGPoint(x: anchorSprite.position.x, y: self.armLeft.frame.maxY))
    self.physicsWorld.add(pinAndLeftArmJoint)

}

以下是运行上述代码的图片（它们靠得很近）。

如何确保线条始终相隔30˚，即使旋转也能保持30˚？

Answer 1

为了使两条线分开30°，您可以使用<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width"> <link rel="Stylesheet" type="text/css" href="style.css"> <script src="main.js"></script> </head> <body> <div id="error_container"></div> <div class="cVal_container"> <button onclick="cVal(0)" type="button">Error Code 0 (Default)</button> <button onclick="cVal(1)" type="button">Error Code 1</button> <button onclick="cVal(2)" type="button">Error Code 2</button> <button onclick="cVal(3)" type="button">Error Code 3</button> <button onclick="cVal(4)" type="button">Error Code 4</button> <button onclick="cVal(5)" type="button">Error Code 5</button> <button onclick="cVal(6)" type="button">Error Code 6</button> <button onclick="cVal(7)" type="button">Error Code 7</button> <button onclick="cVal(8)" type="button">Error Code 8</button> <button onclick="cVal(9)" type="button">Error Code 9</button> <button onclick="cVal(10)" type="button">Error Code 10</button> <button onclick="cVal(11)" type="button">Error Code 11</button> <button onclick="cVal(12)" type="button">Error Code 12</button> <button onclick="cVal(13)" type="button">Error Code 13</button> <button onclick="cVal(14)" type="button">Error Code 14</button> <button onclick="cVal(15)" type="button">Error Code 15</button> <button onclick="cVal(16)" type="button">Error Code 16</button> </div> </body> </html>，这听起来就是这样：它将两个SKPhysicsJointFixed固定在一个固定位置。由于您已经按照自己想要的方式对其进行了定位，因此只需将此代码添加到另一个physicsBodies的位置即可：

SKPhysicsJoints

结果：

Answer 2

如果你让线节点成为锚点精灵的子节点（而不是场景），旋转锚点精灵节点会旋转所有的线条，而不会对物理做任何特殊的事情。你只需要记住锚点，使它们正确对齐（即线的锚在其末端而不是中心）

如何在两条锚点之间保持30˚的距离

2 个答案: