Compasson3dmapScenekit”

使用SceneKit在3D地图上添加指南针。

代码示例：

// 创建一个指南针节点
let compassNode = SCNNode()
compassNode.name = "compass"
    
// 创建一个平面节点来作为指南针底座
let baseNode = SCNNode()
let baseGeometry = SCNPlane(width: 0.3, height: 0.3)
baseGeometry.cornerRadius = 0.15
baseNode.geometry = baseGeometry
baseNode.pivot = SCNMatrix4MakeTranslation(0, -0.15, 0)
baseNode.eulerAngles = SCNVector3(x: 0, y: 0, z: 0.5 * Float.pi)
    
// 创建一个圆环节点来作为指针
let arrowNode = SCNNode()
let arrowGeometry = SCNTorus(ringRadius: 0.15, pipeRadius: 0.01)
arrowGeometry.firstMaterial?.diffuse.contents = UIColor.red
arrowNode.geometry = arrowGeometry
arrowNode.eulerAngles = SCNVector3(x: 0, y: 0, z: -0.5 * Float.pi)
    
// 将底座和指针添加到指南针节点
compassNode.addChildNode(baseNode)
compassNode.addChildNode(arrowNode)
    
// 将指南针节点添加到场景中
scene.rootNode.addChildNode(compassNode)

// 构建一个指向北的向量，然后将圆环节点旋转到该向量
let north = SCNVector3(0, 0, -1)
let cameraDirection = sceneView.pointOfView?.worldTransform
let forward = SCNVector3(-cameraDirection!.m31, -cameraDirection!.m32, -cameraDirection!.m33)
let northProjected = SCNVector3(north.x, 0, north.z)
let forwardProjected = SCNVector3(forward.x, 0, forward.z).normalized()
let angle = acos(forwardProjected.dot(northProjected)) * (forward.x < 0 ? 1 : -1)
arrowNode.eulerAngles = SCNVector3(x: 0, y: 0, z: angle)