我是一名新程序员,正在开发一个简单的演示 iOS 程序,我使用 SceneKit 来渲染场景。
我想旋转相机以查看场景的不同视角。但原来的相机控制有点棘手。特别是当我想朝一个方向旋转场景时。例如如果我从右向左滑动,相机从右向左移动,然后向下,然后向上,然后再次向下,最后再次向左移动。
我想要实现的是,当我从右向左滑动时,相机绕 z 轴旋转。当我上下滑动时,相机也会上下移动。我还可以放大和缩小。此外,我想设置一个约束,以便相机不会进入地下。
所以我想出了一个主意,我固定相机来观察我聚焦的物体。然后将对象放置在场景的中心。当我滑动屏幕时,我想围绕 z 轴旋转场景。
我假设我使用 panGestureRecognizer 并将位置变化转换为旋转顺序。但是我怎样才能实现这一点呢?
或者您还有其他想法来获得此结果?
这是我迄今为止所写内容的简单版本。我尝试过使用 UIPanGestureRecognizer 但它不起作用,所以我将其删除并设置 allowCameraControl = true
let sceneView = SCNView(frame: self.view.frame)
self.view.addSubview(sceneView)
let scene = SCNScene()
sceneView.scene = scene
let camera = SCNCamera()
let cameraNode = SCNNode()
cameraNode.camera = camera
cameraNode.position = SCNVector3(x: -5.0, y: 5.0, z: 5.0)
let light = SCNLight()
light.type = SCNLight.LightType.spot
light.spotInnerAngle = 30
light.spotOuterAngle = 80
light.castsShadow = true
let lightNode = SCNNode()
lightNode.light = light
lightNode.position = SCNVector3(x: 1.5, y: 1.5, z: 1.5)
let ambientLight = SCNLight()
ambientLight.type = SCNLight.LightType.ambient
ambientLight.color = UIColor(red: 0.2, green: 0.2, blue: 0.2, alpha: 1.0)
cameraNode.light = ambientLight
let cubeGeometry = SCNBox(width: 1.0, height: 1.0, length: 1.0, chamferRadius: 0.0)
let cubeNode = SCNNode(geometry: cubeGeometry)
let planeGeometry = SCNPlane(width: 50.0, height: 50.0)
let planeNode = SCNNode(geometry: planeGeometry)
planeNode.eulerAngles = SCNVector3(x: GLKMathDegreesToRadians(-90), y: 0, z: 0)
planeNode.position = SCNVector3(x: 0, y: -0.5, z: 0)
cameraNode.position = SCNVector3(x: -3.0, y: 3.0, z: 3.0)
let constraint = SCNLookAtConstraint(target: cubeNode)
constraint.isGimbalLockEnabled = true
cameraNode.constraints = [constraint]
lightNode.constraints = [constraint]
scene.rootNode.addChildNode(lightNode)
scene.rootNode.addChildNode(cameraNode)
scene.rootNode.addChildNode(cubeNode)
scene.rootNode.addChildNode(planeNode)
sceneView.allowsCameraControl = true
最佳答案
我通过使用球坐标系解决了这个问题。
总体思路是获取起始位置和角度,然后将其转换到球坐标系。然后只需改变两个角度即可进行旋转。
使用球坐标系来处理捏合手势更加容易。您只需更改半径即可。
这是我使用的一些代码。
func handlePan(_ gestureRecognize: UIPanGestureRecognizer) {
// retrieve scene
let carView = self.view as! SCNView
// save node data and pan gesture data
let cameraNode = carView.scene?.rootNode.childNode(withName: "Camera", recursively: true)!
//let translation = gestureRecognize.translation(in: gestureRecognize.view!)
let speed = gestureRecognize.velocity(in: gestureRecognize.view!)
var speedX = sign(Float(speed.x)) * Float(sqrt(abs(speed.x)))
var speedY = sign(Float(speed.y)) * Float(sqrt(abs(speed.y)))
if speedX.isNaN {speedX = 0}
if speedY.isNaN {speedY = 0}
// record start value
let cameraXStart = cameraNode!.position.x
let cameraYStart = cameraNode!.position.y
let cameraZStart = cameraNode!.position.z - 1.0
let cameraAngleStartZ = cameraNode!.eulerAngles.z
let cameraAngleStartX = cameraNode!.eulerAngles.x
let radiusSquare = cameraXStart * cameraXStart + cameraYStart * cameraYStart + cameraZStart * cameraZStart
// calculate delta value
let deltaAngleZ = -0.003 * Float(speedX)
let deltaAngleX = -0.003 * Float(speedY)
// get new Value
var cameraNewAngleZ = cameraAngleStartZ + deltaAngleZ
var cameraNewAngleX = cameraAngleStartX + deltaAngleX
if cameraNewAngleZ >= 100 * Float.pi {
cameraNewAngleZ = cameraNewAngleZ - 100 * Float.pi
} else if cameraNewAngleZ < -100 * Float.pi {
cameraNewAngleZ = cameraNewAngleZ + 100 * Float.pi
} else {
// set limit
if cameraNewAngleX > 1.4 {
cameraNewAngleX = 1.4
} else if cameraNewAngleX < 0.1 {
cameraNewAngleX = 0.1
}
// use angle value to get position value
let cameraNewX = sqrt(radiusSquare) * cos(cameraNewAngleZ - Float.pi/2) * cos(cameraNewAngleX - Float.pi/2)
let cameraNewY = sqrt(radiusSquare) * sin(cameraNewAngleZ - Float.pi/2) * cos(cameraNewAngleX - Float.pi/2)
let cameraNewZ = -sqrt(radiusSquare) * sin(cameraNewAngleX - Float.pi/2) + 1
if cameraNode?.camera?.usesOrthographicProjection == false {
cameraNode?.position = SCNVector3Make(cameraNewX, cameraNewY, cameraNewZ)
cameraNode?.eulerAngles = SCNVector3Make(cameraNewAngleX, 0, cameraNewAngleZ)
}
else if cameraNode?.camera?.usesOrthographicProjection == true {
cameraNode?.position = SCNVector3Make(0, 0, 10)
cameraNode?.eulerAngles = SCNVector3Make(0, 0, cameraNewAngleZ)
}
}
}
关于ios - 使用 panGestureRecognizer 旋转场景,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/46908379/