SceneKit - 获取相机的方向 [英] SceneKit – Get direction of camera

问题描述

我需要找出相机正在看哪个方向，例如如果它正在寻找 Z+、Z-、X+ 或 X-.

I need to find out which direction a camera is looking at, e.g. if it is looking towards Z+, Z-, X+, or X-.

我试过使用 eulerAngles，但偏航的范围是 0 -> 90 -> 0> -> -90 -> 0 这意味着我只能检测相机是否正在朝向 Z 或 X>，而不是看那些轴的正方向或负方向.

I've tried using eulerAngles, but the range for yaw goes 0 -> 90 -> 0 -> -90 -> 0 which means I can only detect if the camera is looking towards Z or X, not if it's looking towards the positive or negative directions of those axes.

推荐答案

您可以创建一个 SCNNode，将其放置在 worldFront 属性中以获取具有 x、y 和 z 方向的向量.

You can create an SCNNode that place it in worldFront property to get a vector with the x, y, and z direction.

另一种你可以做到的方式就像这个项目是如何做到的:

Another way you could do it is like how this project did it:

// Credit to https://github.com/farice/ARShooter

func getUserVector() -> (SCNVector3, SCNVector3) { // (direction, position)
        if let frame = self.sceneView.session.currentFrame {
            let mat = SCNMatrix4(frame.camera.transform) // 4x4 transform matrix describing camera in world space
            let dir = SCNVector3(-1 * mat.m31, -1 * mat.m32, -1 * mat.m33) // orientation of camera in world space
            let pos = SCNVector3(mat.m41, mat.m42, mat.m43) // location of camera in world space

            return (dir, pos)
        }
        return (SCNVector3(0, 0, -1), SCNVector3(0, 0, -0.2))
    }

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