Do depth values in AVDepthData (from TrueDepth camera) indicate distance in meters from the camera, or perpendicular distance from the *plane* of the camera (i.e. z-value in camera space)?

My goal is to get an accurate 3D point from the depth data, and this distinction is important for accuracy. I've found lots online regarding OpenGL or Kinect, but not for TrueDepth camera.

FWIW, this is the algorithm I use. I'm find the value of depth buffer at a pixel found using some OpenCV feature detection. Below is the code I use to find real world 3D point at a given pixel at `let cgPt: CGPoint`. This algorithm seems to work quite well, but I'm not sure whether small error is introduced by the assumption of depth being distance to camera plane.

```
let depth = 1/disparity
let vScreen = sceneView.projectPoint(SCNVector3Make(0, 0, -depth))
// cgPt is the 2D coordinates at which I sample the depth
let worldPoint = sceneView.unprojectPoint(SCNVector3Make(cgPt.x, cgPt.y, vScreen.z))

```