Convert matrix_float4x4 to x y z space

Question

I'm using ARKit and trying to get the position of the camera as a rotation and (x,y,z) coordinates in real world space. All I can manage to get is a matrix_float4x4, which I don't really understand, and euler angles only show the rotation.

Here's what I currently have:

let transform =  sceneView.session.currentFrame?.camera.transform
let eulerAngles =  sceneView.session.currentFrame?.camera.eulerAngles

Here's the output I'm getting:

eulerAngles: float3(-0.694798, -0.0866041, -1.68845)

transform: __C.simd_float4x4(columns: (float4(-0.171935, -0.762872, 0.623269, 0.0), float4(0.982865, -0.0901692, 0.160767, 0.0), float4(-0.0664447, 0.640231, 0.765304, 0.0), float4(0.0, 0.0, 0.0, 1.0)))

Is there a way to convert the matrix_4x4, or is there an easier way to get this information?

Thanks!

Answer 1

I'm using matrix_float4x4 extension for that:

extension matrix_float4x4 {
    func position() -> SCNVector3 {
        return SCNVector3(columns.3.x, columns.3.y, columns.3.z)
    }
}

Using:

let position = transform.position()

Or you can convert position directly in code:

let position = SCNVector3(
    transform.columns.3.x,
    transform.columns.3.y,
    transform.columns.3.z
)