### marker to gl-matrix via OpenCV.js

Let's assume we get `rvecs`

and `tvecs`

via `cv.estimatePoseSingleMarkers()`

Then going through each marker, we can get the 1x3 vectors ~~like:~~like this (found in online samples):

```
const rotation = [rvecs.doublePtr(0, i)[0], rvecs.doublePtr(0, i)[1], rvecs.doublePtr(0, i)[2]];
const translation = [tvecs.doublePtr(0, i)[0], tvecs.doublePtr(0, i)[1], tvecs.doublePtr(0, i)[2]];
```

How can this be converted so it's compatible with gl-matrix's fromRotationTranslation?

Specifically - it seems gl-matrix expects the rotation in a quaternion... I see some sample C++ code to do that conversion here, but it assumes a Rodrigues function in OpenCV to get from the 1x3 vector to a 3x3 rotation matrix - I think?

The Rodrigues function seems to be missing in ~~OpenCV.js...~~OpenCV.js... and it's not clear to me what _exactly_ `cv.estimatePoseSingleMarkers()`

is returning in each `rvec`

(is it euler radians? something else?)