Drawing relative to the camera's position and orientation

Is it possible to draw into the viewer relative to the camera’s position and orientation? Here’s a sample use case.

Imagine you want to film a real world scene. I want to preview that in cesiumjs using with 3d assets representing that scene (like buildings). In the real world, cine cameras draw rectangular outlines of the lens fov onto a digital preview display. For example, it might look like this: Digital Frame Preview, where the black outlines represent various combinations of FoV and sensor cropping.

I understand I can modify the Camera fov to mimic the lens fov, but I’d really like to show an outline of the lens fov/sensor crop inside the camera, like what you’d see in cine camera preview. Is this possible?

Even if this can’t be done in CesiumJS per se, I’m wondering if I could just compute the geometry and draw lines onto a transparent layer above the CesiumJS viewport.

I’m very new to Web technology, so please bear with my naivety.

Thank you!