How to apply a fixed mask to 3D camera?

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:bust_in_silhouette: Asked By chunter

Hi All:

I’m working on making a game that is a simulation of minimally invasive surgery (realistic, not like surgeon simulator). The cameras used in these surgeries produce images that are circular with a small triangle protrusion, and the rest is black (see example below). My question is how to imitate this in Godot - is there any way to apply a mask to the camera output before swapping the image buffers, or can I get Godot to only render a circular field of view?

Any help is appreciated, thanks!

example