Change the perspective camera's perspective origin

Discussion
1

This would be identical to CSS perspective-origin.

For now, I’ll come up with something using camera frustum size and WebGLRenderer.setViewport.

Having the API built into perspective cameras would be nice.

2

Is it the same concept as the one with THREE.StereoCamera? It creates two cameras, for both eyes, and each camera is shifted and the projection is not symmetrical. So, it is a kind of changed perspective origin, I think.

See lines 57-89:

https://github.com/mrdoob/three.js/blob/4503ef10b81a00f5c6c64fe9a856881ee31fe6a3/src/cameras/StereoCamera.js

3

Ah yeah, that may be a hint for the math way of doing it instead of with setViewport. Thanks! Need to figure how to apply that based on a distance from the edge of the viewport.