Hmm. That looks like it takes a projection matrix and makes a frustum that’s symmetrical about it’s centre.
Is that right? I need it to be offset away from the centre.
Or does the calculateProjection function have access to the frustum?
To answer my own question, it looks like calculateProjection does have access to the frustum.
https://forum.playcanvas.com/t/issue-with-non-square-aspect-ratio-and-resizing/10317/10