I know that OpenGL uses a projection matrix to project the view frustum directly into the canoical volume [-1, 1]^3. But how would I project the frustum into an orthographic cuboid, which would then get projected by an orthographic matrix into the canonical volume? This is purely about the theory behind the workings, I don't intend to implement it. I hope somebody can help.
How to project a view frustum in an orthographic cuboid?
projections;perspective