I am trying to implement a 3D portal engine using the algorithm presented in the book "Real-Time Rendering" pg. 201, but I am having troubles with the following thasks:
First of all, as my portals are of diferent shapes, not just rectangulars, I simplify it to a simple AABB, but here comes my troubles.
Could someone tell me how can I project my portal AABB from world space to screen space?, and how can I build a frustum from a AABB?
I really appreciate any help about this.