Occlusion test for occtrees
I'm working on a 3d engine for outdoor enviroments, but also for caverns and closed places. I don't want static solutions (Like BSP), because the engine must handle massive world changes( Quakes, craters, explosions and more destruction effects). I`ve tried with octtrees. Frustum culling works well, but with dense landscapes i get low FPS (4-6). However, I've observed that many objects can be occluded by closed places on average scenes. Perhaps, with an occlusion test the engine would avoid render many fancy objects (like Plants, sharp rocks, peaks etc. ) that are not visible; currently in montain landscapes .
I've thought that testing the visibility of each node of the octtree, by passing the node sphere to the depth buffer ,the engine can avoid render many bounded children by such nodes. So I need to read a feedback buffer for checking what sphere was rendered successfully. Is possible to test node visibility by rendering in FeedbackBuffer mode? How the use of feedbacks affects the performance?