Reflections with Depth Impostors

Since the beginning of the semester I've been researching reflections using Occlusion Camera Depth Impostors. The occlusion camera had been developed in the same graphics lab a few years ago, and my task was to apply it to depth impostors. The idea of using depth impostors is that, you can render a diffuse object to a buffer, and then use the color and depth information to correctly intersect the depth map with reflected rays from a reflective surface. Now the problem here is that we can only see so much from the viewpoint of the reflector. Meaning that some rays would actually intersect the real diffuse object but won't intersect our depth map because we don't have enough information.

What the occlusion camera brings to the table is the ability to store more depth information from the diffuse object. It does this by distorting rays such that we can sample the top and bottom of the diffuse object, where if we were to use a regular camera we wouldn't capture these areas. Yes, kind of vague and hard to visualize without pictures, but those will come in due time. It's a really cool topic of research that I will discuss in more depth once we submit our paper to the Eurographics Symposium.

But for now I'll leave you with some pictures of some early work that I did as a prerequisite for the research. Also, in the coming days (read- after our paper deadline) I will post a tutorial on using billboard impostors for reflections in XNA.

A reflected bunny with correct intersections


3rd order and 2nd order reflections showing the impostor normals


2nd order reflections