Solid Angle Based Ambient Obscurance in Image Space

摘要

We derive a new approximation of ambient obscurance to improve the quality of state-of-the-art techniques used in real-time rendering We attempt to stay close to the original definition of ambient obscurance and, while building on the deferred rendering approach, bring into image-space information that is suitable for accurate estimations of visibility that take account of the position and orientation of near occluding geometry The approach is based on the approximation of a covered solid angle, considering the area of surfaces, and hemisphere partitioning that gives directional information about coverage, both done m image space. The immediate advantage of our technique is that we avoid over-occlusion caused by multiple occluders covering each other but covering from the same direction. In some cases our implementation achieves lower performance with respect to some currently popular and widely adopted screen-space ambient obscurance approximations, but still obtains realtime frame rates on the current generation of hardware.