Inproceedings,
Fast Approximate Visibility on the GPU using pre-computed 4D Visibility Fields
(2010)
Abstract
We present a novel GPU-based method for accelerating the visibility
function computation of the lighting equation in dynamic scenes composed
of rigid objects. The method pre-computes, for each object in the
scene, the visibility and normal information, as seen from the environment,
onto the bounding sphere surrounding the object and encodes it into
maps. The visibility function is encoded by a four-dimensional visibility
field that describes the distance of the object in each direction
for all positional samples on a sphere around the object. In addition,
the normal vectors of each object are computed and stored in corresponding
fields for the same positional samples for use in the computation
of reflection in ray-tracing. Thus we are able to speed up the calculation
of most algorithms that trace rays to real-time frame rates. The
pre-computation time of our method is relatively small. The space
requirements amount to 1 byte per ray direction for the computation
of ambient occlusion and soft shadows and 4 bytes per ray direction
for the computation of reflection in ray-tracing. We present the
acceleration results of our method and show its application to two
different intersection intensive domains, ambient occlusion computation
and stochastic ray tracing on the GPU.
