Hair self shadowing and transparency depth ordering using occupancy maps

This paper presents a method for quickly constructing a high-quality approximate visibility function for high frequency semi-transparent geometry such as hair. We can then reconstruct the visibility for any fragment without the expensive compression needed by Deep Shadow Maps and with a quality that is much better than what is attainable at similar framerates using Opacity Maps or Deep Opacity Maps. The memory footprint of our method is also considerably lower than that of previous methods. We then use a similar method to achieve back-to-front sorted alpha blending of the fragments with results that are virtually indistinguishable from depth-peeling and an order of magnitude faster.