Multi-layer pyramidal displacement mapping

Abstract

Many methods which represent complex surfaces using displacement map without many vertices have been researched. However, a single-layer displacement map cannot present more complex objects because it has only one displacement on every position. In this paper, we introduce the approach to render more complex objects using a multi-layer displacement map. Displacement values of the texture map are arranged by the ascending order. A pair of ordered displacement composes a geometry block and we use this property. For accurate ray search, we store the highest value for odd channels and the lowest value for even channels to generate a quad tree displacement map. Our ray search algorithm finds an accurate intersection between a viewing ray and a displacement using the hierarchical displacement map. We solve aliasing problems on grazing angles occurred in previous methods and render the result scene on real-time.