Usually, terrain rendering relies on a 2D regular grid of height values, the so called height
field. Height fields describe 2.5 D surfaces and are not able to present complex 3D terrain
features. In contrast, a 3D data representation quickly exceeds the available memory
resources. To overcome this problem we apply material stacks. Material stacks combine the
simplicity of 2D height fields and the extended modeling capabilities of 3D volumetric data.
However, this approach requires expensive rendering and is difficult to realize in real-time …