Efficient Bounded Adaptive Tessellation of Displacement Maps

Displacement mapping is a technique for applying fine geometric detail to a simpler base surface. The displacement is often specified as a scalar function which makes it relatively easy to increase visual complexity without the difficulties inherent in more general modeling techniques. We would like to use displacement mapping in real-time applications. Ideally, a graphics accelerator should create a polygonal tessellation of the displaced surface on the fly to avoid storage and host bandwidth overheads. We present an online, adaptive, crack-free tessellation scheme for real-time displacement mapping that uses only local information for each triangle to perform a view-dependent tessellation. The tessellation works in homogeneous coordinates and avoids retransformation of displaced points, making it suitable for high-performance hardware implementation. The use of interval analysis produces meshes with good error bounds that converge quickly to the true surface.