Semi-uniform, 2-Different Tessellation of Triangular Parametric Surfaces

Abstract

With a greater number of real-time graphics applications moving over to parametric surfaces from the polygonal domain, there is an inherent need to address various rendering bottlenecks that could hamper the move. Scaling the polygon count over various hardware platforms becomes an important factor. Much control is needed over the tessellation levels, either imposed by the hardware limitations or by the application. Developers like to create applications that run on various platforms without having to switch between polygonal and parametric versions to satisfy the limitations. In this paper, we present SD-2 (Semi-uniform, 2-Different), an adaptive tessellation algorithm for triangular parametric surfaces. The algorithm produces well distributed and semi-uniformly shaped triangles as a result of the tessellation. The SD-2 pattern requires new approaches for determining the edge tessellation factors, which can be fractional and change continuously depending on view parameters. The factors are then used to steer the tessellation of the parametric surface into a collection of triangle strips in a single pass. We compare the tessellation results in terms of GPU performance and surface quality by implementing SD-2 on PN patches.

Free Adaptive Tessellation Strategy of Bézier Surfaces

“…In (Yeo et al, 2012) an implementation of a tight estimator of the variance between the screen projection of the exact surface and its triangulation is proposed using the GPU tessellation engine. The new tessellation unit also supports regular fractional tessellation, and some works, such as (Munkberg et al, 2008;Amresh and Fünfzig, 2010), add a non-uniform, fractional tessellation to achieve a more uniform screen-space triangle area. Nevertheless, this scheme does not provide enough support for free adaptive tessellation, and the independent processing of primitives requires special care by application developers to prevent cracks.…”