An Evaluation of Two Low-Cost Approximate Models of Refractive Objects

G.A. PATOW; J.L. CASTIGLIONI; C.A. DELRIEUX

Brasilia, Brasil

Congreso; XXIV Semin\'ario Integrado de Software e Hardware; 1997

Sociedade Brasileira de Computaçao

Efficient rendering of refractive objects is of importance in Computer Graphics. However, state-of-the-art solutions are based on computationally prohibitive rendering schemata like Ray Tracing or multipass scan-line techniques.This paper is aimed to model approximations of refrctive objects that are geometrically accurate and of low computational cost. We present a comparison of of two geometric approximations that are adequate to compute refractions in scan-line rendering or acelerated ray tracing algorithms. The first model consist on approximating a translucid object by a spherical lens. The second one is based on Grid Tracing; the refractive object is approximated by a lattice of rectangular prisms. Refracted rays are computed with Snell´s law on a bilinear interpolated normal vector, and within the refractive object are computed through the grid using a DDA-like traversal.