The invention describes a method and system for use in occlusion culling
of polygons in an interactive environment, such as a game. The invention
employs a boundary box to simplify the testing of occludee polygons.
Occluders and occludees are also transformed into non-interpenetrating,
non-overlapping polygons. Winged-edges are employed to minimize a per
occludee computational cost due to precision problems that may arise at
non-overlapping edges. The invention then proceeds through an active edge
list to identify edge discontinuities (e.g., where an edge is added or
removed from the active edge list). Depth analysis is employed to
determine whether an occluder occludes an occludee at the edge
discontinuity. Moreover, the invention only performs depth analysis for
those locations of a screen display where an occludee is determined to
reside, thereby minimizing unnecessary computations.