摘要 |
In apparatus for processing image data representing multi-dimensional objects, data is stored defining the position of a light source, a viewing position, an arrangement of polygons defining an object and a local transform for transforming said object into viewable 3-dimensional space. Processing means (15, 111) defines the extent of points for an object in each dimension, performs said local transform on said points and determines the extent to which said points are transformed into viewing space. Thus, an evaluation can be made as to where the object will lie in viewing space before polygons are transformed. Culling may then be performed at the object level, rather than at the polygon. <IMAGE> |