Object selection detection in a graphics display system.

摘要

A method and apparatus for detecting operator selection of a graphics object prior to rasterization and pixel generation for that object. The method divides screen into regions and analyzes successive end points and vectors based upon their region to determine trivial picks and trivial no picks. Non-trivial conditions are analyzed by evaluating the slope of the line through a test of sample lines drawn through pick window vertices. Apparatus for implementing pick detect is provided that accomplishes pick detect as part of graphics pipeline processing. In the trivial pick or no pick cases, the apparatus does not slow pipeline operation, while in a non-trivial case, extra processing cycles are required.