Method and apparatus for directly evaluating a parameter interpolation function used in rendering images in a graphics system that uses screen partitioning

摘要

A method and apparatus for directly evaluating a parameter interpolation function in a computer graphic system that renders a geometric entity (such as a polygon) by partitioning a display device into a number of local regions. The computer graphic system initially determines that a first set of pixels in a first local region of the display device is covered by a geometric entity. A geometric entity's boundary defining data (e.g., the geometric entity's vertex coordinates defined relative to a display device coordinate system) is employed to generate a local set of coordinates that are defined relative to a first local coordinate system of the first local region for all pixels of the first set of pixels. A first local parameter interpolation function, which represents the parameter values for all pixels of the first set of pixels when these pixels are defined relative to the first local coordinate system, is then generated. The local parameter interpolation function and the local set of coordinates are used to directly calculate the parameter values of the pixels of the first set of pixels.