Apparatus for processing non-planar video graphics primitives and associated method of operation

An apparatus for processing a non-planar video graphics primitive, the non-planar video graphics primitive being defined by a plurality of vertices, each of the plurality of vertices having associated position coordinates and normal vectors, the apparatus comprising:

• a controller for issuing operation codes associated with tessellating the non-planar video graphics primitive into a plurality of planar graphics primitives based on a tessellation level, each operation code including an instruction and at least some operating codes including at least one source address and at least one destination address;
• a computation engine selector, operably coupled to the controller, for selecting one of a plurality of computation engines to produce a selected computation engine to execute an operation code issued by the controller;
• a plurality of computation engines operably coupled to the computation engine selector, one of the plurality of computation engines, when selected by the computation engine selector, determining at least one of:
• (a) a group of control points based on the position coordinates and the normal vectors of the plurality of vertices, and
• (b) position coordinates of a plurality of supplemental vertices defining the plurality of planar graphics primitives based the group of control points and a plurality of weighting factors that provide a cubic relation between the group of control points and the position coordinates of the plurality of supplemental vertices, responsive to at least one series of operation codes issued by the controller;
• a first memory, operably coupled to respective inputs and outputs of the plurality of computation engines, for storing at least the group of control points, the first memory being a destination address for some operation codes of the at least one series of operation codes and being a source address for other operation codes of the at least one series of operation codes;
• at least one lookup table, operably coupled to the respective inputs of the plurality of computation engines, for storing the plurality of weighting factors, the at least one lookup table being a source address some operation codes of the at least one series of operation codes;
• and
• a second memory, operably coupled to the outputs of the plurality of computation engines, for storing the position coordinates of both the plurality of vertices and the plurality of supplemental vertices.

A method for tessellating a non-planar video graphics primitive into a plurality of planar video graphics primitives, the non-planar video graphics primitive being defined by a plurality of vertices, each of the plurality of vertices having associated position coordinates and normal vectors, the method comprising the steps of:

• storing a plurality of weighting factors in at least one lookup table, the plurality of weighting factors providing a cubic relation between a group of control points and position coordinates of a plurality of supplemental vertices defining the plurality of planar video graphics primitives;
• receiving the position coordinates and the normal vectors of the plurality of vertices;
• determining the group of control points based on the position coordinates and the normal vectors of the plurality of vertices;
• storing the group of control points in a first memory;
• determining the position coordinates of the plurality of supplemental vertices based on the group of control points stored in the first memory, the plurality of weighting factors stored in the at least one lookup table, and a tessellation level;
• and
• storing the position coordinates of the plurality of supplemental vertices and the position coordinates of the plurality of vertices in a second memory for further graphics processing of the plurality of planar video graphics primitives.