Canon Kabushiki Kaisha

Canon Information Systems Research Australia Pty. Ltd.

Kia Siverbrook

Simon Robert Walmsley

Vincenzo A Liguori

Jim Mulhearn

In a real-time object (RTO) graphics system, an RTO processor is disclosed which incorporates an object sort unit and an edge calculation unit. Object fragment data for each graphic object is received by the RTO processor, and is temporarily stored in memory. The sort unit sorts the fragment data for each scan line by first decomposing the fragment data into ordered sets, and then, commencing with the first active pixel for each fragment that commences on a line, sorting the data within the set and linking the sorted set with the next ordered set. Once sorted, the edge calculation unit reads the fragment data in line and pixel order from memory and calculates object edge intersections for each fragment on the current line being rendered while updating the memory with data for the respective fragment for the next scan line. The edge intersections are output in real-time and displayed on a display device.

Method and apparatus for performing object sorting and edge calculation

Method and apparatus for converting an object of a computerized graphics system defined by a plurality of spline formats into a corresponding object defined by a plurality of quadratic polynomial fragments (QPF). The method and apparatus include, for each spline of the object, selecting start and end points on the spline and designating the selected start and end points as control start and end points on the corresponding QPF, determining from the control points of the spline coefficients of a quadratic polynomial defining the QPF. The coefficients of the quadratic polynomial are used to determine if an error between the spline and the quadratic polynomial is below a predetermined level. In the case the error is below a predetermined level, QPF data describing the quadratic polynomial is determined from the coefficients of the quadratic polynomial.

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Woollahra, Australia

Kia Siverbrook