Methods of and apparatus for processing computer graphics

US8115783B2 · kind B2 · utility

Assignee

• ARM Norway AS · NO

Inventors

• Jorn Nystad · Trondheim, NO
• Erik Faye-Lund · Oslo, NO

Key dates

• Filing date: Jan 31, 2008
• Grant date: Feb 14, 2012
• Expiry date: Aug 6, 2030

Classification

• Technology area (CPC G): Physics
• CPC primary: G09G2340/12
• WIPO field: Audio-visual technology
• WIPO sector: Electrical engineering

Abstract

In a graphics processing system, the left, right, top and bottom edge planes for the purposes of clipping are set to the maximum values that can be represented using floating-point format numbers, vertex positions are snapped to a grid of predefined vertex positions, and the precision of selected vertices is prioritized when deriving edge functions for a given primitive. In respect of the depth near and far clipping planes, those planes are set to the maximum floating-point number format that can be represented for “Z” in the graphics system, but then fragments that have a Z value that falls outside the range zero to one are discarded using a depth test. In respect of the eye-plane, the need for clipping is avoided by modifying edge equations generated for a primitive in dependence on the sign of a “W” value for each vertex of the primitive.