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Gonzalez-Liang Parameter Storage Scheme for a Graphics Processor

IP.com Disclosure Number: IPCOM000105252D
Original Publication Date: 1993-Jul-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 6 page(s) / 147K

Publishing Venue

IBM

Related People

Johnson, LE: AUTHOR [+2]

Abstract

Described is a parameter storage scheme for use when implementing the Gonzalez-Liang triangle shading algorithm. The

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Gonzalez-Liang Parameter Storage Scheme for a Graphics Processor

      Described is a parameter storage scheme for use when
implementing the Gonzalez-Liang triangle shading algorithm.  The

Gonzalez-Liang algorithm requires a great deal of area in a special
purpose hardware implementation.  Many values are generated, and must
be stored in registers or register files to preserve the advantages
in performance sought in using dedicated hardware.  Also, the
generation of decodes or addresses for the registers or register
files can be expensive in terms of the PLA or random logic
complexity.

      A datapath for Gonzalez-Liang triangle shading consists of the
following major components:

Vertex Register File   - Buffers triangle vertices from the host
                         processor, allows stack manipulation for
                         polygon and mesh rendering.

Cofactor Generator     - Performs the plane equation solution
                         calculations.

Division Stage         - Performs fast integer divisions (20 in all)
                         to complete setup calculations.

Shading Parameter
Buffers                - Provides intermediate storage for Cofactor
and
                         division tasks, and ping-pong queuing for
                         passing  parameters to the interpolation
                         stage.

Vertex Generation
Subsystem              - Operates in parallel with shading setup and
                         shading systems to provide screen address
                         information.

Shading Interpolation
Subsystem              - Provides final per-pixel color and depth
                         information for display.

Fig. 1 shows a block diagram of the entire datapath.

The parameter storage scheme has the following features:

1.  Careful allocation of data types between the Vertex, Vector
    Generation, and Shading register files.  This supports
    consistent, low-cost register fil...