Sun Microsystems, Inc.

Michael J Shantz

Sheue-Ling Lien

Susan Elizabeth Carrie

Jerald R Evans

Serdar Ergene

David Elrod

Jim V Loo

Vaughan R Pratt

Linda Shwetz

Karl Bizjak

Jim Van Loo

An adaptive forward differencing apparatus wherein, when rendering curves, calculated x, y values are increased or decreased in order to create values which correspond to the next pixel of the display CRT, such that curves of substantially one pixel increments are continuously and uniformly generated. The apparatus also provides circuitry for generating coordinates of display elements which approximate an ideal vector and to define curves, vectors or objects within maximum and minimum coordinates of the CRT display. The present invention also provides efficient circuitry for computing the value of 1/w of the homogenous coordinate w.

Method and apparatus for adaptive forward differencing in the rendering

The present invention provides unique methods and apparatus for shading curves, polygons and patches, implementing Phong, Gouraud and other shading techniques in the rendering of images on a cathode ray tube or other display device. The present invention also includes a unique method and apparatus for shading patches by rendering a series of adjacent curves such that no pixel gaps exist between each rendered curve.

Method and apparatus for shading images

An improved display system which includes a central processing unit (CPU) coupled to a display utilizing vertical blanking intervals. A frame buffer memory is coupled to the CPU for storing data representative of color indices for each display pixel. The frame buffer is further coupled to look-up tables (LUTs) for storing color values which are provided through digital/analog converters (DACs) to the display. The CPU updates the contents of the frame buffer and/or LUTs during the vertical blanking interval of the display. A 'first half' status flag is provided to the CPU at the beginning of each vertical blanking interval. This status flag remains true until one half of the period has elapsed. A 'too late' status flag is also provided at the initiation of the interval which remains low until the end of the vertical blanking interval. The CPU may, based upon when the memory update begins relative to the status flags, determine whether or not to continue the update or terminate until the next vertical blanking interval. Accordingly, system efficiency is significantly increased and display integrity preserved.

Vertical blanking status flag indicator system

An adaptive forward differencing apparatus wherein, when rendering curves, calculated x, y values are increased or decreased in order to create values which correspond to the next pixel of the display CRT, such that curves of substantially one pixel increments are continuously and uniformly generated. The apparatus of the present invention also provides circuitry for generating coordinates of display elements which approximate an ideal vector and to define curves, vectors or objects within maximum and minimum coordinates of the CRT display. The present invention also provides efficient circuitry for computing the value of 1/w of the homogenous coordinate w.

Method and apparatus for rendering vectors using bresenham parameters

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Sunnyvale, CA, United States of America

Michael J Shantz