Webtv Networks, Inc.

Other

Adam Malamy

Adrian Sfarti

Robert Laker

Mei-Chi M Liu

Paolo Enrique Sabella

Nicholas Robert Baker

Padma Parthasarathy

Edouard Landau

Paul Paternoster

Victor Tirva

Nicholas M Baker

Nick Baker

John Cumming

A graphics rendering system creates an image based on objects constructed of polygonal primitives, which can generate the perception of three-dimensional objects displayed on a two-dimensional display device. An anti-aliasing operation is applied to silhouette edges of the objects, which are the edges of primitives which are displayed at the perimeter of an object. A silhouette edge can be identified by determining how many times an edge is rendered, with each instance of the rendering of an edge corresponding to the rendering of a primitive that adjoins the edge. An edge that is rendered exactly once is interpreted as a silhouette edge. An example of a silhouette edge is an edge that adjoins one triangular primitive that is viewable and another triangular primitive that is hidden from view by other primitives. Another technique for identifying a silhouette edge can be applied to closed objects by determining whether a first primitive adjoining an edge is hidden from view by other primitives and a second primitive also adjoining the edge is viewable. Once the silhouette edges are identified, the anti-aliasing operation is applied thereto.

Identifying silhouette edges of objects to apply anti-aliasing

A method and system for simulating motion of a polygon on a display screen. The polygon may be included in a set of polygons used to model a three-dimensional object. The position of the polygon is defined by vertices tracked in a subpixel coordinate system existing in a computer-readable medium. The subpixel coordinates of the vertices are used to identify the pixels on the display screen having coordinates that correspond to subpixel coordinates lying within or, optionally, at the boundary of the polygon. The identified pixels are those that are to be lighted on the display screen to generate the image of the polygon. The display properties of the lighted pixels are selected by interpolation based on defined pixel display parameters assigned to the vertices of the triangle. As motion of the polygon is tracked in the subpixel coordinate system, the corresponding display on the display screen is repeatedly adjusted. The method of identifying and interpolating the display parameters of the pixels using the subpixel coordinate system provides the appearance of smooth polygon motion.

System and method for adjusting pixel parameters by subpixel positioning

Performing graphics rendering without the computational expense of hither plane clipping and with only a minimum of display image clipping. Where a three dimensional polygon crosses to both sides of a hither plane, any vertices on the back side of the hither plane are translated to the hither plane, producing polygons which occupy only the area in front of the hither plane. A display image memory, from which display images are generated, is located within a larger guard memory such that many images which would need to be clipped to fit in the display image memory may be written to the guard memory without clipping.

Guard region and hither plane vertex modification for graphics rendering

A graphics rendering system creates an image based on objects constructed of polygonal primitives. Aliasing effects in the image are reduced by applying an anti-aliasing scheme to the areas of the image representing silhouette edges of the objects. The silhouette edges are anti-aliased by creating anti-aliasing primitives which vary in opacity. These anti-aliasing primitives are joined to the silhouetted edges, and create a region in the image where the objects appear to blend into the background.

Object-based anti-aliasing

A system and method of selecting a level of detail in a texture-mapping system. Pixels are processed in a zig-zag traversal pattern to allow determination of vertical and horizontal change values in texture map coordinates. In this manner, accurate level of detail selection is achieved without unduly reducing efficiency or throughput of the graphics system.

System and method of selecting level of detail in texture mapping

A system and method of rendering polygons in graphics system using incremental iterative addition in place of complex division operations. A setup engine provides relevant values to edge and span walk modules for rapid processing and rendering of polygon characteristics including material values. Characteristic functions are iterated with respect to polygon area and along individual spans to derive values for each pixel therein.

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Foster City, CA, United States of America

Adam Malamy