Abstract: A system and method for antialiasing bump texture and bump mapping which overcomes the disadvantages of previous methods of antialiasing bump maps without significantly expanding the required physical hardware needed for the calculations. A bump curvature value computed from the difference in heights between adjacent texels is applied to the specular shading calculations for bump maps. The bump curvature is used to open an “integration window” over the specular highlight of the bump. The resulting integral provides a highlight value which approximates the specular highlight. The highlight value is then added to the pixel shading value in the frame buffer. The process decreases the brightness of the highlights while increasing the overall brightness near the highlights, in a user-controlled blend that preserves the proper average effect of the specularity or reflectiveness. The process has no effect where there are no bumps or where the viewer is so close to the surface.

Abstract: According to the present invention, a method is provided for assigning or converting volume data values defined at the center of cells to volume data values at node points, considering the residuals.

Abstract: A system determines discontinuities on a drawn curve. Local tangent values for a curvilinear segment are generated by determining the most likely tangent value for all points on the segment and by acting on a sampling of points around the current point whose tangent is to be determined. A robust statistical estimator is then applied to all angle values generated for the sample set to determine the likely intended tangent direction of the current focal point. The system then selects points with significant changes in tangent values to determine curve discontinuities such that the corners of the segment can be derived.

Abstract: A volumetric pre-clipping method that guarantees only a minimal number of sample points along rays that pass through a volume data set will need to be processed by a volume rendering system. Pre-clipping is a two step process. First, a projection of the volume is made onto an image plane based on the orthographic or perspective view desired. Each bounding vertex of the volume data set is multiplied by the appropriate transformation matrix to transform the vertices from source space to view space. The transformed vertices establish on the view space image plane the projection outline of the volume data set. By definition, only rays cast from pixels on the image plane within this projection outline will pass through the volume data set. Pixels outside the projection outline do not need to be considered. Rays and pixels in view space are transformed back to source space by multiplication with the appropriate inverse transformation matrix for an orthographic or perspective view.

Abstract: Geometric surfaces of objects are displayed by a method which generates surface data of at least one object and stores this surface data in a first memory, generates data records for all surface data stored in the first memory and stores these data records in a second memory, generates additional surface data for the representation of object segments with a lower level of detail and stores this additional surface data in the first memory, generates and stores a hierarchical data structure with several data records addressable via pointer addresses to represent one part of the objects surface in the second memory, stores the pointer addresses of the data records stored in the second memory which are not referenced by any pointer addresses stored in other data records, computes in a arithmetic unit a minimum level of detail for representation of the object segment, compares the computed minimum level of detail for each data record whose address is stored in a third memory area with the level of detail stored in

Abstract: The described CAD system enables a drafter to easily enter dimension entities, which describe the physical dimensions of an object in a CAD drawing or model. The dimension entities define either linear, angular, or radial dimensions, and for each dimension entity, the user defines a reference origin in addition to the normal dimensional information. The value of each defined dimension entity may be a simple constant, a parameter, or an expression of multiple constants and parameters. By virtue of the added reference origin, a very complex network of related dimension entities can be simply defined and easily modified. The recalculation of the dimension entities is performed by a parametric dimensioning engine that transforms groups of entities from the global space of the general CAD drawing or model into a local space. While in local space, the parametric dimensioning recalculates the coordinate data of the entities.

Abstract: A high definition graphic display apparatus comprises a polygon data inputting means for producing polygon data including coordinates to be displayed; an N times coordinate conversion means for expanding each coordinate value N times; an active list producing means for producing an active list which includes active cells each including information of an X coordinate which has N-times expanded coordinates which represent inclination of a side, and a number of Y coordinate lines which intersect the side, a scan list producing unit for producing a scan list by finding a line scan list of every scan line with a point on a side corresponding to the active cell which is present on the scan line; a scan line information extracting means for deciding whether an unit N lines is directly convertible into compressed display data, the unit N lines which includes a Y coordinate line; a compressed data producing means for producing compressed display data in accordance with an output of the scan line information extracting

Abstract: An antialiasing system is implemented in a graphics system of a computer. A memory control is associated with graphics system for controlling a frame buffer. The antialiasing system is situated in the memory control and is configured to receive from steppers (edge and span) new color values and new depth dimensions z at a plurality of subpixel locations. In turn, the antialiasing system analyzes color data pertaining to each pixel in the frame buffer, and if necessary, updates the color data. The color data is unique and minimizes memory requirements and accesses. Specifically, the color data includes a current display value that corresponds to the pixel, a reference color value that corresponds to one subpixel location, a reference depth dimension that corresponds with the one subpixel location, and reconstruction indicia that correspond with other subpixel locations and that can be utilized to derive respective depth dimensions and colors for the other subpixel locations.

Abstract: The present invention includes a method of dynamic rendering protocol for display of glyphs used in a data processor comprising the steps of listing output image formats of font scalers which can be outputted to a graphics system and listing input image formats which can be inputted to a blitter function. These input image formats and output image formats are intersected, and an ordered list of the intersecting input image formats with output image formats are generated based upon a predetermined criteria. The first of the ordered list can then be selected for use.