Abstract: A floating point rasterization and frame buffer in a computer system graphics program. The rasterization, fog, lighting, texturing, blending, and antialiasing processes operate on floating point values. In one embodiment, a 16-bit floating point format consisting of one sign bit, ten mantissa bits, and five exponent bits (s10e5), is used to optimize the range and precision afforded by the 16 available bits of information. In other embodiments, the floating point format can be defined in the manner preferred in order to achieve a desired range and precision of the data stored in the frame buffer. The final floating point values corresponding to pixel attributes are stored in a frame buffer and eventually read and drawn for display. The graphics program can operate directly on the data in the frame buffer without losing any of the desired range and precision of the data.

Abstract: A graphics system including a custom graphics and audio processor produces exciting 2D and 3D graphics and surround sound. The system includes a graphics and audio processor including a 3D graphics pipeline and an audio digital signal processor. Cartoon lighting and other non-photorealistic effects can be produced by using a lighting calculation to produce a parameter other than color or opacity for use in a later modification of a color or opacity value. In more detail, the example embodiment uses the lighting calculation to generate texture coordinates used in a texture mapping operation. The texture mapping operation allows lighting computation results to select between brush strokes for cartoon lighting and other effects. The resulting dynamic cartoon lighting animation can be performed on a low cost platform such as a home video game system or personal computer.

Abstract: A method and an apparatus for high quality texture mapping. Multi-resolutional texture data for a destination pixel is supersampled at horizontal and vertical screen space sampling rates based on the local rate of change at a texture coordinate. Two-dimensional and/or three-dimensional multi-resolutional texture data is sampled. The calculated local rates of change in texture can be scaled, independently, to allow the effect of each texture dimension upon the horizontal and vertical screen space sampling rates to be controlled separately. Three examples for calculating screen space sampling rates according to the present invention are provided based on a maximum texture gradient, an optimized maximum texture gradient, or a minimum sampling routine which ensures sampling when footprint area collapses to a line. Unnecessary calculations and delays encountered in supersampling an entire display image uniformly are avoided. An excellent filter is obtained for live video texture mapping in real-time.

Abstract: A system and method of interactively generating computer graphic images for incorporating three dimensional textures. The method of the present invention includes defining an orientation of a polygon relative to a plurality of three dimensional (3D) texture data sets, determining a level of detail of a pixel associated with the polygon, and selecting a first 3D texture data set and a second 3D texture data set from the plurality of 3D texture data sets in accordance with the pixel level of detail. The method also includes mapping the pixel to a first position within the first 3D texture data set and to a second position within the second 3D texture data set in accordance with the orientation, and generating a display value for the pixel in accordance with the mapping of the pixel to the first and second positions.

Abstract: An apparatus and method for interactively magnifying a base texture to generate a generally unblurred magnified image of the base texture is disclosed. The present invention includes a base texture generator for filtering a high resolution source image to generate a base texture. A detail texture generator extracts a representative portion of high frequency information from the source image to generate a detail texture, wherein the detail texture comprises the extracted representative portion of high frequency information. An image magnifier, which is coupled to the base texture generator and the detail texture generator, augments the generated base texture with high frequency information from the detail texture to thereby generate a magnified image of the generated base texture at a particular level of detail.

Abstract: A system and method of interactively magnifying a first texture to generate a generally unblurred high resolution display image at a particular level of detail are disclosed. The method of the present invention includes the step of extrapolating from the first texture and a second texture to generate an extrapolated frequency band. The extrapolated frequency band approximates high frequency image information contained in a texture of higher resolution than the first texture. The method also includes scaling the extrapolated frequency band as a function of the particular level of detail to generate a scaled extrapolated frequency band, wherein the scaled extrapolated frequency band approximates high frequency image information contained in a magnified image of the first texture at the particular level of detail.

Abstract: An imaging system for providing apparatus and method for projecting a two dimensional (2D) representation of three dimensional (3D) volumes where surface boundaries and objects internal to the volumes are readily shown, and hidden surfaces and the surface boundaries themselves are accurately rendered. In the present invention, the two dimensional image produced is capable of having the same resolution as the sampling resolution of the input image image volume of interest. This is accomplished through the implementation of methods for determining "partial volumes" of voxels. Partial voluming provides for the assignment of selected colors and opacities to different materials (or data components) represented in an image data volume based on the percentage composition of materials represented in each voxel of the image volume.

Abstract: A graphical display system and process for specifying and controlling a display range in which a specified form of texture mapping is applied or suppressed. Object data from a host computer is processed by four pipelined graphics subsystems before being displayed on a display screen. These graphics subsystems include: 1) a Geometry Subsystem, 2) a Scan Conversion Subsystem, 3) a Raster Subsystem, and 4) a Display Subsystem. Span Processors within the Scan Conversion Subsystem manipulate pixel coordinates in order to handle sitations when coordinates are located out of range of a texture map. Processing logic and hardware registers located within each Span Processor implement two texture modes for handling out-of-range coordinates. First, a mask and comparison register is provided to hold a value specifying a selected range in which texture is applied to a pixel. If a pixel is outside the specified range, texture application is suppressed.

Abstract: Method and apparatus for shading an image volume so that surfaces and boundaries may be rendered to subvoxel accuracy. A gradient vector is generated for each voxel of an image volume by calculating the change in opacity across that voxel in relation to its immediate neighbors. The gradient in the X, Y and Z direction of a three-dimensional voxel array is used to define a gradient length. By multiplying the RGBA values of individual voxels by their gradient length, a image volume may be shaded so that surfaces remain, but the interiors of solids are rendered more transparent revealing additional detail. Surfaces are shaded by multiplying the RGBA values of each voxel by a shading function. A reference point for a light source illuminating the displayed image volume is defined. A light vector is chosen for each voxel, a shading function is then generated based on the angle between the gradient vector and the light vector. The shading function allows for inputs for backlighting and side lighting.