Silicon Graphics, Incorporated

Microsoft Technology Licensing, LLC

James L Foran

Kurt Barton Akeley

Michael Timothy Jones

Mark M Leather

Christopher J Migdal

Christopher Clark Tanner

John Stephen Montrym

Brian Keith Cabral

Douglas A Voorhies

Robert A Drebin

Gregory C Buchner

Rolf A Van Widenfelt

The present invention provides a method and system for presenting three-dimensional computer graphics images using multiple graphics processing units. The dimensions of the scene to be rendered are bounded by a rectangular volume decomposed into rectangular subvolumes. Vertices of graphics primitives are compared with subvolume boundaries to determine to which subvolume a graphics primitive should be assigned. A GPU is assigned to each subvolume to render the graphics data that lies within it. A viewing position point is determined and communicated to each GPU. Rendered graphics data from each GPU are ordered based upon the viewing position Outputs of the individual GPUs are combined by blending within an image combiners. Outputs of image combiners can be presented for viewing or further combined in a subsequent stage image combiner.

Method and system for presenting three-dimensional computer graphics images using multiple graphics processing units

An apparatus and method for quickly and efficiently providing texel data relevant for displaying a textured-image. A large amount of texture source data, such as photographic terrain texture, is stored as a two-dimensional or three-dimensional texture MIP-map on one or more mass storage devices. Only a relatively small clip-map representing selected portions of the complete texture MIP-map is loaded into faster, more expensive memory. These selected texture MIP-map portions forming the clip-map consist of tiles which contain those texel values at each respective level of detail that are most likely to be mapped to pixels being rendered for display based upon the viewer's eyepoint and field of view. To efficiently update the clip-map in real-time, texel data is loaded and discarded from the edges of tiles. Attempts to access a texel lying outside of a particular clip-map tile are accommodated by utilizing a substitute texel value obtained from the next coarser resolution clip-map tile which encompasses the sought texel.

Method and system for providing texture using a selected portion of a texture map

An image processing system is described that receives polygonal image data at the direction of a processor and develops antialiased image data for display on a raster scanned display. In particular, the image system includes a scan convertor for converting the polygonal image data into pixel data, which includes pixel screen coordinates and at least one color value for each polygon covered pixel of the pixel data and a supersample coverage mask indicating an extent of polygon coverage within each polygon covered pixel. The image system also includes a raster system having at least one image processor for receiving the pixel data for each pixel, for developing a region mask based on the supersample coverage mask, and for storing the color value in association with the region mask as anitialiased display data in an image memory in communication with the image processor based on the pixel screen coordinates. The region mask indicates one or more, geographical regions of supersamples within each pixel covered by one or more polygons and indicates a color value stored in the image memory to be assigned to the supersamples in a region. This requires only a single color value for supersamples within a region of a covered pixel to be stored in the image memory. The image system can also be configured to develop and store Z-values, alpha values, stencil values, and texture values for each pixel for storage in the image memory in association with the region mask.

Antialiased imaging with improved pixel supersampling

Volume rendering and tomographic reconstruction center around solving two related integral equations: a volume rendering integral (a generalized Radon transform) and a filtered backprojection integral (the inverse Radon transform). Both of these equations are of the same mathematical form and can be dimensionally decomposed and approximated using Riemann sums over a series of resampled images. When viewed as a form of texture mapping and frame buffer accumulation, enormous hardware enabled performance acceleration is possible.

System and method of performing tomographic reconstruction and volume

In a computer system for creating images of three-dimensional objects, an apparatus and method for processing depth values representing the relative depths of the objects. The depth values are transformed according to projections in order to give the appearance of depth when the objects are displayed on a two-dimensional computer screen. These transformed depth values are then interpolated using N bits of precision. Next, the depth values are encoded into a format whereby the depth values have less than N bits. These encoded depth values are stored into memory. In displaying the objects, the encoded depth values are read from memory and compared to determine the relative depths of the objects.

Apparatus and method for selectively storing depth information of a 3-D

A method and apparatus for generating interactive computer graphics images using projective texture mapping. The projective texture mapping of the present invention involves the mapping of a texture map onto a scene being rendered from the perspective of an arbitrarily positioned and oriented projection light source. The visual effect is as if the texture map were a slide being displayed onto the objects comprising the scene. During this process, homogeneous texture map coordinates are generated for corresponding geometric primitive vertex points. The vertex points of the geometric primitive are defined in terms of a world coordinate system. The homogeneous texture map coordinates of the vertex points are generated using transformation matrices of world coordinates to screen/clip coordinates and world coordinates to light source/texture map coordinates. Texture map coordinates for the remainder of the points of the geometric primitives are derived through interpolation of the vertex homogeneous texture coordinates. Texture map coordinates are generated during a span iteration process by dividing the two spatial homogeneous coordinates by the depth homogeneous coordinate.

Method and apparatus for projective texture mapping rendered from

An apparatus and method for quickly and efficiently providing texel data relevant for displaying a textured image. A large amount of texture source data, such as photographic terrain texture, is stored as a two-dimensional or three-dimensional texture MIP-map on one or more mass storage devices. Only a relatively small clip-map representing selected portions of the complete texture MIP-map is loaded into faster, more expensive memory. These selected texture MIP-map portions forming the clip-map consist of tiles which contain those texel values at each respective level of detail that are most likely to be mapped to pixels being rendered for display based upon the viewer's eyepoint and field of view. To efficiently update the clip-map in real-time, texel data is loaded and discarded from the edges of tiles. Attempts to access a texel lying outside of a particular clip-map tile are accommodated by utilizing a substitute texel value obtained from the next coarser resolution clip-map tile which encompasses the sought texel.

Method and system for providing texture using a selected portion of a

A method and apparatus for creating shadowed scenes for interactive image generation. Shadowing is effected by generation of a shadowing coefficient for each pixel, which is then used when the scene is rendered. The present invention utilizes z-buffer and projective texture mapping facilities of an image generation system. Generation of the shadow coefficient is achieved by the steps of: rendering the scene from the viewpoint of a light source using z-buffering to create a two dimensional depth map from said z-buffer; storing the depth map in texture mapping storage; rendering the scene from the viewpoint of the viewer; for every pixel in view creating an index info said depth map and a iterated depth value; retrieving a predetermined number of depth map samples from the depth map based on the position of a depth map index; comparing said iterated depth value with each of the depth map samples to determine which of the depth map samples are in shadow; creating a weighted average shadow coefficient from the results of the comparisons; and using the shadow coefficient for rendering. Optionally, the values in the depth map are offset by an amount dependent on the slope of the distance function relative to the depth map indices. The scene is then rendered utilizing surfaces and/or shading information. The shadow coefficient is used to calculate the pixel intensity thus creating realistic shadow effect.

Method and apparatus for shadow generation through depth mapping

An apparatus for generating a reflection from a three-dimensional environment map. The apparatus includes a reflection vector generator which receives an eye vector and a normal vector neither of which need be normalized. This reflection vector generator generates a reflection vector without vector normalization. The reflection vector generator then couples to a decoder to supply the generated reflection vector. The decoder, in turn, determines a location where the reflection vector indexes the selected 2-dimensional map which forms part of the environment map.

Method and an apparatus for generating reflection vectors which can be

An image processing system that receives polygonal image data at the direction of a processor and develops antialiased image data for display on a raster scanned display. In particular, the image system includes a scan convertor for converting the polygonal image data into pixel data, which includes pixel screen coordinates and at least one color value for each polygon covered pixel of the pixel data and a supersample coverage mask indicating an extent of polygon coverage within each polygon covered pixel The image system also includes a raster system having at least one image processor for receiving the pixel data for each pixel, for developing a region mask based on the supersample coverage mask, and for storing the color value in association with the region mask as anitialiased display data in an image memory in communication with the image processor based on the pixel screen coordinates. The region mask indicates one or more geographical regions of supersamples within each pixel covered by one or more polygons and indicates a color value stored in the image memory to be assigned to the supersamples in a region. This requires only a single color value for supersamples within a region of a covered pixel to be stored in the image memory. The image system can also be configured to develop and store Z-values, alpha values, stencil values, and texture values for each pixel for storage in the image memory in association with the region mask.

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.

System and method of generating interactive computer graphic images

A method and apparatus for controlling the storage of display information into a frame buffer is disclosed. A memory means is provided for storing information for controlling the storage of display information into the frame buffer where the memory means contains a plurality of locations each of which corresponds to and controls the storing of display information in one location of the frame buffer. A pass/fail ALU is coupled to the memory means to obtain a value for a particular pixel; this ALU provides a signal indicative of one of a first or second state which state indicates whether storage of display information to the frame buffer will occur. A first function is stored in a register, which function specifies the first signal. A first storage register and a second storage register store a second function and a third function respectively and provide a second value and a third respectively. The second value or third value is stored as a new value in the first memory for said first pixel location depending upon the state indicated by tile first signal. An application of the method and device of the invention includes a method for generating hollow polygons having an interior region and a perimeter in said frame buffer for display on said display device.

Apparatus and method for controlling storage of display information in a

A method and apparatus for controlling the storage of display information into a frame buffer is disclosed. A memory means is provided for storing information for controlling the storage of display information into the frame buffer where the memory means contains a plurality of locations each of which corresponds to and controls the storing of display information in one location of the frame buffer. A pass/fail ALU is coupled to the memory means to obtain a value for a particular pixel; this ALU provides a signal indicative of one of a first or second state which state indicates whether storage of display information to the frame buffer will occur. A first function is stored in a register, which function specifies the first signal. A first storage register and a second storage register store a second function and a third function respectively and provide a second value and a third respectively. The second value or third value is stored as a new value in the first memory for said first pixel location depending upon the state indicated by the first signal. An application of the method and device of the invention includes a method for generating hollow polygons having an interior region and a perimeter in said frame buffer for display on said display device.

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Milpitas, CA, United States of America

James L Foran