U.S. Philips Corporation

Koninklijke Philips Corporation N.v.

Rediffusion Simulation Limited

Karl J Wood

Douglas R M Patterson

Graham J Olive

Stephen J Baker

David E Penna

Hendrik Tjalling Dijkstra

Cornelis W A M Van Overveld

Dennis A Cowdrey

Jeffrey N Smith

An apparatus for texture mapping in a computer graphics system, using a predetermined set of standardized textures. Each texture of the standardized set is a procedural texture, and is supplied to the apparatus as one or a sequence of program commands the execution of which will result in the generation of the respective procedural texture. In a preferred embodiment, the means for processing the program commands comprises a processor operable to implement only those input program commands or sequences of input program commands as are required to generate the procedural textures of the standardized set.

Graphic image texture generation

In a method of image processing for rendering a two-dimensional pixel image from a plurality of triangular image primitives to be projected onto an image plane, parameter values at positions within the triangles are translucency values. All the translucent pixel fragments are characterised as partial fragments, and the fragments are inserted into a pixel fragment buffer from front to back. The final colour of a pixel is determined from the foremost fragment.

Method and apparatus for handling translucency in 3D graphics

A circuit arrangement and display apparatus are described for use in 3-D graphics, where 2-D texture mass stored at different resolutions in a pyramidal array are indexed by a pair of texture coordinates and an associated level coordinate (L). In order to introduce depth cues to the 2-D transformed image of the 3-D environment, a focus depth (F) for the image is specified and those image components having a depth (z) other than the focus depth have their texture blurred to direct the viewer's eye to the depth of interest. The texture blurring is introduced by applying an offset (FS) to the level coordinate (L) indexing the pyramidal array in an amount determined by the distance to the focus depth.

Three-dimensional image texture mapping

An image processing method and apparatus are described for rendering two dimensional pixel images composed of triangular image primitives. Prior to their projection into the image plane, each triangle is parameterised with a respective two-dimensional coordinate system with the coordinate axes (s,t) concurrent with respective edges of the triangle and the origin (0,0) coincident with the vertex (V.0) between those edges. A generalised interpolation function, applied in terms of the parameterising (s,t) coordinate system, determines parameter values at positions (P) within the triangle in terms of the two-dimensional coordinate system. These parameter values determine contributions from stored values for one or more attributes, such as surface normal or texturing, stored for each vertex, to give attribute values at each pixel. In a final stage, the per pixel attribute values from all triangles are used to jointly determine an output color for each pixel.

Attribute interpolation in 3D graphics

A circuit arrangement and display apparatus are described for use in 3-D graphics, where 2-D texture maps stored at different resolutions in a pyramidal array are indexed by a pair of texture coordinates and an associated level coordinate (L). In order to introduce depth cues to the 2-D transformed image of the 3-D environment, a focus depth (F) for the image is specified and those image components having a depth (z) other than the focus depth have their texture blurred to direct the viewer's eye to the depth of interest. The texture blurring is introduced by applying an offset (FS) to the level coordinate (L) indexing the pyramidal array in an amount determined by the distance to the focus depth.

An image processing method and apparatus are described for rendering two dimensional pixel images composed of triangular image primitives. Prior to their projection into the image plane, each triangle is parameterised with a respective two-dimensional coordinate system with the coordinate axes (s,t) concurrent with respective edges of the triangle and the origin (,) coincident with the vertex (V.,) between those edges. A generalised interpolation function, applied in terms of the parameterising (s,t) coordinate system, determines parameter values at positions (P) within the triangle in terms of the two-dimensional coordinate system. These parameter values determine contributions from stored values for one or more attributes, such as surface normal or texturing, stored for each vertex, to give attribute values at each pixel. In a final stage, the per pixel attribute values from all triangles are used to jointly determine an output color for each pixel.

A hybrid driving arrangement of multiple 3D graphics renderers and multiple synthetic stereo processors is provided for driving multiple view displays such as four view display devices. The device is an LCD screen device with an overlying lenticular screen, with the arrangement of pixels driven from the four different sources relative to the individual lenticular arrays being such that, at viewing locations V1 to V4, the images from respective ones of the four sources (76-79) can be seen. As the main viewer of such a multiple view display will typically be positioned in the center of the display as shown, and as such will only see a stereoscopic image provided by the two central views V2 and V3, the image sources for the two center views V2,V3 are respective 3-D graphics renderers, and those for the other views, post-processing stages. Thus the main viewer has the best quality view while viewers to the side suffer some (acceptable) degradation.

Stereoscopic image display driver apparatus

A post-processing method and apparatus are described whereby a second image is formed by horizontally shifting pixel primitives of a first image by an amount determined by their respective depths to give a parallax shift. To avoid gaps appearing in the shifted image, two z-buffers are maintained during rendering of the first image with the second being loaded by discarded values of the first such as to provide a record of the first occluded primitive for each pixel. The horizontal shift is applied to the contents of both z-buffers and the results written to a third z-buffer such that gaps due to the varied shift applied to the first image values (the unshifted contents of the first buffer are filled by previously occluded values from the second buffer. The two images may then be output to a suitable stereoscopic display such as a Virtual Reality headset.

Image generation using three z-buffers

An image processing method and apparatus are described for polygon rendering in two dimensional screen space, where the rendering includes mapping of texels from a texture map onto pixels within the polygon. The texture map (18) holds fewer texels than would be required to render a full screen of pixels, or even a large polygon, and the rendering process is carried out in a sequence of rendering windows overlying successive areas of a polygon, with the texture memory (18) being refreshed from mass storage (12) as required between windows. Storage (20) is provided for calculated polygon edge data to enable continuous edges to be maintained over two or more rendering windows to avoid discontinuity effects.

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Crawley, United Kingdom

Karl J Wood