International Business Machines Corporation

William Bryan Tiernan

Daniel Alan Brokenshire

Matthew Edward King

Patrick Richard Brown

David Nolan Ault

David Arthur Dick

Mark Anthony Nadon

A method and an apparatus for retrieving a mipmap from memory. The method and apparatus provide an efficient method of determining the location of the desired mipmap in memory by storing the address of each row of mipmaps and calculating the offset from the start of the row to the desired mipmap. The mipmap is retrieved from memory at the location corresponding to the sum of the start address and the offset.

Method and apparatus for rectangular mipmapping

A texture image that comprises a set of texels wherein each texel is assigned a (u,v) coordinate pair of a texture coordinate space. Each texel is then stored in memory at a memory address determined by applying a transformation function to the texel's (u,v) coordinate pair. The transformation function is customized to associate two dimensional portions of the texture coordinate space to each page of memory. When the texture image (or a portion of the texture image) stored in memory is later mapped to an object during rendering the object, the allocation of two dimensional portions of the texture coordinate space to each memory page reduces the number of memory pages accessed during the rendering of the object. The reduction in the number of memory pages accessed during the texture mapping process translates into improved texture mapping performance. Preferably, the memory in which the texture image is stored comprises a dedicated texture memory of the graphics display system to eliminate contention with the frame buffer. In the presently preferred embodiment, the transformation function is accomplished by interleaving alternating u-bits and v-bits of the (u,v) coordinate pair to generate an offset value. The offset value is then added to a base address of the memory in which the texture image is stored to generate the memory address.

Method and apparatus for storing and accessing texture maps

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Round Rock, TX, United States of America

William Bryan Tiernan