Abstract: A method for performing image decompression. The method includes identifying a pixel in an image, wherein the image comprises a plurality of tiles including color data that is displayed by a plurality of pixels, wherein each tile is associated with a base value, a delta value, and a plurality of indices. One or more tiles associated with the pixel are identified. An interpolated base is determined by interpolating decompressed bases of the one or more tiles. An interpolated delta is determined by interpolating deltas of the one or more tiles. An index is determined for the pixel. A color value is determined for the pixel based on the interpolated base, interpolated delta, and the index.

Abstract: Image scaling techniques, in accordance with embodiments of the present technology, include directionally interpolating blocks of pixel data of an image, sharpening the directional interpolated blocks of pixel data, and optionally clamping the sharpened, directional interpolated blocks of pixel data.

Abstract: A method for encoding at least one extra bit in an image compression and decompression system. The method includes accessing an input image, and compressing the input image into a compressed image using an encoder system, wherein said encoding system implements an algorithm for encoding at least one extra bit. The method further includes communicatively transferring the compressed image to a decoding system, and decompressing the compressed image into a resulting uncompressed image that is unaltered from said input image, wherein the algorithm for encoding enables the recovery of the at least one extra bit.

Abstract: A method for performing image decompression. The method includes identifying a pixel in an image, wherein the image comprises a plurality of tiles including color data that is displayed by a plurality of pixels, wherein each tile is associated with a base value, a delta value, and a plurality of indices. One or more tiles associated with the pixel are identified. An interpolated base is determined by interpolating decompressed bases of the one or more tiles. An interpolated delta is determined by interpolating deltas of the one or more tiles. An index is determined for the pixel. A color value is determined for the pixel based on the interpolated base, interpolated delta, and the index.

Abstract: One embodiment of the present invention sets forth a technique for converting alpha values into pixel coverage masks. Geometric coverage is sampled at a number of “real” sample positions within each pixel. Color and depth values are computed for each of these real samples. Fragment alpha values are used to determine an alpha coverage mask for the real samples and additional “virtual” samples, in which the number of bits set in the mask bits is proportional to the alpha value. An alpha-to-coverage mode uses the virtual samples to increase the number of transparency levels for each pixel compared with using only real samples. The alpha-to-coverage mode may be used in conjunction with virtual coverage anti-aliasing to provide higher-quality transparency for rendering anti-aliased images.

Abstract: A method for encoding at least one extra bit in an image compression and decompression system. The method includes accessing an input image, and compressing the input image into a compressed image using an encoder system, wherein said encoding system implements an algorithm for encoding at least one extra bit. The method further includes communicatively transferring the compressed image to a decoding system, and decompressing the compressed image into a resulting uncompressed image that is unaltered from said input image, wherein the algorithm for encoding enables the recovery of the at least one extra bit.

Abstract: Image scaling techniques, in accordance with embodiments of the present technology, include directionally interpolating blocks of pixel data of an image, sharpening the directional interpolated blocks of pixel data, and optionally clamping the sharpened, directional interpolated blocks of pixel data.

Abstract: A method for performing image rendering. The method includes identifying a tile in an image, wherein the image comprises a plurality of tiles including color data that is displayed by a plurality of pixels. A quantized first base value and a quantized second base value are accessed from a block of memory, wherein the block is associated with the tile. Reverse quantization is performed on the quantized first and second base values to obtain a reproduced first base value, and a reproduced second base value corresponding to the tile for purposes of determining color values for corresponding pixels.

Abstract: A method for compressing normal maps in a computer system. The method includes accessing a map of input normals. A memory block having a first portion and a second portion is defined. A table of indices is stored in the first portion of the memory block and a table of normals is stored in the second portion of the memory block. The indices of the first portion of the memory block reference the normals of the second portion. The normals in the second portion of the memory block are unit normals of a sphere defined to represent the map of input normals.

Abstract: A method for encoding at least one extra bit in an image compression and decompression system. The method includes accessing an input image, and compressing the input image into a compressed image using an encoder system, wherein said encoding system implements an algorithm for encoding at least one extra bit. The method further includes communicatively transferring the compressed image to a decoding system, and decompressing the compressed image into a resulting uncompressed image that is unaltered from said input image, wherein the algorithm for encoding enables the recovery of the at least one extra bit.

Abstract: A method for performing indexing in an image decoder. The method includes identifying a tile in an image, wherein the image comprises a plurality of tiles, and wherein each tile includes color data associated with a plurality of pixels. The method includes asymmetrically providing a plurality of indices throughout the tile. The method includes identifying a pixel in the tile. The method also includes determining a corresponding rectangular grid that includes the pixel, wherein the corresponding rectangular grid comprises at least one indices in a group of indices. The method includes determining an index for the pixel by bilinearly filtering the group of indices that is associated with the corresponding rectangular grid, wherein the filtering is performed in relation to the pixel.

Abstract: Methods and systems for decompressing data are described. The relative magnitudes of a first value and a second value are compared. The first value and the second value represent respective endpoints of a range of values. The first value and the second value each have N bits of precision. Either the first or second value is selected, based on the result of the comparison. The selected value is scaled to produce a third value having N+1 bits of precision. A specified bit value is appended as the least significant bit of the other (non-selected) value to produce a fourth value having N+1 bits of precision.

Abstract: One embodiment of the present invention sets forth a technique for converting alpha values into pixel coverage masks. Geometric coverage is sampled at a number of “real” sample positions within each pixel. Color and depth values are computed for each of these real samples. Fragment alpha values are used to determine an alpha coverage mask for the real samples and additional “virtual” samples, in which the number of bits set in the mask bits is proportional to the alpha value. An alpha-to-coverage mode uses the virtual samples to increase the number of transparency levels for each pixel compared with using only real samples. The alpha-to-coverage mode may be used in conjunction with virtual coverage anti-aliasing to provide higher-quality transparency for rendering anti-aliased images.

Abstract: A method for encoding at least one extra bit in an image compression and decompression system. The method includes accessing an input image, and compressing the input image into a compressed image using an encoder system, wherein said encoding system implements an algorithm for encoding at least one extra bit. The method further includes communicatively transferring the compressed image to a decoding system, and decompressing the compressed image into a resulting uncompressed image that is unaltered from said input image, wherein the algorithm for encoding enables the recovery of the at least one extra bit.

Abstract: A method of organizing memory for storage of texture data, in accordance with one embodiment of the invention, includes accessing a size of a mipmap level of a texture map. A block dimension may be determined based on the size of the mipmap level. A memory space (e.g., computer-readable medium) may be logically divided into a plurality of whole number of blocks of variable dimension. The dimension of the blocks is measured in units of gobs and each gob is of a fixed dimension of bytes. A mipmap level of a texture map may be stored in the memory space. A texel coordinate of said mipmap level may be converted into a byte address of the memory space by determining a gob address of a gob in which the texel coordinate resides and determining a byte address within the particular gob.

Abstract: A method of organizing memory for storage of texture data, in accordance with one embodiment of the invention, includes accessing a size of a mipmap level of a texture map. A block dimension may be determined based on the size the mipmap level. A memory space (e.g., computer-readable medium) may be logically divided into a plurality of whole number of blocks of variable dimension. The dimension of the blocks is measured in units of gobs and each gob is of a fixed dimension of bytes. A mipmap level of a texture map may be stored in the memory space. A texel coordinate of said mipmap level may be converted into a byte address of the memory space by determining a gob address of a gob in which the texel coordinate resides and determining a byte address within the particular gob.

Abstract: A method for performing indexing in an image decoder. The method includes identifying a tile in an image, wherein the image comprises a plurality of tiles, and wherein each tile includes color data associated with a plurality of pixels. The method includes asymmetrically providing a plurality of indices throughout the tile. The method includes identifying a pixel in the tile. The method also includes determining a corresponding rectangular grid that includes the pixel, wherein the corresponding rectangular grid comprises at least one indices in a group of indices. The method includes determining an index for the pixel by bilinearly filtering the group of indices that is associated with the corresponding rectangular grid, wherein the filtering is performed in relation to the pixel.

Abstract: A method for performing image rendering. The method includes identifying a tile in an image, wherein the image comprises a plurality of tiles including color data that is displayed by a plurality of pixels. A quantized first base value and a quantized second base value are accessed from a block of memory, wherein the block is associated with the tile. Reverse quantization is performed on the quantized first and second base values to obtain a reproduced first base value, and a reproduced second base value corresponding to the tile for purposes of determining color values for corresponding pixels.

Abstract: A method of organizing memory for storage of texture data, in accordance with one embodiment of the invention, includes accessing a size of a mipmap level of a texture map. A block dimension may be determined based on the size of the mipmap level. A memory space (e.g., computer-readable medium) may be logically divided into a plurality of whole number of blocks of variable dimension. The dimension of the blocks is measured in units of gobs and each gob is of a fixed dimension of bytes. A mipmap level of a texture map may be stored in the memory space. A texel coordinate of said mipmap level may be converted into a byte address of the memory space by determining a gob address of a gob in which the texel coordinate resides and determining a byte address within the particular gob.

Abstract: One embodiment of the present invention sets forth a technique for transitioning from bilinear sampling to filter-4 sampling, while avoiding the visual artifacts along the boundary between the two different types of filters. The technique may be implemented using a linear transition function or an arbitrary transition function stored in a lookup table. The transition to filter-4 sampling occurs when the view of a textured object includes both minified and magnified levels of texture detail. Using this technique, high image quality is maintained for texture mapped images that include both highly minified pixels as well as highly magnified pixels, without suffering the performance penalty associated with using a filtering operation such as filter-4 sampling across all pixels.