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S3TC
S3 Texture Compression (S3TC) (sometimes also called DXTn, DXTC, or BCn) is a group of related lossy texture compression algorithms originally developed by Iourcha et al. of S3 Graphics, Ltd. for use in their Savage 3D computer graphics accelerator. The method of compression is strikingly similar to the previously published Color Cell Compression, which is in turn an adaptation of Block Truncation Coding published in the late 1970s. Unlike some image compression algorithms (e.g. JPEG), S3TC's fixed-rate data compression coupled with the single memory access (cf. Color Cell Compression and some VQ-based schemes) made it well-suited for use in compressing textures in hardware-accelerated 3D computer graphics. Its subsequent inclusion in Microsoft's DirectX 6.0 and OpenGL 1.3 (via the GL_EXT_texture_compression_s3tc extension) led to widespread adoption of the technology among hardware and software makers. While S3 Graphics is no longer a competitor in the graphics accelerator ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Savage 3D
Savage was a product-line of PC graphics chipsets designed by S3. Graphics Processors Savage 3D At the 1998 E3 Expo S3 introduced the first Savage product, Savage3D. Compared to its ViRGE-derived predecessor (Trio3D), Savage3D was a technological leap forward. Its innovative feature-set included the following: * "free" (single-cycle) trilinear-filtering * hardware motion-compensation and subpicture alpha-blending (MPEG-2 video) * integrated NTSC/PAL TV-encoder, (optional) Macrovision * S3 Texture Compression (S3TC) * multi-tap X/Y interpolating front-end (BITBLT) and back-end (overlay) video-scaler Unfortunately for S3, deliveries of the Savage3D were hampered by poor manufacturing yields. Only one major board-vendor, Hercules, made any real effort to ship a Savage3D product. S3's yield problems forced Hercules to hand pick usable chips from the silicon wafers. Combined with poor drivers and the chip's lack of multitexturing support, the Savage3D failed in the market. S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Color Cell Compression
Color Cell Compression is a lossy compression, lossy image compression algorithm developed by Campbell et al., in 1986, which can be considered an early forerunner of modern texture compression algorithms, such as S3 Texture Compression and Adaptive Scalable Texture Compression. It is closely related to Block Truncation Coding, another lossy image compression algorithm, which predates Color Cell Compression, in that it uses the dominant luminance of a block of pixels to partition said pixels into two representative colors. The primary difference between Block Truncation Coding and Color Cell Compression is that the former was designed to compress grayscale images and the latter was designed to compress color images. Also, Block Truncation Coding requires that the standard deviation of the colors of pixels in a block be computed in order to compress an image, whereas Color Cell Compression does not use the standard deviation. Both algorithms, though, can compress an image down to ef ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
S3 Graphics
S3 Graphics, Ltd. was an American computer graphics company. The company sold the S3 Trio, Trio, S3 ViRGE, ViRGE, S3 Savage, Savage, and S3 Chrome, Chrome series of graphics processors. Struggling against competition from 3dfx Interactive, ATI Technologies, ATI and Nvidia, it merged with hardware manufacturer Diamond Multimedia in 1999. The resulting company renamed itself to SONICblue Incorporated, and, two years later, the graphics portion was spun off into a new joint effort with VIA Technologies. The new company focused on the mobile graphics market. VIA Technologies' stake in S3 Graphics was purchased by HTC in 2011. History S3 was founded and incorporated in January 1989 by Dado Banatao and Ronald Yara. It was named S3 as it was Banatao's third startup company. The company's first products were among the earliest graphical user interface (GUI) accelerators. These chips were popular with video card manufacturers, and their followup designs, including the S3 Trio, Trio64, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lossy Data Compression
In information technology, lossy compression or irreversible compression is the class of data compression methods that uses inexact approximations and partial data discarding to represent the content. These techniques are used to reduce data size for storing, handling, and transmitting content. Higher degrees of approximation create coarser images as more details are removed. This is opposed to lossless data compression (reversible data compression) which does not degrade the data. The amount of data reduction possible using lossy compression is much higher than using lossless techniques. Well-designed lossy compression technology often reduces file sizes significantly before degradation is noticed by the end-user. Even when noticeable by the user, further data reduction may be desirable (e.g., for real-time communication or to reduce transmission times or storage needs). The most widely used lossy compression algorithm is the discrete cosine transform (DCT), first published by N ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Texture Compression
Texture compression is a specialized form of image compression designed for storing texture maps in 3D computer graphics rendering systems. Unlike conventional image compression algorithms, texture compression algorithms are optimized for random access. Texture compression can be applied to reduce memory usage at runtime. Texture data is often the largest source of memory usage in a mobile application. Tradeoffs In their seminal paper on texture compression, Beers, Agrawala and Chaddha list four features that tend to differentiate texture compression from other image compression techniques. These features are: ;Decoding Speed: It is highly desirable to be able to render directly from the compressed texture data and so, in order not to impact rendering performance, decompression must be fast. ;Random Access: Since predicting the order that a renderer accesses texels would be difficult, any texture compression scheme must allow fast random access to decompressed texture data. Thi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lossy Compression
In information technology, lossy compression or irreversible compression is the class of data compression methods that uses inexact approximations and partial data discarding to represent the content. These techniques are used to reduce data size for storing, handling, and transmitting content. Higher degrees of approximation create coarser images as more details are removed. This is opposed to lossless data compression (reversible data compression) which does not degrade the data. The amount of data reduction possible using lossy compression is much higher than using lossless techniques. Well-designed lossy compression technology often reduces file sizes significantly before degradation is noticed by the end-user. Even when noticeable by the user, further data reduction may be desirable (e.g., for real-time communication or to reduce transmission times or storage needs). The most widely used lossy compression algorithm is the discrete cosine transform (DCT), first published by N ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FourCC
A FourCC ("four-character code") is a sequence of four bytes (typically ASCII) used to uniquely identify data formats. It originated from the OSType or ResType metadata system used in classic Mac OS and was adopted for the Amiga/Electronic Arts Interchange File Format and derivatives. The idea was later reused to identify compressed data types in QuickTime and DirectShow. History In 1984, the earliest version of a Macintosh OS, System 1, was released. It used the single-level Macintosh File System with metadata fields including file types, creator (application) information, and forks to store additional resources. It was possible to change this information without changing the data itself, so that they could be interpreted differently. Identical codes were used throughout the system, as type tags for all kinds of data. In 1985, Electronic Arts introduced the Interchange File Format (IFF) meta-format (family of file formats), originally devised for use on the Amiga. These fi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pixel
In digital imaging, a pixel (abbreviated px), pel, or picture element is the smallest addressable element in a Raster graphics, raster image, or the smallest addressable element in a dot matrix display device. In most digital display devices, pixels are the smallest element that can be manipulated through software. Each pixel is a Sampling (signal processing), sample of an original image; more samples typically provide more accurate representations of the original. The Intensity (physics), intensity of each pixel is variable. In color imaging systems, a color is typically represented by three or four component intensities such as RGB color model, red, green, and blue, or CMYK color model, cyan, magenta, yellow, and black. In some contexts (such as descriptions of camera sensors), ''pixel'' refers to a single scalar element of a multi-component representation (called a ''photosite'' in the camera sensor context, although ''wikt:sensel, sensel'' is sometimes used), while in yet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RGB Color Space
RGB color spaces are a category of additive colorimetric color spaces specifying part of its absolute color space definition using the RGB color model. RGB color spaces are commonly found describing the mapping of the RGB color model to human perceivable color, but some RGB color spaces use imaginary (non-real-world) primaries and thus can not be displayed directly. Like any color space, while the specifications in this category use the RGB color model to describe their space, it is not mandatory to use that model to signal pixel color values. Broadcast TV color spaces like NTSC, PAL, Rec. 709, Rec. 2020 additionally describe a translation from RGB to YCbCr and that is how they are usually signalled for transmission, but an image can be stored as either RGB or YCbCr. This demonstrates using the singular term "RGB color space" can be misleading, since a chosen color space or signalled colour can be described by any appropriate color model. However the singular can be seen in spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RGBA Color Space
RGBA stands for red green blue alpha. While it is sometimes described as a color space, it is actually a three-channel RGB color model supplemented with a fourth ''alpha channel''. Alpha indicates how opaque each pixel is and allows an image to be combined over others using alpha compositing, with transparent areas and anti-aliasing of the edges of opaque regions. Each pixel is a 4D vector. The term does ''not'' define what RGB color space is being used. It also does not state whether or not the colors are premultiplied by the alpha value, and if they are it does not state what color space that premultiplication was done in. This means more information than just "RGBA" is needed to determine how to handle an image. In some contexts the abbreviation "RGBA" means a specific memory layout (called RGBA8888 below), with other terms such as "BGRA" used for alternatives. In other contexts "RGBA" means any layout. Representation In computer graphics, pixels encoding the RGBA c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ATI Technologies
ATI Technologies Inc. was a Canadian semiconductor industry, semiconductor technology corporation based in Markham, Ontario, that specialized in the development of graphics processing units and chipsets. Founded in 1985, the company listed publicly in 1993 and was acquired by AMD in 2006. As a major fabless semiconductor company, ATI conducted research and development in-house and outsourcing, outsourced the manufacturing and assembly of its products. With the decline and eventual bankruptcy of 3dfx in 2000, ATI and its chief rival Nvidia emerged as the two dominant players in the graphics processors industry, eventually forcing other manufacturers into niche roles. The acquisition of ATI in 2006 was important to AMD's strategic development of its AMD Accelerated Processing Unit, Fusion series of computer processors, which integrated general processing abilities with graphics processing functions within a single chip, which would become a popular option on computers in the foll ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Normal Mapping
In 3D computer graphics, normal mapping, or Dot3 bump mapping, is a texture mapping technique used for faking the lighting of bumps and dents – an implementation of bump mapping. It is used to add details without using more polygonal modeling, polygons. A common use of this technique is to greatly enhance the appearance and details of a low poly, low polygon model by generating a normal map from a high polygon model or Heightmap, height map. Normal maps are commonly stored as regular RGB images where the RGB components correspond to the X, Y, and Z coordinates, respectively, of the surface normal. History In 1978 Jim Blinn described how the normals of a surface could be perturbed to make geometrically flat faces have a detailed appearance. The idea of taking geometric details from a high polygon model was introduced in "Fitting Smooth Surfaces to Dense Polygon Meshes" by Krishnamurthy and Levoy, Proc. SIGGRAPH 1996, where this approach was used for creating displacement mappi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
