Texture compression

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Texture compression is used in computer graphics to reduce the memory and bandwidth requirements of textures .

conditions

The requirements for texture compression systems differ from those for ordinary image compression , as fast access to random texels is required:

  • Fixed compression rate to simplify address calculations
  • Few indirections because of the long pipelines in graphics chips
  • Compatibility with texture caches, i.e. H. Preservation of the locality
  • Simple, faster, and easy to implement in hardware decompression algorithm (on the other hand, the compression algorithm can be very complex)

Systems

In the early days, vector quantization , especially indexed colors, was used, but this was replaced by other methods because of the indirection that occurred. Indexed colors were used for a long time in the area of embedded systems and were part of OpenGL ES 1.x.

Most widespread on the desktop is S3 Texture Compression (S3TC) , which is included in DirectX and supported in OpenGL via an extension .

The ETC developed by Ericsson is widespread in high-end smartphones .

FXT1 was a texture compression system from 3Dfx . It is only supported by Intel today .

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