DirectX Texture compression 5: Difference between revisions
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{{lang| | {{lang|DirectX Texture compression 5|title=DirectX Texture Compression 5}} | ||
'''DirectX Texture compression 5''', or DXT5, is a variation of the S3TC (S3 Texture Compression) image [[compression]] algorithm included in DirectX (since DX 6.0). <code>DXT5</code> is also the [[Vtex compile parameters|Vtex compile parameter]] used to utilize this algorithm even if there is no alpha channel in the source image. | |||
DXT5 converts a 4x4 block of pixels into 128 bits of output (consisting of 64 bits of alpha channel data (two 8 bit alpha values and a 4x4 3 bit lookup table) followed by 64 bits of encoded color data) resulting in a 4:1 compression ratio with 8-bit RGBA input data. | DXT5 converts a 4x4 block of pixels into 128 bits of output (consisting of 64 bits of alpha channel data (two 8 bit alpha values and a 4x4 3 bit lookup table) followed by 64 bits of encoded color data) resulting in a 4:1 compression ratio with 8-bit RGBA input data. | ||
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However, it is a lossy compression algorithm, resulting in image quality degradation, an effect which is minimized by the ability to increase texture resolutions while maintaining the same memory requirements. Hand-drawn cartoon-like images do not compress well, nor does [[Normal Maps|normal map]] data, both of which usually results in very poor image quality. | However, it is a lossy compression algorithm, resulting in image quality degradation, an effect which is minimized by the ability to increase texture resolutions while maintaining the same memory requirements. Hand-drawn cartoon-like images do not compress well, nor does [[Normal Maps|normal map]] data, both of which usually results in very poor image quality. | ||
==See | ==See also== | ||
* [[Wikipedia:DXT5]] - a more in-depth explanation of DTX5. | * [[Wikipedia:DXT5]] - a more in-depth explanation of DTX5. | ||
[[Category:Glossary]][[Category:Material System]] | [[Category:Glossary]][[Category:Material System]] | ||
Latest revision as of 15:04, 7 January 2024
DirectX Texture compression 5, or DXT5, is a variation of the S3TC (S3 Texture Compression) image compression algorithm included in DirectX (since DX 6.0). DXT5 is also the Vtex compile parameter used to utilize this algorithm even if there is no alpha channel in the source image.
DXT5 converts a 4x4 block of pixels into 128 bits of output (consisting of 64 bits of alpha channel data (two 8 bit alpha values and a 4x4 3 bit lookup table) followed by 64 bits of encoded color data) resulting in a 4:1 compression ratio with 8-bit RGBA input data.
Usage
Some consider DXT5 to be the most flexible general purpose compression codec. It can handle gradient alpha textures (using an interpolated alpha scheme for good results).
However, it is a lossy compression algorithm, resulting in image quality degradation, an effect which is minimized by the ability to increase texture resolutions while maintaining the same memory requirements. Hand-drawn cartoon-like images do not compress well, nor does normal map data, both of which usually results in very poor image quality.
See also
- Wikipedia:DXT5 - a more in-depth explanation of DTX5.