Saturday, 2 January 2016

etcpak 0.4

New year, new etcpak. Previously etcpak was an order of magnitude faster than the competing ETC compressors. This new version is yet another order of magnitude faster.

Time to compress 8K image:
etcpak 0.3: 655 ms
etcpak 0.4: 77 ms

This is thanks to Daniel Jungmann, who submitted patches implementing SSE 4.1 and AVX2 instructions. SSE 4.1 is now default and required (supported by Core 2 and AMD Bulldozer CPUs) and AVX2 is detected at runtime (support added in Haswell CPUs).

Other new features:
  • ETC1 dissection mode, allowing in-depth inspection of compressed images.
  • Mip-maps will be calculated only if needed (doh!).
  • Alpha channel compression is now deterministic.
  • Minor changes in compression precision. This will change checksums of most compressed images, compared with previous versions.
  • Multithreaded job dispatch algorithm was improved.
  • zlib/PNG checksum validation was removed, resulting in 12% improvement in image load times.

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