Wednesday, 27 January 2016

etcpak 0.5

etcpak strikes again, this time with version 0.5, which has the ability to calculate planar blocks from the ETC2 standard. Color gradients, which were a sore spot in the image quality previously, will now have a much smoother look. This new option is activated by passing -etc2 parameter and comes at a small time cost (152% of pure ETC1 mode, 77 ms vs 117 ms). Example compressed image:

Planar block count in this image is quite high, as can be seen on the following debug image, where blue color indicates planar mode:

It should be noted that AVX2 version of planar block compression does not produce the same results as scalar one. Keep that in mind on pre-Haswell machines.


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.

Tuesday, 16 September 2014

Review of two bad joysticks

Logitech Attack 3

I don't even know why I have it. Doesn't have twist handle, nor any hat, so it's likely to be never actually used by me. Let's see some customer reviews:
So it's quite good, right?

Lol nope. Have fun trying to fly something with this absolute turd.

Madcatz and/or Saitek Cyborg F.L.Y. 5

Cheap(ish) and I think a long time ago the Internets said it was good. Let's see.

Definitely better than that shit above, but still not quite good. Discontinuities at centers of axes and a massive dead zone. As for the twist axis:

That's a constant rotary motion, without any pauses at center. When you combine it with bad build quality you get something you don't really want to have.

Saturday, 6 September 2014

Glany Heavy Duty - co jest w środku?

Miałem buty. Chyba HD 863. Pękła podeszwa i zaczęły siorbać wodę. Nie pamiętam po ilu latach noszenia, ale pewnie coś koło 3-4. Potrzebowałem kawałka dobrej skóry, a w lumpeksach się nie orientuję, więc trzeba było korzystać z tego co jest.

Po spruciu listwy. Usztywnienie zapiętka wykonane ze skóry, wklejone.

Podkładka pod nity. Szyta i klejona.
Podkładki po odpruciu.
Język po odpruciu od obłożyny.
Obłożyna odpruta od przyszwy.
Widok z boku.
Język odpruty od przyszwy.
Podeszwa środkowa z jakiegoś filcu, kompletnie zalana klejem. Sztywna i twarda.
Widok do środka.
Obłożyna po odcięciu.
Kolejne warstwy zapiętka.
Odcięta przyszwa.
Odcięty nosek.
Pęknięcie podeszwy. Zawinięte kawałki skóry są przybity gwoździkami i przyszyte do podeszwy środkowej. Przy okazji widać ile warte są śmiech-śrubki w podeszwie i śmiech-przeszycie na otoku.
Po rozcięciu podeszwy, przeszycia i wyciągnięciu gwoździka.
Grubość skóry.
Drugie życie buta.

Friday, 30 May 2014

etcpak 0.3

New major version, new features:
  • Ability to create mipmaps (only POT, not in benchmark mode).
  • Optional dithering of input image.
  • Small quality improvements at basically no cost.
Image minification algorithm used for generating mipmaps is stupid simple, but it already beats the implementation in PVRTexTool:
Left: PVRTexTool, Right: etcpak
Notice the high frequency artifacts present in the PVRTexTool image, particularly near the eyes of parrots. etcpak generates smoother and more natural look. Further refinements will be able to improve the image quality even more.

Dithering basically improves the appearance of gradients or smooth areas in photos:
Left: no dithering, Right: dithering enabled
It comes at a small cost however. Here are the timings for normal compression:
$ x64/Release/etcpak.exe 8192.png -b
Image load time: 1352.646 ms
Mean compression time for 50 runs: 630.855 ms
And this is the run with dithering enabled:

$ x64/Release/etcpak.exe 8192.png -b -d
Image load time: 1312.084 ms
Mean compression time for 50 runs: 744.394 ms

Thursday, 13 March 2014

etcpak 0.2.2

This version contains some minor performance improvements and a benchmark mode, which can be activated using the -b parameter. It will perform 50 compression passes and print out the average time for one pass. It should provide better environment for measurements, as the PNG decode is the slowest component during normal operation.

I've also made an example 8192x8192 image available for test purposes. It is based on the Carina Nebula shot from Hubble.

For comparison, here's the previous method of speed measurement, heavily influenced by the PNG decoder:
$ time etcpak.exe 8192.png

real    0m1.471s
user    0m0.000s
sys     0m0.030s
And here's the new benchmark mode:
$ etcpak.exe 8192.png -b
Image load time: 1330.949 ms
Mean compression time for 50 runs: 631.308 ms


Saturday, 10 August 2013

etcpak 0.2.1

A new version of etcpak has been published today. What's new:
  • Reduced number of spawned threads and context switches.
  • Memory mapped files are used for output. This allows writing compressed data to disk during compression. The downside is that writing PVR output files no longer can be disabled.
  • 32 bit version has been discontinued. From now on only 64 bit version will be provided. It was always the recommended one to use, anyways, as it performed much better than the 32 bit one.
  • Various optimizations.
etcpak 0.2.1 is 10% faster than etcpak 0.2, with the compression time measured at 0.08 s (after deducting PNG load time).