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Posts from the ‘Code’ Category

21
Jun

Using Qemu and Chroot to replace your cross-compile toolchain

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Awhile back I wrote about how you can set up a cross-compile toolchain for compiling on x86_64 with the Raspberry Pi as a target. There is another, perhaps easier way to do the same thing by using Qemu 2.0 as your backend.

By installing and enabling Qemu support, you can run code compiled for another architecture (that is supported by Qemu) on your native machine. You can then create a Chroot environment, perhaps similar to what you have on your Raspberry Pi, and run it as if it was natively.

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8
Jul

WildMIDI 0.4 is here with support for other formats!

WildMIDI

WildMIDI 0.4 is released!

It has been two years in development and we’ve pushed WildMIDI 0.4 beyond just MIDI support, we’ve branched out into MIDI like files as well. We’ve worked together with other projects like GStreamer, OpenTESArena, XLEngine (DaggerXL), Thirdeye, ZDoom and more to ask what we can do to make their lives easier, as a result we now support rendering, streaming and playback of many older MIDI-like formats!

What’s new in this release

We’ve added support for KAR (MIDI with Karaoke) files, MIDI Type 2 and many MIDI-like formats such as HMI, HMP, MUS (Id) and XMI! We’ve also expanded our API in libwildmidi to support getting text/karaoke out of files, seeking songs in multi song MIDI Type 2, get errors instead of having a noisy library, setting conversion options, converting MIDI-like files into MIDI files and library now returns a buffer in the Endian format of the host.
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8
Apr

New releases of WorldEngine, OpenMW and TESAnnwyn

Rivers

WorldEngine 0.19 has been released! In case you’re wondering, WorldEngine is the combination of two projects: Lands and WorldSynth. The biggest gain in the merge is that we’re now two developers on the same wavelength and we’ve added plate tectonic simulations! As things have become more serious and complicated, we’ve had to write tests suites to cover our bases. We’re currently about 86% code coverage and the tests guarantee reproducibility which aids us in finding regressions. We’ve got many contributions, so having these in place are crucial for project stability.

What’s new in WorldEngine 0.19:

  • Speed of generation increased by almost a factor of 3 (due to update to Platec and making heavy use of numpy).
  • World-generation is now deterministic, i.e. generation is 100% reproducible.
  • Added support for exporting heightmaps using libgdal (see http://www.gdal.org/formats_list.html for possible formats).
  • Added the ability to modify temperature and humidity ranges as well as the temperature/precipitation curve.
  • Added the ability to generate scatter plots showing temperature and humidity of all terrestrial cells.
  • Added small variations to the temperature-map based on basic orbital parameters.
  • Added a satellite-like view of the world.
  • Added support to save/load worlds in/from HDF5-format.

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6
Nov

Deadlines and Timeouts for Realtime MongoDB Access with TxMongo

2000px-Twisted_Logo_(software).svg

Murphey had an adage: “Anything that can go wrong, will go wrong.” The best we can do is attempt to anticipate any problems that might come up and keep ‘the machine’ running. From an end-user perspective that means being responsive, even with errors. If there is a network error, we want to know as soon as possible with the guarantee that state of ‘the machine’ was not effected by the error.

With the release of TxMongo 15.3.1 we’ve introduced a few things that are useful when creating real-time applications.

We now have per-call deadline and timeouts!

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7
May

Cross-compiling for Raspberry Pi on Ubuntu

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While the Raspberry Pi 2 has four cores to churn through code, it still takes longer to compile than on most workstations and laptops. If you are feeling adventurous, you can try cross-compiling which has become easier to set up and get working.

Cross-compiling is when binaries created are for another target architecture than the one you are compiling on. This kind of set up is very typical when creating Android applications. The end result is that you can take the resulting binary and place on its target platform, and it will run there.

There are even tricks to getting the cross-compiled binary to also run on your native system!

In this guide, I’ll walk you through:

  • Setting up a cross-compile toolchain in Ubuntu (15.04 Vivid)
  • Setting up the proper exports
  • Compiling a test program for your native and target armhf platform
  • Compiling the latest Raspberry Pi 2 kernel with VC4 support.

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