E-Mail backup in 2009

Are you still one of those using POP to pull E-Mails and save them locally? Are you then using some kind copy to back-up the local mails? At least so did I until recently… But welcome to 2009!

Today the serious e-mail providers also offer IMAP access and pulling e-mails from other servers using POP. Furthermore you get about 7GB(at gmail at least) of online storage and you can configure IMAP to maintain a full local copy. (hint: default of Thunderbird 3)

So instead of fiddling with some local back-ups you can just let gmail pull and save your mail in one place. Then you can clone all your mail locally with thunderbird and you have a reasonable backup. (also recommended for offline usage)

But what to do with your mail collection from the last years? Luckily IMAP has also push support, so you can upload them to gmail and maybe to a bunch of other email providers if you feel safer. 🙂

YouAmp 0.6 has grown

After several betas the final release of YouAmp 0.6 is almost there. You can find the current versions in the launchpad PPA for Ubuntu and in maemo-extras for N8x0.

YouAmp DesktopYouAmp Maemo

the new features are:

  • Playlists
  • Automatic Cover Download
  • Adding Files from anywhere, not just the music library (just drag and drop in Desktop version)
  • you can pay for YouAmp now

I would like to emphasise the last feature: make me a millionaire! No seriously – if you like YouAmp consider a small donation > 0,30€ (otherwise everything goes to paypal) which will help developing the program in my free-time. 😉

As I did not get into the Developers programme for the N900, I also accept unused discount codes – in case you would like to see YouAmp on the N900.

First serious YouAmp release for Desktop

YouAmp is yet another music player for Linux. But it is different than the other players as it is written by me! Here is a screenshot

youamp-0.6

if you are convinced by these outstanding features you can give it a try here. Do not be afraid if nothing happens on first startup as it will index your whole home directory which takes a while.

Basically this re-implements Tracker for music files – and indeed one of the features of this release is that I throw away Tracker. Although the Tracker devs never get tired of praising the cool new features they are implementing, their last stable release Tracker 0.6 is an unusable piece of crap. But I am actually looking forward to try out Tracker 0.7 once it gets an stable release for using it with YouAmp.

For those waiting for playlist in YouAmp on maemo: this release means they are not far away. The main purpose of the last release on maemo was basically to sync the code with the desktop version. Now it only needs some polish and UI love, so it works well on the small screen.

ARToolkitPlus 2.1.3

I just released ARToolkitPlus 2.1.3 based on the new development on launchpad. While the last official release 2.1.1 was back in 2006 and the intermediate release 2.1.2 just contained some build fixes, this version is actually useful.

It has the following features/ fixes:

  • build fixes with GCC 4.4
  • allow build with -std=c++0x
  • allow system-wide installation (allows packaging)
  • add debian packaging information

therefore you can find some ARToolkitPlus packages in my PPA now.

In case you wonder about the differences between ARToolkit and ARToolkitPlus or you are searching for more documentation, I also set up an FAQ.

OpenGL on the N900

some people already got enthusiastic because they heard that the N900 – nokias latest Linux phone supports OpenGL. Playing games like Frets On Fire on your phone as soon as you got one was a common expectation. But this will not be possible – at least not as easy as you might think.

OpenGL does not always mean OpenGL. There is OpenGL1, OpenGL2, OpenGL3, OpenGL ES1 and last but not least OpenGL ES2. While all contain OpenGL in the name and are somewhat similiar they are not compatible with each other. Basically only GL2 is compatible with GL1 programs. As soon as the deprecated stuff will be removed from GL3, GL2 programs wont run any more. Generally GLES is also not compatible with GL – but programs written in GL2 are very similar to GLES1 and programs written in GL3 are likewise similar to GLES2. So porting between this two pairs is easily possible. The problem is that Quake3 was written with GL1 and the N900 only supports GLES2. This means that basically the whole renderer of the game has to be rewritten.

Another problem is that FretsOnFire uses SDL1.2 for input/ output handling and context creation(through pygame). But SDL1.2 uses GL1 for context creation so you cant use that. Luckily there is SDL1.3 which also supports GLES2 but it is not available on the N900 yet.

So in order to get an existing game running on the N900 one would have to rewrite the engine using the GLES2/GL3 model and replace any libraries  (SDL1.2, GLUT) with direct calls to EGL for context creation and Xlib to get the window . The port of Quake3 to Maemo shows that this is possible – but it will usually take more time than a simple recompile.

HD movies with crappy Open Source drivers

do you want to watch a HD film on your Ubuntu Box? Most likely this will be a choppy experience unless you have a NVidia card with VDPAU decoding support. With ordinary open source radeon or intel drivers, your CPU wont get any help with decoding and thus the decoding will be most likely be not fast enough.

But the good news is that you dont have to wait until next christmas, when the Gallium based open source drivers will probably be able to offer video decoding acceleration. In case you have a multi-core system you probably dont need any GPU based acceleration at all, since your CPU is basically fast enough, but is just not programmed properly. Currently ffmpeg(the library which does the decoding) only uses one core of your quad-core CPU ideling the other 3 while your video is stuttering.

Luckily there is a branch of ffmpeg which uses all 4 cores called ffmpeg-mt and there is also a special version of mplayer(mplayer-mt) available in this PPA which uses this ffmpeg branch. If you use this you most likely will be able to watch HD movies now – but the proper fix would be patching the system ffmpeg library so totem, VLC et. al. would benefit from it as well…

Developing OpenGL 3 when all you have is OpenGL 1.5

As you probably should know by now there was a big cleanup with OpenGL 3.1, when the functions deprecated with OpenGL 3.0 were removed. This means that the immediate mode is gone as well as all fixed function options, which results in a more flexible and Object Oriented API.

But this also means that programs written with OpenGL3.1+ are fundamentally different than those written with OpenGL 2 and before. So if you develop a new application it makes sense to stick to the OpenGL3 model. The problem is that the current Linux open source drivers are stuck to at most OpenGL 1.5 support due to missing GLSL support. But what if you want to develop a OpenGL3 compatible renderer today?

This post will cover how to create a renderer based on the OpenGL3 model, but only using OpenGL 1.5 constructs. If you want to know more about the OpenGL3 model, read here.

The core of OpenGL3 probably is that you feed arbitary data into vertex/ fragment shaders which do something useful with them, instead of specifying directly what to do. These shaders are written in GLSL, which is a sort of a C dialect. But as I said there is no GLSL with OpenGL 1.5, so we will have to use vertex/ fragment programs. They do basically the same as shaders, but are written in assembly.

Luckily one can compile GLSL Shaders to vertex/ fragment programs using Nvidias CG so we obviosly need the nvidia-cg-toolkit. Vertex/ Fragment programs are also loaded differently, so while for a vertex shader you do

unsigned int prog = glCreateProgram();
unsigned int id = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(id, 1, (char**)&progStr.c_str(), NULL);
glCompileShader(id);
glAttachShader(prog, id);
glLinkProgram(prog);

you do for a vertex program

unsigned int id;
glGenProgramsARB(1, &id);
glBindProgramARB(GL_VERTEX_PROGRAM_ARB, id);
glProgramStringARB(GL_VERTEX_PROGRAM_ARB, GL_PROGRAM_FORMAT_ASCII_ARB,
 progStr.length(), progStr.c_str());

The pushing of data into the shader is also handled differently. For GLSL Shader:

// we bind the uniform variable "matPMV" from the vertex shader
int loc = glGetUniformLocation(prog, "matPMV");
glUniformMatrix4fv(loc, 1, GL_FALSE, matPMV);

// bind the attribute "vertexPos" in the shader
#define VERTEX_ATTR 0
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBindAttribLocation(prog, VERTEX_ATTR, "vertexPos");
glEnableVertexAttribArrayARB(VERTEX_ATTR);
glVertexAttribPointerARB(VERTEX_ATTR, 3, GL_FLOAT, false, 0, 0);

for a vertex program

// we have no uniforms here yet
// this binds the C0..C3 to the model view matrix
glBindProgramARB(GL_VERTEX_PROGRAM_ARB, id);
glProgramLocalParameters4fvEXT(GL_VERTEX_PROGRAM_ARB, 0, 4, matPMV);

// attributes work almost the same
#define VERTEX_ATTR 0
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glEnableVertexAttribArrayARB(VERTEX_ATTR);
glVertexAttribPointerARB(VERTEX_ATTR, 3, GL_FLOAT, false, 0, 0);

but since we could specify the variable name in the code, we have to do it in the Shader:

uniform mat4 matPMV : C0;
attribute vec4 vertexPos : ATTR0;

the ordinary GLSL Vertex shader would just read

uniform mat4 matPMV;
attribute vec4 vertexPos;

But wait, I said there is no shader support in OpenGL 1.5. Right – this is where cgc comes into play. You have to compile your shader manually with it into a vertex program, which you finally load. The command for this is:

cgc -oglsl -profile arbvp1 vertexShader.cg -o vertexProg.vp

As you can see, the differences are pretty small using this technique, so you can start developing using the Open Source drivers now 🙂

Creating Augmented Reality

In case you want to create some augmented reality application(example), you need a library which provides you with geometry information for a given video stream based on some kind of markers.

Luckily there is already a library, which uses quite obvious, yet easy to use markers and was actually a pioneer in this area: ARToolkit. Unluckily the developers decided to continue the development closed source as ARToolkit4. So the last freely available version is ARToolkit2, whose core recognition routines have not been touched since 2006. Nevertheless the SVN of the branch still shows some activity, so it seems to be at least maintained.

But even before the library went closed source, several forks of it were created:

  • ARToolkitPlus: uses an improved algorithm and claims to have better performance. No longer developed
  • OSGART: wraps ARToolkit and combines it with Open Scene Graph
  • NyARToolkit: seems to me like an overengineered rewrite in C++. Pointless.

Comparing the available choices, ARToolkitPlus is the most advanced one, although it was not updated since 2006 (but neither was the core of ARToolkit) and it even does not compile on a current GCC. But looking at the code it is still much more solid than ARToolkit, that is why I decided to pick up the development. I spent several hours to make it compile again and ported the build system from qmake to scons. You can see the results at launchpad. By using launchpad there is now even a bug-tracker and a question system, so you are welcome to join me there.

Currently ARToolkitPlus lacks the camera and rendering support to be feature complete with ARToolkit and give users an easy start. So this is obviously the next on the Todo list.

bzr is really great

I just moved the code hosting of YouAmp from garage.maemo.org to launchpad and thus also moved the source code management from svn to bzr. And I must say bazaar is really great. I have already had some experience with git before, but I could never really wrap my head around it, but I got the workflow if bazaar in just about 5 minutes.

I do not want to start another VCS war here, since there are already enough of them ongoing – instead I just want to mention some things bzr got right:

  • it lets you accomplish your task without getting in your way: if you want just to publish your code on a public repository, it just does that instead of trying to teach you the concept of decentralised VCS
  • if you try to do something which requires knowledge of  the concept decentralised VCS, it points you directly to some instructions to what you have to do and why
  • it is really greatly integrated with launchpad: you can have the translations on launchpad synced up with the ones in your repository automatically 😀
  • it displays only the basic(mostly used) commands as default so you can quickly find the right one

In other news YouAmp now uses launchpad for the hosting, which means you can start help translating it there. Since I have not posted about YouAmp for some time, here is the current status:

  • it was ported to Tracker, currently waiting for the 0.7 release to take real advantage of it
  • it also uses GtkBuilder now so you can easily change the interface
  • there is basic Playlist support, but it has to be reworked
  • once the Playlist rework is done, there will be a new release
  • and a backport to Maemo4 using the new codebase

First usable open-source phone arriving

Have you ever dreamed of to ssh into your phone and install Gnome stuff with apt-get? Well at least some have and thus created OpenMoko but sadly they only managed to produce two prototypes with unusable software. Well you can still install android on them, but then you basically use Java instead of the traditional Linux software stack. This is also the “problem” which you get most of the current Android phones. Well of course apart from being locked in to google.

But there is hope! It seems like Nokia is finallay putting Maemo on a real phone. See this photo for the looks. In case you have missed the Maemo up to now: it is a Gnome based desktop for MID – just like Ubuntu MID, but better designed. And the best news is that it will use a Clutter based interface for the next release – just like Moblin. This makes Maemo look really slick.

Besides of the looks it uses all the Gnome internals which Ubuntu uses (at least Karmic): Telepathy for Messaging, Firefox as the browser an evolution based Mail client. I currently use it on my N800 and it is really great; want to try out Fennec instead of the pre-installed browser? One click automatically adds a new apt repository.

This probably reads like a straight advert, but I really waited for a phone like this.

As a sidenote: clutter seems to have quite a momentum this days: Moblin, Maemo, Gnome3 …