FoF - PyOpenGL = miniFoF (possibly for n810)

After spending some time on the Frets-on-Fire code I have managed to liberate it from PyOpenGL dependency.

In first step, I bypassed all the GUI code, without making any changes to the audio and input processing components. So I ended up with a completely blank window with a default song playing and me pressing the keyboard frets blindly.

In second step, I wrote only few lines of code to draw the notes on the screen using basic pygame.draw functions.

Here is a screen shot of the minimal UI.



Then I realized that, in theory this minimal version can also run on n810. I tested it in Diablo SDK and it runs. I couldn't hear the sound, but that's an issue with my scratchbox settings. I am sure that this will run on n810, however I am not sure if it will have real time response times. Unfortunately, I don't have a n810 to try this on (mine must be changing hands in black market as I write this :( ). Nevertheless I made necessary changes so that someone can try it on real n810 if they wish to.

If you have played FoF on keyboard, you would know F1-F5 keys are used to control frets and RETURN key is used to pluck the string. One possible way to achieve this with n810 is to use the keys on the keypad.

Following mockup should give you an idea.



F1 = Quote, F2 = K, F3 = H, F4 = F, F5 = S

In place of RETURN we can use the square key as shown above, but I couldn't find what its keycode is. So for now I have assigned that functionality to Q. If someone can provide with that keycode in pygame, I will fix it.

The gameplay is for single song only. I have bypassed all the menus for now. As the song starts the goal is to hit the note when it reaches the white line. You can play different songs by specifying their name as --play command line option.

This is not (yet) a single click install app, however.

I have put together the steps that you will need to follow, to get it working on actual n810. Those should work to the best of my knowledge, but you may run into errors. If you do, please report them in comments and I can help with them.

If you are interested in the changes I had to make, then here is the list of changes starting from the baseline FoF code (r1165 - r1176)

Give it a try. If it runs slow, let me know how slow. There still must be bunch of code paths that we can eliminate to improve the response times.

Frets on Fire on Maemo 5 (Fremantle)

Couple days ago I played Frets on Fire (FoF) for the first time. I was totally hooked on to it. After going through its hilarious tutorial and starting with a pathetic performance, I managed to score 37K points with 87% accuracy on the "Defy the Machine" song a few moments ago.

Couple days ago Nokia released the alpha version of Maemo 5 SDK (Fremantle) too.

I woke up next morning with an inevitable thought of porting the former on the later.

After a day's work here is a video demo of "Frets on Fire" running in the Maemo scratchbox SDK. And find below a list of things I had to do to get it working.

[If you don't know about FoF, it's an open source Guitar Hero clone that runs on many desktop platforms. It is written completely in python. While playing it you hold your keyboard in an unusual fashion so that it simulates a rockstar's guitar. (wikipedia)]



In future we can tweak FoF's UI so that the strings could be pressed against the frets using the touch screen itself.

There is no sound in the video, but it's just because I couldn't channel the sound through two layers of virtualization and into the video recorder software. I could hear the songs alright though after transporting them over wire using pulseaudio.

[Note that scratchbox is running on Ubuntu which itself is a KVM virtual machine. That should put the poor framerate into perspective.]

Here are the things I had to do:

• Fremantle SDK doesn't have python distutils. In diablo it comes from extras repo, so I borrowed it from there as well. (Added diablo extras repo in /etc/apt/sources.list)
  
• Fremantle SDK has a bug that I had discussed on mailing list during pre-alpha release, due to which the SDL/pygame applications cannot use the OpenGL support of the SDK. Due to same bug, FoF would also not work. After some googling I figured out the root cause and a work around. I built a private version of libsdl with --enable-video-opengl option. That did the trick. I have filed a bug to get this fixed in Fremantle.
• I also had to build custom packages of PIL (python imaging library) and numpy. I believe these libraries are available in diablo through extras repository, so I guess they will also be available in fremantle in future.
  
• Next I had to modify src/Input.py to comment out pygame's joystick initialization code.
• The really tough part was getting sound working. I found an old post to get sound working in scratchbox. Although it was a correct procedure, it didn't work for me. After a while I remembered from the Maemo summit that Fremantle runs pulseaudio (as opposed to esound in diablo). After that I did some googling and figured how to transport the sound over network using pulseaudio server and client. Here are couple useful links. [1] [2]
• The job on sound wasn't over yet. FoF runs all its music from ogg files. pygame won't play ogg files on fremantle. I dabbled into recompiling SDL_mixer with ogg support, but that didn't help. Then another discussion from Maemo summit came to mind, and I remembered for some (non-technical ?!) reason Maemo doesn't play ogg. So to get around it, I converted all .ogg files into .wav using ffmpeg. Changed the code wherever necessary to replace the file name extensions from ogg to wav. That did the trick and finally I could hear the sound.
• The game by default used 600x480 resolution. After some analysis of the code, I found fretsonfire.ini file in my home directory. I changed it to set the resolution to 800x480 to fit into the Xephyr window.
• There is one thing that I couldn't get to work. Arrow keys won't work. I found that the scan codes sent through Xephyr to the pygame were different from what are put in pygame constants.
  

... so when Nokia releases that next device, we will have an electric guitar in our pocket. :)

Inkface+pygame v0.2.0

As per the plan for v0.2, I am ready with a working implementation of inkface. I also made few more design decisions after my last design post. Here are the highlights:

1. All code is in python
2. For X11 surfaces, pygame is used.

I found that pygame (python bindings for SDL) is a mature library for drawing on X11 surfaces. It also has some optimizations which help in 2D animations. There is also OpenGL support, but I do not plan to use it inside inkface library. It is also well supported on Maemo.

I have written my favorite twitter client app with the new inkface-pygame library. The following video demo shows, how I could quickly code 2D scrolling animation with the help of pygame.



The v0.2.0 is delivered as a tarball. I have also updated the inkface wiki with some getting-started tips.

Smooth scrolling with Inkface+pygame

Preview of what's coming out later in the week. A v0.2 drop of inkface-pygame package for maemo and others should be ready in coming few days.