README.md

   1 Arpeggigon
   2 ===
   3
   4 The arpeggigon is a music instrument inspired by Mark
   5 Burton's [reacTogon][].
   6
   7 It is written in Haskell using the FRP
   8 library [Yampa](http://hackage.haskell.org/package/Yampa-0.10.4) for
   9 the music
  10 generation, [Gtk2Hs](https://hackage.haskell.org/package/gtk-0.14.5)
  11 for the Graphical User Interface (GUI)
  12 and [jack](http://hackage.haskell.org/package/jack-0.7.1) for handling
  13 MIDI I/O. The code to interface with the exterior world is structured
  14 using reactive values and relations
  15 (see
  16 [this paper](http://www.cs.nott.ac.uk/~psxip1/papers/2015-HaskellSymposium-Perez-Nilsson-BridingGUIGapReactiveValues.pdf) and
  17 the
  18 libraries
  19 [here](https://hackage.haskell.org/package/keera-hails-reactivevalues-0.2.2.0) and
  20 [here](https://hackage.haskell.org/package/keera-hails-reactive-gtk-0.3)).
  21
  22 Install guide
  23 ---
  24
  25 The arpeggigon needs the [GTK+ 2.0 C API](http://www.gtk.org/) and
  26 the [JACK C API](http://jackaudio.org/) to be built. Note that Gtk2Hs
  27 depends on external program such
  28 as [alex](http://hackage.haskell.org/package/alex)
  29 or [happy](http://hackage.haskell.org/package/happy). It is known to
  30 work with GHC 7.10.3 and GHC 8.0.1.
  31
  32 Running the arpeggigon is then possible with:
  33
  34         cabal sandbox init
  35         cabal install --only-dependencies
  36     cabal run arpeggigon
  37
  38 To install the arpeggigon globally, one can call:
  39
  40         cabal install
  41
  42 This will create an executable located in
  43 `<path_to_repo>/.cabal-sandbox/bin/` from where it is possible to create a
  44 symbolic link to an object in the `PATH`.
  45
  46         ln -s <path_to_repo>/.cabal-sandbox/bin/arpeggigon <somewhere_in_PATH>/arpeggigon
  47
  48 Description
  49 ---
  50
  51 ### The reacTogon
  52
  53 The [reacTogon][] is a musical instrument invented based upon
  54 the
  55 [harmonic table](https://en.wikipedia.org/wiki/Harmonic_table_note_layout),
  56 a way of arranging notes where the various directions correspond to
  57 meaningful musical intervals. From that layout, the reacTogon defines
  58 an automaton: tokens of different kinds interact with *play heads*
  59 moving around on the board, altering their directions and eventually
  60 playing a note.
  61
  62 The arpeggigon is an extended reacTogon. It is for instance possible
  63 to have multiple layers with different characteristics running in
  64 parallel, or to modify the way individual notes should be played, etc.
  65
  66 ### Music generation
  67
  68 The arpeggigon doesn't directly produce music, but is
  69 a
  70 [MIDI](https://en.wikipedia.org/wiki/MIDI) [JACK](http://jackaudio.org/) client. It
  71 then requires a JACK server to run when it is launched and to be
  72 connected to a MIDI synthetizer to produce music.
  73
  74 ### Tokens
  75
  76 There are five kinds of tokens currently supported, that appear in the
  77 following order in the arpeggigon's GUI:
  78 * ricochet token: plays a note and reorients the play head toward the
  79   direction it's pointing to,
  80 * start token: like the ricochet token but generated an impulsion when
  81   the machine starts,
  82 * stop token: plays a note and makes the play head disappear,
  83 * absorb token: like the stop token but doesn't play any note,
  84 * split token: splits the impulsion into five.
  85
  86 ### Multiple layers
  87
  88 It is possible to have multiple layers running in parallel, each one
  89 having it's own control settings. Adjustable parameters include:
  90 * the layer beat,
  91 * the strength at which notes should be played,
  92 * the volume,
  93 * the instrument,
  94 * the beats per bar for the given layer,
  95 * the possibility to make the layer restart automatically after a
  96   certain number of bars, specifying if the layer should completly
  97   restart or not.
  98
  99 ### Note attributes
 100
 101 Each tile, whether it's inhabited by a token or note is attributed a
 102 repeat counter, telling how long a play head should stay on it.
 103
 104 For tiles inhabited by a token giving the possibility of a note being
 105 played, it is possible to adjust some parameters, including:
 106 * the note duration,
 107 * an articulation, allowing the note to be played stronger depending
 108   on its position in the bar,
 109
 110 **Warning:** *Though it appears a slide can be specified, it is for
 111 now a missing feature.*
 112
 113 ### Button semantics
 114
 115 The start/restart button has a particular semantic. Pressing the start
 116 button makes the machine start and turns the button into a restart
 117 button. When pressed it will restart all the layers but take into
 118 account the layer restart policy to know if it should completely
 119 restart the layer or simply add the start heads to the already running
 120 ones.
 121
 122 The stop button simply stops all the layers.
 123
 124 ### Missing features
 125
 126 This lists the buttons that have no effect but are yet present at the
 127 moment in the GUI. This features are being worked on in priority.
 128 * Recording a performance is not yet possible.
 129 * Configuration saving and loading is unavailable (soon to be fixed).
 130 * Slides are not implemented.
 131 * Tabs are not really named.
 132
 133 ### Future features
 134
 135 This lists the features that would be nice to add to the arpeggigon at
 136 some point:
 137 * a nicer GUI, with the possibility to display note names on the
 138   board, and see which note is being focused on.
 139 * a new “random split token”, that would redirect a play head in a
 140   random direction, or more generally split it in a random way.
 141 * an ALSA backend for Linux.
 142
 143 [reacTogon]:https://www.youtube.com/watch?v=AklKy2NDpqs
 144
 145 Copyright and license
 146 ---
 147
 148 Copyright 2016, Guerric Chupin and Henrik Nilsson.
 149
 150 The arpeggigon is licensed under the BSD 3-Clause License. A copy of
 151 the license is included in the [LICENSE](LICENSE) file.
 152
 153 Credits
 154 ---
 155
 156 We would like to thank the following people for their help, support
 157 and feedback on the arpeggigon:
 158 * Ivan Perez
 159 * Henning Thielemann
 160 * Michel Mauny
 161 * François Pessaux