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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 **WARNING:** to run, the Arpeggigon needs a running Jack server. If it cannot
39 find one on startup it will crash. Experience has shown that it can be quite
40 difficult to set up such a server, however there are good tools and tutorials
41 online to help you with that task, in particular
42 [qjackctl](https://qjackctl.sourceforge.io/) often does a good job at easing
43 it.
44
45 **WARNING (bis):** as will be stated after, the Arpeggigon is a MIDI event
46 producer, therefore it needs to be connected to a synthetizer to produce music.
47 Again, [qjackctl](https://qjackctl.sourceforge.io/) makes this task quite easy,
48 but it is also possible to do it via the command line.
49
50 Description
51 ---
52
53 ### The reacTogon
54
55 The [reacTogon][] is a musical instrument invented based upon
56 the
57 [harmonic table](https://en.wikipedia.org/wiki/Harmonic_table_note_layout),
58 a way of arranging notes where the various directions correspond to
59 meaningful musical intervals. From that layout, the reacTogon defines
60 an automaton: tokens of different kinds interact with *play heads*
61 moving around on the board, altering their directions and eventually
62 playing a note.
63
64 The arpeggigon is an extended reacTogon. It is for instance possible
65 to have multiple layers with different characteristics running in
66 parallel, or to modify the way individual notes should be played, etc.
67
68 ### Music generation
69
70 The arpeggigon doesn't directly produce music, but is
71 a
72 [MIDI](https://en.wikipedia.org/wiki/MIDI) [JACK](http://jackaudio.org/) client. It
73 then requires a JACK server to run when it is launched and to be
74 connected to a MIDI synthetizer to produce music.
75
76 ### Tokens
77
78 There are five kinds of tokens currently supported, that appear in the
79 following order in the arpeggigon's GUI:
80 * ricochet token: plays a note and reorients the play head toward the
81 direction it's pointing to,
82 * start token: like the ricochet token but generated an impulsion when
83 the machine starts,
84 * stop token: plays a note and makes the play head disappear,
85 * absorb token: like the stop token but doesn't play any note,
86 * split token: splits the impulsion into five.
87
88 ### Multiple layers
89
90 It is possible to have multiple layers running in parallel, each one
91 having it's own control settings. Adjustable parameters include:
92 * the layer beat,
93 * the strength at which notes should be played,
94 * the volume,
95 * the instrument,
96 * the beats per bar for the given layer,
97 * the possibility to make the layer restart automatically after a
98 certain number of bars, specifying if the layer should completly
99 restart or not.
100
101 ### Note attributes
102
103 Each tile, whether it's inhabited by a token or note is attributed a
104 repeat counter, telling how long a play head should stay on it.
105
106 For tiles inhabited by a token giving the possibility of a note being
107 played, it is possible to adjust some parameters, including:
108 * the note duration,
109 * an articulation, allowing the note to be played stronger depending
110 on its position in the bar,
111
112 **Warning:** *Though it appears a slide can be specified, it is for
113 now a missing feature.*
114
115 ### Button semantics
116
117 The start/restart button has a particular semantic. Pressing the start
118 button makes the machine start and turns the button into a restart
119 button. When pressed it will restart all the layers but take into
120 account the layer restart policy to know if it should completely
121 restart the layer or simply add the start heads to the already running
122 ones.
123
124 The stop button simply stops all the layers.
125
126 ### Missing features
127
128 This lists the buttons that have no effect but are yet present at the
129 moment in the GUI. This features are being worked on in priority.
130 * Recording a performance is not yet possible.
131 * Configuration saving and loading is unavailable (soon to be fixed).
132 * Slides are not implemented.
133 * Tabs are not really named.
134
135 ### Future features
136
137 This lists the features that would be nice to add to the arpeggigon at
138 some point:
139 * a nicer GUI, with the possibility to display note names on the
140 board, and see which note is being focused on.
141 * a new “random split token”, that would redirect a play head in a
142 random direction, or more generally split it in a random way.
143 * an ALSA backend for Linux.
144
145 [reacTogon]:https://www.youtube.com/watch?v=AklKy2NDpqs
146
147 Copyright and license
148 ---
149
150 Copyright 2016, Guerric Chupin and Henrik Nilsson.
151
152 The arpeggigon is licensed under the BSD 3-Clause License. A copy of
153 the license is included in the [LICENSE](LICENSE) file.
154
155 Credits
156 ---
157
158 We would like to thank the following people for their help, support
159 and feedback on the arpeggigon:
160 * Ivan Perez
161 * Henning Thielemann
162 * Michel Mauny
163 * François Pessaux