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Corrections to the beat generation.
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1 {-# LANGUAGE Arrows, TupleSections #-}
2
3 module RMCA.Translator.Translator where
4
5 import Control.Arrow
6 import Data.Function (on)
7 import qualified Data.IntMap as M
8 import Data.List (groupBy, sortBy)
9 import Data.Maybe
10 import Data.Ord
11 import Data.Ratio
12 import FRP.Yampa
13 import RMCA.Global.Clock
14 import RMCA.Semantics
15 import RMCA.Translator.Message
16
17 messageToNote :: Message -> Note
18 messageToNote (NoteOn _ p s) = Note { notePch = p
19 , noteStr = s
20 , noteDur = 1 % 4
21 , noteOrn = noOrn
22 }
23 messageToNote m = error $ "In messageToNote: the message "
24 ++ show m ++ " is not a note message"
25
26 -- noteToMessage gives a pair of two time-stamped messages. The one on
27 -- the left is a note message, the other a note off.
28 noteToMessages :: SampleRate
29 -> Int -- channel number
30 -> LTempo
31 -> (Frames,Note)
32 -> [(Frames,Message)]
33 noteToMessages sr chan lt (t,n@Note { noteDur = d })
34 | d == 0 = []
35 | otherwise = [(t,nm),(t + dn,switchOnOff nm)]
36 where nm = noteOnToMessage chan n
37 dt :: Double
38 dt = fromRational (d * toRational (tempoToQNoteIvl lt))
39 dn = floor $ dt * fromIntegral sr
40
41 noteOnToMessage :: Int -> Note -> Message
42 noteOnToMessage c Note { notePch = p
43 , noteStr = s
44 } = NoteOn (mkChannel c) p s
45
46 sortRawMessages :: [(Frames, RawMessage)]
47 -> ([(Frames,Message)], [(Frames,RawMessage)])
48 sortRawMessages = sortRawMessages' ([],[])
49 where sortRawMessages' r [] = r
50 sortRawMessages' (m, rm) (x@(n,xm):xs)
51 | isNothing nm = sortRawMessages' (m, x:rm) xs
52 | otherwise = sortRawMessages' ((n,fromJust nm) :m, rm) xs
53 where nm = fromRawMessage xm
54
55 -- Direct each message to a specific channel.
56 -- /!\ To be modified.
57 sortChannel :: [Message] -> [(Int,[Message])]
58 sortChannel = map ((,) <$> (fst . head) <*> map snd)
59 . groupBy ((==) `on` fst) . map sortChannel'
60 where sortChannel' :: Message -> (Int, Message)
61 sortChannel' m = let c = getChannel m in (c,m)
62
63 -- NoteOn messages are on the right, other Control messages are on the
64 -- left. For now we throw away NoteOff messages.
65 sortNotes :: [(Frames, Message)]
66 -> ([(Frames,Message)], [(Frames,Message)])
67 sortNotes = sortNotes' ([],[])
68 where sortNotes' r [] = r
69 sortNotes' (n, c) (x@(_,m):xs)
70 | isNoteOn m = sortNotes' (x:n, c) xs
71 | isNoteOff m = sortNotes' (n,c) xs
72 | isControl m = sortNotes' (n,x:c) xs
73 | otherwise = sortNotes' (n,c) xs
74
75 -- Note messages are converted to PlayHeads
76 convertMessages :: [(Frames,Message)] -> [(Frames,Note)]
77 convertMessages = map (second messageToNote)
78
79
80 -- Uses function defined in SortMessage. This is a pure function and
81 -- it might not need to be a signal function.
82 readMessages' :: [(Frames,RawMessage)]
83 -> ([(Frames,Note)], [(Frames,Message)], [(Frames,RawMessage)])
84 readMessages' = proc r -> do
85 (mes, raw) <- sortRawMessages -< r
86 (notes, ctrl) <- first convertMessages <<< sortNotes -< mes
87 returnA -< (notes, ctrl, raw)
88
89 readMessages :: SF [(Frames, RawMessage)]
90 ([(Frames,Note)], [(Frames,Message)], [(Frames,RawMessage)])
91 readMessages = arr readMessages'
92 {-
93 gatherMessages' :: LTempo
94 -> SampleRate
95 -> Int
96 -> ([(Frames,Note)],[(Frames,Message)],[(Frames,RawMessage)])
97 -> [(Frames, RawMessage)]
98 gatherMessages' layTempo sr chan = proc (notes, ctrl, raw) -> do
99 notes' <- concat <<< map (noteToMessages layTempo sr chan) -< notes
100 rawNotes <- map (second toRawMessage) -< notes'
101 rawCtrl <- map (second toRawMessage) -< ctrl
102 returnA -< rawNotes ++ rawCtrl ++ raw
103
104 gatherMessages :: SF
105 ( LTempo, SampleRate, Int
106 , ([(Frames,Note)],[(Frames,Message)],[(Frames,RawMessage)]))
107 [(Frames, RawMessage)]
108 gatherMessages = arr $ uncurry4 gatherMessages'
109 -}
110
111 gatherMessages :: SampleRate
112 -> Tempo
113 -> M.IntMap ([Note],[Message])
114 -> M.IntMap [(Frames,RawMessage)]
115 gatherMessages sr t = M.map (map (second toRawMessage)) .
116 M.mapWithKey gatherMessages'
117 where gatherMessages' :: Int
118 -> ([Note],[Message])
119 -> [(Frames,Message)]
120 gatherMessages' chan (notes,messages) =
121 zip (repeat 0) messages ++
122 concatMap (noteToMessages sr chan t . (0,)) notes
123
124 -- Takes a list of time stamped "things", a sample rate and a buffer
125 -- size. The function argument is a function that needs to tell which
126 -- arguments are kept in the case where two would come into
127 -- contact. On the left are the events that can be thrown into the
128 -- buffer, on the right are the events that will need to wait. Both
129 -- list are sorted.
130 --
131 -- /!\ The frame number is relative. A preprocessing operation
132 -- removing all events too soon to be happening and shifting them is
133 -- necessary.
134 schedule :: Frames
135 -> [(Frames, a)]
136 -> ([(Frames,a)], [(Frames,a)])
137 schedule size = {-first scatterEvents
138 . -}break ((>= size) . fst) . sortBy (comparing fst)
139
140 -- When to events are at the same frame, shift them so that they are
141 -- all separated by one frame. Then take every list and make sure that
142 -- the first frame of the next list is at least one frame after the
143 -- last frame of that list.
144 scatterEvents :: [(Frames, a)] -> [(Frames, a)]
145 scatterEvents (x@(n,_):(m,b):xs) = x:scatterEvents ((m',b):xs)
146 where m' = m + max 0 (1 + n - m)
147 scatterEvents [x] = [x]
148 scatterEvents _ = []