csound-expression-0.1.0: src/CsoundExpr/Tutorial/Orchestra.hs
-- | Guide to instrument-making
--
-- * Prev : "CsoundExpr.Tutorial.Composition"
--
-- * Next : "CsoundExpr.Tutorial.Limits"
module CsoundExpr.Tutorial.Orchestra (
-- * Instruments
{-|
Instruments are functions from some signal representation to signal.
'Score' is a 'Functor', so to play on instrument means to apply instrument
to 'Score' of its notes. Instrument can be made with opcodes.
Translator derives p-fields from instrument structure. There are only
two explicit p-fields 'itime' and 'idur' (@p2@ and @p3@ in csound).
-}
exmpInstr,
-- * Signals / Types
{-|
Signals are represented with trees. Tree contains information about how
signal was build.
There are five types for signals ("CsoundExpr.Base.Types").
'Arate' is audio rate signal
'Krate' is control rate signal
'Irate' is init value
'SignalOut' is no output at all (it's produced by opcodes like out, outs, xtratim)
'BoolRate' is comparision of two control or init rate signals
There are two classes to allow csound's polymorphism : 'X' and 'K'
'X' = 'Arate' | 'Krate' | 'Irate'
'K' = 'Krate' | 'Irate'
Csound's S - signal is represented with 'String'.
Ftable is represented with 'Irate'.
There are two special types 'MultiOut'
(for opcodes that may produce several outputs, see "CsoundExpr.Base.MultiOut")
and 'SideEffect'
(for opcodes that rely on number of appearances in csound code,
like @unirand@, see "CsoundExpr.Base.SideEffect")
-}
-- * Opcodes
{-|
Naming conventions : Opcodes are named after csound's counterparts usually.
Some opcodes in csound can produce signals of different rates by request (oscil, linseg).
Those opcodes are labelled with suffix. Suffix defines output rate of signal (oscilA, oscilK).
Some opcodes in csound have unfixed number of inputs due to setup parameters, almost all of them.
Those opcodes have first argument that is list of setup parameters.
example
>oscilA :: (X a, X b) => [Irate] -> a -> b -> Irate -> Arate
>oscilK :: (K a, K b) => [Irate] -> a -> b -> Irate -> Krate
-}
-- * Imperative style csound code
{-|
Most of csound opcodes can be used in functional way. You can plug them in one another,
and make expressions, but some of them behave like procedures and rely on order
of execution in instrument. Module "CsoundExpr.Base.Imperative" provides functions
to write imperative csound code.
'outList' - to sequence procedures
'(/<=/>)' - Assignment
'ar', 'kr', 'ir', 'gar', 'gkr', 'gir' - named values, to produce signal with specified name and rate.
Functional style :
>exmpInstr :: Irate -> SignalOut
>exmpInstr pch = out $ oscilA [] (num 1000) (cpspch pch) $ gen10 4096 [1]
Imperative style :
>exmpImper :: Irate -> SignalOut
>exmpImper pch = outList [
> ir "amp" <=> num 1000,
> ir "cps" <=> cpspch pch,
> ir "ft" <=> gen10 4096 [1],
> ar "sig" <=> oscilA [] (ir "amp") (ir "cps") (ir "ft"),
> out (ar "sig")]
-}
exmpImper,
-- * Arithmetic
{-|
You can use polymorphic operations to do some arihmetic on signals
from "CsoundExpr.Base.Arithmetic". And Signal is 'Num'. 'Eq' is undefined though.
-}
exmpArith,
-- * Preview
{-|
To see what will come out of an expression you can print it. Signal is 'Show'.
-}
exmpPreview,
-- * User Defined opcodes
{-|
You can add your own opcodes to library, see "CsoundExpr.Base.UserDefined"
-}
-- * MIDI
{-|
There are two ways to tell 'csd' to include instrument in csound file.
Instrument can be a part of 'Score' or it can be midi instrument, then it should
be mentioned in 'massign' or 'pgmassign' function. If you want to play midi-instr
for some time @t@, you can tell it to 'csd' function by invoking 'csd' with @'rest' t@
in place of 'EventList' value.
>flags = "-odac -iadc -+rtmidi=virtual -M0"
>
>header = [massign [] 1 instrMidi]
>
>instrMidi :: SignalOut
>instrMidi = out $ oscilA [] (num 1000) cpsmidi $ gen10 4096 [1]
>
>-- play instrMidi for 2 minutes
>exmpMidi = print $ csd flags header (rest 120)
-}
exmpMidi,
-- * Example
-- | Song, see src
main
)
where
import CsoundExpr.Base
import CsoundExpr.Base.Pitch
import CsoundExpr.Opcodes hiding (delay)
------------------------------------
exmpInstr :: Irate -> SignalOut
exmpInstr pch = out $ oscilA [] (num 1000) (cpspch pch) $ gen10 4096 [1]
exmpImper :: Irate -> SignalOut
exmpImper pch = outList [
ir "amp" <=> num 1000,
ir "cps" <=> cpspch pch,
ir "ft" <=> gen10 4096 [1],
ar "sig" <=> oscilA [] (ir "amp") (ir "cps") (ir "ft"),
out (ar "sig")]
exmpArith pch = out $ (env <*>) $ oscilA [] (num 1000) (cpspch pch) $ gen10 4096 [1]
where env = lineK 1 idur 0
exmpPreview = mapM_ print $ map ( $ (a 1)) [exmpInstr, exmpImper, exmpArith]
flagsMidi = "-odac -iadc -+rtmidi=virtual -M0"
header = [massign [] 1 instrMidi]
instrMidi :: SignalOut
instrMidi = out $ oscilA [] (num 1000) cpsmidi $ gen10 4096 [1]
-- play instrMidi for 2 minutes
exmpMidi = print $ csd flagsMidi header (rest 120)
----------------------------------------------------------------
----------------------------------------------------------------
-- Example
--
-- Song
--
mapSnd f (a, b) = (a, f b)
flags = "-d"
dot = stretch 1.5
wn = note 1
hn = note 0.5
qn = note 0.25
en = note 0.125
sinWave = gen10 4096 [1]
expWave = gen05 4096 [0.01, 4070, 1, 26, 0.01]
-- volume levels
--
v1 = 1.3 * v0
v0 = 10000
-- instruments
--
-- plucked
pluckInstr :: (Irate, Irate) -> SignalOut
pluckInstr (amp, pch) = outList [
out $ env <*> wgpluck2 0.75 amp (cpspch pch) (num 0.75) (num 0.5),
xtratim 1]
where env = linsegrK [0, idur * 0.05, 1, idur * 0.9, 1] 1 0
guitar = pluckInstr . mapSnd (+ (-1))
bass = pluckInstr . mapSnd (+ (-2))
-- drums
qCabasa = out $ cabasa [] 9000 0.01
qBamboo = out $ bamboo [] (num 2500) 0.01
shh = out $ (env <*> ) $ fst $ se1 $ unirandA (num 1000)
where env = exponK 1 idur 0.001
-- aahs
aahs :: Dur -> (Irate, Irate) -> SignalOut
aahs t (amp, pch)
| t < tShort = out $ env1 <*> osc pch
| otherwise = outList [out $ env2 <*> osc pch, xtratim 1]
where osc x = oscilA [] amp (cpspch x) tab
env1 = linsegK $ norm (ps ++ [0.025, 0])
env2 = linsegrK (norm $ ps ++ [0.025, 1]) 1 0
norm = zipWith (<*>) (cycle [1, idur])
tab = gen10 4096 [1, 0.7, 0.2, 0.7]
tShort = 0.6/2
ps = [0, 0.5, 0.2, 0.25, 0.3, 0.125, 0.5, 0.1, 1 :: Irate]
-- piece
--
-- chords
bassChord, guitarChord :: (Irate, Irate, Irate, Irate) -> Score (Irate, Irate)
bassChord (n1, _, _, _) = loop 4 $ line $ map en [(v1, n1), (v0, n1), (v0, n1), (v0, n1)]
guitarChord (n1, n2, n3, n4) = line $ [qn (v1, n1)] ++
map (dot . qn) [(v0, n3), (v0, n2), (v1, n4), (v0, n3)] ++ [qn (v0, n4)]
ch1 = (b (-1), d 0, a 0, cs 1)
ch2 = ( d 0, fs 0, cs 1, d 1)
ch3 = (g (-1), a (-1), fs 0, g 0)
chordSeq = line $ map wn [ch1, ch2, ch1, ch3]
-- solo
soloNotes :: [Irate] -> Score (Irate, Irate)
soloNotes notes = stretch 2 $
(line $ map return notes) >>= pulse
pulse :: Irate -> Score (Irate, Irate)
pulse = line . zipWith note durs . zip vols . repeat
where vols = map ((0.3 * v0) *) [0.2, 0.4, 0.6, 0.8, 0.6, 0.4]
durs = norm [1, 1.2 , 1, 1, 1, 1.5]
norm xs = map ( /sum xs) xs
-- scores
scoBamboo = stretch 0.5 $ loop 15 $ delay 1 $ line $ map (note 1) $ replicate 3 qBamboo
scoCabasa = loop (4*16) $ line [rest 0.25, qn qCabasa]
scoShh = delay 2 $ loop 8 $ line [wn shh, rest 3]
scoDrums = chord [scoBamboo, delay 12 scoCabasa, delay 12 scoShh]
scoGuitar = fmap guitar $ chordSeq >>= guitarChord
scoBass = fmap bass $ chordSeq >>= bassChord
accomp = chord [
delay 4 $ loop 5 scoGuitar,
delay 12 $ loop 4 scoBass,
scoDrums]
scoAahs1 = loop 2 $ tmap aahs $ soloNotes [d 1, cs 1, e 0, fs 0]
scoAahs2 = loop 2 $ tmap aahs $ soloNotes [d 1, cs 1, a 0, d 0]
scoAahs3 = loop 2 $ tmap aahs $ soloNotes [a 0, cs 1, g 0, fs 0]
solo = delay 20 $ chord [
scoAahs1,
delay 5 $ stretch 1.3 scoAahs2,
delay 7 $ stretch 1.5 scoAahs3]
sco = stretch 2.0 $ chord [solo, accomp]
main = print $ csd flags headerMono $ toList sco