src/RMCA/Layer/Board.hs

   1 {-# LANGUAGE Arrows #-}
   2
   3 module RMCA.Layer.Board where
   4
   5 import FRP.Yampa
   6 import RMCA.Auxiliary
   7 import RMCA.Layer.Layer
   8 import RMCA.Semantics
   9
  10 data BoardRun = BoardStart | BoardStop deriving Eq
  11
  12 singleBoard :: [PlayHead]
  13             -> SF (Board, Layer, Event BeatNo) (Event ([PlayHead], [Note]))
  14 singleBoard iPh = proc (board, Layer { relPitch = rp
  15                                      , strength = s
  16                                      }, ebno) ->
  17   accumBy advanceHeads' (iPh,[]) -< ebno `tag` (board, fromEvent ebno, rp, s)
  18   where advanceHeads' (ph,_) (board,bno,rp,s) = uncurry5 advanceHeads (board,bno,rp,s,ph)
  19
  20 boardSF :: SF (Board, Layer, Tempo, BoardRun) (Event ([PlayHead], [Note]))
  21 boardSF = proc (board, l, t, br) -> do
  22   ebno <- layerMetronome -< (t,l)
  23   ess <- onChange -< br
  24   boardSwitch [] -< ((board, l, ebno), ess `tag` (br, startHeads board))
  25
  26 boardSwitch :: [PlayHead]
  27             -> SF ((Board, Layer,Event BeatNo), Event (BoardRun, [PlayHead]))
  28                (Event ([PlayHead],[Note]))
  29 boardSwitch rPh = dSwitch (singleBoard rPh *** (identity >>> notYet)) fnSwitch
  30   where fnSwitch (BoardStart, iPh) = boardSwitch iPh
  31         fnSwitch (BoardStop, _) = boardSwitch []