diff options
Diffstat (limited to 'applause.lua')
| -rw-r--r-- | applause.lua | 23 |
1 files changed, 19 insertions, 4 deletions
diff --git a/applause.lua b/applause.lua index 2bab871..abb17f3 100644 --- a/applause.lua +++ b/applause.lua @@ -1678,24 +1678,39 @@ end function Stream:ftom() return self:map(ftom) end +-- Tick an instrument only when an inputstream (note_stream), +-- gets ~= 0. When it changes back to 0 again, an "off"-stream +-- is triggered. This allows the construction of instruments with +-- Attack-Sustain and Decay phases based on real-time control signals. +-- The note values can be passed into the constructor by using functions +-- for the "on" and "off" streams. +-- Usually, the note stream will be a MIDIVelocityStream, so the two +-- instrument streams can be based on the MIDI velocity (but don't have +-- to be if the velocity is not important). InstrumentStream = DeriveClass(MuxableStream) InstrumentStream.sig_last_stream = 1 function InstrumentStream:muxableCtor(note_stream, on_stream, off_stream) - self.note_stream = tostream(note_stream):cache() + note_stream = tostream(note_stream) + local note_stream_cached if type(on_stream) == "function" then - self.on_stream = on_stream(self.note_stream) + note_stream_cached = note_stream:cache() + self.on_stream = on_stream(note_stream_cached) else self.on_stream = tostream(on_stream) end if type(off_stream) == "function" then - self.off_stream = off_stream(self.note_stream) + note_stream_cached = note_stream_cached or note_stream:cache() + self.off_stream = off_stream(note_stream_cached) else -- The "off" stream is optional self.off_stream = off_stream and tostream(off_stream) end + + -- `note_stream` is cached only when required + self.note_stream = note_stream_cached or note_stream end function InstrumentStream:gtick() @@ -1720,7 +1735,7 @@ function InstrumentStream:gtick() -- FIXME: This is not strictly real-time safe on_tick = nil - off_tick = off_stream and off_stream:gtick() + if off_stream then off_tick = off_stream:gtick() end return off_tick() or 0 end end |