function _init()
 local bgm=build_bgm()
 local free_patterns={}
 for i=4,63 do add(free_patterns,i) end

 bgm:build(free_patterns,0)

 cstore(0x3100,0x3100,0x1200)
 music(0)
end
function _update()
end
function _draw()
 cls(0)
 print("enjoy the music!")
end

function build_bgm()
 local bgm=track:new()

 bgm:add(32)
 bgm:add(32)
 bgm:add(32)
 bgm:add(32)

 local bassline=instrument:new(devil(8,2,7,4))
 local yowler=instrument:new(devil(9,2,7,4))
 local melo1=instrument:new(melo1)
 local drums=instrument:new(drums)
 local p0=performer:new(bgm,0,bassline,0,{10})
 local p1=performer:new(bgm,1,yowler,0,{10})
 local p2=performer:new(bgm,2,melo1,0,{10})
 local pd=performer:new(bgm,2,drums,0,{0})
 local ph=performer:new(bgm,2,drums,0,{0})
 --local pm=performer:new(bgm,2,melo1,0,{48-2})

 conductor:new(bgm,0):perform(
  {p0,p1,p2,pd,ph},
  pitchblocks:new(4)
   :add(8,{0,7,15,27})
   :add(4,{0,8,15,27})
   :add(4,{5,9,15,27})
   :add(8,{3,10,15,27})
   :add(4,{5,9,15,27})
   :add(4,{5,8,15,27})
  ,
  {
   "Aa.Aa.Aa.Aaa..Aa" .. "Aa.Aa.A.Aa..Aaaa",
   "Aa.BbbBbbAaa..Aa" .. "Aa.BbbBbbBbbBbbb",
   "Aa.CccCccAaa..Aa" .. "Aa.CccCccCccCccc",
   "@...!...@...!..." .. "@...!...@.@.!.@.",
   "..'...'...'...'." .. "..'...'...'...'."
  }
 )

 conductor:new(bgm,32):perform(
  {p0,p1,p2,pd,ph},
  pitchblocks:new(4)
   :add(4,{0,7,15,27})
   :add(4,{0,10,15,27})
   :add(4,{5,12,15,29})
   :add(4,{5,14,15,29})
   :add(4,{3,12,15,31})
   :add(4,{3,10,15,31})
   :add(4,{5,9,15,33})
   :add(4,{5,8,15,32})
  ,
  {
   "Aa.Aa.A.Aa..Aaab" .. "BA.Aa.Aa.Aa...Aa",
   "Bb.BbbBbbBbb..Cc" .. "Cc.BbbBbbBbbBbbb",
   "Cc.CccCccDdd..Dd" .. "Dd.DddDddDddDddd",
   "@.@.!.@.@.@.!.@." .. "@...!...@.@...@.",
   "..''..'...''..'." .. "..'...'...'...'."
  }
 )

 return bgm
end

function devil(w,e,v0,v1)
 return function(duration,pitch,verbs)
  local out={}
  for i=1,duration do
   local v=v1
   if (i == 1) v=v0
   out[i]=nflags:new{p=pitch,v=v,w=w,e=e}
  end
  if (verbs.slide and #out>0) out[1].e=1
  if (verbs.chop and #out>0) out[1].e=3
  return out
 end
end

function drums(duration,pitch,verbs)
 if verbs.kick then 
  return {
   -- kind of a cool sidechained bass effect, but not useful here
   -- nflags:new{p=10,v=7,w=8,e=0},
   -- nflags:new{p=0,v=5,w=8,e=1}

   nflags:new{p=19,v=7,w=10,e=0},
   -- nflags:new{p=12,v=5,w=2,e=0}
  }
 end
 if (verbs.snare) return {nflags:new{p=30,v=7,w=6,e=3}}
 if (verbs.hihat) return {nflags:new{p=30,v=2,w=11,e=3}}

 return {}
end

function melo1(duration,pitch,verbs)
 do return {} end
 local v=3
 local out={}
 for i=1,duration do
  out[i]=nflags:new{p=pitch,w=1,v=v,e=5}
 end
 return out
end