Generate EDM (but the code is bad)

shared/performer.lua

@@ -8,6 +8,7 @@ function performer:init(track,channel,instrument,time,roots)
  self.time=time
  self.roots=roots
  self.selected_root=1
+ self.offset=0
 end
 
 function performer:root(root)
@@ -16,7 +17,7 @@ function performer:root(root)
 end
 function performer:play(duration,note,verbs)
  local base=self.roots[self.selected_root]
- local note=base+note
+ local note=base+note+self.offset
  local t0=self.time
  local t1=t0+duration
  self.time+=duration