your-own-drum/recorder.lua

--Record demos.
local love = love
local recorder = {}
recorder.isLoaded = false
local ddxs, ddys
local i = 0

function recorder.Reset()
  i = 1
  for k, _ in ipairs( recorder ) do recorder[k] = nil end
end

function recorder.Update( ddx, ddy )
  i = i + 1
  recorder[i] = love.data.pack( "string", "!16<dd", ddx, ddy )
end

--[[function recorder.Update( ddx, ddy )
  local byte = 0
  if ddx > 0.5 then byte = byte + 1 end
  if ddy > 0.5 then byte = byte + 2 end
  if ddx < -0.5 then byte = byte + 4 end
  if ddy < -0.5 then byte = byte + 8 end
  
  i = i + 1
  recorder[i] = string.char( byte + 48 )
end]]

function recorder.Load( filename )
  ddxs, ddys = {}, {}
  local s = love.filesystem.read( filename )
  if not s then return end
  local j = 1
  local score, ticks, k = love.data.unpack( "!16<dJ", s, 1)
  local n = s:len()
  while k < n do
    ddxs[j], ddys[j], k = love.data.unpack( "!16<dd", s, k)
    j = j + 1
  end
  recorder.isLoaded = true
  i = 0
  
  return true
end

function recorder.NextTick( )
  i = i + 1
  return ddxs[i], ddys[i]
end

function recorder.Save( score, ticks )
  recorder[1] = love.data.pack( "string", "!16<dJ", score, ticks )
  love.filesystem.createDirectory( "demos" )
  return assert( love.filesystem.write( "demos/"..os.time()..".yod" , table.concat( recorder ) ) )
end

return recorder