playt1 prototype

local byte = string.byte --chr, index
local char = string.char
local concat = table.concat --table, separator, [i], [j]
local min = math.min
local unpack = table.unpack

local mon = peripheral.find("monitor")
assert(mon, "no monitor found")





local function resolveInvLine(s)
  local chars = {}
  for i=1, #s do
    chars[#chars+1] = char(319-byte(s,i))
  end
  return concat(chars,"")
end





local function writeWrap(monitor, str, col, row, w)
  local f = 1
  local len = str:len()

  local diff = w-col+1
  local len2 = min(diff,len)
  local line = str:sub(f,f+len2-1)
  monitor.write(line)

  f=f+len2
  col=col+len2


  if len-len2 ~= 0 then
    for i=f, len, w do
      col=1
      row=row+1
      monitor.setCursorPos(1,row)

      line = str:sub(i,i+w-1)
      monitor.write(line)
      col=col+line:len()

    end

    if col > w then
      col=1
      row=row+1
      monitor.setCursorPos(1,row)
    end

  end


  return col, row

end





local function drawFrame(monitor, inputFile, _w, _h)
  if monitor.setTextScale then
    monitor.setTextScale(0.5)
  end

  local w, h  =  monitor.getSize()
  if _w then  w = _w  end
  if _h then  h = _h  end

  local str = inputFile:read(w*h)
  if not str then return false end



  local length          = str:len()
  local inverted        = byte(str,1) >= 160
  local firstIsInverted = inverted

  local   i, j  =  0, 1
  local chunks  =  {}

  while i <= length do
    while not inverted do
      i=i+1
      if i > length then break end
      if byte(str,i) >= 160 then
        chunks[#chunks+1] = str:sub(j,i-1)
        j=i
        inverted = true
      end
    end

    while inverted do
      i=i+1
      if i > length then break end
      if byte(str,i) < 160 then
        chunks[#chunks+1] = resolveInvLine(str:sub(j,i-1))
        j=i
        inverted = false
      end
    end

  end


  if i ~= j then
    if not inverted then
      chunks[#chunks+1] = str:sub(j,i-1)
    else
      chunks[#chunks+1] = resolveInvLine(str:sub(j,i-1))
    end
  end



  monitor.setBackgroundColor(colors.black)
  monitor.setTextColor(colors.white)
  --causes bottom-side screen artifacts
   --in the event of render lag
  --monitor.clear()
  inverted = false

  if firstIsInverted then
    monitor.setBackgroundColor(colors.white)
    monitor.setTextColor(colors.black)
    inverted = true
  end



  local col, row  =  1, 1
  monitor.setCursorPos(1,1)


  for c=1, #chunks do
    col, row = writeWrap(monitor, chunks[c], col, row, w)

    inverted = not inverted
    if not inverted then
      monitor.setBackgroundColor(colors.black)
      monitor.setTextColor(colors.white)
    else
      monitor.setBackgroundColor(colors.white)
      monitor.setTextColor(colors.black)
    end

  end



  return true

end





local argv = {...}
if not argv[1] then argv[1] = "konosuba_20.kv3" end

local file = io.open(argv[1], "rb")
assert(file, "failed to open file")


local nolag = true

while true do
  local timeStart = os.time()

  if not drawFrame(mon, file) then break end

  local timeDiff = os.time()-timeStart
  print(nolag, timeDiff)

  if timeDiff < 0.000001 then
    os.sleep(0.05) --1 tick
  else
    nolag = false
  end

end


file:close()