fn-commands

Lua library for describing chart content of Falling Nikochan.

Falling Nikochan uses this library with Lua 5.4 internally, but it does not depend on other libraries and can be used in any Lua environment.

API

Chart Data

require("fn-commands")
return fnChart({
  version = "0.2", -- fn-commands library throws error if this is newer than library version
  offset = 0.5,
  ytId = "123456789ab",
  title = "song title",
  composer = "song composer",
  chartCreator = "chart creator",
  zoom = 0, -- only used in chart editor
  levels = {
    {
      name = "optional level name",
      type = "Single",
      unlisted = false,
      ytBegin = 0,
      ytEndSec = 10,
      ytEnd = "note", -- only used in chart editor
      snapDivider = 4, -- only used in chart editor
      content = function() -- LEVEL_CODE_BEGIN --
        BPM(170)
        -- ...
      end, -- LEVEL_CODE_END --
    },
  },
  copyBuffer = {
    ["0"] = { -3, 1, 3, false, true },
    ["1"] = nil,
    -- ...
  },
})

Executing this will give you data that matches the Chart15 format used by the /api/chartFile API, except that the lua field is missing. Please insert the lua field as shown below, using a regular expression to extract the content portion of the original code:

{
  ...luaExecResult,
  lua: rawCode.match(/LEVEL_CODE_BEGIN(?:(?!LEVEL_CODE_BEGIN)[\w\W])\*?LEVEL_CODE_END/g) ?? [],
}

Level Data

• Note(x, vx, vy, big, fall): Places a note.
  • Specify x, vx, vy as numbers, and big, fall as true or false.
• Step(a, b): Represents a rest for a b-note.
  • a must be an integer greater than or equal to 0, and b must be an integer greater than or equal to 1.
• BPM(bpm value): Changes the BPM. Must be a positive number.
• Accel(speed value): Changes the speed. 0 and negative values can also be used.
• AccelBegin(speed value) 〜 AccelEnd(speed value): Smooth speed change.
  • (Due to specifications, Accel and AccelBegin are the same. The change starts from the last Accel or AccelBegin before AccelEnd.)
• Beat(beat) or Beat(beat, a, b): Changes the beat.
  • For example, {{4, 4, 4, 4}} is 4/4 beat, {{4, 4, 4, 8}} is 7/8 beat, {{4, 4, 4, 4}, {4, 4, 4}} is 4/4 + 3/4 beat.
    • (Counts from left to right, the opposite of )
  • You can specify a beat count offset ( a / b ) after the beat. a is an integer 0 or greater, and b is an integer 1 or greater.

Running Tests

luarocks test --local