# atlas.ludic — render a Kenney tile pack as one index-labeled sheet, so you can
# see which sprite id is which before referring to it in a game.
#
#   bin/ludicc --headless tools/atlas.ludic -o build/atlas
#   ./build/atlas < /dev/null && sips -s format png build/out.ppm --out atlas.png
#
# A tool written in the language it is a tool for: one Start handler draws every
# tile with its number underneath and quits, and the headless build leaves the
# frame in build/out.ppm.
program Atlas {
  const DIR: string = "assets/kenney/tiny-dungeon/Tiles"
  const TILE_COUNT: int = 132          # tile_0000.png … tile_0131.png
  const COLUMNS: int = 12
  const CELL: int = 24
  const SPRITE_INSET_X: int = 4        # centre a 16px sprite in a 24px cell
  const SPRITE_INSET_Y: int = 2
  const LABEL_INSET_X: int = 1
  const LABEL_INSET_Y: int = 18
  const BACKDROP: int = 0x101018
  const LABEL_COLOR: int = 0x8090b0

  # "<DIR>/tile_0007.png" — the id is the file's zero-padded number
  function tile_path(i: int) -> string {
    var digits = Text.from_int(i)
    while Text.length(digits) < 4 { digits = "0" + digits }
    return `{DIR}/tile_{digits}.png`
  }

  handler Sheet phase Start {
    Screen.clear(BACKDROP)
    for i in 0 .. TILE_COUNT {
      let x = (i % COLUMNS) * CELL
      let y = (i / COLUMNS) * CELL
      let id = Assets.image(tile_path(i))
      if id >= 0 { Screen.sprite(id, x + SPRITE_INSET_X, y + SPRITE_INSET_Y) }
      Screen.draw_number(x + LABEL_INSET_X, y + LABEL_INSET_Y, i, LABEL_COLOR, 1)
    }
    Screen.show()
    quit()
  }
}