Chunks

Planetary Processing works by dividing your world into chunks. Chunks are cuboid segments of the world of fixed width and depth, and of infinite height.

Chunk Information

One can access information about the current chunk from the global variable 'chunk'.

Field	Type	Description
X	int	X coordinate in chunk space (world x coordinate divided by chunk size).
Y	int	Y coordinate in chunk space (world y coordinate divided by chunk size).
Size	int	Size of the chunk in world units.
Generated	bool	Indicates whether or not this chunk has been loaded before. This should not be used outside of the init function (see below).
Dimension	string	ID of the current dimension.

Initialising a Chunk

You may have noticed the existence of a file called init.lua in the root of your game's git repository. This should contain a function called init which is called whenever this chunk is loaded and is designed to initiate the state of this chunk.

Below is the example from the template that comes pre-installed in your repository. You can see that we spawn things only if chunk.Generated is false, this is to ensure we only spawn things on the first load. However, in a game where state is not persisted (i.e. entities have entity.Transient = true, this might be useful on every load).

--[[ init is called every time a chunk is loaded
if the chunk has been loaded before then chunk.Generated will be true, else it will be false ]]
function init()
  -- do this block of code if the chunk is at (0,0) in chunk space and has not been generated yet
  if chunk.X == 1 and chunk.Y == 1 and not chunk.Generated then
    for i=1,20 do
      -- type, x, y, z, data
      -- type must match the name of one of the lua files in entity folder of this repo
      -- data is an arbitrary lua table
      api.entity.Create("cat", -35, 25, 1, {name="jar jar "..i})
    end
  end
  if not chunk.Generated then
    for i=1,math.random(4) do
      --[[ create some tree entities at random locations
      'math' and other standard lua library functions (excluding io/os operations) are included ]]
      api.entity.Create("tree", chunk.X*chunk.Size + math.random()*chunk.Size, chunk.Y*chunk.Size + math.random()*chunk.Size, 1, {})
    end
  end
end