Saving a table (containing many other tables, btw)

[Maggots]

I made a kind of level editor that lets you choose what image you want to use to make a platform,
using a grid and all that good stuff, and it puts all the bodies, shapes and what-not into a table.

Everything works very well, but I'm having trouble wrapping my head around how I can save a table to a text file. Also, I'm quite
new to Lua, so please try not to suggest anything that may be too hard for me

If it's any help, here's my code.
Beware, it's not very organized (in my opinion anyway).

Code: Select all

function love.load()
	editor = {}--Create a table to hold all the editor elements
	editor.grids = {}--Create a table to hold the grid bodies and shapes
	editor.gridOn = true--Is the grid on or not?
	editor.gridWorld = love.physics.newWorld(960,704)--Create a world to hold the grids.
	editor.gridWorld:setMeter(64)
	editor.gridWorld:setGravity(0,0)
	--It's better when it's a multiple of 64.
	editor.mode = "blocks"
	editor.modes = {}
	editor.modes[1] = "blocks"
	editor.modes[2] = "objects"
	createGrid()

	map = {}--Create a table to hold all the map elements
	map.materials = {--Table to hold the images used for blocks
		woodfloor = love.graphics.newImage("materials/wood-floor.png"),
		grassdirt = love.graphics.newImage("materials/grass-dirt.png"),
		testplatform = love.graphics.newImage("materials/testplatform.png"),
		boxfloor = love.graphics.newImage("materials/box-floor.png"),
		metalwall = love.graphics.newImage("materials/metal-wall.png"),
		brickwall = love.graphics.newImage("materials/brick-wall.png"),
		spacefloor = love.graphics.newImage("materials/space1-floor.png"),
	}
	map.blocks = {--Table to hold all the data for the static blocks (or just blocks)
	--w = width, h = height, ox = offset x, oy = offset y
		[1] = {i = map.materials.woodfloor, w = 64, h = 64, ox = 32, oy = 32, m = 0},
		[2] = {i = map.materials.grassdirt, w = 64, h = 64, ox = 32, oy = 32, m = 0},
		[3] = {i = map.materials.testplatform, w = 64, h = 64, ox = 32, oy = 32, m = 0},
		[4] = {i = map.materials.boxfloor, w = 64, h = 64, ox = 32, oy = 32, m = 0},
		[5] = {i = map.materials.metalwall, w = 64, h = 64, ox = 32, oy = 32, m = 0},
		[6] = {i = map.materials.brickwall, w = 64, h = 64, ox = 32, oy = 32, m = 0},
		[7] = {i = map.materials.spacefloor, w = 64, h = 64, ox = 32, oy = 32, m = 0},
	}
	map.objects = {}--Table to hold all the objects
	map.entities = {}--Table to hold all the entities in the map.
	map.entitynum = 0
	map.world = love.physics.newWorld(960,704)
	map.world:setMeter(64)
	map.world:setGravity(0,0)

	editor.mat = map.blocks[1]
	editor.matn = 1
	editor.obj = nil
	editor.objn = 1

	love.graphics.setLineWidth(2)--Thicker lines
	editor.font = love.graphics.newFont(20)
	love.graphics.setFont(editor.font)

	love.graphics.setMode(1440,800)--Set the resolution to 1440*800
	love.graphics.setCaption("Level Editor")
end

function love.update(dt)
	editor.gridWorld:update(dt)--Update the grid.
	map.world:update(dt)--Update the map

	if love.mouse.isDown("l") and editor.hitGrid == true and editor.selectGrid.occupied == false then
		addBlock(editor.selectGrid)
	end

	if love.mouse.isDown("r") and editor.hitGrid == true and editor.selectGrid.occupied == true then
		removeBlock(editor.selectGrid)
	end

	if love.keyboard.isDown('g') then--Turn on the grid when G is pressed.
		if editor.gridOn == false then
			editor.gridOn = true
		elseif editor.gridOn == true then
			editor.gridOn = false
		end
		love.timer.sleep(100)--To stop the grid from flickering
	end
end

function love.draw()
	editor.hitGrid, editor.selectGrid = hoverGrid()
	love.graphics.setColor(255,255,255)
	if editor.gridOn == true then--Draw the grid if it's on
		drawGrid()
	end

	for i,v in pairs(map.entities) do--Draw all the map entities
		love.graphics.draw(v.i, v.b:getX(), v.b:getY(), v.b:getAngle(), 1, 1, v.ox, v.oy)
	end

	showBlock()

	printMode()
end

function drawGrid()--Draw the grid lines
	love.graphics.setColor(255,255,255)
	for a = 0, 14 do
		for n = 0, 10 do
			love.graphics.rectangle("line",a*64,n*64,64,64)
		end
	end
end

function createGrid()--Create bodies and shapes for the grids to detect when the mouse is placed on top of one of them
	for a = 1,15 do
		for n = 1, 11 do
			local t = {}
			t.b = love.physics.newBody(editor.gridWorld,a*64-32,n*64-32,0,0)
			t.s = love.physics.newRectangleShape(t.b,0,0,64,64,0)
			t.occupied = false
			t.entity = nil
			table.insert(editor.grids,t)
		end
	end
end

function hoverGrid()--Display a yellow square over the grid where the mouse is
	for i,v in pairs(editor.grids) do
		local mx,my = love.mouse.getPosition()
		local hit = v.s:testPoint(mx, my)
		if hit == true then
			love.graphics.setColor(255,255,0)
			love.graphics.rectangle("fill",v.b:getX()-32,v.b:getY()-32,64,64)
			return hit,v
		end
	end
end

function printMode()--Print the current brush mode
	love.graphics.setColor(0,150,255)
	love.graphics.print("Mode: "..editor.mode, 0, 800)
end

function showBlock()--Show the image of the currently selected block
	love.graphics.setColor(255,255,255)
	love.graphics.draw(editor.mat.i, 1100, 100, 0, 1, 1, editor.mat.ox, editor.mat.oy)
end

function love.keypressed(k)
	if k == "1" then--Use number keys to change the brush mode
		editor.mode = editor.modes[1]
	elseif k == "2" then
		editor.mode = editor.modes[2]
	end

	if k == "right" then--Use the arrow keys to change the selected block
		if editor.mode == "blocks" then
			editor.matn = editor.matn + 1
			if editor.matn > table.getn(map.blocks) then editor.matn = 1 end--Loop the list
			editor.mat = map.blocks[editor.matn]
		elseif editor.mode == "objects" then
			editor.objn = editor.objn + 1
			if editor.matn > table.getn(map.blocks) then editor.matn = 1 end--Loop the list
			editor.obj = map.blocks[editor.objn]
		end
	elseif k == "left" then--Use the arrow keys to change the selected block
		if editor.mode == "blocks" then
			editor.matn = editor.matn - 1
			if editor.matn < 1 then editor.matn = table.getn(map.blocks) end--Loop the list
			editor.mat = map.blocks[editor.matn]
		elseif editor.mode == "objects" then
			editor.objn = editor.objn - 1
			if editor.objn < 1 then editor.objn = table.getn(map.blocks) end--Loop the list
			editor.obj = map.blocks[editor.objn]
		end
	elseif k == "s" then table.save(map,"level.txt") end--ignore that!

end

function addBlock(grid)--Add a block to the map at the currently selected grid
	if editor.mode == "blocks" then
		local t = {}
		local x, y = grid.b:getPosition()
		t.b = love.physics.newBody(map.world, x, y, editor.mat.m, 0)
		t.s = love.physics.newRectangleShape(t.b,
											t.b:getX(),
											t.b:getY(),
											editor.mat.w,
											editor.mat.h,
											0)
		t.i = editor.mat.i
		t.ox = editor.mat.ox
		t.oy = editor.mat.oy
		table.insert(map.entities,t)
		grid.occupied = true
		map.entitynum = map.entitynum + 1
		grid.entity = map.entities[map.entitynum]
	elseif editor.mode == "objects" then
		local t = {}
		local x, y = grid.b:getPosition()
		t.b = love.physics.newBody(map.world, x, y, editor.obj.m, 0)
		t.s = love.physics.newRectangleShape(t.b,
											t.b:getX(),
											t.b:getY(),
											editor.obj.w,
											editor.obj.h,
											0)
		t.i = editor.obj.i
		t.ox = editor.obj.ox
		t.oy = editor.obj.oy
		table.insert(map.entities,t)
		grid.occupied = true
		map.entitynum = map.entitynum + 1
		grid.entity = map.entities[map.entitynum]
	end
end
function removeBlock(grid)--Remove a block
	local entity = grid.entity
	entity.b:setPosition(-10000,-10000)
	love.graphics.draw(entity.i, entity.b:getX(), entity.b:getY(), entity.b:getAngle(), 1, 1, entity.ox, entity.oy)
	table.remove(entity)
	grid.occupied = false
end

Thanks in advance!

[Fruchthieb]

Dont have read your code, I´m sorry, no time for that

Maybe you need something like the following

Code: Select all

	
tablefile = love.filesystem.newFile("filename")
tablefile:open('w')
tablefile:write("table = {} \n")
tablefile:write("table.dumdidum = 'value of dumdidum, this is a string for example' \n")

Iterating over lines should be clear. You should also be able to load the table with love.filesystem.load("filename").

Hope i could help. Regards! Fruchthieb.

[Maggots]

Thanks a lot! That does clear a lot of things up, but I'm worried about having to use a for loop to find all the data.

As for anybody else who may want to shed some more light on my situation, go ahead, I could probably use some.

[Fruchthieb]

Find data? Its a table, via loading it, you can use it as normal. Anyway, for finding data you might take a look at that: http://www.lua.org/manual/5.1/manual.html#5.4
Exspecially this function: string.find (s, pattern [, init [, plain]])
Regards!

[Maggots]

Well, I made a function that saves using this code:

Code: Select all

function saveLevel(filename)
	local f = love.filesystem.newFile(filename)
	f:open('w')
	f:write("map = {}\n")
	for i,v in pairs(map) do

		if type(v) == "table" then

		local subt = i

			for i,v in pairs(v) do

				if type(v) == "table" then

					local subt2 = i

					for i,v in pairs(v) do

						f:write("map."..subt.."."..subt2.."."..i.."="..tostring(v))

					end

				else f:write("map."..subt.."."..i.."."..tostring(v))

				end

			end

		else f:write("map."..i.."."..tostring(v))

		end

	end
end

But when I press the S button to save, it doesn't do anything. When I press it a second time, it tells me that I can't write to file, cause the file isn't open.

...Help?

[Benamas]

This is how I managed to do it, but I use a bizarre method to store my data by creating two discrete tables and then looking up an element by number in both.

Code: Select all

function loadhiscores()

  hiscore_scores = {} -- score
  hiscore_wizard = {} -- character used
  if love.filesystem.exists( "hiscores.txt" ) then
    -- read scores from file
    file = love.filesystem.newFile("hiscores.txt")
    file:open('r')
    currentline = file:lines()
    for i = 1, 10 do
      if file:eof() then -- Did something weird happen? BAIL OUT AND BS THE WHOLE THING
        hiscore_scores = { 1000, 900, 800, 700, 600, 500, 400, 300, 200, 100}
        hiscore_wizard = { 1, 2, 3, 2, 3, 2, 1, 2, 3, 2 }
        file:close()
        break
      end
      hiscore_wizard[i] = tonumber(currentline())
      hiscore_scores[i] = tonumber(currentline())
    end
    file:close()

  else
    -- BS ten scores from scratch
    hiscore_scores = { 1000, 900, 800, 700, 600, 500, 400, 300, 200, 100}
    hiscore_wizard = { 1, 2, 3, 1, 2, 3, 1, 2, 3, 1 }
  end

end

then later to save the file:

Code: Select all

  -- replace hiscores.txt with current tables in memory
    file = love.filesystem.newFile("hiscores.txt")
    file:open('w')
    for i = 1, 10 do
	file:write(hiscore_wizard[i] .. "\r\n")
	file:write(hiscore_scores[i] .. "\r\n")
    end
    file:close()

This ends up with each element in the table separated in the hiscore.txt by a linebreak, which is working just fine for me.

[Robin]

You might find one of these helpful: http://lua-users.org/wiki/TableSerialization

[Maggots]

Okay, I was playing around with the save function that I made... It doesn't work very well. I mean, I tell it to save every table and variable's data.
Sadly, it doesn't show me all the data. Instead of showing me something like

Code: Select all

map.entities[4].image = map.objects[2].i (Used for drawing the images and stuff)

instead it'll show me something like

Code: Select all

map.entities[4].image = Image

without actually telling me what the image is.

Any idea what went wrong? Here's my save code:

Code: Select all

function saveLevel(filename)
	local f = love.filesystem.newFile(filename)
	f:open('w')
	f:write("map = {}\n")
	for i,v in pairs(map) do

		if type(v) == "table" then

		local subt = i

			for i,v in pairs(v) do

				if type(v) == "table" then

					local subt2 = i

					for i,v in pairs(v) do

						f:write("map."..subt.."."..subt2.."["..i.."]".."="..tostring(v).."\n")

					end

				else f:write("map."..subt.."["..i.."]"..tostring(v).."\n")

				end

			end

		else f:write("map.".."["..i.."]"..tostring(v).."\n")

		end

	end
end

[Robin]

That's because Images etc. don't have a string representation. One option would be to do:

Code: Select all

map.entities[4].image = 2

and when drawing:

Code: Select all

love.graphics.draw(map.objects[map.entities[4].image].i, x, y) --you get the idea

Furthermore, I strongly suggest you use one of the Serialization examples on the Lua-Users Wiki. They are stable and the more complex ones even work well with recursion and cross-referencing.

[schme16]

I use this script, it adds a couple of values to the table call: .save and .load

eg:

Code: Select all

require 'tablePersistence.lua'
	
	newTable = {}
	newTable.data = 'this is some sting data!'
	newTable.tableData = {'This is a sub table with string data!', 1337,{'sub, sub table with string data'}}

--Serialise the table
	tableAsString = table.save(newTable)

--Save the serialised table to a file
	local f = love.filesystem.newFile('myTable.txt')
	f:open('w')
	f:write(tableAsString)


--now we'll load it again
	local fr = love.filesystem.read('myTable.txt')
	tableAsTable = table.load(fr)

works like a charm!