Callbacks

Callbacks are functions that are called on the main script file.

start()

This function is called only at the beginning of the game.

function start()
   initVar = 0   
   initTable = {1,1,1}
   print("this is will only be displayed on the start of the game!")
end

render()

This function is used to render on screen

function render()
   litgraphics.newText("this is a hello world", 120, 120, 8, 3, 1)
end

Also this function can be used with start() to define the sprites at beginning of the game and draw then to screen:

function start()
   -- create a sprite table --
   sprite = {
      {1,3,1},
      {3,1,3},
      {1,3,1},
   }
end

function render()
    -- render the sprite to the screen --
    litgraphics.newSprite(sprite, 90, 90, 5)
end

update(dt)

This function is called every frame and updates the game state.

function update(dt)
   i = i + 1  -- increment this variable every frame
   print(i)   -- print the current value of "i"
end

This function also works with the other two:

function start()
   -- create a sprite table --
   sprite = {
      {1,3,1},
      {3,1,3},
      {1,3,1},
   }
   x = 90     -- set the x pos to 90 --
end

function render()
    -- render the sprite to the screen --
    litgraphics.newSprite(sprite, x, 90, 5)
end
function update()
    -- update x variable every time, this means the sprite will move --
    x = x + 3
end

keydown(k)

This function is called when a key is pressed.

function keydown(k)
    -- if key 1 is pressed, it will print on console
    if k == "1" then
       print("Key down!") 
   end
end

keydown(k)

This function is called when a key is released.

function keydown(k)
    -- if key 1 is released, it will print on console
   if k == "1" then
       print("Key up!") 
   end
end