Not sure why I get "function arguments expected near 'function'" error!

MidnightCoffee · December 2017

Hi all! New here, and am so far loving Gideros... just suddenly I have a problem...

Everything worked fine up until just today where I started getting a "function arguments expected near 'function'" error whenever I try to run the game.
If I add "local" before it, I get "function arguments expected near 'local'"

My code:

onMouseUp = function (self, event)
	playerMoving = true
	print(playerMoving)
end

I have tried changing it to

function onMouseUp(self, event)

(with the function name before "function") but that didn't help either.
If I delete that section, I get the same error on the next function.

Everything worked fine before which is strange.

I get the error with simple functions like above, and longer--but still relatively simple-- ones (that worked fine a few hours ago!) like this:

newRect = function(w,h,c)
 
	local shape = Shape.new()
 
	shape:setFillStyle(Shape.SOLID,c, 1)
 
	shape:beginPath()
	shape:moveTo(0,0)
	shape:lineTo(w,0)
	shape:lineTo(w,h)
	shape:lineTo(0,h)
 
	shape:endPath()
 
	stage:addChild(shape)
	return(shape)
end

Any help would be most appreciated!

Thanks!

hgy29 · December 2017

Hi @MidnghtCoffee,

Do you use latest gideros ? If so does the editor (gideros studio) warns you about the same issue ? It looks like the lua parser is stuck at a point it expects function arguments, so probably after an opening parenthesis. What is the code right before the point where it fails ?

MidnightCoffee · December 2017

I am using the version 11.2 of this year, which I believe is the latest version.
It seems like any function above this bit of code works fine.

for a = 1, 8, 1 do
	isDone = false
	numGen = math.random(2)
	local newBlock
	print(numGen)
	if (numGen == 1 and isDone == false) then
		newBlock = Bitmap.new(Texture.new("images/Ground1.png"))
		newBlock:setScale(4,4)
		isDone = true
		stage:addChild(newBlock)
	end
	if (numGen == 2 and isDone == false) then
		newBlock = Bitmap.new(Texture.new("images/Ground2.png"))
		newBlock:setScale(4,4)
		stage:addChild(newBlock)
	end
	newBlock.name = ("block" .. a)
	newBlock.id = a
 
	newBlock:setX(a *140-140)
	newBlock:setY(groundLevel)
end

That block is something I "translated" from Corona SDK to Gideros, if that matters, but it works as it should.

Thank you!

EDIT: And, if I remove the block of code I pasted above, everything works fine...
Weird...

antix · December 2017

@MidnightCoffee, welcome

Try these...

local function onMouseUp(self, event)
	playerMoving = true
	print(playerMoving)
end

local function newRect(w,h,c)
 
	local shape = Shape.new()
 
	shape:setFillStyle(Shape.SOLID,c, 1)
 
	shape:beginPath()
	shape:moveTo(0,0)
	shape:lineTo(w,0)
	shape:lineTo(w,h)
	shape:lineTo(0,h)
 
	shape:endPath()
 
	stage:addChild(shape)
	return(shape)
end

Would the following code serve the same purpose as the block above??

for a = 1, 8 do
  local random = math.random
  local newBlock
 
	if random() < 0.5 then
		newBlock = Bitmap.new(Texture.new("images/Ground1.png"))
  else
		newBlock = Bitmap.new(Texture.new("images/Ground2.png"))
  end
 
  newBlock.name = ("block" .. a)
  newBlock.id = a
 
  newBlock:setScale(4)
  newBlock:setPosition(a *140-140, groundLevel)
 
  stage:addChild(newBlock)
end

MidnightCoffee · December 2017

I apologize for the late reply. I actually just sent in my laptop for emergency repair and am currently using a different device.
That code does work exactly the same way and works well. The only reason why I was hesitant to do it any other way is because I am translating from corona and intend on having the ground moving as in the code below. But, I guess it should work the same, if I change it to use Gideros's API...?

From Corona SDK:

function updateBlocks()
	if playerMoving == true then
		for a = 1, blocks.numChildren, 1 do
			if(a > 1) then
				newX = (blocks[a - 1]).x + 140
			else
				newX = (blocks[8]).x +140 - speed
			end
			if ((blocks[a]).x <-55) then
				-- Add to score
				score = score + 1
				scoreText.text = score
				scoreText.anchorX = 400
				scoreText.anchorY = 500
				scoreText.x = display.contentWidth/2 + 25
				scoreText.y = 150
				(blocks[a]).x, (blocks[a]).y = newX, (blocks[a]).y
			else
				(blocks[a]):translate( speed * -1, 0 )
			end
		end
		updateSpeed()	
	end
end 
 
timer.performWithDelay(1, update, -1)

Thanks so much!

SinisterSoft · December 2017

Use a tilemap as it's much better than moving all the blocks like you would have done with Corona SDK.

http://docs.giderosmobile.com/reference/gideros/TileMap#TileMap

MidnightCoffee · December 2017

What exactly do you mean by that? (Forgive me, I'm new to Gideros) I only have 2 tiles that I would like to appear in a random order, then scroll/loop like in an endless runner.

Thanks!

SinisterSoft · December 2017

Ahh - I thought you had more than 2 tiles on screen.

With a tilemap the entire screen full of tiles is drawn as a single mesh. I personally would use it also for an endless runner.

MidnightCoffee · December 2017

Is there a tutorial you could recommend for this? I simply want to have the ground autoscroll (and have it stop when the screen is held down).
I don't need any complicated tilemaps because there is only one row in a loop.

Thank you for your help!

antix · December 2017

@MidnightCoffee okay cool, just use whatever works. I started with Marmalade Quick which was so slow, then went to Corona SDK which was better but needed internet for compiling, and finally found Gideros and have been here ever since, so I totally get it can be a bit daunting adapting to a new way of doing things.

@SinisterSoft is correct about TileMaps, they are very powerful. Maybe a little more advanced for a new Gideros user so use whatever works for you now but do have a look at them sometime. If you ever saw "Million Tile Engine" for Corona then that's similar to what the Gideros Tilemap class can do :bz

Your updateBlocks() function would take some conversion. I start to remember now just how different Corona is from Gideros

SinisterSoft · December 2017

@MidnightCoffee if you post a fake screen of what you want and the actual graphics then I should be able to make a quick demo of an everlasting tilemap for you.

antix · December 2017

@MidnightCoffee please post a screendump of what it will look like so we can see how many tiles will appear across the screen. and you are going to use only 2 different tile graphics or will there be more?

MidnightCoffee · December 2017

Thank you @SinisterSoft, I appreciate that, but I just have a question:
Is there a reason why I can't just (and forgive me if this is a stupid question) have a block (and subsequently the rest of the blocks behind) move to the end of the screen, and when it gets off the edge, jump to the other side and continue?

MidnightCoffee · December 2017

The image of the blocks put into place via the code above is attached.
I am currently using two, and at the moment don't plan on adding more...
Thanks!

antix · December 2017

@MidnightCoffee, there's no reason at all. If you want to do it your way then do it

@SinisterSoft is just saying Tilemaps are better. For a very simple starter project I'd recommend just going with what you are comfortable with and ramp up to more complex things as you get to grips with Gideros

totebo · December 2017

Just a footnote here; in my game Miner Z I built a custom system to deal with tiles AND collision. In retrospect it may have made more sense for me to use TileMap and Bump, which would have been a lot more efficient. But I would have had to spend the time learning them too, so as @antix says, do whatever you feel comfortable with.

antix · December 2017

@MidnightCoffee here is a small example (need a break from user interface coding *yawn*)..

local floor, random = math.floor, math.random
 
application:setBackgroundColor(0x4186f4)
 
local TILE_WIDTH, blockCount
 
local groundLevel = 300
local scrollSpeed = 1
local distance = 0 -- distance travelled
 
local blocks = Sprite.new() -- a container to hold our blocks
local regions = {} -- table to hold TextureRegions
 
 
-- create TextureRegions
local function createRegions()
  local insert = table.insert
  local texture = Texture.new("block1.png", true) -- our texture
  TILE_WIDTH = texture:getWidth() -- we will use this a lot so save it now
  insert(regions, TextureRegion.new(texture, 0, 0, TILE_WIDTH, texture:getHeight())) -- our textureregion
 
  texture = Texture.new("block2.png", true)
  insert(regions, TextureRegion.new(texture, 0, 0, TILE_WIDTH, texture:getHeight()))
end
 
 
-- create blockCount blocks
local function createBlocks()
  local x = -TILE_WIDTH
  for i = 1, blockCount do
    local region = regions[random(1, 2)] -- get a random graphic
    local block = Bitmap.new(region) -- create the block
    block:setPosition(x, groundLevel) -- set the blocks position
    blocks:addChild(block) -- attach block to container
    x += TILE_WIDTH -- determine where the next block will be placed
  end
end
 
 
-- scroll and reset blocks
local function scrollBlocks()
  for i = 1, blockCount do
    local block = blocks:getChildAt(i) -- next block to scroll
    local x = block:getX() - scrollSpeed -- scroll block
 
    if x <= -TILE_WIDTH then -- block exited left
      distance += 1 -- increment distance travelled
      x = x + blockCount * TILE_WIDTH -- reposition current block off screen to right
      if random() < 0.5 then -- choose a new random graphic for the block
        block:setTextureRegion(regions[1])
      else
        block:setTextureRegion(regions[2])
      end
    end
    block:setX(x) -- update blocks position
  end
end
 
 
-- call every frame
local function onEnterFrame(e)
  local dt = e.deltaTime
 
  scrollBlocks()
 
end
 
-- kick everything off
createRegions()
 
blockCount = floor(application:getContentWidth() / TILE_WIDTH) + 3 -- how many blocks there will be (+3 for scrolling purposes)
createBlocks()
 
stage:addChild(blocks)
blocks:setX(-TILE_WIDTH)
 
stage:addEventListener(Event.ENTER_FRAME, onEnterFrame)

You will notice in the example that we make as many bitmaps as required and then change their graphics using TextureRegions. This improves performance because you won't be creating bitmap objects endlessly (pun intended). Things like this will become more apparent as you become more familiar with Gideros.

The example could be optimized further by using TexturePacks and classes which are also really fantastic. I'm sure you will learn about those soon.

In fact I would recommend you get the hang of classes and TexturePacks quickly because later you will use them pretty much exclusively.

MidnightCoffee · December 2017

Ah, I understand. Thank you so much for the example!

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