Why is my code so inefficient?

[Bambo.]

Hey i've been creating a tiny... visual aid with LÖVE and this programme makes my CPU usage go crazy!

is there anything i've done wrong or could improve on?

http = require("socket.http")
url = require("socket.url")

function love.load()
	block = love.graphics.newImage("content/images/Block.png")
	blocks = 0
	chatbox = "Type in your minecraft username and press Enter"
	inputa = ""
	ent = {}
	speed = 100
	i = 0
	flag = false
end
    
function love.update( dt )
	for k,v in pairs(ent) do
		v.pos.y = v.pos.y + (speed * dt)	
	end
	
	while i < tonumber(blocks) do
		i = i + 1
		createEnt()
	end
end

function love.draw()
	if go == true then
	if flag == false then
	for k,v in pairs(ent) do
		love.graphics.draw(block, v.pos.x, v.pos.y)
	end
	end
	end
	
	love.graphics.print(chatbox, 10, 50)
	love.graphics.print(inputa, 10, 100)
	love.graphics.print(blocks, 10, 200)
	if i ~= nil then
		love.graphics.print(i, 10, 150)
	end
end

function request(name)
	blocks = http.request("http://kuro.bambofy.co.uk/grab.php?user="..name.."")
	if blocks == nil then
		chatbox = "Sorry we cannot find your username in our database! please contact Bambo if this error occurs frequently."
		go = false
	else
		chatbox = "Success!"
		go = true
	end
end

function love.keypressed(k)
	if k == "escape" then
		love.event.push('q')
		
	elseif k == "return" then
		inputa = url.escape(inputa)
		request(inputa)
		
	elseif k == "backspace" then
		inputleng = string.len(inputa) - 1
		newinput = string.sub(inputa, 0, inputleng)
		inputa = newinput
	
	elseif k == "lshift" then
		v = true
		inputa = inputa
		
	elseif v == true then
		inputa = ""..inputa..""..string.upper(k)..""
		
	else
		inputa = ""..inputa..""..k..""
	end
end

function love.keyreleased( k )
	if k == "lshift" then
		if v == true then
			v = false
		end
	end
end

function createEnt()
	table.insert(ent, returnInfo())
end

function round(num, idp)
  local mult = 10^(idp or 0)
  return math.floor(num * mult + 0.5) / mult
end

function returnInfo(x, y)
	if x == nil then
		x = math.random(800)
	end
	
	if y == nil then
		y = math.random(600)
		y = y * -1
	end
	
	return {pos={x=x,y=y}, speed=speed}
end

any help is appreciated, this has been annoying me for a while now.

[Ortzinator]

High CPU usage doesn't necessarily make it inefficient as long as it's running fast enough.

[WiZzArD]

Unless you have statistics to compare it against...

In my Lua game engine, displaying a couple hundred networked entities and calculating their movement and collision on both a client and a server does not take my dual core 2.13 GHz processor up more than 35% of what it was before running the applications at any given time during the applications running. Displaying 20 lines of text on a single instance of the application does not take more than 12% of the CPU usage at any given time. I think that the OP is safe to consider his program inefficient if it's greater than double or so my tested CPU usages on a similar processor.

Besides for ranting about what inefficient is, I think the best way to get an answer to your problem, OP, is to post on the LÖVE forums. Your general operations that aren't specific to LÖVE are very miniscule.

[20k]

Im not really sure where LOVE enters so i cant check this, but if you have an infinite loop with no particularly expensive operations in, normally a main loop, it tends to max out a cpu. Not really a massive issue though

[robmaister12]

CPU usage doesn't necessarily reflect on the efficiency of your program. Most games are run in an infinite loop, meaning it'll render a frame, then go back and render another frame as fast as it can, meaning it'll utilize as much of the CPU as possible. You should be worried about how many milliseconds it's taking you to render a frame instead.

[editline]16th April 2011[/editline]

enabling VSync caps your framerate at 60 (usually), which means that the processor has time to idle between frames and the CPU utilization looks lower.

[Bambo.]

My framerate is fine, 60 FPS all time, i was just getting worried about the CPU going crazy. Thanks for all the help guys!

[yngndrw]

From what I can tell, you're making loads of entities every frame and they aren't ever getting removed.

Also this:

	if go == true then
	if flag == false then
	for k,v in pairs(ent) do
		love.graphics.draw(block, v.pos.x, v.pos.y)
	end
	end
	end

Can be wrote like this:

	if go and not flag then
		for k, v in pairs(ent) do
			love.graphics.draw(block, v.pos.x, v.pos.y)
		end
	end

Just makes it a little more readable.

[Bambo.]

[QUOTE=yngndrw;29273704]From what I can tell, you're making loads of entities every frame and they aren't ever getting removed.

Also this:

	if go == true then
	if flag == false then
	for k,v in pairs(ent) do
		love.graphics.draw(block, v.pos.x, v.pos.y)
	end
	end
	end

Can be wrote like this:

	if go and not flag then
		for k, v in pairs(ent) do
			love.graphics.draw(block, v.pos.x, v.pos.y)
		end
	end

Just makes it a little more readable.[/QUOTE]

i see, thanks alot. I was wondering about that.