Slower update(dt) function?

[Dangleberries]

How would I go about writing an update(dt) function that is not called every frame, but let's say every second or so?

I've seen that this is possible in BölderDäsch (http://love2d.org/forum/viewtopic.php?f=5&t=1136 - The rocks physics only tick every half second or so), but that sourcecode is unusually complicated and I could not find it there.

[bartbes]

The update function is probably still called every frame, but using a counter you can choose on which frames you actually want to do something. (or you can sleep the whole code making it unresponsive)

[Robin]

Well, you can use your own love.run():

Code: Select all

function love.run()
 	if love.load then love.load() end
	-- Main loop.
	local timepassed = 0
	while true do
		love.timer.step()
		timepassed = timepassed + love.timer.getDelta()
		if love.update and timepassed > 1 then timepassed = timepassed - 1 ; love.update() end
		love.graphics.clear()
		if love.draw then love.draw() end
 		-- Process events.
		for e,a,b,c in love.event.get() do
			if e == love.event_quit then return end
			love.handlers[e](a,b,c)
		end
		love.graphics.present()
	end
end

Disclaimer: untested, blah blah, own risk, blah blah... you get the idea.

[Dangleberries]

The update function is probably still called every frame, but using a counter you can choose on which frames you actually want to do something. (or you can sleep the whole code making it unresponsive)

I tried the counter method, but that would clog up the whole program and still kill performance. I did not dare to use sleep, since I need the calls every frame as well.

Well, you can use your own love.run():

Code: Select all

function love.run()
 	if love.load then love.load() end
	-- Main loop.
	local timepassed = 0
	while true do
		love.timer.step()
		timepassed = timepassed + love.timer.getDelta()
		if love.update and timepassed > 1 then timepassed = timepassed - 1 ; love.update() end
		love.graphics.clear()
		if love.draw then love.draw() end
 		-- Process events.
		for e,a,b,c in love.event.get() do
			if e == love.event_quit then return end
			love.handlers[e](a,b,c)
		end
		love.graphics.present()
	end
end

Disclaimer: untested, blah blah, own risk, blah blah... you get the idea.

That worked perfectly, thanks a lot Robin.

Just as a general question: Why do you tend to separate Graphics and Processing in game engines? As far as I can tell, love2d on Windows only uses one thread anyways.

[Robin]

Just as a general question: Why do you tend to separate Graphics and Processing in game engines? As far as I can tell, love2d on Windows only uses one thread anyways.

I suspect it's a "proper game design" thing: mixing game logic and drawing code is a Bad Thing.
Also, at least in 0.6.0, the screen is cleared between calling love.update() and love.draw(): if you move all the game logic in love.draw(), any hick-ups are going to result in screen flicker.

[TechnoCat]

I thought love.update was called many times before love.draw depending on your cpu? Then love.draw is called once per frame.

[Robin]

I thought love.update was called many times before love.draw depending on your cpu? Then love.draw is called once per frame.

I'm not sure how it works in 0.5.0 and earlier, but in 0.6.0 every update is followed by a draw.

[bartbes]

0.5.0 works the same way, and I expect every version before it too, it's just a loop with update called, the screen cleared, draw called and the screen updated. (basically)

[appleide]

Code: Select all

function love.load()
  frame = 0;
end
function love.update(dt)
  frame = frame + dt;
  if frame > 1 then
    frame = 0
     do your stuff()
  end
end

I've done this before... I'm not sure its what you described though.