Is auto cull happens when sprite is out of view?

Nascode · August 2012

Hello,

I am testing the performance of Gideros on term of displaying many sprites. Looks like there are no culling (getting rid of uneeded render) happens even when sprites are out of view. Should we do cull by ourself by using setVisible or removeChild?

Sample codes:

local texture = Texture.new('coin.png')
for i = 1,2000 do
	local coin = Bitmap.new(texture)
	coin:setPosition(-10000,-10000) -- try to get it out of viewable area, uneeded render
	stage:addChild(coin)
end

atilim · August 2012

exactly as you've said. culling is only implemented for tile maps.

Nascode · August 2012

@atilim would be lovely if we could set auto-cull of a sprite parent, which affecting every children of those sprite

techdojo · August 2012

I understand "culling" to mean removing the sprite from the display list which would in turn mean that the sprite wouldn't then be drawn if it was moved BACK into view.

What you need is an efficient manner of clipping sprites that are completely off screen (I suspect this is already implemented).

@Atilim - is it more efficient to call :setVisible(false) when you know a sprite is offscreen or doesn't it make any difference?

Nascode · August 2012

@techdojo yes, efficient manner of clipping sprites off screen, in which this is currently not in Gideros yet according to @atilim , maybe culling is not correct word? Only tilemap got this support for now

atilim · August 2012

I think culling (or more specifically view frustum culling) is the correct keyword here. We all mean "automatically (and efficiently) not drawing the sprites that are completely outside of the screen".

@Atilim - is it more efficient to call :setVisible(false) when you know a sprite is offscreen or doesn't it make any difference?

Yes it's more efficient. For example this code works faster:

local texture = Texture.new('coin.png')
for i = 1,2000 do
	local coin = Bitmap.new(texture)
	coin:setPosition(-10000,-10000) -- try to get it out of viewable area, uneeded render
	coint:setVisible(false)
	stage:addChild(coin)
end

Let me add this as a feature request.

techdojo · August 2012

That's good to know, thanks.

Nascode · August 2012

@atilim thank you for adding this as a feature request

hnim · August 2012

@atilim can you add new function that we can ignore sprite update (draw itself and its child) in code, ex: Sprite:setIgnoreUpdate(true/false) ?
Thanks

techdojo · August 2012

@hnim - can you explain your request a bit further? what would be the use case for that?

If you want to ignore the sprite update, then dont update it, if you don't want it to be drawn then use Sprite:setVisible(false)

hnim · August 2012

oh, sorry. a bit confuse when i make my object pool. thanks techdojo

Tom2012 · July 2014

Sorry to bring back an old thread but I did some testing today on my game and using setVisible on any off-screen sprites has DRASTICALLY improved the performance of my game. As in I can't get it under 60fps on device testing.

I made a class like this:

SpritesOffScreen = Core.class(Sprite)
 
function SpritesOffScreen:init(scene)
 
	self.scene = scene
	self:addEventListener(Event.ENTER_FRAME, self.cullOffScreenSprites, self)
 
end
 
 
 
 
 
function SpritesOffScreen:cullOffScreenSprites()
 
	for i,v in pairs(self.scene.sprites) do
 
		if(self.scene.playerMovement.heroX) then
 
			local spriteX, spriteY = v:getPosition()
 
			--print(self.scene.playerMovement.heroX)
 
			local xDist = math.abs(self.scene.playerMovement.heroX - spriteX)
			local yDist = math.abs(self.scene.playerMovement.heroY - spriteY)
 
			if(xDist > 500 or yDist > 400) then
				v:setVisible(false)
			else
				v:setVisible(true)
			end
		end
 
 
	end
 
end

Basically just loop though every sprite and, if it's not on screen, use setVisible to turn it off. If you've got any game where you can use this, do! It saves LOADS of CPU!

ar2rsawseen · July 2014

Wow @Tom2012
nice to see you back in the game

Better do something like that internally, and look also not for specific sprites, but the whole sprite trees to disable.
But on the other hand, if it is not needed then looping from sprites will only take resources, and probably with LuaJIT it won't matter much if it is done natively or not

Thanks for sharing

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