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is it necessary to "free" texture data / love.graphics.Image ?
Posted: Tue Sep 17, 2019 6:21 pm
by trabitboy
Hi!
In the context of a paint app,
I tend to create a lot of new textures / images,
each time I save the GPU canvas:
Code: Select all
--TODO REMOVE try disable display as workaround on android
function saveCanvasToFrame(idx)
disableDisplay=true
love.graphics.setCanvas()
fromGpu=cvs:newImageData()
frames[idx].data=fromGpu
frames[idx].pic=love.graphics.newImage(fromGpu)
--pic is not referenced anymore but is it enough for it to be freed?
disableDisplay=false
end
it's not clear to me if you need to call any kind of deallocation function for the texture data on the GPU to be released?
Re: is it necessary to "free" texture data / love.graphics.Image ?
Posted: Tue Sep 17, 2019 9:30 pm
by raidho36
It will be freed automatically once Lua garbage-collects discarded items. You can manually release the associated memory, but it's not strictly necessary. Keep in mind that ImageData resides in RAM and Texture resides in VRAM.
Re: is it necessary to "free" texture data / love.graphics.Image ?
Posted: Tue Sep 17, 2019 11:24 pm
by pgimeno
I've found that in a similar situation, if I didn't force garbage collection, the memory grew and grew out of control until the memory was completely filled. My hypothesis is that, since Lua does not know the size of the underlying object, it doesn't care that there are many big ones waiting to be garbage-collected, so if their number doesn't reach a high enough threshold, GC doesn't happen. Since in the Lua side the memory used by UserData is very small, many objects can accumulate until GC is triggered.
Manually running GC every 5 seconds worked for me.
https://notabug.org/pgimeno/Thrust-II-r ... e.lua#L557
Re: is it necessary to "free" texture data / love.graphics.Image ?
Posted: Wed Sep 18, 2019 1:54 am
by slime
If that situation happens in code like the above where the lifetime of the texture is obvious,
Object:release (new in LÖVE 11.0) is probably a better solution – it'll perform better, at least.
Re: is it necessary to "free" texture data / love.graphics.Image ?
Posted: Wed Sep 18, 2019 8:54 am
by raidho36
pgimeno wrote: ↑Tue Sep 17, 2019 11:24 pmSince in the Lua side the memory used by UserData is very small, many objects can accumulate until GC is triggered.
This implies that Lua would trigger GC sooner if it knew about object sizes, but that's not the case. Plain Lua objects that take up a lot of memory don't trigger GC any quicker than normal. GC only cares about reference counting.
Re: is it necessary to "free" texture data / love.graphics.Image ?
Posted: Wed Sep 18, 2019 9:05 am
by trabitboy
thanks a lot,
I will add a call to release() explicitly when an Image ( or other gpu resource ) gets out of scope.
maybe we should add a mention on the wiki about this ?
Re: is it necessary to "free" texture data / love.graphics.Image ?
Posted: Wed Sep 18, 2019 11:19 am
by raidho36
Wiki does tell about this. Maybe you missed it because you were focused on whatever you were looking for.
Re: is it necessary to "free" texture data / love.graphics.Image ?
Posted: Thu Sep 19, 2019 2:26 pm
by trabitboy
:release() exists on the wiki page of love.graphics.Image , but the particular context of objects having allocated gpu memory, and the preventive use of release() in this context, is not explained.
Re: is it necessary to "free" texture data / love.graphics.Image ?
Posted: Thu Sep 19, 2019 5:48 pm
by zorg
trabitboy wrote: ↑Thu Sep 19, 2019 2:26 pm
:release() exists on the wiki page of love.graphics.Image , but the particular context of objects having allocated gpu memory, and the preventive use of release() in this context, is not explained.
https://love2d.org/wiki/Object:release
It's defined for all Object types, even though it isn't explained what will happen to specific memory areas whether in the gpu or in main RAM; It does say that the lua reference will be cleaned up and if that was the only one it had, the object itself will be
completely deleted, so one could infer that to mean freeing up all areas of memory.
Re: is it necessary to "free" texture data / love.graphics.Image ?
Posted: Mon Jan 24, 2022 12:25 am
by m0nkeybl1tz
This thread saved my life! I'm drawing to and sampling from a canvas every frame, and I was having my framerate drop in half every few seconds. Calling Object:release() on my ImageData stopped it from spiking, as well as saved me 5 FPS overall.