May 28th, 2021 Dev Vlog

Snutt & Ben Talk: Impact of the Engine Upgrade on Conveyor Belt performance

https://youtube.com/embed/dyqOMITwLsY?autoplay=1&start=1330&end=1727

Topics

• Features > Buildables > Conveyor Belts
• Technology > Graphics
• Satisfactory Updates > Released > Satisfactory Update 4
• Technology > Unreal Engine

Transcript

should we move on to the next thing we're going to the big bus the big bus this one doesn't mess around the big bus so this is my beautiful test case for oh and realistic conveyor belt case I recognize let's talk about conveyor belts, with the engine upgrade we faced the same issue that we got with the loading the conveyor belts got way more expensive to render I kind of figured out why but we cannot change it because it's like in the core of the rendering system of unreal which is such a black box to me that it's like can't touch this so we decided to find our way around it, let's disable the average heifer to begin with and go to the old system of whereabouts so this is the old conveyor belt system that's still accessible to everybody you can see the beautiful colors just to turn like are yellow even on my shitty screen share what I don't even get like a proper frame rate- I'm like noticing the difference here yep, also a lot of items look like they're moving backwards, thanks to the framerate but we figured out that updating instances became more expensive sadly enough I assume it has to do with gpu bandwidth and threading and all that stuff that got improved so they had to cut corners elsewhere I assume I still didn't fully figure out but we'll see so our solution to that is what if we don't update the instances so that was the solution in the end so what we do instead we render the positions of the items on a texture and in the material we read where those items are so if I can find that subsystem here we can see how it looks like if it doesn't crash please okay so here we see all the items in the scene right now on the texture what a weird way to present that or look at it so technically it's it's just an array to the array of items, it's a floating texture which is not representable in colors so that's why it looks super weird every row is an item at least every three rows is an item because the first id is the lot zero then lot one lot and then the last slot and then we store xyz of this of course and the alpha is just there interesting and we do the same for the orientation which is looking even more weird yeah because this is this is readable but it's not because we're using quaternions yeah, I don't want to go into quaternions because nobody wants to because they're weird yeah, they're super weird it's like let's represent an orientation with four numbers yep yeah, and also they are going from negative one to positive one to make it even more obvious what it is so yeah we're using quaternions for that the reason for that it's easier to do it in the shader you can just multiply by quaternion and they get the right offset instead of doing xyz rotation then you have to do the right order and yeah right do you get like precision issues being that you render it to a buffer or does it actually like not really matter surprisingly I haven't noticed anything yet because it's in 32-bit buffer per channel yeah so it's quite memory expensive but it's again it's cheaper than having and and okay just just do a few step back we used to have a instance component per unique item per conveyor belt right let it sink in so if you would have five different items on the long conveyor belt you have five unique components in the end that was more of a memory sink than having a big ass texture or 32, 32 bits per channel, that was just cheaper like in the end this is taking 1100 kilobytes to render, so that that's pretty cheap how does it scale when you have like 10 times as many conveyor belts as you have in this scene versus like you know a million millions of creative ones or whatever it has a cutoff point at one point it just doesn't render the last lot right I'm not sure if we can get there that's pretty far away yeah here you can see that the purple line and the purple fade away it's really difficult to see but it's quite far you can almost not see the items anymore, and there is consideration to make like a far distant version for far distance only but if we get there yeah and, the biggest cost of this system is on the cpu right now which is costing this scene is costing 1.1 milliseconds to do to render all these items and update it because it needs to run on the game thread sadly enough okay it was fully threaded it was fully working and then I pushed it out and everybody in the studio was crashing I was like but it works on my machine so one of those classic ones like with threading that works in your machine and then other people yeah except for only me and dylan were were running it and everybody else was crashing so I was like yay well obviously you and dylan were doing something much better than everyone else of course obviously, so yeah I had to strip it out and have to add that back one day cool so yeah those those are the items they are nice so I guess there's still like a couple of, I've seen some people say that there's still a couple of parts that haven't moved over to like the new system, if you do find these make sure to go to our qa site questions outside of factorygame.com and let us know and that goes for all rendering issues you might face in the game I remember there being a