If the render targets get so large that they don't fit the eSRAM anymore, it could become a performance issue.
Xbox One (Durango) Technical hardware investigation
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Plenty of deferred renderers work on the X360's 10MB EDRAM. Crysis 2-3, Battlefield 3, Trials 1-2 and so on.
Even if you double the resolution there's still proportionally more space to use so it shouldn't be a problem at all.
Yeah, but I guess they had to make a lot of compromises to make it fit. It's not just the increased resolution, I guess some devs would like to use more bytes per pixel in their g-buffer.
The engineers were pretty clear and honest again, on top of possible lower resolution I expect lots more "tricks" on the xb1 like calculations done at lower precision.
I expect that it will take a while before devs do the most of the ability to render both in the esram and main RAM in the most efficient manner and it will never be as convenient (and may have performance overhead) as a single pool of memory.
The whole point to me is that they explain pretty well their design choices, the strength of their system and sugar coated the weakness of their baby though in a pretty honest manner as I believe they are right when they say that the differences between system A and B are overstated by a lots of people on the webs. Now it is obvious that the systems are different but it is not like say system A doesn't not have its strength, disregarded any time possible by a lot of trolls on the web at large (imo even here and to be clear you are not part of that noise).
That's rumour, not technical investigation.
hesido
Regular
Speaking of render targets, there was a slide in Shadow fall post mortem that talked about GPU memory allocations, and the render targets weighed at 800MB. That's more than current gen total ram, I don't know what to make of that number, can anybody explain why it would be so high? I'm guessing they keep and re-use quite a bit of rendered elements.
http://www.slideshare.net/guerrillagames/killzone-shadow-fall-demo-postmortem
Slide #9
Shadow maps, cube maps, lightmaps, and all kinda of intermediary buffers in multipass rendering.
hesido
Regular
Slide #35 reveals some details on the render targets e.g.:
Shadow maps: 4*2048*2048*32 bits (32 bits shadow maps? Why would you need so many bits? Maybe for their area light solution with soft shadows?)
And that means even their shadow maps take up 64MB. For G-Buffer, they say they use 5 MRT's, RGBA16f, at 1080p, and 32bit depth. If they are talking about 5 different G-Buffers each RGBA16f (I think it means 64bit per pixel). Their G-Buffers + Z Buffer would be more than 85MB, I'm probably making a fool of myself with these calculations but even if they are skewed, what would the information in these slides mean if they had to work within the constraints of a 32MB Esram?
@scently: Yes
Killzone is a PlayStation exclusive...
Hypothetically, for starters, you probably pick a slim buffer that uses 4B instead of 8B. You probably try to fit the frame buffers in the eSRAM to utilize the high bandwidth, you can probably also span the buffer across both memory pools, but I'm not sure what benefits that brings. You reduce the resolution on the intermediary buffers to save you bandwidth, then you try to bump up the fps from sub-30 to maybe 45-60.
hesido
Regular
You don't say.
TheWretched
Regular
Well. What he's implying with this comment is, that if this game wasn't a PS4 exclusive, it wouldn't have been designed like this in the first place.
Isn't a Xbox One thread?
Direct3D 11.x (Direct3D 11.2 superset on hardware) for Xbox One. OpenGL and Mantle are not available on Xbox One.
http://blogs.windows.com/windows/b/appbuilder/archive/2013/10/14/raising-the-bar-with-direct3d.aspx
Direct3D 11.x (Direct3D 11.2 superset on hardware) for Xbox One. OpenGL and Mantle are not available on Xbox One.
http://blogs.windows.com/windows/b/appbuilder/archive/2013/10/14/raising-the-bar-with-direct3d.aspx
hesido
Regular
And I'm asking exactly that. How would it have to be designed? Would those design changes have to mean quality compromise, or just a different way to get to the same point? Do you at all need to fit every render target into the ESRAM, but maybe some of them? Maybe render them to the ESRAM at a time, and move them to main memory - blending as you go, while the next render target is rendered? edit: The Data move engines could help with that, unlike Xbox360, gpu wouldn't be busy copying things to main ram.
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I hate to point out the obvious, but if you double the resolution, you quadruple the memory use, though 720P to 1080P is roughly 2x.
I hate to point out that it's exactly what he meant by double the resolution. 2x the pixels.
forumaccount
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I attended this presentation, he said that the number in the slides was too high and he needed to investigate why.
FYI it was only a post-mortem of their demo for the PS4 reveal, not of the full game. So it was quite unfinished.
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