Metro Redux: What it's really like to develop for PS4 and X1

[MeachTheMonster]

http://www.eurogamer.net/articles/d...its-really-like-to-make-a-multi-platform-game

Long read. It's worth it if your into this kinda thing.

Pulled out some quotes for the Tl/dr crowd

I think what we achieved with the new consoles was a really good job given the time we had with development kits in the studio - just four months hands-on experience with Xbox One and six months with the PlayStation 4 (I guess the problems we had getting kits to the Kiev office are well-known now).

But the fact is we haven't begun to fully utilise all the computing power we have. For example we have not utilised parallel compute contexts due to the lack of time and the 'alpha' state of support on those consoles at that time. That means that there is a lot of untapped performance that should translate into better visuals and gameplay as we get more familiar with the hardware.

Digital Foundry: Xbox 360 and PS3 were highly ambitious designs for the 2006/7 era. Xbox One and PS4 are much more budget conscious - have they got what it takes to last as long as their predecessors?

Oles Shishkovstov: Well obviously they aren't packing the bleeding edge hardware you can buy for PC (albeit for insane amounts of money) today. But they are relatively well-balanced pieces of hardware that are well above what most people have right now, performance-wise. And let's not forget that programming close to the metal will usually mean that we can get 2x performance gain over the equivalent PC spec. Practically achieving that performance takes some time, though!

Digital Foundry: Xbox One's lower compute unit count, memory bandwidth and ESRAM issues are well documented. Resolution differences in multi-platform games are commonplace and in some titles we're even looking at 720p vs 1080p. What's your take on the differences between Xbox One and PlayStation 4?

Oles Shishkovstov: Well, you kind of answered your own question - PS4 is just a bit more powerful. You forgot to mention the ROP count, it's important too - and let's not forget that both CPU and GPU share bandwidth to DRAM [on both consoles]. I've seen a lot of cases while profiling Xbox One when the GPU could perform fast enough but only when the CPU is basically idle. Unfortunately I've even seen the other way round, when the CPU does perform as expected but only under idle GPU, even if it (the CPU) is supposed to get prioritised memory access. That is why Microsoft's decision to boost the clocks just before the launch was a sensible thing to do with the design set in stone.

Counting pixel output probably isn't the best way to measure the difference between them though. There are plenty of other (and more important factors) that affect image quality besides resolution. We may push 40 per cent more pixels per frame on PS4, but it's not 40 per cent better as a result... your own eyes can tell you that.

Digital Foundry: The Metro games have a reputation for pushing visual boundaries, but even high-end PCs can struggle to sustain 60fps. I've played Metro Last Light for hours on PS4 and Xbox One and that 60fps is basically locked. Obviously some of the PC high-end features are reduced or altered, but in an age where not even Naughty Dog can't run its last-gen title consistently at 1080p60 on PS4, what is the secret of your success?

Oles Shishkovstov: There is no secret. We just adapted to the target hardware.

GCN doesn't love interpolators? OK, ditch the per-vertex tangent space, switch to per-pixel one. That CPU task becomes too fast on an out-of-order CPU? Merge those tasks. Too slow task? Parallelise it. Maybe the GPU doesn't like high sqrt count in the loop? But it is good in integer math - so we'll use old integer tricks. And so on, and so on.

That's just the art of optimisations and that's it. By the way, the PC version directly benefits from those optimisations as well, especially CPU-wise, as all of the platforms have out-of-order CPUs.

Digital Foundry: What's your take on DirectX 12 and Mantle? Is it all about making PC games development tie in more closely with Xbox One and PlayStation 4?

Oles Shishkovstov: Aside from them being much more close to the (modern) metal, those APIs are a paradigm-shift in API design. DX11 was 'I will keep track of everything for you'. DX12 says 'now it's your responsibility' - so it could be a much thinner layer. As for Mantle, it is a temporary API, in my honest opinion.

Digital Foundry: To what extent will DX12 prove useful on Xbox One? Isn't there already a low CPU overhead there in addressing the GPU?

Oles Shishkovstov: No, it's important. All the dependency tracking takes a huge slice of CPU power. And if we are talking about the multi-threaded command buffer chunks generation - the DX11 model was essentially a 'flop', while DX12 should be the right one.

Digital Foundry: Microsoft returning the Kinect GPU reservation in the June XDK made a lot of headlines - I understand you moved from a 900p to a 912p rendering resolution, which sounds fairly modest. Just how important was that update? Has its significance been over-played?

Oles Shishkovstov: Well, the issue is slightly more complicated - it is not like 'here, take that ten per cent of performance we've stolen before', actually it is variable, like sometimes you can use 1.5 per cent more, and sometimes seven per cent and so on. We could possibly have aimed for a higher res, but we went for a 100 per cent stable, vsync-locked frame-rate this time That is not to say we could not have done more with more time, and per my earlier answer, the XDK and system software continues to improve every month.

 

[Rekkapryde]

 

[Fatboi1]

Don't nobody care breh.

Xb1 version inferior, tough luck.
*leaves thread permanently. *