Having powered five of the ten most highly-rated games on Xbox 360, it's no exaggeration to suggest that the Epic Unreal Engine 3 middleware played a unique role in shaping the visual make-up of 21st century video gaming. With Unreal Engine 4, the company is hoping to take point in defining next-generation rendering once again, and at GDC it revealed a brand new, breathtaking showcase that it hopes will help extend its advantage, giving us our first look at UE4 running in real-time on PlayStation 4 hardware in the process.
The new showcase is called Infiltrator, running on a PC utilising a Core i7 CPU matched with an Nvidia GeForce GTX 680 and 16GB of DDR3 RAM. It's obviously impressive stuff, but the fact is that a Core i7/GTX 680 combo has a clear horsepower advantage over the mooted specs for the next generation consoles. The question is to what extent these demos and this technology can scale across to those platforms.
Presumably with that in mind, early on in its presentation Epic sought to comprehensively address the issue by showing last year's Unreal Engine 4 debut, Elemental, this time rendered by PS4 hardware. Changes have been made in transitioning across the demo, but the overall impact remains much the same as the original prototype demo seen last year.
"We've seen the Elemental demo before. The difference is, now it's running in real-time on PS4 dev hardware."
The key differentiating factor between last year's demo and this newer iteration is that the Sparse Voxel Octree Global Illumination (SVOGI) lighting system hasn't made the cut. Instead, Epic is aiming for very high quality static global illumination with indirect GI sampling for all moving objects, including characters.
"[SVOGI] was our prototype GI system that we used for Elemental last year. And our targets, given that we've had announced hardware from Sony, that's where we're going to be using Lightmass as our global illumination solution instead of SVOGI," senior technical artist and level designer Alan Willard told Eurogamer, stressing that this new iteration of the technology has evolved significantly beyond the current-gen system used in titles like Mass Effect 3. Certainly, just the presence of so much more memory on next-gen platforms should improve lightmap quality on its own.
"We took advantage of the fact that we'd already written a distributed computation system for rendering it all out and we can add on features and refine it as needed. That's been a really powerful tool for us to evolve our ability to render our scenes and pre-compute or re-compute anything we want."
The implication Epic was making in revealing the Elemental demo running on PS4 development hardware was obvious - that today's cutting-edge PC tech demo is tomorrow's run-time on next-gen console hardware. Asked directly if its brand new Infiltrator demo could run on next-gen console, Epic vice president Mark Rein replied:
"Well, let's put it this way. Last year we saw the Elemental demo running on the same piece of hardware and this year we saw the Elemental running on PS4, so I'd say draw your own conclusions... The feeling around Epic on Infiltrator is that this is the pipeline, this is the way we're going to work, making games that are going to have this kind of feel to them, this much detail, this many shadows and it'll just get better and better as we optimise the engine further and further."
That's an exciting prospect, because Infiltrator - running on the same high-end PC host hardware Epic chose for the original Elemental unveiling - is spectacular, featuring levels of detail, effects work, lighting, cloth simulation and animation beyond anything we've seen running on current-gen technology.
Epic then demonstrated its Blueprint editor, allowing developers - even those who aren't primarily programmers - to build their own games quickly and easily, as well as a new animation tool dubbed Persona where skeletons, meshes and animations are all centralised. An Unreal landscaping tool was also discussed, where large open worlds can be quickly generated and foliage sprayed on, quickly and easily. Epic revealed that it is using IES profiles for ultra-realistic lighting.
PS4 Elemental was impressive, but it's in the Infiltrator demo that UE4 really flexes its muscles, with Willard on-hand to provide some behind-the-scenes detail, putting the demo into context with the tools demonstrated earlier.
"A lot of the features that I showed you - thing like the reflections and the IES profiles - they're all here," he said. "As [the protagonist] steps through the cloaking field you actually see the boot reflected in the wet panelling below. And this is all throughout the demonstration. And some of them come across as somewhat subtle, but without them your eye would notice the difference."
"Epic expects its next-gen titles to have the same level of detail and visual accomplishment we see in the Infiltrator demo."
The quality of the dynamic lighting is one of the most impressive elements of the Infiltrator demo, but it's not as much of a performance hot-spot as you may imagine.
"The dynamic lights are not our current performance limit. Our limits come more from the amounts of massive overlapping shadow-casting lights," Willard said. "That's not been a huge challenge because typically we don't need that many to get a perfect-looking scene."
Willard confirmed that Infiltrator was running in real-time on the PC hardware by adjusting layers and lighting as the demo played out. He also cited elements of the demo that would have been far more difficult - or even impossible - without the new workflow Unreal Engine 4 offers.
"One thing to note - as the protoganist comes up to the city and we have a nice wide shot of the vista, that's actually built out geometrically all the way out to the horizon line rather than having the equivalent of a matte painting as you'd see in a movie," he explained. "We actually built that entire cityscape out, including the mountains. The only things that aren't are the clouds that are embedded into the city. Everything else is full geometry from foreground to background."
At the FOX Engine GDC presentation earlier in the week, Kojima Productions focused on a photo-realistic approach to rendering where the look of individual elements is procedurally generated rather than crafted by hand; materials are given attributes and their impact on the environment is dynamically rendered by the tech. In this respect we see a similar approach in Epic's new engine.
"As the physically-based materials inform the scene we end up with more and more things that are procedurally done... Because the end result is physically correct for the scene, we don't need as much detail built into the base textures," Willard observed. "Our materials system in conjunction with our physically correct lighting and shadowing really has a huge impact on the kind of time that we had to spend... We're much more productive. We're able to put a huge amount of detail in for a fraction of the time we would have spent to achieve the same level of detail - or not even been able to achieve in previous generations."
Seeing Elemental running on PS4 was an important moment in the next-generation coming-out party that's going to run all year long - and if Epic can repeat the trick of scaling down high-end PC rendering onto console hardware at the visual level Infiltrator represents, the next gaming age should be absolutely spectacular.
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