Last week's GDC reveal of Unreal Engine 4 running on PlayStation 4 hardware gave us a revised look at 2012's Elemental PC demo - at the time operating on Core i7 in combination with Nvidia's powerful GTX 680 - and after the dust settled we were curious to see how the two renditions compared directly. This should give us some idea of the ways in which Epic has reshaped its code to better suit the new console platform. Of course, it's early days and UE4 in itself is still in development, but the question remains - to what extent can PS4 match up to a top-end PC?
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So just how has the first UE4 tech demo transitioned across from PC to PS4? The biggest casualty is the omission of real-time global illumination, which produced some really impressive lighting in the original presentation - specifically in the way that light sources "bounce" off different materials. Dynamic generation of shadows also appears to be an issue, but we can't really read too much into that as positioning of the sun appears to have changed significantly from PC to PS4, altering the way the scenes are lit.
While the lack of real-time GI is a bit of a blow, we get the impression that this really heavy tech proved too much for the new console hardware (and bearing in mind the power of the PS4, an array of lower/mid-range PC graphics cards too) because it's been replaced with an enhanced solution of the "baked", pre-computed lighting system used in Unreal Engine 3: Lightmass. This works in combination with a form of real-time global illumination on objects - not exactly a new approach, as the same basic principles were in place on Halo 3.
Other effects have definitely been scaled back, but not to an extent that has much of an impact on the presentation - GPU particles are fewer in number, depth of field has been significantly retooled and isn't quite as impactful on PS4, while object-based motion blur appears to have been removed. The flowing lava effect had real depth and texture to it in the original PC version - on PS4, it's significantly flatter.
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With all of this in mind, the fact that PS4 is within striking distance at all is a fairly substantial achievement. Only the omission of Sparse Voxel Octree Global Illumination tech (SVOGI) comes across as a disappointment - and from this, it's difficult to avoid the conclusion that at a base-line level, the next generation of console hardware isn't quite as powerful as Epic was hoping for this time last year.