Microsoft's Xbox One X enhanced programme for classic Xbox 360 games recently added support for a very special last-gen release: The Witcher 2: Assassin of Kings. I was particularly keen to check this one out because CD Projekt Red's 360 conversion effort was absolutely outstanding and with its arrival on the X, you might describe it as one technological miracle layered on top of another. The 360 release wasn't just a port, it was a top-to-bottom revamp of a PC original specifically built for the strengths of a far more capable platform. The port had many cutbacks, of course, but in some respects, I thought it actually improved on its counterpart. So with that remarkable port now upgraded for Microsoft's latest console, how does it look running on 4K displays? And how does the PC original hold up running at an equivalent ultra HD resolution, almost seven years on from its initial release?
Whether it's a driver problem, or simply the concept of running a game never designed for operating at extreme resolutions, the fact is that running the PC version of The Witcher 2 at max settings on a 4K screen is surprisingly onerous to say the least. Combine rich layers of alpha transparency textures with the game's still beautiful bokeh depth of field implementation, and even with a top-end Titan X Pascal, you'll still see frame-rates dip beneath 30 frames per second. In this sense, the game's actually harsher in terms of hardware requirements than its sequel - and that's without the notorious 'uber-sampling' preset active.
But this is a game built for PC and it looks gorgeous, bespoke and like nothing else on the market and it even stands apart from its successor in many ways. Of course, there are aspects that date it somewhat - animation and facial movements in particular - but beyond that, it's simply beautiful. For its part, Xbox One X can't really compare to the PC version at its most majestic, but there are still plenty of 'wow' moments to savour, and similar to many of the other X-enhanced releases, side-by-side comparisons show a careful teasing of the original renderer to bring out the console port at its very best, albeit still within the confines of the Xbox 360's pared back feature set.
Some of the starkest comparisons are found in The Witcher 2's initial flashback scenes. CD Projekt Red wanted its sequel to instantly impress and this area sees the artists throw everything at the player right from the off. Just the arrival of one of Foltest's men in Geralt's tent at the beginning of the game sees the effects come thick and fast: bloom, god rays and bokeh depth of field paired with extreme quality textures. Side-by-side with Xbox 360 - and indeed the One X - it's clear that we're not getting anything like the full-fat experience on console. What's most impressive here is that everything holds up at 4K; CDPR's work still looks immense at extreme resolutions, authored at a time when ultra HD resolution was nothing but the stuff of a madman's dreams.
Just a few seconds of one cutscene shows a remarkable level of difference between the two versions, and inevitably, that's just the beginning. It's no real surprise, of course. CD Projekt Red rewrote the entire post-process pipeline for The Witcher 2's transition to Xbox 360, and rebuilt the majority of the shaders. An entire year was spent redesigning the lighting for the Microsoft console to make everything fit within the harsh confines of hardware originally released in 2005. Fundamental changes were made to the deferred shading set-up for starters, with a much simpler g-buffer set-up, while 16-bit precision render targets were replaced with 10-bit equivalents on the console.
Faced with a wholesale revamp of the game's rendering foundations, the studio adapted the content and in some respects, I prefer the overall look of the console edition. The PC game is heavy on bright, vibrant colour that just looks a touch odd in many scenes, and some of the bloom effects are extravagant to say the least - integral to the aesthetic but not quite fitting realistically into the scene. Xbox 360 is muted by comparison, but overall it can be more realistic-looking, let down only the removal in many scenes of significant visual features like volumetric light and dust. Depth of field is also pared back to a simpler gaussian effect, which doesn't match the majesty of the full bokeh seen on PC (or perhaps more likely unseen on PC if you prefer a manageable frame-rate at 4K on affordable hardware).
It's fascinating to stack up these two alternative ultra HD experiences side-by-side, and in some respects it reminds me of the pre-Xbox 360 era where in many cases, it was the PC format that was the lead platform. A combination of crippling memory restrictions and reduced CPU and GPU power led to conversions often handing in very different interpretations of what was fundamentally the same content. The Witcher 2 on Xbox 360 was almost miraculous in a sense because it's clear that the original was built to fully leverage the PC's strengths and the port to console required a magnificent marshalling of resources, a fundamental understanding of how the game was constructed, how it could be adapted along with the courage to make substantial changes to the look of the game.
As powerful as Xbox One X is, it's no Titan X, and of course, any enhanced version of The Witcher 2 will be based on the 360 'remix', so in many ways, it's perhaps unfair to compare any form of the console release to the fully maxed out PC original. What the X does deliver is a great experience that teases out the very best the 360 original had to offer. The basics are all present and correct, of course. The 1280x672 resolution of the Xbox 360 game scales up by 9x, handing in a 3840x2016 total, vertically stretched to full 4K (and making everything look a touch taller and thinner than the PC original). Again, the back-compat team play with render targets and level of detail settings - higher resolution textures and shadow maps are presented in most scenes and even geometry LODs seem to be pushed out and improved for a richer scene.
Curiously, anisotropic filtering seems to be about the same as the Xbox 360 game - you get higher levels of detail overall owing to the enforced use of the higher quality mip maps, but viewing artwork at oblique angles reveals commonality with the original 360 game and indeed the PC version, where texture filtering was somewhat broken. But curiously, there are some unexpected bonuses too - while the HUD elements and text are mostly upscaled from the original 720p art, the pointer on the mini-map is a pristine asset as opposed to the collection of blobby pixels on Xbox 360.
There's good news in terms of performance too. The original Xbox 360 game had a 30fps cap, but often fell short of its frame-rate target, with adaptive sync keeping the action relatively smooth - albeit with obvious, noticeable screen-tearing. In common with all other back-compat games, v-sync is enforced via Microsoft's emulator, but more than that, frame-rates only rarely waver from a locked, consistent 30 frames per second. The heaviest of cutscenes can cause momentary drops and we noted very rare judder caused by some incorrect frame-pacing, but for the most part, The Witcher 2 on Xbox One X delivers a mighty visual upgrade in combination with a clear uplift in frame-rate. Put simply, you won't be needing to access the emulator's performance mode - the graphics preset offers a big upgrade with no real drawbacks.
In conclusion, it's well worth revisiting this title, whether you're gaming on Xbox One X or indeed on PC. Microsoft's back-compat team have teased out the definitive version of a game that shouldn't really exist on console, expertly building upon CD Projekt Red's brilliant conversion work. However, if you're a PC owner, it's also worth revisiting The Witcher 2 - one of the last triple-A titles truly built from the ground up for the platform, a bespoke experience built with scalability in mind that still looks rather sensational on ultra HD displays.