Tech Focus: The Quest for Console Quality Mobile Graphics
Digital Foundry on how the gap between smartphone and current gen console is rapidly closing
The release last week of NOVA 3 on iOS and Android devices highlighted once again that the perceived gap between mobile and current gen HD console gaming is beginning to close - and it's a notion that publisher Gameloft has exploited beautifully in its marketing campaign.
Extremely well-edited trailers show a game with similar characters and settings to one of the current generation's most technologically advanced games: Crysis 2. Meanwhile the game's developers got in front of the cameras to talk about the enhanced visual effects they've incorporated, staking a claim to the technological high ground in mobile gaming. Reviews have been generally been complimentary and user comments on iTunes often describe the "console quality" graphics.
"Just how far are we away from mobile processing power being able to match Xbox 360 and PS3 visuals? The generational leap in spec is coming, but will the final products match the potential?"
Clearly there has been a technological shift on mobile: Unreal Engine 3 is available and Infinity Blade 2 looks beautiful. Last-gen classics like GTA3 and Max Payne have been brought to iOS and Android with improved visuals. Titles like Sky Gamblers: Air Supremacy and Modern Combat 3 are effectively mobile re-imaginings of Ace Combat and Call of Duty, and while they may well lack the polish and visual accomplishment of their inspirations, you can buy them for just £6.50/$10. Even at the 69p/$1 level there are still some pretty decent 3D titles: Wave Race-a-like Riptide GP being one of them. Remedy sometimes even gives away the graphically superb Death Rally.
PlayStation Vita may well be struggling to attract the size of audience its games deserve but the success of premium titles on mobile suggests that it is clearly not the concept of AAA games on the move that is the problem - it's almost certainly the idea of having to spend £200+ on the hardware and £25+ per game.
But just how close are the mobile platforms to hitting the current gen console standard, or even Vita level? Infinity Blade 2 is an interesting example. Since the launch of iOS 5, the game has featured a wealth of effects hitherto only seen in abundance on current gen consoles: real-time lighting and shadows, tone-mapping, god-rays - the list is immense. But Epic has gone on the record about the compromises it makes in running Unreal on mobile: materials and textures are downscaled for example and Infinity Blade 2 is built around other constraints imposed on the platform: those levels are divided up into small, distinct areas for a very good reason.
Up close with final code and judged in relation to console shooters, NOVA 3 comes across as a praise-worthy effort with some nice effects work, but artwork quality is variable, frame-rate is all over the shop (particularly so on iPad 3), lighting is often very flat and polycounts vary dramatically. Pick and choose your moments - as Gameloft did in its excellent marketing materials - and we have a game that looks to be punching well above its weight. In terms of actual gameplay though, it's very similar indeed to Modern Combat 3 - coming across very much like an interesting half-way house between Xbox and Xbox 360 in terms of visual quality and graphical features.
It's also a game that also highlights an important distinction between mobile and console: resolution. Compared to current gen consoles, even the current top-end PowerVR graphics core found in iPad 3 can't really compete with the 360's Xenos or PS3's RSX. Yet we find the IMG tech being asked to address increasingly more pixel-dense displays - the PowerVR SGX543 4MP in the new iPad runs NOVA 3 at native "Retina" resolution, and it's clearly struggling compared to the lower res iPad 2 game - which also features more lavish effects work. This is a clear example of 2x the GPU power being inadequate to service 4x the resolution.
"Mobile displays are pulling away from traditional 720p console resolutions, but GPU power isn't rising fast enough to compensate."
So if NOVA 3 doesn't quite make the grade in terms of being "console quality", to what extent is current generation mobile technology able to bridge the gap? Ironically it's a console platform holder that helps provides the answers. PlayStation Vita eschews Sony's previous policy of custom hardware and uses off-the-shelf mobile technology combined into a single processor: quad core ARM Cortex A9s (only three of which are available to games developers) are paired with a slightly enhanced version of the same PowerVR SGX543 4MP found in the new iPad.
Vita possesses several advantages over the iOS and Android platforms, however. Firstly, it services a much lower resolution: 960x544 vs the iPad 2's 1024x768 and its successor's 2048x1536. Secondly, 128MB of dedicated video RAM is attached, presumably with faster access and more bandwidth than the A5 and A5X chips in the iOS machines. Finally, and perhaps most crucially, Vita developers have complete access to the hardware at a much lower level thanks to an implementation of the same libgcm interface found in PlayStation 3, along with tools created by a team with years of experience in working exclusively on games development.
In essence, Vita offers us a glimpse into a world of mobile games development where creators have access to much more raw power concentrated into a smaller area of pixels, and the results are fascinating. Take Uncharted: Golden Abyss for example. It features state-of-the-art lighting technology - a variation of the deferred shading technique used in the PlayStation 3 Drake games, while motion capture is effectively on a par with current generation consoles. There are clearly some cutbacks in terms of polygon count and texture quality, and the lack of performance sapping transparency effects is telling, but on a mobile screen there's still very much the sensation that this is a full-fat console experience.
It's not just the mega budget Uncharted that shows us what mobile tech can do. Titles like Virtua Tennis 4, Ultimate Marvel vs. Capcom and WipEout 2048 also demonstrate dramatically that while some of the bells and whistles may be missing (or not, in the case of VT4 which is a carbon copy of the console game - with extra content), the gap between handheld tech and the six-year-old PS3 is closing rapidly. The question is, factoring in Vita's advantages over current mobile games machines, how long will it take for smartphones and tablets to catch up?
id software's John Carmack has previously speculated that the direct interface with the hardware gives Vita a generational edge over other mobile devices using the same technology, but perhaps didn't consider that iPad's resolution would be increasing so dramatically. The contest here isn't just Vita native 960x544 vs. Retina 2048x1536 - several of Sony's titles actually run at 720x405, the technologically superb Uncharted: Golden Abyss amongst them. On a 5-inch screen, gamers are less likely to notice sub-native resolutions compared to the same trick being pulled on a 9.7-inch display.
Games like Riptide GP and the newly updated Galaxy on Fire 2 now contain resolution selectables, effectively allowing you to choose your own balance between clarity and frame-rate. The Retina-enabled Infinity Blade 2 plays it safe simply by doubling iPad 2 resolution, relying on that 2x GPU power to maintain frame-rate and on the scaler to do the rest. If that resolves - at least partially - the resolution differential, all that remains is that generational leap in GPU power.
Enter PowerVR "Rogue", the next generation of mobile GPU from British firm IMG. Insiders in the smartphone business tell me that it's the point at which graphics processing power in Xbox 360 is finally exceeded. Combined in SoCs with the new ARM Cortex-A15 and potentially we have a viable platform not just for more visually rich titles, but a new target for direct ports of existing 360/PS3 games. There are still issues in terms of bandwidth, memory speed etc, but I would expect mobile devices to have a great chance of at least matching Vita graphical performance within the next 12 months.
Whether the theoretical capabilities of these parts can be actualised in the final product remains to be seen (the original iPhone was famously compared to Dreamcast by John Carmack - the reality was anything but), but Rogue would surely be an excellent jump-on point for a manufacturer like Apple looking to incorporate a powerful games platform into a new product launch - like a smart TV, for example...