In an ongoing series of articles, Digital Foundry takes an in-depth look at the most high-profile PlayStation Vita releases, talking with the developers and gaining new perspective on what it's like creating games for Sony's brilliant - but underperforming - handheld. In this second instalment, our focus is Need for Speed: Most Wanted, one of the most fascinating games available for the platform. Criterion Games' objective here was ambitious: to incorporate PlayStation Vita into the cross-platform development workflow of what turned out to be one of the most technologically advanced current-gen games on the market. As you might expect from the Guildford studio, the result isn't just a great game but a remarkable technological achievement.
"For the first time in the handheld's history, we can happily transpose all of our praise and criticism of a home console game to the PlayStation Vita version - which is something of an occasion in itself," wrote Martin Robinson in the Eurogamer review. "Much of the credit must go to Criterion, which handled the Vita version of Most Wanted itself. Perhaps unsurprisingly, given the studio's pedigree, it's done an impeccable job... Understandably, it's taken something of a visual hit, but it's never enough to undermine the incredible achievement or the immense novelty of having a faithful handheld port day and date with its bigger cousin."
A lot of this article is going to discuss that "visual hit", so it's important to put Vita Most Wanted into context. Your PlayStation 3 or Xbox 360 - assuming they are the latest models - draw something like 70 to 80 watts of juice from the mains. In contrast, PlayStation Vita uses just five per cent of that total, burning up around 3.5 to 4W during gameplay. Even up against the highly efficient Wii U at 33W, we're talking about a tiny amount of physical power available to power a triple-A game designed for much more capable systems. While efficiency in rendering has come on by leaps and bounds over the years, that's still a huge gap to close. To tell the truth, it can't be closed, and compromises need to be made. Most Wanted is one of five renditions of the same game produced by Criterion, and the team simply didn't have the luxuries open to developers of first-party Vita titles like Uncharted: Golden Abyss and WipEout 2048, where the game design and core rendering technology could be shaped around the strengths and weaknesses of the mobile hardware.
"The Vita version is the same game," confirms Idries Hamadi, technical director at Criterion Games. "There's a machine in the depths of our basement somewhere that's syncing our Perforce and building all five versions of the game every three minutes. It is not a bespoke version, it's a first-class platform for all of them."
"The Vita version is the same game. There's a machine in the depths of our basement somewhere that's syncing our Perforce and building all five versions of the game every three minutes."
The comparison video spells that out. The exact same methodology we use for all of our head-to-head videos - frame-accurate excerpts running side by side - works here because the game logic is effectively identical, the visuals drawn from the same core asset base, the handling model built around the same physics.
Game content is also a match between the handheld and console versions - the open world map's the same, the collectables (or rather, the "smashables") are the same, the car roster is identical. However, the visual compromises are apparent in the comparison. In terms of processing power, Vita occupies an undefined space somewhere between PS2 and PS3 - while less ambitious current-gen games can be replicated very closely on PS Vita, a top-of-the-line experience like Need for Speed: Most Wanted needs a different kind of approach.
So what was Criterion's methodology in getting to grips with the Vita hardware? What was the process in discerning whether Sony's handheld could deal with a game designed primarily with current-generation console hardware in mind?
"There's a few different aspects to that kind of operation," Hamadi reveals. "One is an on-paper analysis - but we didn't put much stock in that because we understood that once we peeled back the first layer of 'let's just look at numbers' you're talking about very different beasts and the numbers you've got only go so far. It's like we said with Wii U - we got some running software, we pulled out everything we possibly could to get a real stripped-down version of the game."
After that, it becomes an exercise in putting back in as much as possible, optimising and adding more. Where some systems are simply not a good fit for the handheld, alternatives are produced. Resolution aside, lighting is the biggest difference between the mobile version and the full-fat console edition.
"We get it to the point where it's running, we strip down the things you can strip down without actually ruining the game - you want to have a playable game - then you bring things up."
The Vita release drops the deferred shading techniques of the other versions which allow for the use of massive amounts of light sources, resulting in a more stark, less subtle rendition of Fairview, also shorn of some of the advanced shader work - wet roads, for instance. While the deferred approach is utilised on some key Vita titles (Uncharted: Golden Abyss and Assassin's Creed 3: Liberation to name a couple of noteworthy examples), Criterion opted for a more traditional forward renderer, allowing the studio to use hardware anti-aliasing - 4x MSAA - to offset the impact of a drop from native 960x544 resolution down to something close to 640x368.
"You've got some choices to make, basically," says Hamadi. "The hardware... obviously for some titles it does go native resolution but for the feature-set we wanted to put in that just wasn't feasible. There's only so much you can get out of it."
Other compromises are self-evident: environmental detail is high for a mobile title but clearly pared down from the other versions, while texture assets are also of a much lower resolution. While PlayStation Vita actually has more RAM overall than PS3, it only has half the video memory while the OS footprint on the handheld is also much, much higher (hence the ability to run 'small apps' with the game state frozen). It's clear that getting a game designed for more powerful, resource-rich platforms to run on the handheld was a considerable challenge for the Criterion team.
"When you look at the game there's only so much physics you can cut before you don't have a game anymore, so you cut more into the effects - especially when you have a much smaller screen."
"There were a lot of times when we were saying 'this is the budget for this, we need to cut that in half' and then we go and look at the actual assets and they were 30 per cent over budget on the other platforms already. How are we going to cut even further?" shares Hamadi.
The established methodology used by some developers in allocating set amounts of processing budget for each particular sub-system wasn't a good fit for developing the Vita version either.
"A lot of people try to approach ports that way, it's not the right way to go about things. The compromises you have to make don't always fall in line with the way you budget for a higher-end platform. Certain aspects need to be cut more than other aspects but when it came to beta. For example, the physics was way more over budget than effects."
The fact that Most Wanted is running on a mobile platform helped define some of the compromises. For example, processing resources weren't there to maintain native res, but the combination of the Vita's rich OLED screen and the 4x MSAA make for a clean presentation overall. Criterion quickly realised that certain systems should take priority over others which weren't so important factoring in how the game is actually played on handheld hardware.
"There were a lot of times when we were saying 'this is the budget for this, we need to cut that in half' and then we go and look at the actual assets and they were 30 per cent over-budget on the other platforms already."
"When you look at the game there's only so much physics you can cut before you don't have a game anymore, so you cut more into the effects - especially when you have a much smaller screen. People don't really see the effects anyway. You don't want to give so much run-time resources," Hamadi says.
"We don't sit down and say, 'right you're going to get this much of this and this much of this'. It's much more holistic. We get it to the point where it's running, we strip down the things you can strip down without actually ruining the game - you want to have a playable game - then you bring things up. You add a bit more here, then you see that you have a bit more CPU to spend - where are you going to put that?"
Response to Need for Speed: Most Wanted has been almost uniformly positive from the core Vita fanbase - a fair reflection on a game that is undoubtedly one of the most fun, playable racing games available on any mobile platform. Criterion's choices in how to re-factor a cutting-edge current-gen title for the handheld have, by and large, paid off. Our analysis assets put into perspective the gulf between the power of Vita and PS3 - at times, there's a sense that the handheld hardware is kicking and screaming at the stress being exerted on it - but overall it seems clear that the trades made were the right ones and Most Wanted enjoys a well-earned reputation as one of the most impressive, ambitious cross-platform games available for Sony's mobile platform.