Tuesday, 17 August 2010

Tech Analysis: Mafia II Demo (PS3 vs 360)

It is pretty commonplace to say that titles which feature much in the way of dense foliage, high levels of geometry and plenty of alpha-based transparency effects usually have serious issues with performance on consoles. The framerate often tends to suffer, texture detail gets scaled back, and sometimes the framebuffer resolution takes a massive dive. All of these things not only impact on overall image quality but also take you firmly out of the lavish world the developers have tried so hard to create.

Large, open-world, sandbox type affairs is where this kind of thing happens the most. These types of games are rarely suited to the constrained nature of home console hardware specifications. Even when properly optimised, they still require a large memory footprint, not to mention a hefty chunk of GPU power - a commodity not quite as widely available as you might think given the Uncharted’s and Killzone’s of this world.

Mafia II is one of those games. But unlike the with Red Dead Redemption, the game isn’t anywhere near as polished, with the developers attempting to cram in every last detail of the lead PC version onto the consoles with somewhat mixed results. The world created here is huge and incredibly detailed, with not only high poly counts, but also lots of small intricate touches which really bring out the noticeable attention to detail that has gone into nearly every facet of the game’s visual make up. It’s this approach, which not only provides a genuinely immersive experience, but one that also causes the game no end of problems on both platforms.

It’s also these problems that at times really threaten to derail the experience - the feel that you are indeed part of a living, breathing 1950’s videogame world, and your enjoyment of that world. Although after playing each demo for several hours this doesn’t always seem to be the case. But the problems are pretty distracting at times, and at the very least the game could have benefited from additional polish and optimisations before release. Maybe in the final game we shall see some changes, but we’ll just have to wait and see.

Despite what the screenshots on this page might be telling you on first glance, Mafia II actually renders in 720p (1280x720) on both platforms, with the blurriness found in some of the screens down to an additional blur filter being layered over parts of the image during the final stage of rendering.

As per usual the 360 version of the game receives 2xMSAA (multisampling anti-aliasing), while the PS3 is left with no AA at all, which is pretty much what we’ve come to expect from most multiplatform conversions these days. However, it is apparent that the 360’s use of AA here in Mafia II isn’t quite as good as it could be, as although 2x is applied largely to the whole image it also fails to succeed in managing the amount of jagged edges which appear throughout the game.

In any given scene some parts of it clearly get 2x AA, whilst other obviously do not. This faliure of dealing with aliasing also doesn’t appear to be due to any high contrasting pixel edges, as even in mid to dark areas with very little in the way of drastic contrast changes the AA fails as effortlessly as it does elsewhere. Instead, it simply appears that 2K Czech’s method of implementing 2xMSAA simply isn’t all that effective when mixed with all the other rendering elements in the engine. Comparatively, the PC version also suffers from this problem also, proving that it is definitely something with how the AA conflicts with other parts of the graphics make up.

As we mentioned earlier Mafia II also includes an additional blur filter on top of the 2xMSAA found in the 360 build, and no AA in the PS3 one. This is basically a 1-pxel wide edge blur, and it is applied to surfaces after the anti-aliasing has been done, much like the effect we saw back in the Dante’s Inferno demo on the 360.

Effectively, this results in a heightened amount of softness in the overall image which almost negates the use of rendering in full 720p. Instead the developers could have cut out the blur, rendered in slightly lower sub-HD resolution, and clawed back some of the performance they so seem to be missing.

The PS3 build also gets the same method of blur. However, the lack of AA means that despite this additional effect the overall image is sharper compared to that of the 360 build.

Bizarrely, this effect on the PS3 is pretty inconsistent compared to the one found on the 360 game, and also doesn’t seem to be as strong either. Sometimes the entire scene is completely blurred, while at other times it only seems to affect certain objects rather than everything on screen. The blur doesn’t appear to be selective either, so we’re not sure quite what is going on. It’s rather strange to say the least.

Now given the overall open world nature of the game the use of a full 720p frame buffer with or without AA is pretty impressive, especially when you consider how much stuff is being rendered in order to make up the richly detailed game world. It is no surprise then, to learn that certain effects have had to be paired back in order to allow for this feat to happen.

For one, much of the game’s foliage - simple 2D sprites which always turn and rotate towards facing the camera – and other such parts of the world are rendered in a lower resolution compared to the rest of the scene. And this applies to both platforms, which generally share similar compromises in maintaining high detail levels. There are of course some differences between the two versions, mainly pertaining to the use of varying blend effects for transparencies, the amount of foliage on screen, and the higher saturation of lighting in the 360 game.

As you can see in the screenshots below, the 360 build is using A2C for blending all of it’s alpha effects on foliage, while the PS3 is using some other method, though apparently it isn’t plain old alpha coverage.

A2C is normally chosen in order to save on overall memory bandwidth costs and additional processing power. Basically transparencies and objects which use it are rendered in an interlaced manner of sorts, effectively halving their resolution. The result is a screendoor look to everything that uses it, and a distinctly grainy appearance. This grainy look is usually blended away through the use of high levels of MSAA making this side effect far less noticeable. However, since the 360 build’s implementation of AA is less than successful it fails to work in doing this.

Combined with the blur filter and broken AA solution the foliage, like the rest of the game, appears very soft and distinctly sub-HD even in areas when it is not. By comparison, the PS3 build features much sharper looking foliage due to not using A2C, and by skipping over the broken AA solution entirely.

This additional sharpness, along with using a different blend technique for transparencies means that unlike on 360 the foliage tends to suffer from terrible shimmering, and plenty of crawling jagged edges. Pretty much everything from the foliage, to the buildings and power lines are affected by this, and it can be really unsightly.

Furthermore, the PS3 version has also seen additional cut backs to the levels of detail on offer throughout the game, and lacks the distinct shading method known as SSAO (screen-space ambient occlusion).

In order to work around the tighter memory constraints found in Sony’s machine, including the lack of available EDRAM (read: none) the developers have paired back much of the foliage on the PS3 game, reducing certain areas from densely packed fields of front lawn grass into a series of flat looking texture maps. It’s pretty disappointing to say the least, and really gives the game a flatter look overall compared to the other versions of the game.

Another thing is that the LOD system appears to be slightly more forceful on the PS3 build leading to higher levels of pop-up and less immediately visible on screen details. Thankfully it is only subtly worse than the 360 build, with the LOD issue being more noticeable in certain areas than others.

However, the foliage and LOD is really the only elements which has been noticeably cut back in terms of creating environment detail on PS3, leaving the rest of the game looking basically the same. This is both a good and a bad thing as it means that the un-optimised code constantly struggles to maintain any kind of consistent framerate, with lots of screen tear and heavy dips in smoothness.

In terms of shadowing differences, on the 360 side of things you have the inclusion of SSAO, which used to create an extra sense of depth to the image that you wouldn’t find with traditional shading alone. Sadly the use of this effect is particularly bad, and so inconsistently poor in its implementation that I have to wonder why the developers even decided to include it. Instead they could have feed up additional GPU power for other things if it simply wasn’t there. Certainly, the additional impression of depth wasn’t worth the effort.

The SSAO in Mafia II is clearly rendered in a very low resolution and suffers from noticeable pixelation at times, leading to shadows that can appear fuzzy and rather shimmery as a result, making the game look more rough around the edges than perhaps it should.

Shadows also appeared dithered on the 360 causing further artifacts which stick out noticeably compared to the PS3 build’s cleaner approach. Like with the use of A2C on the foliage, shadows look somewhat grainy, and are pretty fuzzy around the edges. The PS3 game also features slightly dithered shadows, but thankfully not to the same extent as found on the 360.

Outside of these graphical differences both versions of the game look very similar, if not mostly identical. That is to say that they are both lavishly detailed, and contain lots of neat little touches throughout. Everything from power lines to small backyard and side street fences are represented here, along with cracked kerbside slabs and subtle differences in similar building architecture have been meticulously implemented. It’s pretty impressive to say the least, and accurately matches up to the high-spec PC version.

Having this level of attention to detail on any console game compared to its PC counterpart is looking for trouble, especially when trying to achieve a decent level of performance without sacrificing playability. And this is exactly where Mafia II falls down. The game simply cannot hope to achieve a stable framerate when so much is being pushed around on screen at any given time, not to mention a near constant lack of being able to hold v-sync.

It is pretty obvious that the developers were originally aiming for a baseline framerate around the 30fps mark, with the overall framerate being allowed to drop off in heavy load situations. However, the game very rarely reaches that point at all throughout the demo. Even when starting out in the confines of your home, free from all the dense levels of detail visible outside, the framerate still takes a heavy dive below the expected 30fps, ending up somewhere in the mid 20’s, or often less.

In fact, the game regularly runs at between 20 to 25fps with drops venturing down to the 15fps mark in busy situations, and this causes no end of problems from erratic controller responsiveness, to an increase in noticeable jagged edges and aliasing artifacts. The additional controller lag when such constant drops in smoothness happen is what really impacts on the gameplay experience on offer here. I would even go as far as to say that it can make the game near unplayable at times, with your ability to accurately aim and take out the enemy being compromised continuously.

Most titles that suffer from such heavy framerate drops do so because the developers have decided to use v-sync in order to prevent the noticeable screen-tearing that would otherwise occur due to the constant changes in screen refresh. Sadly, Mafia II isn’t one of them. And as far as I can tell the game doesn’t even try to employ any kind of v-sync to help balance out the terrible framerate issues. Instead, what you are left with is a title that suffers from both large constant drops in framerate, and heavy screen tear – mostly at the same time - which affects both platforms to an almost equal extent, with the PS3 version coming off worse in the end.

Most noticeable is the fact that a large percentage of the tearing is happening right in the centre of the screen, thus greatly impacting on not only your overall field of view, but also providing a clear distraction which serves only to further hinder your progress. At worst, the game will decide to drop down to around 20fps and allow for heavy mid-screen tearing to occur, during which a reduction in controller response time, and the uneven refresh rate make any kind of quick and concise play completely useless in larger action sequences.

The PS3 game also tends to tear slightly more frequently than the 360 one. Thankfully this occurs mostly in the overscan area of the screen, so it’s not noticeable in real-world terms. However, the game does drop its framerate more heavily in the same situations as the 360 build, which is a different story altogether.

Overall, there’s simply no question that Mafia II’s general performance is sub-par, and is perhaps one of the worst titles that I have come across this generation when comparing games on either platform to other similar releases.

Despite featuring copious amounts of detail, and lots of subtleties everywhere you look, Mafia II clearly suffers from huge framerate issues, intrusive screen tearing, and a host of other noticeable graphical problems, all of which really show up the game’s original ‘made for PC’ heritage. Failing to properly optimise the title for consoles is exactly why, unlike Red Dead Redemption, Mafia II fails to command your senses in the way Rockstar’s title does so effortlessly.

It’s such a shame as 2K Games have created a world that is so full of personality, packed with intricate little details that it is so easy to initially become immersed in when you are first starting out. Unfortunately the game’s poor framerate, terrible jagged edges, and overall soft looking display completely take you out of the experience. Also hampering your potential enjoyment of the title is the laggy control which manifests itself whenever the framerate drops. And sadly that is pretty much continuously, regardless of whether anything intensive is happening on screen or not.

In conclusion, it is hard to recommend either console version of Mafia II. Both builds suffer terribly from various performance and graphical related problems. Although in the end it is the 360 version which is slightly less unsightly to look at, due to less edge shimmering and aliasing, even if the result is a blurrier image overall. The use of low-res SSAO and dithered shadows is a strong negative point however, and does distract from the noticeably more detailed foliage.

Personally, when it comes down to it I’d track down the vastly superior PC version of the game, in which it should be possible to achieve at least 720p with 2xMSAA at 60fps on a mid-spec gaming rig - something which both the PS3 and 360 can only dream of with regards to this release.

Thanks to Mr Deap for our comparison screens, and as always to AlStrong for his superb pixel counting skills.

No comments:

Post a Comment