Tuesday, 26 January 2010

Ninja Gaiden Sigma 2 - Tech Analysis

The original Ninja Gaiden Sigma (NGS) represented one of the first wave of 1080p enabled games to hit the PS3, which showed that despite the obvious limitations in pixel rendering power and somewhat strict memory constraints, it was possible to have a fully crafted next-gen title running in Full HD 1080… almost. You see NGS used a little trick of rendering in 960x1080, having only half of the 1920 horizontal resolution required for true 1080p, but also only using a small percentage of processing power, and framebuffer memory over the standard 1280x720. The PS3 then took care of scaling the horizontal res of 960 to a full 1920x1080. This didn’t look half bad to be honest, and showed up slightly more detail than the standard 720p mode. However overall IQ was diminished as a result, with more jaggies appearing on screen along with some unwanted screen-tear.

In addition to this neat 1080p trick, NGS featured some lovely HDR styled bloom lighting, coupled with hi-res texturing and improved shadowing over its Xbox counterpart, all at a glorious 60 frames per-second with 2xAA in 720p mode. This made NGS look good enough to stand against most competing titles at the time of its release, although this impact was not felt across all stages, and not at all times throughout the game.

Ninja Gaiden 2 (NG2) however did not feature a 1080p mode as such, instead opting for the 360’s scaler to do the work previously half done by the GPU in Ninja Gaiden Sigma. In addition, the game lacked intensity in its bloom lighting so heavily featured in NGS and featured some low resolution, rather flat looking texture work. The overall lighting appeared to be mostly static, comprised of pre-calculated shadow maps, which failed to react with moving objects on screen, and with just a single light source to engage with the scenery and characters. It felt like a bit of a rush job compared to NGS. Though the fact that the game was pushing around so much more stuff on screen, with limbs being hacked off and blood gushing out of every gaping wound, understandably meant that certain cuts had to be made visually.

Now Ninja Gaiden Sigma 2 doesn’t live up to the lofty claims of 1080p made by the first game. Not that it really needs to, seeing as it looks so much clearer and better polished in 720p than both the previous title and the 360 sequel. And that’s without any sniff of a good 1080p upscaling solution.

The first thing to address here is that NGS2 is rendering with a full 1280x720p framebuffer compared with a mere 1120x585 on 360 NG2, with both games using 2xMSAA for anti-aliasing. This means that before any other graphical upgrades are put into equation, Sigma 2 has a clear IQ advantage over the 360 game, both with regards to jaggies reduction, and cleaner polygon edges due to the absence of any upscaling being present.

The difference is instantly visible, as the polygon edges lose the slight softness they used to have on the 360 original, appearing much sharper and looking noticeably smoother, whilst at the same time showing increased clarity across the entire range of character and background models, along with the higher res visual effects. This in turn helps bring out more detail in the textures, which have also been either improved or completely redone from scratch. This improvement in IQ also puts NGS2 over the first NGS game on PS3 with both running in 720p as a direct comparison.

However not all is quite right, as there is something strange happening with regards to the AA in NGS2. It appears that there are times when it is seemingly disabled and then a few seconds, or even a few frames later re-enabled, with from what I can see, no logical explanation for this to occur. The loss of AA can bizarrely happen at any given time regardless of how much is being pushed on screen at once, or how the game is rendering its frames. There doesn’t seem to be a visible pattern when looking at frame grabs to determine if it’s some kind of variable AA, like seen in DMC4 or a new solution which provides a similar effect.

You can see below just what is happening, with the top screenshot clearly showing 2xMSAA and the bottom with no AA.



As you can see the IQ is temporarily reduced when the AA is disabled, producing some jagged edges but hardly any real loss of meaningful detail. Of course the above is almost impossible to spot when playing the game, with only slightly more jaggies briefly appearing if the lack of AA lasts for more than a second or too. So it’s not really an issue just a strange observation, which in the interests of being thorough, felt that you guys should really know about it.

Earlier we mentioned that NGS2’s textures have either been improved or completely redone for this version over NG2. Well both have been reworked to a greater extent than what was done with the first game. Higher res textures have been used throughout, complete with a healthy dose of anisotropic filtering, which allows texture detail to be visible much further on in the distance than with basic bilinear or trilinear methods. The use of this filtering is greater than with NG2, again empathising the better IQ NGS provides when coupled with all the other improvements.

In addition moderate bump mapping and subtle specular highlights have also been applied, creating a mild sheen and depth that otherwise, would have the game’s many lovely floors and walls look flat and shallow, a problem which NG2 suffered from, and that is now absent here in NGS2.

The game’s upgraded lighting system also helps to provide both much needed depth and atmosphere to the proceedings. One of the main criticisms with the original NG2 was the flat looking, pre-calculated lighting model, which made the game look at times like an enhanced 720p Dreamcast game. Not so with NGS2, which features the return of the intense HDR bloom lighting from the first Sigma, and a greater use of spot lighting effects to create the illusion of at least some basic dynamic lighting. However the shadows cast by buildings and static objects still don’t react with Ryu or any of his enemies, with only the main lights affecting how bright of dark he becomes when in the shadows of large objects etc. There is never a transition when emerging to and from the shadows, just a subtle darkening caused by being further away, or in a different direction to the main lighting. When HDR is present this effect is heightened slightly, and distracts you from some of the last-gen shadowing on offer here.

Overall Sigma 2 presents us with a major improvement over both the original NG2 and NGS, with IQ, texture detail and lighting effects all extensively reworked giving us a much better looking game for it. Of course this improvement does come at a price, and this is in the shape of dismemberment being removed from the game, along with free flowing blood gushing from lacerated wounds. Instead we have simple decapitations, in which the heads will fade away as soon as they are cut, and the replacement of blood with a blue mist much smaller in size.

There is no doubt, whilst this change was mainly an artistic one, with NGS2 having a different director, it has played a large part in allowing the team to enhance the overall game engine back up to the standards set by the first NGS and beyond. Granted there is less chaos on the screen than before (and enemies are now more resilient to balance this out), but having a full 720p image with 2XAA is a worthy trade off compared to the lacklustre effort shown with NG2.

Lastly a point we haven’t yet touched upon with NGS2 is with regards to screen tear. Sigma 2 tears far more frequently than in Ninja Gaiden 2, which is no doubt due to the engine having to handle the extra workload of more pixels to render in addition to the other effects displayed over what NG2 had to do. It’s not a major issue, but like on occasion in 360 Resident Evil 5, can be a bit of a nuisance during a hard fought boss battle, or whilst scaling the games many attractive stages. The difference isn’t huge, but someone who’s played both versions will definitely notice.

The only other slight change we have left is with regards to the cut scenes. In NGS2 they are locked at 30fps, whilst in NG2 they are variable between 30 to 50fps depending on the scene complexity and effects used. If anything having the cut scenes locked to 30fps is a better choice as in NG2 they never reached 60fps, and barely hit a framerate close to that in most situations during those cut scenes.

Ultimately though for all the little changes, and that small increase in screen tear, Sigma 2 manages to fix most of the issues surrounding the 360 original, and more importantly manages to eclipse the first game without resorting to any kind of 1080p trickery. So from a pure technical perspective, NGS2 is the finest version of Ninja Gaiden 2 available.

Now all that’s left to see is if Team Ninja can get the Sigma engine running equally on both PS3 and 360 for the inevitable Ninja Gaiden 3, working on the strengths and weaknesses of both systems like Capcom and their MT Framework Engine 2.

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