Tuesday, 7 September 2010

Tech Report: A Look At Epic Citadel

With the impressive specs of the recent iPhone 4, along with the iPad and iPhone 3GS, we always new that Apple’s stylish little handhelds had tantalizing potential that seemed destined to be unlocked at some point. The question was whether or not the system’s slightly limiting development environment, in combination with the high development costs in creating graphically fully featured releases would prevent such a thing from ever happening. With Epic Games’ Epic Citadel Demo a glimpse of that potential has been realised, finally showcasing just what the iPhone range of Power VR SGX GPU’s can do.

This is probably the first time that we have seen anything that pushes Apple’s mobile devices in such a way, as although titles such as Epic’s own Doom Resurrection, and Capcom’s Resident Evil 4 looked good, they were far from demonstrating what was really possible. Despite this, the Epic Citadel demo whilst appearing very impressive is actually not that technologically advanced, featuring very few high-end shader effects and a lack of heavy dynamic lighting – something usually found in UE3 games. It does look very good however, and makes the point that having good art is sometimes more important that having the most advanced tech.

The above screenshots show the game running on an iPhone 3GS (pinched from a friend while on lunch) and are easily above original Xbox quality. The level of texture detail is incredible for a handheld device, looking far better than anything we have seen on either the PSP or even Nintendo’s 3DS, and the subtle but pleasing inclusion of some basic dynamic lighting, plus additional tone mapping brings a sense of depth to the image.

More impressive still is the use of a very cleaver LOD system, which means that pop up is never as intrusive as you’d expect when looking upon far away areas, and that the high levels of detail effectively remain on screen for longer.

The iPhone version of the UE3 only supports the use of OpenGL ES 2.0, thus only working on the latest models of the device. Although it’s not just iPhone 4 users that will benefit from this upgrade in graphical quality with titles that use the engine. The demo even manages to run smoothly on the older iPhone 3GS or iPad whilst either missing, or simply toning down specific visual effects.

iPhone 4


iPhone 3GS

On the 3GS that I used to sample the demo, the framerate largely hovered around the 30fps mark, only really dropping down in areas where lots of detail is visible in wide open spaces. In these areas the framerate can, and will frequently drop down to around the 20fps mark, whilst also introducing some serious input lag that temporality ruins the otherwise responsive controls.

Available memory, and memory bandwidth for the GPU seems to be the main issue here, as does GPU clock speed – it’s faster in the iPhone 4 compared to the 3GS and iPad. However, even with these small cutbacks in visual fidelity Epic Citadel is firmly above other titles on either device, and represents just the kind of visual step forward we could be seeing in future titles.

Outside of the highly polished nature of the demo’s texture mapping, and filtering providing us with lavish image quality, and the subtle inclusion of dynamic lighting (backed up by a custom lightmass GI baking solution), there isn’t much that is all that technically impressive - Specular reflections are hardly new even if the still look great. Most of what makes Epic Citadel look so good comes down to using high quality art assets, and good overall art in general – both of which are lacking in most current iPhone releases.

This is especially true for games running on lower spec platforms. Some of the most impressive looking PS2 titles used good art to simulate far more advanced effects without the means to do them natively, thus holding up against their Xbox counterparts.

Of course, increasing the quality of the art assets used takes both time and money, and one of the reasons that we haven’t seen such high production values in a iPhone game yet is largely down to the software market that it will be entering into. Most titles sell for less than £7 on the AppStore, even less than £3 in many cases, meaning that it will be harder for developers to claw back the increased costs involved of embarking on higher-end projects. And the risks may not be worth the rewards.

However, at least the option is now wide open for software houses to choose, and it’s likely that getting your game up and running using a decent middleware solution like UE3 is far easier than developing your own advanced, fully custom iPhone engine. The real question is whether or not it circumvents enough of the additional development costs incurred by significantly ramping up your art assets. But that is something that can only be answered by individual publishers themselves, and until then, all we can do is watch, wait, and see what happens.

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