While we've yet to see Unreal Engine 3 ported to Nintendo's Wii or Sony's PSP, Epic did undertake the considerable task of squeezing its seemingly ubiquitous middleware platform onto Apple's similarly ubiquitous iPhone. According to Epic's Josh Adams – Epic Games' senior console programmer – that could be due to fundamental hardware limitations in the other platforms. You see, the iPhone 3GS has a PowerVR SGX graphics processor which supports programmable shaders. According to Adams, "Programmable shaders are something UE3 is pretty much dependent on."
Though you're probably most familiar with Unreal Engine on Windows, Xbox 360, and PS3, Adams says the engine also runs on Nvidia's Tegra 2 platform, on Linux, and on Mac, though (Adams notes) "we haven't shipped any games on those platforms yet." Adams says the iPhone port was "a fun 'Can we get UE3 onto the iPhone?' kind of project." Though Adams' presentation was exceptionally technical – this is the Game Developers Conference, after all! – it's fascinating to hear about the technical underpinnings and workflows that result in this type of outcome.
Since iPhone development is Mac-based, Epic has had to work to include Macs in its workflow. As for the Unreal Engine tools? Those will remain Windows-only – only game subsystems run on Mac OS X and that's not likely to change. "The more we go along, the more we're using Windows," says Adams. He says the engine is mostly CPU limited on the iPhone adding, "The GPU is not doing all that much at the moment." Still, they're able to eke out framerate of twenty to thirty frames per second. When asked how the engine would perform on the iPad, Adams responded, "If I had an iPad, I'd put it on there and try it." And when asked about the potential for Android support, Adams laughed and said, "I don't think I should talk about that." We'll take that as a tentative "yes."
As a relatively small project inside Epic's relatively massive engine team, Adams said the iPhone port was "probably three to five man months" of work. The next step: actual software! If you wanted to test this out on the freely available Unreal Development Kit, Adams said he's not sure if it's available there, "but it would be cool if it was." But now that it's available to engine licensees, we imagine it won't be long before we see the very first UE3-powered game make its way to the iPhone App Store.