Following this morning's announcement of the release of Unity iPhone version 1.5, we grabbed further comment from Nicholas Francis, Unity Technologies' COO, concerning how the company had managed to get such a significant performance boost out of its engine.

It's claiming a threefold overall improvement, as well as up to fourfold in tasks such as animation skinning.

"We've gone over our code and optimised the bejeezus out it," says Francis.

"A bunch of animation skinning code has been redone in custom VFD assembly, so people can skin meshes using the iPhone's vector co-processor. The rendering pipeline also got a big performance overhaul, and the math from scripting gets offloaded from the main CPU.

"Basically, when you're playing games on an iPhone, it's easy to forget you're holding a phone in your hand. From a development perspective however, it's still quite a low-powered device. Hence it's very important to eke out every bit of performance from the device.

"The second thing is we've made it a lot easier to integrate your own extensions in Unity iPhone, so people can take advantage of all the OS 3.0 features. We integrated the ones that were complete slam-dunks to integrate, so this is more about making sure our customers can be as creative as they want."

Preparing for 3GS boost

As for his views on the iPhone, Francis says. "We're really impressed and inspired by the continued success of the iPhone platform. This is both about the platform itself as well as what we're doing on it.

"I also think the advances in the iPhone 3GS shows that Apple is taking gaming very seriously. It's a bit too early for most developers to do 3GS-only games, but once it has a bit of a wider userbase, it'll be great to see what can be achieved.

"The great part for us is that with 3GS, we can finally get the full Unity experience with shaders, pixel lighting, bumpmaps etc. We're working on this as we speak, but I think in another six months, the advantages to using mature middleware like Unity will show its strength."

There are two versions of Unity for iPhone available: Unity iPhone Advanced and Unity iPhone Basic. Licensing costs start at $399 and there's an unlimited 30 day trial version of the full technology available for evaluation purposes.