"The next generation of consoles is a lot more efficient on math operations, which allows us to use more complex lighting and shading models," adds Nicolas Schulz, the Senior Rendering Engineer at Crytek.
"This, together with the increased memory enabling more dense surface information, helps to achieve a quality level for materials that hasn't been possible before. The way that light interacts with objects is a lot closer to how things work in reality now."
Doing the calculations
Developing for the Xbox One and PS4 is now easier, according to developers, thanks to a long history of programming for legacy platforms and the greater amount of RAM, which provides more flexibility in controlling game files. The 64-bit architecture also means dev teams have more control over the type of data they can load, the quality of those assets and the memory size - without any slowdowns.
"Direct3D11 [which is the latest Microsoft graphics engine for creating 3D effects] gives us access to features like compute shaders," says Greenawalt. "In addition, we can now count on virtual memory for the GPU.
"This allows us to, with less effort and without brute force, stream in higher quality assets dynamically where we want them. And, of course we have a very lean OS that stays out of our game's way –the Xbox One OS."
Greenawalt says another big change in how they created Forza had to do with the Xbox One's built-in hard drive. While the Xbox 360 had a drive option, the team had to program for the lowest common denominator - no drive. They had to stream content directly from the game disc and make sure everything stayed smooth.
With Forza 5, they used much more caching from the hard drive as you play, loading assets before you reach a segment of the track. Greenawalt says that to do this, his team used a variety of apps that are publically available but also relied on custom-built internal tools.
"We used Visual Studio, Incredibuild, and TFS for code validation and testing, as well as 3DSMax, Photoshop and Expression Blend for content creation. In addition we have invested heavily in developing internal tools for things like track and car scene construction, material graphs and other content paths, all with real-time updates running into the game engine."
Play when you're not playing
All that is impressive enough. But Forza 5 has one other trick that sounds truly mind-blowing: in a new mode called Drivatar, the game's AI uses Bayesian learning techniques in programming to actually become you. You won't even have to be online to interact with friends when Drivatar is expertly mimicking your personality and habits.
Of course, connectivity is more than just multiplayer matches and avatars. Mikael Rudberg, the Senior Development Director for Need for Speed Rivals, told TechRadar his team looked for ways to enhance the game outside of the direct console experience.
In Rivals, they created a mode called Overwatch which runs on a tablet but connects into the game. "You can call in a helicopter while you're on your iPad on a bus to help a friend bust a racer," he says. This is an expansion of Xbox 360's SmartGlass control, which allows players to use a Microsoft Surface tablet to, for example, explore a map while driving a car.
The Kinect 2 sensor is much more precise than the previous gen. In Forza 5, when gamers look at the angle of an approaching turn, the Xbox One will offer that viewing angle. In fact, the new sensor can track your head movements precisely, something the previous generation could not do.
On the PlayStation 4, the new DualShock 4 controller features new gyroscope that senses motion in a similar way to the PS3 Move controller. The applications are amazingly exciting, and Sony has already had great creative (if not so much commercial) success with motion control on the Vita. But with details tightly controlled for now, Sony isn't saying much yet about exactly how this will work.
When the consoles finally debut in time for Christmas, more games will start exploiting these features - and the increased RAM size and powerful AMD architecture. We will undoubtedly be amazed by what's on offer, but that will only be the beginning of the next-gen consoles' potential. As Christopher Evans, Art Technical Director at Crytek, says: "You just have to keep pushing."