The State of DirectX 11 - Image Quality & Performance
Unigine: Image Quality
The last game we'll be looking at in this article isn't really a game at all, but a benchmark and demo for a game engine. The game engine in question is called Unigine and it's being developed by Unigine Corp. for licensing to other developers. They are also developing their own game using the engine. Unigine developed from the Frustum open source project which has made a few showings at Siggraph over the years. The engine is currently being licensed to over two dozen clients, over a dozen of which are using it for game development. While no currently available retail titles make use of Unigine, several upcoming titles will be built on it including Afterfall Universe and Primal Carnage.
Despite not having any shipping titles under its belt, Unigine has kept a relatively high profile by releasing a string of compelling benchmark demos, the latest of which, called Heaven, shows off the latest iteration of the engine which offers full DirectX 11 support. Unigine's Heaven benchmark features one of the most extreme and noticeable implementation of tessellation out of the games featured in this article, as demonstrated by the video below.
The Heaven benchmark features an extreme level of reliance on tessellation to achieve its image quality. This reliance on tessellation can be noticed nearly everywhere, but is most noticeable on the stairs, cobblestone roads and roof shingles. The geometry of the stairs is entirely dependent on tessellation and actually appear as a flat ramp in DirectX 9 when tessellation is unavailable. While the extreme reliance on tessellation would be unacceptable in a retail title since it significantly decreases the image quality for DirectX 9 users, Heaven is a benchmark and tech demo, and as a result we finally have a vivid example of what tessellation can do for the graphics in a game.
While our comparison images are with DirectX 9 and 11, it's worth noting that tessellation is also unavailable in DirectX 10. Overall, Unigine Heaven's DirectX 10 mode looks roughly similar to its DirectX 9 mode, in terms of overall image quality.
Other areas where tessellation plays a key role in providing image quality are the stone blocks which frame the bridge in the second to last comparison image (below, left) and the cobblestone roads in the last image (below, right). Without tessellation, the DirectX 9 rendering makes the bridge and road appear relatively smooth while the tessellated DirectX 11 rendering is extremely bumpy with significantly elevated geometry detail.
Tessellation certainly isn't the only DirectX 11 feature implemented by Unigine, it also claims to implement screen-space ambient occlusion (SSAO) and makes use of the DirectCompute API and the new Shader Model 5.0 features like compute shaders. However, the only DirectX 11 feature we really noticed in the Heaven benchmark is the tessellation effect. If SSAO and the other features are implemented in Heaven, we didn't notice them.
It's worth noting that we performed our image quality comparison with the first version of the Heaven benchmark, since we performed our Unigine Heaven image quality analysis a while back. But before this article was completed, a second version of Heaven was released. Heaven 2.0 extends the first edition with the addition of a new airship area to the map, which may implement some of the features we found lacking in the first edition of Heaven. You can view a video of Heaven 2.0 here, or (especially if you have DirectX 11 hardware) head over to the Unigine website and try the benchmark on your own system.
Overall, the Unigine Heaven benchmark is a very good looking tech demo. It certainly makes the Unigine engine look very impressive and we can't wait for retail titles built on Unigine to start appearing. Unigine also offers us the first truely vivid example of tessellation in action, but many of the other DirectX 11 image quality features, many of which are implemented by the other games featured in this article, are oddly missing from the benchmark. Or perhaps they are so subtle that they were lost among the extreme use of tessellation.