![[H]ardOCP](/images/blank.gif){kind=small}
- Date:
- Wednesday, December 23, 2009
- Author:
- Mark Warner
- Editor:
- Brent Justice
- Google +1
DiRT 2 Gameplay Performance and Image Quality
Have we go a treat for you; a detailed evaluation of real-world gameplay performance and image quality in the first newly shipped DX11 capable game title, DiRT 2. Does DX11 take a nose dive in performance compared to DX9 and does it provide real-world gameplay benefits? The results may surprise you.
Introduction
DiRT 2 is the sequel to 2007’s Colin McRae: DiRT from Codemasters. DiRT 2launched for consoles in September 2009, but launched for Windows three months later on December 8th. Part of the reason for the delay is that DiRT 2 for PC comes out of the box with DirectX 11 support, which is officially enabled by Microsoft in Windows 7, and by AMD in the ATI Radeon HD 5000 series of video cards. DiRT 2 is a racing game which celebrates off-road racing of all types, including Rally races, the Baja, Trophy Trucks, and many others. Originally named Colin McRae: DiRT 2 (and still known by that moniker in Europe), it is the first game bearing his name since the revered Scottish driver’s death by helicopter crash in late 2007.
The console versions of DiRT 2 were well-received, garnering high marks from game critics and an aggregate score of 87/100 on metacritic. The PC version has been slightly better rated, scoring 89/90.
DiRT 2
DiRT 2 is an off-road arcade racing game, with five types of races. Rally mode is the "pure" rally racing experience with staggered driver starts, and takes place on point-to-point trails and roads. RallyCross uses the same cars as Rally, but features closed circuit tracks and lap-based technical racing. In TrailBlazer mode, drivers have staggered starts like in Rallies, but also feature more heavily modified cars featuring large aerodynamic aids. Raid races are like Rally races in that they are on point-to-point trails, but all of vehicles start at the same time in Raid mode, and it uses heavier vehicles such as trophy trucks and buggies. Landrush race events are similar to Raid races, except that they use closed circuit tracks, like RallyCross.
There are also special events, like GateCrasher, Domination, and Last Man Standing. GateCrasher is like Rally, except that the driver must knock over several yellow barriers on the trail. Domination is like RallyCross, except that drivers compete for the best time in a circuit’s sector, rather than entire laps. Last Man standing is an elimination-style race, in which the last place driver is ejected at the end of each lap.
DiRT 2 is a latecomer to the PC, and one of the last AAA gaming titles to be released for this holiday season. The PC version of DiRT 2 is coming to market with graphical features and advances that are not supported by the current-generation of video game consoles, which is reportedly the reason that the PC version’s release was delayed for three months.
The Technology
DiRT 2 uses the EGO engine, which also powered Colin McRae: DiRT, Race Driver: GRID, F1 2009, and even Operation Flashpoint: Dragon Rising, a tactical first-person shooter. Both of those games featured very lush and colorful graphics which ran beautifully on the hardware of the day, so we expect the same great performance from DiRT 2. The game engine was developed by CodeMasters and Sony, using Sony’s cross-platform "PhyreEngine" for graphics. The EGO Engine is not currently available for licensing by 3rd parties, so very little is actually known about its inner workings or technology outside of CodeMasters. Please note that CodeMasters’ EGO Engine is not the same as the graphics engine of the same name by independent Russian programmer Vyacheslav Egorov.
What we do know is that the iteration of EGO which powers DiRT 2 has DirectX 11 support, and we do have some specific information on the implementation of that API, provided to us by AMD. According to AMD, the following DirectX 11 features are built into DiRT 2:
For water, DiRT 2 actually uses the CPU to generate a height map for displacement of the water when a car drives through it. In DirectX 9, the height-map is applied to the surface of the water as a lighting modification to create the illusion of depth when the water splashes. In DirectX 11, the tessellation engine uses the height-map to generate new triangles with which to actually distort the surface of the water in 3-dimensions, instead of the 2D illusion we see in DX9. For the crowds, DiRT 2 utilizes Curved PN-Triangles ("N-Patches") to increase the smoothness of the spectators during rendering to save memory, so that more detailed meshes can be displayed without the high cost of storing more complex models in memory. The game uses the same Curved PN-Triangles to make cloth more complex. In DX9, the flags and banners consist of just a few polygons, while the tessellation engine in DX11 significantly increases the complexity of these simple objects.
DiRT 2 uses a DirectCompute 11 shader program to accelerate the production of HDAO by quickly detecting valleys in depth and adding the appropriate shadow. Without DirectCompute, this process is an expensive task which must sample the hardware depth buffer frequently. With the DX11 shader program, however, the game can store a tiled region of the depth buffer locally to the shader, which significantly decreases the burden of texture sampling. For HDR, the game uses a 64-bit texture format (R16G16B16A16, which is twice the resolution of DX9’s 32-bit (R8G8BA88) HDR format. The result should be smoother lighting gradients with less evidence of sharp transitions or banding. Post-processing in DiRT 2 is done at full-screen resolution, rather than one quarter of the screen resolution, which is used in DX9. This results in better quality lighting bloom and motion blurring with less flickering when the scene is in motion.
In our short look at the DiRT 2 demo, which came with all the same graphics features, we found that some of these options made very little difference at all, while some others were noticeable and appreciable. We certainly look forward to seeing what the full retail version of DiRT 2 has to offer.
The Video Cards
We have nine video cards for your reading enjoyment in this evaluation, including five from AMD and four from NVIDIA. From AMD, we have the ATI Radeon HD 5970, the Radeon HD 5870, the Radeon HD 5850, the Radeon HD 5770, and the Radeon HD 5750. From NVIDIA, we have the GeForce GTX 295, the GeForce GTX 285, the GeForce GTX 275, and the GeForce GTS 250.