Call of Duty: Black Ops II moves to DirectX 11 API from DirectX 9, bringing about improvements in lighting, shadows, depth of field, ambient occlusion and anti-aliasing. The move to DirectX 11 also means that the game engine is less CPU dependent and is much more highly optimized to utilize video card resources compared to older Call of Duty titles.
Ambient Occlusion and Depth of Field
A shading technique most modern gamers are familiar with, the image improvement brought upon by this global shading method is very noticeable, compared to previous titles lacking this technique. Screen Space Ambient Occlusion is hardly a new technique, implemented first in Crysis back in 2007. It is an efficient and dynamic implementation executed entirely from the GPU. Image performance is almost imperceptible between having Ambient Occlusion turned off vs. having it turned on with a noticeable framerate penalty, so users with a weaker graphics card can opt to disable this feature to gain framerate boost before they look to tweak anything else in their graphical setting.
As with previous Call of Duty games, there is a Depth of Field enhancement in effect in certain scenes, especially when aiming down sights. The surrounding areas lose focus while not completely blurred or imperceptible thanks to the DirectX11 improvement, which brings a more accurate depth of field calculation compared to the depth of field mask from the first Call of Duty: Black Ops title.
The merit of FXAA has been known for some time now and is present in most of the recent crop of popular games. It presents an efficient anti-aliasing solution over the traditional MSAA with nominal penalty to framerates. As we have also seen in some games, there is image quality degradation visible as blurry textures when this technique is used. Setting FXAA to Very High doesn't seem to have as much of a negative impact to the texture quality in Black Ops II, however, perhaps due to the massive texture size that the details are not lost. FXAA is especially useful for ultra-high resolution settings, such as 2560x1600, or triple-monitor surround, allowing playable framerates with maximum setting, even on just a single GeForce GTX 670.
The latest Kepler cards are capable of TXAA, which comes in 2X and 4X modes. TXAA is essentially an improved MSAA that fixes temporal aliasing artifact issues allowing for a smoother motion sequence compared to traditional anti-aliasing modes. TXAA should not be enabled when using FXAA or Ambient Occlusion, however, as it will result in blurriness.