Creative 3D Blaster 5 FX5900 Ultra Review - Page 3 Of 7
By Steve Angelly & Mike Chambers - September 11, 2003
ANTIALIASING IMAGE QUALITY
Antialiasing is a useful feature that unofficially debuted over three years ago in the leaked Detonator 5.08 drivers. The supersampling antialiasing algorithm NVIDIA employed was effective in smoothing the stairstep-like effect on edges and reducing artifacts like texture aliasing and moiré patterns. The Detonator driver allowed antialiasing as an option on the GeForce and GeForce2 although the performance hit was steep.
No AA vs. 3x3 Supersampling
With the GeForce3, NVIDIA's engineers designed multisampling antialiasing in hardware and performance skyrocketed in OpenGL and Direct3D games. As memory bandwidth and fill rate increased, new forms of antialiasing were devised by NVIDIA that included using a combination of multisampling and supersampling. Senior nV News forum moderator StealthHawk has put together an excellent source of information on the subject, which you can read about here.
While the hybrid multisampling and supersampling modes such as 4XS, 6XS and 8XS provide better quality than their multisampling counterparts, their use can result in a substantial loss in performance - even on the GeForce FX 5900 Ultra. However, we have found 4XS to a viable choice at 1024x768 for slower paced games like flight and race sims and role playing games. Unfortunately, 4XS is limited to Direct3D applications. Overall, the GeForce FX 5900 Ultra seems to work best with 4X antialiasing at a resolution of 1024x768, 1280x1024 and 1600x1200 in some cases.
Interactive Antialiasing Comparison
Another factor in determining the overall quality of antialiasing is the sub-pixel sampling pattern. The GeForce FX makes use of ordered grid and rotated grid sampling patterns. High quality antialiasing solutions generally rely on rotated grid sampling patterns although the difference in quality between ordered and rotated grids is becoming less as we begin to use antialiasing at high resolutions like 1280x1024 and 1600x1200. More information on sampling patterns can be found in this article at 3D Center.
The following images were taken from the Midway map starting point in Battlefield 1942 and illustrate the various modes of antialiasing supported by the GeForce FX. Each image was enlarged by 50% to provide you with a better perspective on how effective a particular method of antialiasing is. The frame rate as reported by FRAPS at the time the screenshot was taken is also displayed in the title that appears above each image.
The performance associated with 6X AA and higher will limit their use to special circumstances.
Antialiasing In Motion
Better examples of antialiasing in action are illustrated in the following video clips that we recorded using a GeForce FX 5900 Ultra. The first video, which contains around 10 seconds of footage, shows a teapot being rendered at a constant rate of 20 frames per second. These videos serve a couple of purposes. First, they illustrate antialiasing in motion, which cannot be captured in a static screenshot. Second, the non-antialiased video shows the "texture crawling" effect that is prevalent on the edges of the teacup as it rotates. Decreasing the video playback speed illustrates the effect very well. When viewing the 8X antialiasing video, you'll find that the edges are extremely smooth and the texture crawling effect has been virtually eliminated.
Teapot Video Clip
The teapot video was captured with the program avicap, which was developed by Tom Nuydens at Delphi3D to demonstrate capturing video in an OpenGL program. The program is based on software from NVIDIA's OpenGL SDK. The videos were recorded using the Detonator FX 44.03 drivers, which we could only get 8X antialiasing to record. Note that Microsoft's MPEG4 Codec is needed to play the videos using Windows Media Player.
The next set of video clips were generated by FRAPS and were compressed in DivX format using VirtualDub. The videos were recorded at a resolution of 1024x768 at 25 frames per second and are around 6 seconds in length.
Quake 3 Video Clip
In these Quake 3 videos, the player was positioned at a starting point and remained stationary while the view was being panned towards the left. To slow down the movement rate while panning, the cl_yawspeed variable was set to 5.
As with the teapot video, you'll find a large amount of texture crawling that is reduced as the level of antialiasing increases.
It's very important that your desktop resolution be large enough to support playing back the videos at the recorded resolution of 1024x768. You want to avoid the video playback software from automatically resizing the video to a resolution lower than 1024x768.