nVidia Cards for CAVE Apps - Antialiasing

GeForce and Quadro cards include a so-called FSAA (full-scene antialiasing) feature, which is basically oversampling. However, it does not use the OpenGL multi-sampling extensions, as found on Onyxes, but instead does it in a more 'hidden' way - programs don't have any direct control over it, it's simply enabled or disabled by the user at run-time.

To turn on FSAA, do

        setenv __GL_ENABLE_FSAA 1 
Then select what level of antialiasing you want by setting the environment variable __GL_FSAA_QUALITY to 0, 1, or 2. 0 is 1.5 x 1.5 oversampling, 1 is 2x2 oversampling with a texture LOD bias, and 2 is 2x2 oversampling without texture LOD bias.

[Update: the way to enable FSAA has changed in more recent drivers from nVidia (1.0 and later); consult nVidia's documentation for the currently correct method.]

The following pictures show a view of Virtual Harlem, with and without FSAA. First, the scene without antialiasing:

Next, with antialiasing enabled, with quality set to 1 (2x2 and texture LOD bias):

Finally, with antialiasing quality 2 (2x2, no texture LOD bias):

Below are three closeups from the above images.

withoutAA-closeup.png withAA1-closeup.png withAA2-closeup.png
Last modified 3 October 2001.
Dave Pape, pape@evl.uic.edu