In multisample anti-aliasing mode, the Z-buffer informntion is retained all the way to
the Sub-sample level in order to retain hidden surface accuracy to the sub-pixel level.
When transparency is used, the Alpha value determines how much to blend the color
of the closer pixel with the color of the farther pixel at that same location.
5.6.7 Anti-aliasing
 
Perhaps the most radical new feature of the RealityEngine graphics architecture is the
high-performance anti-aliasing hardware.  To provide the highest available image
quality, memory and processors have been placed in the Raster Management
subsystem to provide multisampled anti-aliasing at no performance penalty.  Anti-
aliasing with RealityEngine requires no sorting of data and operates in conjunction
with the Z-buffer far superior hidden surface removal.

Anti-aliasing is accomplished by retaining subpixel information for all vertices as they
are transformed and processed through the pipeline.  Each vertex is computed with an
accuracy down to an 8x8 subplxel grid.  Thus, there are 64 subpixel locations for each
pixel rendered.  When deciding how to color a pixel, the system samples the subpixel
grid with a certain number of samples per pixel, then determines the pixel coverage
based upon the number of samples hit.

TABLE 4 Anti-aliasing Sample Memory Options
 
With One Raster Manager, there is sufficient memory for:
640x512 resolution 16 samples 8 bits/sub-sample component for RGB 24-bit Z-buffer
8 samples 12 bits/sub-sample component for RGBA 32-bit Z-buffer
1280x1024 resolution 0 samples 12 bits/sub-sample component for RGBA 32-bit Z-buffer
With Two Raster Managers, there is sufficient memory for:
1280x1024 resolution 8 samples 8 bits/sub-sample component for RGB 24-bit Z-buffer
4 samples 12 bits/sub-sample component for RGBA 32-bit Z-buffer
1600x1200 resolution 0 samples 12 bits/sub-sample component for RGBA 32-bit Z-buffer
With Four Raster Managers, there is sufficient memory for:
1280x1024 resolution 16 samples 8 bits/sub-sample component for RGB 24-bit Z-buffer
8 samples 12 bits/sub-sample component for RGBA 32-bit Z-buffer
1600x1200 resolution 8 samples  8 bits/sub-sample component for RGB 24-bit Z-buffer
0 samples 12 bits/sub-sample component for RGBA 32-bit Z-buffer

Point Sampled

During point sampling, the system determines, for each sample location within the
pixel, whether that sample is covered by the rendered polygon, vector, or point.

Area Sampled

In area sampling, however, the system measures the percentage of the pixel covered
by the primitive and translates that into the nearest covered point samples.  In both