Chapter 6
Using Sun XVR-4000 Graphics Accelerator Features
49
Controlling Jitter and Filtering
The following briefly describes jitter and filtering, which are set through
fbconfig
.
See the
SUNWzulu_config(1M)
man page for more details.
Jitter
Jitter indirectly determines the subpixel (X,Y) locations of the samples stored in the
sample buffer. The sample density also affects the sample locations.
describes the
fbconfig -jitter
options.
-jitter [regular | random | permuted | auto]
Because the subpixel locations of samples within pixels varies from pixel to pixel,
windows containing multisampled graphics should be redrawn after they are
moved. Until the application redraws the window, the window displays a crude
approximation of the original contents; straight lines or edges may appear jagged.
3D applications started after changing the
-jitter
option parameters will look
correct. Any 3D applications running when jitter is changed should be restarted. You
do not need to restart the window system.
TABLE 6-3
-jitter
Options
Option
Description
regular
Samples are regularly-spaced both vertically and horizontally.
However, the sample locations may differ between even and odd
pixels (repeating every 2 pixels in X and Y).
random
Samples are pseudo-randomly spaced within the pixel. The sample
locations repeat every 2 pixels in X and Y.
permuted
S
a
mples are pseudo-randomly spaced within the pixel, and also
permuted (stirred) in hardware so that the sample locations repeat
every 128 pixels in X and Y. At moderate to high sample density, this
choice can improve visual quality. At low sample densities, straight
lines or edges might appear jagged.
auto
Automatically selects the best jitter option for the current sample
density. This is the default.
