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Setting PEX Configuration Parameters

This section describes the PEX remote configuration parameters. In the Setup menus, some PEX parameters are in Change Setup Parameters (in the PEX and PEX Colors hide boxes), and some are in Change User Preferences (in the PEX hide box). PEX parameters are not saved in NVRAM.

Setting the Parameters Listed in Change Setup Parameters

The PEX parameters in Change Setup Parameters take effect after rebooting, so they must be set in a remote configuration file.

The parameters described in this section control the maximum number of half-spaces for model clipping, the maximum number of name set identifiers, and the maximum number of non-ambient light sources. The default values of these parameters are the defaults specified by the PHIGS standard and should work for most applications.

The recommended terminal memory listed in the Release Notes is based on the default values of these parameters. Increasing the values of these parameters places increased demands on terminal memory.

Specifying the Number of Clipping Planes

The pex-max-model-clip-planes parameter specifies the maximum number of half-spaces that can be defined for the purpose of model clipping. Half-spaces are defined by the clipping plane. A half-space is an infinite region of modeling coordinate space bounded on one side by the clipping plane.

Table 14-1 pex-max-model-clip-planes Parameter
Possible Values
Result
default 64
integer The maximum number of model clipping half-spaces that can be defined. Range: 6 to 65535.

Specifying the Number of Name Sets

The pex-max-nameset-names parameter specifies the maximum number of name set identifiers that can be defined. This value must be a power of two. Setting this parameter to an integer that is not a power of two causes the parameter setting to be ignored.

A name set provides an identifier (unique name) for an individual primitive or a group of primitives. The identifier can then be used to pick or highlight all the primitives in the group or make them invisible.

Table 14-2 pex-max-nameset-names Parameter
Possible Values
Result
default 256
64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, or 32768 The maximum number of identifiers that can be defined.

Specifying the Number of Non-Ambient Light Sources

The pex-max-non-ambient-lights parameter specifies the maximum number of non-ambient light sources that can be defined.

The non-ambient light source types are directional light, positional light, and spot light.

Table 14-3 pex-max-non-ambient-lights Parameter
Possible Values
Result
default 64
integer The maximum number of non-ambient lights that can be defined. Range: 0 to 65535.

PEX Color Parameters

You may need to adjust PEX color parameters if:

Color parameters specify the color components of the properly adjusted display monitor according to the CIE (Commission Internationale de l'Eclairage) color space definition. The three color components (red, green, and blue) and the reference white value each consist of three coordinates (values). Each value is a floating point number ranging from a minimum of 0.0 to a maximum of 1.0. The three values are:

Color parameters do not directly affect colors displayed on the terminal. A client can use these values (for example, to set up a colormap to send to the server), but it is not required to use them.

Blue Color Component

The following parameters specify the three values that make up the blue color component of the properly adjusted display monitor. Each value can range from 0.0 to 1.0.

Table 14-4 pex-monitor-reference-blue-u Parameter
Possible Values
Result
default 0.1756
floating point number The u' CIE-chromaticity coordinate for the blue color component of the properly adjusted display monitor.

Table 14-5 pex-monitor-reference-blue-v Parameter
Possible Values
Result
default 0.1785
floating point number The v' CIE-chromaticity coordinate for the blue color component of the properly adjusted display monitor.

Table 14-6 pex-monitor-reference-blue-y Parameter
Possible Values
Result
default 1.0
floating point number The Y CIE-luminance coordinate for the blue color component of the properly adjusted display monitor.

Green Color Component

The following parameters specify the three values that make up the green color component of the properly adjusted display monitor. Each value can range from 0.0 to 1.0.

Table 14-7 pex-monitor-reference-green-u Parameter
Possible Values
Result
default 0.1169
floating point number The u' CIE-chromaticity coordinate for the green color component of the properly adjusted display monitor.

Table 14-8 pex-monitor-reference-green-v Parameter
Possible Values
Result
default 0.559
floating point number The v' CIE-chromaticity coordinate for the green color component of the properly adjusted display monitor.

Table 14-9 pex-monitor-reference-green-y Parameter
Possible Values
Result
default 1.0
floating point number The Y CIE-luminance coordinate for the green color component of the properly adjusted display monitor.

Red Color Component

The following parameters specify the three values that make up the red color component of the properly adjusted display monitor. Each value can range from 0.0 to 1.0.

Table 14-10 pex-monitor-reference-red-u Parameter
Possible Values
Result
default 0.4288
floating point number The u' CIE-chromaticity coordinate for the red color component of the properly adjusted display monitor.

Table 14-11 pex-monitor-reference-red-v Parameter
Possible Values
Result
default 0.5249
floating point number The v' CIE-chromaticity coordinate for the red color component of the properly adjusted display monitor.

Table 14-12 pex-monitor-reference-red-y Parameter
Possible Values
Result
default 1.0
floating point number The Y CIE-luminance coordinate for the red color component of the properly adjusted display monitor.

Reference White Value

The following parameters specify the three values that make up the reference white value of the properly adjusted display monitor. Each value can range from 0.0 to 1.0.

Table 14-13 pex-monitor-reference-white-u Parameter
Possible Values
Result
default 0.1884
floating point number The u' CIE-chromaticity coordinate for the reference white value of the properly adjusted display monitor.

Table 14-14 pex-monitor-reference-white-v Parameter
Possible Values
Result
default 0.4463
floating point number The v' CIE-chromaticity coordinate for the reference white value of the properly adjusted display monitor.

Table 14-15 pex-monitor-reference-white-y Parameter
Possible Values
Result
default 1.0
floating point number The Y CIE-luminance coordinate for the reference white value of the properly adjusted display monitor.

Setting the Parameters Listed in Change User Preferences

PEX user preference parameters allow users to manipulate PEX rendering by setting attributes such as shading, dithering, and light sources.

When set through Change User Preferences (Setup -> Change User Preferences), these parameters offer dynamic control over the client. All of the PEX preference parameters take effect immediately after they are applied.

Specifying the Nominal Line Width

The pref-pex-nominal-line-width parameter controls the nominal width (in pixels) of lines and curves. The nominal line width is a default size from which other line sizes are derived by applying a scaling factor (Setup -> Change User Preferences -> PEX -> Nominal Line Width).

This parameter allows you to match the appearance of lines and curves on an NCD terminal to their appearance on other displays.

Table 14-16 pref-pex-nominal-line-width Parameter
Possible Values
Result
default 1
integer Standard width of lines and curves (in pixels). Range: 1 to 64.

Specifying the Nominal Edge Width

The pref-pex-nominal-edge-width parameter controls the nominal width (in pixels) of edges of surface primitives when such edges are displayed. The nominal edge width is a default width from which other edge sizes are derived by applying a scaling factor (Setup -> Change User Preferences -> PEX -> Nominal Line Width).

Table 14-17 pref-pex-nominal-edge-width Parameter
Possible Values
Result
default 1
integer Standard width of surface primitive edges (in pixels) when edges are displayed. Range: 1 to 64.

Specifying the Nominal Marker Size

The pref-pex-nominal-marker-size parameter controls the nominal size (in pixels) of marker primitives. For example, if a + (plus) marker is 3 pixels wide, a nominal marker size of 2 makes the plus marker 6 pixels wide. Other marker types (except for dot markers) are scaled accordingly (Setup -> Change User Preferences -> PEX -> Nominal Marker Size).

Table 14-18 pref-pex-nominal-marker-size Parameter
Possible Values
Result
default 1
integer Standard width of marker primitives (in pixels). Range: 1 to 64.

Specifying Surface Dithering

The pref-pex-dither-flat-shaded-surface parameter controls flat-shaded surface dithering (Setup -> Change User Preferences -> PEX -> Dither Flat Shaded Surface).

Table 14-19 pref-pex-dither-flat-shaded-surface Parameter
Possible Values
Result
default by-request
by-request Flat-shaded surfaces are dithered only when the client requests it.
off Flat-shaded surfaces are never dithered.
on Flat-shaded surfaces are always dithered.

The pref-pex-dither-interpolated-surface parameter controls Gouraud-shaded surface dithering (half-toning) (Setup -> Change User Preferences -> PEX -> Dither Interpolated Surface).

Table 14-20 pref-pex-dither-interpolated-surface Parameter
Possible Values
Result
default on
on Gouraud-shaded surfaces are always dithered.
by-request Gouraud-shaded surfaces are dithered only when the client requests it.
off Gouraud-shaded surfaces are never dithered.

Specifying Surface Interior Style, Shading, and Lighting

The pref-pex-surface-interior-style parameter specifies how to render the interiors of surfaces (Setup -> Change User Preferences -> PEX -> Surface Interior Style).

Table 14-21 pref-pex-surface-interior-style Parameter
Possible Values
Result
default by-request
by-request Surface interiors are rendered as requested by the client.
hollow All surface interiors are rendered hollow.
solid All surface interiors are rendered solid.
empty All surface interiors are rendered empty.

The pref-pex-surface-interp-method parameter specifies how to shade the interiors of surfaces (Setup -> Change User Preferences -> PEX -> Surface Interpolation Method).

Table 14-22 pref-pex-surface-interp-method Parameter
Possible Values
Result
default by-request
by-request Surface interiors are shaded as requested by the client.
none All surface interiors are flat-shaded.
color All surface interiors are Gouraud-shaded.

The pref-pex-surface-reflect-model parameter specifies how to apply lighting effects to all surfaces (Setup -> Change User Preferences -> PEX -> Surface Reflection Model).

Table 14-23 pref-pex-surface-reflect-model Parameter
Possible Values
Result
default by-request
by-request Surface lighting effects are applied as requested by the client.
none Surfaces are not lighted.
ambient Only ambient lighting is used.
diffuse Ambient and diffuse lighting are used.
specular All lighting effects are used.

Specifying the Color Clipping Method

The pref-pex-color-clipping-method parameter specifies the method for clipping colors that cannot be displayed because their RGB (red, green, blue) components are outside the displayable range (0.0 through 1.0). Although the display hardware automatically clips values that are out of range, the resulting displayed color is unpredictable (Setup -> Change User Preferences -> PEX -> Color Clipping Method).

Color components may exceed the displayable range, for example, when numerous light sources are applied.

Table 14-24 pref-pex-color-clipping-method Parameter
Possible Values
Result
default none
none The RGB components are not corrected.
scale The RGB components are scaled proportionately if any components exceed 1.0. For example, if the red component has a value of 1.2, it is scaled to 1 and the green and blue components are scaled by the same percentage. Hue and saturation are maintained, while intensity is clipped.
desaturate The color saturation (contrast) of the RGB components is clipped, while the hue and intensity are maintained.
clamp The RGB components are set to 0 if they are less than 0.0 or to 1.0 if they are greater than 1.0. Clamping can potentially alter hue, saturation, and intensity.


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