In the first part of the Display menu you can select the display mode:
A similar pullright menu is available for the interactive display
mode, which is applied during navigation.
An extra item "the same" uses the same display mode during navigation
and for still images.
The default display mode is Smooth Shading, meaning you have to change
to Texturing yourself to display or load textures. The Mesa version by default
uses Flat Shading and Wireframe during navigation.
toggles line (wireframe) antialiasing. Antialiasing is currently not
supported by Mesa.
The OpenGL version of VRweb lets you control texture antialiasing
(filtering and mipmapping), features not yet supported by Mesa. To
turn it on (best quality) use the shortcut ^M
(shift-ctrl-M). To turn it off (faster, aliasing effects during
motion) ^N (shift-ctrl-N). There are also 4 intermediate levels
available.
displays the time it took to draw the last image and the
frame-per-second rate. The time is measured from the completion of one
drawing to the next and therefore also includes the time for putting
the image on screen and event processing.
switches back to the title or URL in the status line if hidden by
navigation hints.
in VRML polygons are visible from both sides by default and there is a
ShapeHint for showing polygons from the front only. Single-sided
polygon rendering (known as backface culling) is faster (because only
half of the polygons are visible), but requires properly oriented
facets. With setting "on" or "off" you can force two-sided or
single-sided polygons. The default "auto" tracks the ShapeHint.
normally, under VRML, lighting calculations are always
performed. However they can be computationally expensive and therefore
there is a LightModel extension node to VRML, which is recognized by
VRweb on setting "auto". With "on" or "off" you can force lighting
calculations to be made always or never. Lighting calculations are
usually turned off for prelit scenes. This yields faster rendering,
but causes unrealistic effects in other scenes.
The color of a texture map can be combined with the material color (if
this option is active), or mapped directly to the object ignoring the
material color (if this option is inactive). In the latter case
lighting calculations are turned off for textures. Future versions
will support a third option for performing light calculations using
the color of the texture.
Texture maps in GIF or PNG format (and also inline textures) may
contain transparency information, which is used unless you turn off
this option. You must also have turned on texture lighting to have
transparent textures (otherwise you see the untextured face through
parts where the texture is transparent).
Future releases will contain an option for setting the transparency
method for untextured scenes (stipple, blending).
toggles the use of an additional headlight, a light source shining in
the current view direction. When viewing scenes that contain no light,
the headlight is turned on automatically and this switch has no
influence. Of course, when lighting calculations are turned off, light
sources (incl. the headlight) have no influence. You can change the
intensity or color of the headlight
(see below).
Additionally, you can change the ambient light
intensity/color. This is a global, undirected light added to the
scene. Instead of brightening up colors (like the headlight) however,
it usually increases the intensity by a grey level (based on the
ambient material coefficients).
If you use the Mesa version, you can set up gamma correction to
brighten up the drawings. You have to set the environment variable
SGI supports gamma correction via the Xserver (see man gamma), so
there is no need to do it in Software. OpenGL itself provides
no way to change gamma.
Supported texture image formats are JPEG, GIF, TIFF, PNG, and VRML
inline-textures. Transparent textures (GIF, PNG, inline) are supported
also.
Common platform specific formats like SGI/RGB and BMP may be supported
in a future version - their use is discouraged for cross platform
portability and because of their poor compression (also TIFF falls
into this category).
Texture transfer is initiated when switching the drawing mode to
texturing (ctrl-t). The right field of the status line contains the
hint "textured" if there are any texture references in the scene. For
more details on transfer issues see description for inline scenes. For antialiasing and transparency settings
for textures see above.
These options concern anchor
display and appearance.
Display (accelerator key F9) toggles anchor
highlighting.
The effect of the different hightlighting methods are also described on
the anchor page.
Via Choose... you can open a dialog for interactive color
selection. In the listbox in the top-right select the color you wish
to change:
You can use the RGB or HLS color space for selections. Values can be
changed with the sliders or by typing in the new values and entering
Return. The field on the left side contains a predefined color map to
choose from. With the Apply button you can test the changes;
when finished, confirm them with OK or press Cancel to
reject all changes.
The other items contain a set of predefined colors, e.g. for quick
change of the background color to black, grey, lightgrey or white.
Back to overview.
Drawing Style
(use the
accelerator keys above, holding both the shift and ctrl key)
(accelerator key ctrl-u)
Display Options
Lighting Options
Gamma Correction
MESA_GAMMA
before starting VRweb. Some examples for
uniform and non-uniform (RGB separately) gamma correction and
deactivating it (depends on shell used):
[csh/tcsh etc.:] setenv MESA_GAMMA 2.0
setenv MESA_GAMMA "1.6 1.7 1.9"
unsetenv MESA_GAMMA
[sh/ksh/bash etc.:] MESA_GAMMA=2.0 ; export MESA_GAMMA
MESA_GAMMA="1.6 1.7 1.9" ; export MESA_GAMMA
unset MESA_GAMMA
Texturing
Anchor Settings
Also available as button in the toolbar.
Color Selection