Graphics Reference
In-Depth Information
Functions in the glman Interface Window
The
glman
user interface window includes a number of other functions besides
loading GLIB files, which we saw at the beginning of this chapter. In this sec-
tion, we will look at them so you can use them easily in your work.
Generating and Displaying a Hardcopy of Your Scene
Generating a hardcopy.
Because you will be doing cool things with
glman
,
you will often want to write your output to an image file. The Hardcopy and
Display buton shown in Figure 4.2 expands as shown in Figure 4.5. This gives
you a Create Hardcopy File buton that will write output (at the resolution you
specify in the resolution window) to a BMP file and will
bring up a file browser window that lets you specify the
name of the BMP file to write into. This does not just do a
raw pixel dump of the graphics window area; it generates
the scene into a separate framebuffer and writes that buf-
fer into the file, which means you can ask for a hardcopy
image that has higher resolution than your screen has. This
is useful when generating hardcopy for high-quality pub-
lications and large posters.
Figure 4.5.
The expanded screen
capture and display area.
Display the hardcopy file.
To confirm the hardcopy file you got, and perhaps
to send it to a printer, click on the Display the Hardcopy File buton.
Global Scene Transformation
The Global Scene Transformation widgets at the top of the transformation
group in Figure 4.6 let you transform the entire scene in the graphics window.
There are mouse buton shortcuts; the scene can be rotated by holding down
the left mouse buton and moving the cursor in the graphics window, or it can
be scaled by holding down the middle mouse buton (if you have one) and
moving the cursor in the graphics window.
It is important to realize that, unlike what is normally done in an OpenGL
program, these transformations do not end up in the ModelView matrix. In
glman
, they end up in the Projection matrix, so they have no impact on any-
thing your shaders do in eye coordinates. For example, these scene transfor-
mations can be used to see the back side of a scene without changing the eye
coordinate behavior of the shaders.
