Using glman - Graphics Shaders - page 78

MessageBox An informative
text message

Put up a Message Box with the text message in it so
you can show an informative message to the user.

Sets the system to output all actions to the console
window, overriding the function in the interface
window.

Verbose

The text conventions in GLIB files are
• Multiple whitespace characters in a row are treated as a single whitespace
character.
• A # causes the rest of the line to be treated as a comment and ignored.
• A / causes the rest of the line to be treated as a comment and ignored (so
that // will act as expected).
• A backslash (\) at the end of a line causes the carriage return to be
ignored. The current line is continued onto the next line. This must be the
last character on that line before the return.

You can see that the available geometry in glman is good, but it is prob-
ably not rich enough to support many real applications. That is deliberate—
glman is only intended to give you a testbed to support your experimentation
with shaders. From the experience of students and others who have used it, it
does that well.

Specifying Uniform Variables
Uniform variables are specified on the Program command line in a tag-value
pair format. The values may be scalars, arrays, range variables, or colors.
• Scalar variables are just listed as numbers.
• Array variables are enclosed in square brackets, as [ ].
• Range variables are enclosed in angle brackets, as < >. These are scalar
variables, and glman automatically generates a slider in the Uniform
Variable user interface for each range variable, so that you can then
change this value as glman executes. The three values in the brackets are
<min current max>, e.g., <0. 5. 10.>. To decide if this range variable should
be a float or an int, glman will look into your shader program's symbol
table, and will create a slider of the appropriate type.
• Boolean variables can also end up in your user interface as well. In the
GLIB file, a Boolean variable has a name, and then the word true or the
word false inside angle brackets, e.g., “<true>.” The glman user interface
will automatically create a checkbox in the user interface window. The
value in the brackets is the initial seting of the checkbox.