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<div class="moz-cite-prefix">On 09/16/14 10:46, wrote:<br>
</div>
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cite="mid:C40B2F181831EF44A88CD73525827803130B16680D@MERCERMAIL.MercerU.local"
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<p>Okay!</p>
<p><br>
</p>
<p>For displayFunc(), can we only call that once?</p>
<p><br>
</p>
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Generally yes -- you should only have one display function -- BUT --
your display function can have multiple functions/methods etc. Most
of the code in your programs will be tied to the display func.
Once we hit animation the linkages between all of these glut
functions will become clearer. <br>
<br>
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cite="mid:C40B2F181831EF44A88CD73525827803130B16680D@MERCERMAIL.MercerU.local"
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</p>
<p>For the interact.c, why is it necessary to erase the box? Why
can't we run the initializing functions again?</p>
</blockquote>
<br>
In this particular program eraseBox sets the color back to white
(the background color) and replaces the selected pixels with that
color. I've never tried calling init again. Give it a shot. In
general, however, you only want to initialize your environment once
and then do all of the manipulations within your code. Later on,
when we start talking about all of the buffers and matrix stacks, if
you reinitialize these you will throw away information related to
the transforms on which you are working. Let's say you have a
matrix stack that has transformed you into a new coordinate system
for your viewport and another matrix stack that has transformed your
model into a different orientation. If you reinitialize you would
typically (at least in earlier versions of GL) loose all of the
information stored in your matrix stacks -- and you have no way to
re-create it.<br>
<br>
<br>
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cite="mid:C40B2F181831EF44A88CD73525827803130B16680D@MERCERMAIL.MercerU.local"
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<p><br>
</p>
<p>How exactly does the glutMainLoop work?</p>
<p><br>
</p>
</blockquote>
<br>
glutMainLoop runs the "callback processor". It is what looks for
events that change in the state of the system and then calls the
appropriate glut function (glutKeyboardFunc, glutDisplayFunc, etc.,
to process the event.) <br>
<br>
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</p>
<p>For the rastered black box in parts 1 and 2 for the assignment,
assuming its a function, would we call the rastering function in
the initializing function or use the DisplayFunc? Why?</p>
</blockquote>
<br>
I personally would call it in the displayFunc. Again, this is my
preference because I like to separate out the pieces of the code to
things that I am "initializing" and things that I am responsible for
doing myself. As you will see later, I generally have individual
functions for all of these things. I have had students set up the
black box in both locations.<br>
<br>
<br>
Great questions! Keep 'em coming!<br>
<br>
<pre class="moz-signature" cols="72">--
Andrew J. Pounds, Ph.D. (<a class="moz-txt-link-abbreviated" href="mailto:pounds_aj@mercer.edu">pounds_aj@mercer.edu</a>)
Professor of Chemistry and Computer Science
Mercer University, Macon, GA 31207 (478) 301-5627
<a class="moz-txt-link-freetext" href="http://faculty.mercer.edu/pounds_aj">http://faculty.mercer.edu/pounds_aj</a>
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