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<pre style="max-height: 500px; overflow: auto;">*** Found expression $left = -right$
*** Found expression $right = (top) (aspect)$
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So problem 1 on page 145 of whitrow is basically asking you to
convert the glFrustum matrix<br>
<br>
<a class="moz-txt-link-freetext" href="https://www.opengl.org/sdk/docs/man2/xhtml/glFrustum.xml">https://www.opengl.org/sdk/docs/man2/xhtml/glFrustum.xml</a><br>
<br>
to a gluPerspective matrix. I was hoping this would help you with
your programming assignment, but it has apparently caused some of
you a great deal of trouble.<br>
<br>
According to the man page, gluPerspective takes the following
arguments...<br>
<br>
void gluPerspective( GLdouble fovy, GLdouble aspect, GLdouble
zNear, GLdouble zFar )<br>
<br>
<br>
glFrustum, however, takes a different set of arguments,<br>
<br>
void glFrustum( GLdouble left, GLdouble right,<br>
GLdouble bottom, GLdouble top,<br>
GLdouble zNear, GLdouble zFar )<br>
<br>
<br>
So, we have to use the fovy and aspect ratio (look these up in the
OpenGL Red Book online) to come up with equations for<br>
left, right, bottom, top.<br>
<br>
Here they are... Happy Thankgiving...<br>
<br>
<img style="vertical-align: middle"
src="cid:part2.09010501.08030107@mercer.edu" alt="$top =
\tan(\frac{fovy}{360}\pi) ( zNear)$"><br>
<img style="vertical-align: middle"
src="cid:part3.09000303.01020508@mercer.edu" alt="$bottom = -top$"><br>
<img style="vertical-align: middle"
src="cid:part4.09050909.05060607@mercer.edu" alt="$right = (top)
(aspect)$"><br>
<img style="vertical-align: middle"
src="cid:part5.07080604.00030501@mercer.edu" alt="$left = -right$"><br>
<br>
<br>
<br>
Now, because I have given you this you do not have to do problem 1
on page 145 of Whitrow -- but you MUST correctly<br>
implement the glFrustum command (as described in the programming
assignment) to receive credit for getting problem 1 on page 145 of
Whitrow correct.<br>
<br>
Got it?<br>
<br>
<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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