<!--#set var="name" value="Written Exercise 3" -->
<!--#include virtual="header.html" -->
<!--
<head><title>COS 526, Fall 2006: Written Exercise 3</title></head>
<body bgcolor="#ffffff" text="#000000">
<center><h2>COS 526 - Advanced Computer Graphics</h2></center>
-->


<h2>Written Exercise 3</h2>
<b>Due Tuesday, Nov. 28</b>

<ol>
<li> A diffuse light source with area <i>A</i> emits equal radiance <i>L</i>
everywhere across its surface, uniformly in all directions.  Find the total
power emitted.

<li> A point light source having an intensity of 1 watt per steradian
(emitting uniformly in all directions) is 1 meter away from the center
of a square patch of surface, of edge length 1 meter.  Find the
irradiance at the center of the square, and at the corner.
<center>
<br>
<br>
<img src="exercise3_fig.gif"
<br>
<br>
<br>
</center>

<li> Following are three different versions of the rendering equation.
For each one, provide a picture ad short phrase or equation describing each
term (e.g., <i>I(x' -> x'')</i> is the intensity of light traveling from point
<i>x'</i> to point <i>x''</i>).  Then, show that the equations are the same by
deriving two of them from one of the others.
<center>
<img src="exercise3_eqn.gif">
</center>
</ol>

<p>
<h3> Submitting </h3>
<p>
Please submit the answers to these questions in writing in class on
November 28 or by pdf via email to
<tt>funk@princeton.edu</tt> (please include "CS526" in the 
subject line).
<p>
Please see the <a href="assignments.html#submitting">general
notes on submitting your assignments</a>, as well as the
<a href="assignments.html#late">late policy</a> and the
<a href="assignments.html#collaboration">collaboration policy</a>.


<!--#include virtual="footer.html" -->
