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	xmlns:mml="http://www.w3.org/1998/Math/MathML"
><head><title>gluLookAt</title><link rel="stylesheet" href="style.css" type="text/css"/><meta name="generator" content="DocBook XSL Stylesheets V1.59.1"/><link rel="home" href="index.xml" title="PyOpenGL 2.0.1.07 Man Pages"/><link rel="up" href="reference-GLU.xml" title="GLU"/><link rel="previous" href="gluLoadSamplingMatrices.3G.xml" title="gluLoadSamplingMatrices"/><link rel="next" href="gluNewNurbsRenderer.3G.xml" title="gluNewNurbsRenderer"/></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">gluLookAt</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="gluLoadSamplingMatrices.3G.xml">Prev</a> </td><th width="60%" align="center">GLU</th><td width="20%" align="right"> <a accesskey="n" href="gluNewNurbsRenderer.3G.xml">Next</a></td></tr></table><hr/></div><div class="refentry" lang="en"><a name="gluLookAt.3G"/><div class="titlepage"/><div class="refnamediv"><a name="gluLookAt.3G-name"/><h2>Name</h2><p>gluLookAt &#8212; define a viewing transformation</p></div><div class="refsynopsisdiv"><a name="gluLookAt.3G-c_spec"/><h2>C Specification</h2><table class="funcprototype" border="0" cellpadding="0" cellspacing="0"><tr><td valign="top"><code>void <tt>gluLookAt</tt></code></td><td valign="top"><code>(</code></td><td valign="top"><code>GLdouble <i><tt>eyeX</tt></i>, GLdouble <i><tt>eyeY</tt></i>, GLdouble <i><tt>eyeZ</tt></i>, GLdouble <i><tt>centerX</tt></i>, GLdouble <i><tt>centerY</tt></i>, GLdouble <i><tt>centerZ</tt></i>, GLdouble <i><tt>upX</tt></i>, GLdouble <i><tt>upY</tt></i>, GLdouble <i><tt>upZ</tt></i>);</code></td></tr></table></div><div class="refsynopsisdiv"><a name="gluLookAt.3G-python_spec"/><h2>Python Specification</h2><table class="funcprototype" border="0" cellpadding="0" cellspacing="0"><tr><td valign="top"><code><tt>gluLookAt</tt></code></td><td valign="top"><code>(</code></td><td valign="top"><code><i><tt>eyeX</tt></i>, <i><tt>eyeY</tt></i>, <i><tt>eyeZ</tt></i>, <i><tt>centerX</tt></i>, <i><tt>centerY</tt></i>, <i><tt>centerZ</tt></i>, <i><tt>upX</tt></i>, <i><tt>upY</tt></i>, <i><tt>upZ</tt></i>) &#8594; <tt>None</tt></code></td></tr></table></div><div class="refsect1" lang="en"><a name="gluLookAt.3G-parameters"/><h2>Parameters</h2><div class="variablelist"><dl><dt><span class="term"><i><tt>eyeX</tt></i>, <i><tt>eyeY</tt></i>, <i><tt>eyeZ</tt></i></span></dt><dd>
						Specifies the position of the eye point.
					</dd><dt><span class="term"><i><tt>centerX</tt></i>, <i><tt>centerY</tt></i>, <i><tt>centerZ</tt></i></span></dt><dd>
						Specifies the position of the reference point.
					</dd><dt><span class="term"><i><tt>upX</tt></i>, <i><tt>upY</tt></i>, <i><tt>upZ</tt></i></span></dt><dd>
						Specifies the direction of the <i><tt>up</tt></i> vector.
					</dd></dl></div></div><div class="refsect1" lang="en"><a name="gluLookAt.3G-description"/><h2>Description</h2><p>
			<tt>gluLookAt</tt> creates a viewing matrix derived from an eye point, a reference point indicating the
			center of the scene, and an <i><tt>UP</tt></i> vector.
		</p><p>
			The matrix maps the reference point to the negative <i><tt>z</tt></i> axis and the eye point to the origin. When
			a typical projection matrix is used, the center of the scene therefore maps to the center of the viewport. Similarly,
			the direction described by the <i><tt>UP</tt></i> vector projected onto the viewing plane is mapped to the
			positive <i><tt>y</tt></i> axis so that it points upward in the viewport. The <i><tt>UP</tt></i> vector
			must not be parallel to the line of sight from the eye point to the reference point.
		</p><p>
			Let </p><div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" mode="display" overflow="scroll">
					<mml:mrow>
						<mml:mi>F</mml:mi>
						<mml:mo>=</mml:mo>
						<mml:mrow>
							<mml:mo>(</mml:mo>
							<mml:mrow>
								<mml:mtable>
									<mml:mtr>
										<mml:mtd columnalign="center">
											<mml:mi>centerX</mml:mi>
										</mml:mtd>
										<mml:mtd columnalign="center">
											<mml:mo>-</mml:mo>
										</mml:mtd>
										<mml:mtd columnalign="center">
											<mml:mi>eyeX</mml:mi>
										</mml:mtd>
									</mml:mtr>
									<mml:mtr>
										<mml:mtd columnalign="center">
											<mml:mi>centerY</mml:mi>
										</mml:mtd>
										<mml:mtd columnalign="center">
											<mml:mo>-</mml:mo>
										</mml:mtd>
										<mml:mtd columnalign="center">
											<mml:mi>eyeY</mml:mi>
										</mml:mtd>
									</mml:mtr>
									<mml:mtr>
										<mml:mtd columnalign="center">
											<mml:mi>centerZ</mml:mi>
										</mml:mtd>
										<mml:mtd columnalign="center">
											<mml:mo>-</mml:mo>
										</mml:mtd>
										<mml:mtd columnalign="center">
											<mml:mi>eyeZ</mml:mi>
										</mml:mtd>
									</mml:mtr>
								</mml:mtable>
							</mml:mrow>
							<mml:mo>)</mml:mo>
						</mml:mrow>
					</mml:mrow>
				</mml:math></div><p>
		</p><p>
			Let <i><tt>UP</tt></i> be the vector <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
					<mml:mrow>
						<mml:mo>(</mml:mo>
						<mml:mi>upX</mml:mi>
						<mml:mi>upY</mml:mi>
						<mml:mi>upZ</mml:mi>
						<mml:mo>)</mml:mo>
					</mml:mrow>
				</mml:math>.
		</p><p>
			Then normalize as follows: </p><div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" mode="display" overflow="scroll">
					<mml:mrow>
						<mml:mi>f</mml:mi>
						<mml:mo>=</mml:mo>
						<mml:mfrac>
							<mml:mi>F</mml:mi>
							<mml:mrow>
								<mml:mo>|</mml:mo>
								<mml:mo>|</mml:mo>
								<mml:mi>F</mml:mi>
								<mml:mo>|</mml:mo>
								<mml:mo>|</mml:mo>
							</mml:mrow>
						</mml:mfrac>
					</mml:mrow>
				</mml:math></div><p>
		</p><p>
			</p><div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" mode="display" overflow="scroll">
					<mml:mrow>
						<mml:msup>
							<mml:mi>UP</mml:mi>
							<mml:mo>'</mml:mo>
						</mml:msup>
						<mml:mo>=</mml:mo>
						<mml:mfrac>
							<mml:mi>UP</mml:mi>
							<mml:mrow>
								<mml:mo>|</mml:mo>
								<mml:mo>|</mml:mo>
								<mml:mi>UP</mml:mi>
								<mml:mo>|</mml:mo>
								<mml:mo>|</mml:mo>
							</mml:mrow>
						</mml:mfrac>
					</mml:mrow>
				</mml:math></div><p>
		</p><p>
			Finally, let <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
					<mml:mrow>
						<mml:mi>s</mml:mi>
						<mml:mo>=</mml:mo>
						<mml:mi>f</mml:mi>
						<mml:mo>×</mml:mo>
						<mml:msup>
							<mml:mi>UP</mml:mi>
							<mml:mo>'</mml:mo>
						</mml:msup>
					</mml:mrow>
				</mml:math>, and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
					<mml:mrow>
						<mml:mi>u</mml:mi>
						<mml:mo>=</mml:mo>
						<mml:mi>s</mml:mi>
						<mml:mo>×</mml:mo>
						<mml:mi>f</mml:mi>
					</mml:mrow>
				</mml:math>.
		</p><p>
			M is then constructed as follows: </p><div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" mode="display" overflow="scroll">
					<mml:mrow>
						<mml:mi>M</mml:mi>
						<mml:mo>=</mml:mo>
						<mml:mrow>
							<mml:mo>(</mml:mo>
							<mml:mtable>
								<mml:mtr>
									<mml:mtd columnalign="center">
										<mml:mi>s</mml:mi>
										<mml:mo>[</mml:mo>
										<mml:mn>0</mml:mn>
										<mml:mo>]</mml:mo>
									</mml:mtd>
									<mml:mtd columnalign="center">
										<mml:mi>s</mml:mi>
										<mml:mo>[</mml:mo>
										<mml:mn>1</mml:mn>
										<mml:mo>]</mml:mo>
									</mml:mtd>
									<mml:mtd columnalign="center">
										<mml:mi>s</mml:mi>
										<mml:mo>[</mml:mo>
										<mml:mn>2</mml:mn>
										<mml:mo>]</mml:mo>
									</mml:mtd>
									<mml:mtd columnalign="center">
										<mml:mn>0</mml:mn>
									</mml:mtd>
								</mml:mtr>
								<mml:mtr>
									<mml:mtd columnalign="center">
										<mml:mi>u</mml:mi>
										<mml:mo>[</mml:mo>
										<mml:mn>0</mml:mn>
										<mml:mo>]</mml:mo>
									</mml:mtd>
									<mml:mtd columnalign="center">
										<mml:mi>u</mml:mi>
										<mml:mo>[</mml:mo>
										<mml:mn>1</mml:mn>
										<mml:mo>]</mml:mo>
									</mml:mtd>
									<mml:mtd columnalign="center">
										<mml:mi>u</mml:mi>
										<mml:mo>[</mml:mo>
										<mml:mn>2</mml:mn>
										<mml:mo>]</mml:mo>
									</mml:mtd>
									<mml:mtd columnalign="center">
										<mml:mn>0</mml:mn>
									</mml:mtd>
								</mml:mtr>
								<mml:mtr>
									<mml:mtd columnalign="center">
										<mml:mo>-f</mml:mo>
										<mml:mo>[</mml:mo>
										<mml:mn>0</mml:mn>
										<mml:mo>]</mml:mo>
									</mml:mtd>
									<mml:mtd columnalign="center">
										<mml:mo>-f</mml:mo>
										<mml:mo>[</mml:mo>
										<mml:mn>1</mml:mn>
										<mml:mo>]</mml:mo>
									</mml:mtd>
									<mml:mtd columnalign="center">
										<mml:mo>-f</mml:mo>
										<mml:mo>[</mml:mo>
										<mml:mn>2</mml:mn>
										<mml:mo>]</mml:mo>
									</mml:mtd>
									<mml:mtd columnalign="center">
										<mml:mn>0</mml:mn>
									</mml:mtd>
								</mml:mtr>
								<mml:mtr>
									<mml:mtd columnalign="center">
										<mml:mn>0</mml:mn>
									</mml:mtd>
									<mml:mtd columnalign="center">
										<mml:mn>0</mml:mn>
									</mml:mtd>
									<mml:mtd columnalign="center">
										<mml:mn>0</mml:mn>
									</mml:mtd>
									<mml:mtd columnalign="center">
										<mml:mn>1</mml:mn>
									</mml:mtd>
								</mml:mtr>
							</mml:mtable>
							<mml:mo>)</mml:mo>
						</mml:mrow>
					</mml:mrow>
				</mml:math></div><p>
		</p><p>
			and <tt>gluLookAt</tt> is equivalent to glMultMatrixf(M); glTranslated (-eyex, -eyey, -eyez);
		</p></div><div class="refsect1" lang="en"><a name="gluLookAt.3G-see_also"/><h2>See Also</h2><p>
			<span class="simplelist"><a href="glFrustum.3G.xml">glFrustum</a>, <a href="gluPerspective.3G.xml">gluPerspective</a></span>
		</p></div></div><div class="navfooter"><hr/><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="gluLoadSamplingMatrices.3G.xml">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="reference-GLU.xml">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="gluNewNurbsRenderer.3G.xml">Next</a></td></tr><tr><td width="40%" align="left" valign="top">gluLoadSamplingMatrices </td><td width="20%" align="center"><a accesskey="h" href="index.xml">Home</a></td><td width="40%" align="right" valign="top"> gluNewNurbsRenderer</td></tr></table></div></body></html>
