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><head><title>glOrtho</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-GL.xml" title="GL"/><link rel="previous" href="glNormalPointer.3G.xml" title="glNormalPointer"/><link rel="next" href="glPassThrough.3G.xml" title="glPassThrough"/></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">glOrtho</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="glNormalPointer.3G.xml">Prev</a> </td><th width="60%" align="center">GL</th><td width="20%" align="right"> <a accesskey="n" href="glPassThrough.3G.xml">Next</a></td></tr></table><hr/></div><div class="refentry" lang="en"><a name="glOrtho.3G"/><div class="titlepage"/><div class="refnamediv"><a name="glOrtho.3G-name"/><h2>Name</h2><p>glOrtho &#8212; multiply the current matrix with an orthographic matrix</p></div><div class="refsynopsisdiv"><a name="glOrtho.3G-c_spec"/><h2>C Specification</h2><table class="funcprototype" border="0" cellpadding="0" cellspacing="0"><tr><td valign="top"><code>void <tt>glOrtho</tt></code></td><td valign="top"><code>(</code></td><td valign="top"><code>GLdouble <i><tt>left</tt></i>, GLdouble <i><tt>right</tt></i>, GLdouble <i><tt>bottom</tt></i>, GLdouble <i><tt>top</tt></i>, GLdouble <i><tt>zNear</tt></i>, GLdouble <i><tt>zFar</tt></i>);</code></td></tr></table></div><div class="refsynopsisdiv"><a name="glOrtho.3G-python_spec"/><h2>Python Specification</h2><table class="funcprototype" border="0" cellpadding="0" cellspacing="0"><tr><td valign="top"><code><tt>glOrtho</tt></code></td><td valign="top"><code>(</code></td><td valign="top"><code><i><tt>left</tt></i>, <i><tt>right</tt></i>, <i><tt>bottom</tt></i>, <i><tt>top</tt></i>, <i><tt>zNear</tt></i>, <i><tt>zFar</tt></i>) &#8594; <tt>None</tt></code></td></tr></table></div><div class="refsect1" lang="en"><a name="glOrtho.3G-parameters"/><h2>Parameters</h2><div class="variablelist"><dl><dt><span class="term"><i><tt>left</tt></i>, <i><tt>right</tt></i></span></dt><dd>
						Specify the coordinates for the left and right vertical clipping planes.
					</dd><dt><span class="term"><i><tt>bottom</tt></i>, <i><tt>top</tt></i></span></dt><dd>
						Specify the coordinates for the bottom and top horizontal clipping planes.
					</dd><dt><span class="term"><i><tt>zNear</tt></i>, <i><tt>zFar</tt></i></span></dt><dd>
						Specify the distances to the nearer and farther depth clipping planes. These values are negative if the
						plane is to be behind the viewer.
					</dd></dl></div></div><div class="refsect1" lang="en"><a name="glOrtho.3G-description"/><h2>Description</h2><p>
			<tt>glOrtho</tt> describes a transformation that produces a parallel projection. The current matrix (see
			<a href="glMatrixMode.3G.xml">glMatrixMode</a>) is multiplied by this matrix and the result replaces the current matrix, as if <tt>glMultMatrix</tt> were called with the following matrix as its argument: </p><div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" mode="display" overflow="scroll">
					<mml:mrow>
						<mml:mo>(</mml:mo>
						<mml:mtable>
							<mml:mtr>
								<mml:mtd columnalign="center">
									<mml:mfrac>
										<mml:mn>2</mml:mn>
										<mml:mrow>
											<mml:mi>right</mml:mi>
											<mml:mo>-</mml:mo>
											<mml:mi>left</mml:mi>
										</mml:mrow>
									</mml:mfrac>
								</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:msub>
										<mml:mi>t</mml:mi>
										<mml:mi>x</mml:mi>
									</mml:msub>
								</mml:mtd>
							</mml:mtr>
							<mml:mtr>
								<mml:mtd columnalign="center">
									<mml:mn>0</mml:mn>
								</mml:mtd>
								<mml:mtd columnalign="center">
									<mml:mfrac>
										<mml:mn>2</mml:mn>
										<mml:mrow>
											<mml:mi>top</mml:mi>
											<mml:mo>-</mml:mo>
											<mml:mi>bottom</mml:mi>
										</mml:mrow>
									</mml:mfrac>
								</mml:mtd>
								<mml:mtd columnalign="center">
									<mml:mn>0</mml:mn>
								</mml:mtd>
								<mml:mtd columnalign="center">
									<mml:msub>
										<mml:mi>t</mml:mi>
										<mml:mi>y</mml:mi>
									</mml:msub>
								</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:mfrac>
										<mml:mn>-2</mml:mn>
										<mml:mrow>
											<mml:mi>zFar</mml:mi>
											<mml:mo>-</mml:mo>
											<mml:mi>zNear</mml:mi>
										</mml:mrow>
									</mml:mfrac>
								</mml:mtd>
								<mml:mtd columnalign="center">
									<mml:msub>
										<mml:mi>t</mml:mi>
										<mml:mi>z</mml:mi>
									</mml:msub>
								</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:math></div><p>
		</p><p>
			where </p><div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" mode="display" overflow="scroll">
					<mml:mrow>
						<mml:msub>
							<mml:mi>t</mml:mi>
							<mml:mi>x</mml:mi>
						</mml:msub>
						<mml:mo>=</mml:mo>
						<mml:mo>-</mml:mo>
						<mml:mfrac>
							<mml:mrow>
								<mml:mi>right</mml:mi>
								<mml:mo>+</mml:mo>
								<mml:mi>left</mml:mi>
							</mml:mrow>
							<mml:mrow>
								<mml:mi>right</mml:mi>
								<mml:mo>-</mml:mo>
								<mml:mi>left</mml:mi>
							</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:msub>
							<mml:mi>t</mml:mi>
							<mml:mi>y</mml:mi>
						</mml:msub>
						<mml:mo>=</mml:mo>
						<mml:mo>-</mml:mo>
						<mml:mfrac>
							<mml:mrow>
								<mml:mi>top</mml:mi>
								<mml:mo>+</mml:mo>
								<mml:mi>bottom</mml:mi>
							</mml:mrow>
							<mml:mrow>
								<mml:mi>top</mml:mi>
								<mml:mo>-</mml:mo>
								<mml:mi>bottom</mml:mi>
							</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:msub>
							<mml:mi>t</mml:mi>
							<mml:mi>z</mml:mi>
						</mml:msub>
						<mml:mo>=</mml:mo>
						<mml:mo>-</mml:mo>
						<mml:mfrac>
							<mml:mrow>
								<mml:mi>zFar</mml:mi>
								<mml:mo>+</mml:mo>
								<mml:mi>zNear</mml:mi>
							</mml:mrow>
							<mml:mrow>
								<mml:mi>zFar</mml:mi>
								<mml:mo>-</mml:mo>
								<mml:mi>zNear</mml:mi>
							</mml:mrow>
						</mml:mfrac>
					</mml:mrow>
				</mml:math></div><p>
		</p><p>
			Typically, the matrix mode is <tt>GL_PROJECTION</tt>, and (<i><tt>left</tt></i>,
			<i><tt>bottom</tt></i>, -<i><tt>zNear</tt></i>) and (<i><tt>right</tt></i>,
			<i><tt>top</tt></i>, -<i><tt>zNear</tt></i>) specify the points on the near clipping plane that are
			mapped to the lower left and upper right corners of the window, respectively, assuming that the eye is located at (0,
			0, 0). -<i><tt>zFar</tt></i> specifies the location of the far clipping plane. Both <i><tt>zNear</tt></i>
			and <i><tt>zFar</tt></i> can be either positive or negative.
		</p><p>
			Use <a href="glPushMatrix.3G.xml"><tt>glPushMatrix</tt></a> and <a href="glPushMatrix.3G.xml"><tt>glPopMatrix</tt></a> to
			save and restore the current matrix stack.
		</p></div><div class="refsect1" lang="en"><a name="glOrtho.3G-errors"/><h2>Errors</h2><p>
			<tt>GL_INVALID_OPERATION</tt> is generated if <tt>glOrtho</tt> is executed between the
			execution of <a href="glBegin.3G.xml"><tt>glBegin</tt></a> and the corresponding execution of <a href="glBegin.3G.xml"><tt>glEnd</tt></a>.
		</p></div><div class="refsect1" lang="en"><a name="glOrtho.3G-associated_gets"/><h2>Associated Gets</h2><p>
			<tt>glGet</tt> with argument <tt>GL_MATRIX_MODE</tt>
		</p><p>
			<tt>glGet</tt> with argument <tt>GL_COLOR_MATRIX</tt>
		</p><p>
			<tt>glGet</tt> with argument <tt>GL_MODELVIEW_MATRIX</tt>
		</p><p>
			<tt>glGet</tt> with argument <tt>GL_PROJECTION_MATRIX</tt>
		</p><p>
			<tt>glGet</tt> with argument <tt>GL_TEXTURE_MATRIX</tt>
		</p></div><div class="refsect1" lang="en"><a name="glOrtho.3G-see_also"/><h2>See Also</h2><p>
			<span class="simplelist"><a href="glFrustum.3G.xml">glFrustum</a>, <a href="glMatrixMode.3G.xml">glMatrixMode</a>, <a href="glMultMatrix.3G.xml">glMultMatrix</a>, <a href="glPushMatrix.3G.xml">glPushMatrix</a>, <a href="glViewport.3G.xml">glViewport</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="glNormalPointer.3G.xml">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="reference-GL.xml">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="glPassThrough.3G.xml">Next</a></td></tr><tr><td width="40%" align="left" valign="top">glNormalPointer </td><td width="20%" align="center"><a accesskey="h" href="index.xml">Home</a></td><td width="40%" align="right" valign="top"> glPassThrough</td></tr></table></div></body></html>