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+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "xhtml1-transitional.dtd">
+<!-- saved from url=(0013)about:internet -->
+<?xml-stylesheet type="text/xsl" href="mathml.xsl"?><html xmlns="http://www.w3.org/1999/xhtml" xmlns:pref="http://www.w3.org/2002/Math/preference" pref:renderer="mathplayer-dl"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><link rel="stylesheet" type="text/css" href="opengl-man.css" /><title>glViewport</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.2" /></head><body><div class="refentry" title="glViewport"><a id="glViewport"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glViewport — set the viewport</p></div><div class="refsynopsisdiv" title="C Specification"><h2>C Specification</h2><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">void <b class="fsfunc">glViewport</b>(</code></td><td>GLint <var class="pdparam">x</var>, </td></tr><tr><td> </td><td>GLint <var class="pdparam">y</var>, </td></tr><tr><td> </td><td>GLsizei <var class="pdparam">width</var>, </td></tr><tr><td> </td><td>GLsizei <var class="pdparam">height</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1" title="Parameters"><a id="parameters"></a><h2>Parameters</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>x</code></em>, </span><span class="term"><em class="parameter"><code>y</code></em></span></dt><dd><p>
+ Specify the lower left corner of the viewport rectangle,
+ in pixels. The initial value is (0,0).
+ </p></dd><dt><span class="term"><em class="parameter"><code>width</code></em>, </span><span class="term"><em class="parameter"><code>height</code></em></span></dt><dd><p>
+ Specify the width and height
+ of the viewport.
+ When a GL context is first attached to a window,
+ <em class="parameter"><code>width</code></em> and <em class="parameter"><code>height</code></em> are set to the dimensions of that
+ window.
+ </p></dd></dl></div></div><div class="refsect1" title="Description"><a id="description"></a><h2>Description</h2><p>
+ <code class="function">glViewport</code> specifies the affine transformation of
+ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">x</mml:mi></mml:math>
+ and
+ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">y</mml:mi></mml:math>
+ from
+ normalized device coordinates to window coordinates.
+ Let
+ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
+
+ <mml:mfenced open="(" close=")">
+ <mml:msub><mml:mi mathvariant="italic">x</mml:mi>
+ <mml:mi mathvariant="italic">nd</mml:mi>
+ </mml:msub>
+ <mml:msub><mml:mi mathvariant="italic">y</mml:mi>
+ <mml:mi mathvariant="italic">nd</mml:mi>
+ </mml:msub>
+ </mml:mfenced>
+ </mml:math>
+ be normalized device coordinates.
+ Then the window coordinates
+ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
+
+ <mml:mfenced open="(" close=")">
+ <mml:msub><mml:mi mathvariant="italic">x</mml:mi>
+ <mml:mi mathvariant="italic">w</mml:mi>
+ </mml:msub>
+ <mml:msub><mml:mi mathvariant="italic">y</mml:mi>
+ <mml:mi mathvariant="italic">w</mml:mi>
+ </mml:msub>
+ </mml:mfenced>
+ </mml:math>
+ are computed as follows:
+ </p><p>
+ </p><div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
+
+ <mml:mrow>
+ <mml:msub><mml:mi mathvariant="italic">x</mml:mi>
+ <mml:mi mathvariant="italic">w</mml:mi>
+ </mml:msub>
+ <mml:mo>=</mml:mo>
+ <mml:mrow>
+ <mml:mfenced open="(" close=")">
+ <mml:mrow>
+ <mml:msub><mml:mi mathvariant="italic">x</mml:mi>
+ <mml:mi mathvariant="italic">nd</mml:mi>
+ </mml:msub>
+ <mml:mo>+</mml:mo>
+ <mml:mn>1</mml:mn>
+ </mml:mrow>
+ </mml:mfenced>
+ <mml:mo></mml:mo>
+ <mml:mfenced open="(" close=")">
+ <mml:mfrac>
+ <mml:mi mathvariant="italic">width</mml:mi>
+ <mml:mn>2</mml:mn>
+ </mml:mfrac>
+ </mml:mfenced>
+ <mml:mo>+</mml:mo>
+ <mml:mi mathvariant="italic">x</mml:mi>
+ </mml:mrow>
+ </mml:mrow>
+ </mml:math></div><p>
+ </p><p>
+ </p><div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
+
+ <mml:mrow>
+ <mml:msub><mml:mi mathvariant="italic">y</mml:mi>
+ <mml:mi mathvariant="italic">w</mml:mi>
+ </mml:msub>
+ <mml:mo>=</mml:mo>
+ <mml:mrow>
+ <mml:mfenced open="(" close=")">
+ <mml:mrow>
+ <mml:msub><mml:mi mathvariant="italic">y</mml:mi>
+ <mml:mi mathvariant="italic">nd</mml:mi>
+ </mml:msub>
+ <mml:mo>+</mml:mo>
+ <mml:mn>1</mml:mn>
+ </mml:mrow>
+ </mml:mfenced>
+ <mml:mo></mml:mo>
+ <mml:mfenced open="(" close=")">
+ <mml:mfrac>
+ <mml:mi mathvariant="italic">height</mml:mi>
+ <mml:mn>2</mml:mn>
+ </mml:mfrac>
+ </mml:mfenced>
+ <mml:mo>+</mml:mo>
+ <mml:mi mathvariant="italic">y</mml:mi>
+ </mml:mrow>
+ </mml:mrow>
+ </mml:math></div><p>
+ </p><p>
+ Viewport width and height are silently clamped
+ to a range that depends on the implementation.
+ To query this range, call <a class="citerefentry" href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument
+ <code class="constant">GL_MAX_VIEWPORT_DIMS</code>.
+ </p></div><div class="refsect1" title="Errors"><a id="errors"></a><h2>Errors</h2><p>
+ <code class="constant">GL_INVALID_VALUE</code> is generated if either <em class="parameter"><code>width</code></em> or <em class="parameter"><code>height</code></em> is negative.
+ </p></div><div class="refsect1" title="Associated Gets"><a id="associatedgets"></a><h2>Associated Gets</h2><p>
+ <a class="citerefentry" href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument <code class="constant">GL_VIEWPORT</code>
+ </p><p>
+ <a class="citerefentry" href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument <code class="constant">GL_MAX_VIEWPORT_DIMS</code>
+ </p></div><div class="refsect1" title="See Also"><a id="seealso"></a><h2>See Also</h2><p>
+ <a class="citerefentry" href="glDepthRange.xml"><span class="citerefentry"><span class="refentrytitle">glDepthRange</span></span></a>
+ </p></div><div class="refsect1" title="Copyright"><a id="Copyright"></a><h2>Copyright</h2><p>
+ Copyright <span class="trademark"></span>© 1991-2006
+ Silicon Graphics, Inc. This document is licensed under the SGI
+ Free Software B License. For details, see
+ <a class="ulink" href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>.
+ </p></div></div></body></html>
HCoop / clinton / guile-figl.git / blobdiff