upstream-doc/man4/xhtml/glViewportArray.xml

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   4 <?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>glViewportArray - OpenGL 4 Reference Pages</title><meta name="generator" content="DocBook XSL Stylesheets V1.69.1" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="glViewportArray"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glViewportArray — set multiple viewports</p></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><tr><td><code class="funcdef">void <b class="fsfunc">glViewportArrayv</b>(</code></td><td>GLuint  </td><td><var class="pdparam">first</var>, </td></tr><tr><td> </td><td>GLsizei  </td><td><var class="pdparam">count</var>, </td></tr><tr><td> </td><td>const GLfloat * </td><td><var class="pdparam">v</var><code>)</code>;</td></tr></table></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="parameters"></a><h2>Parameters</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>first</code></em></span></dt><dd><p>
   5                    Specify the first viewport to set.
   6                 </p></dd><dt><span class="term"><em class="parameter"><code>count</code></em></span></dt><dd><p>
   7                    Specify the number of viewports to set.
   8                 </p></dd><dt><span class="term"><em class="parameter"><code>v</code></em></span></dt><dd><p>
   9                    Specify the address of an array containing the viewport parameters.
  10                 </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
  11             <code class="function">glViewportArrayv</code> specifies the parameters for multiple viewports
  12             simulataneously. <em class="parameter"><code>first</code></em> specifies the index of the first viewport
  13             to modify and <em class="parameter"><code>count</code></em> specifies the number of viewports to modify.
  14             <em class="parameter"><code>first</code></em> must be less than the value of <code class="constant">GL_MAX_VIEWPORTS</code>,
  15             and <em class="parameter"><code>first</code></em> + <em class="parameter"><code>count</code></em> must be less than or equal to
  16             the value of <code class="constant">GL_MAX_VIEWPORTS</code>. Viewports whose indices lie outside
  17             the range [<em class="parameter"><code>first</code></em>, <em class="parameter"><code>first</code></em> + <em class="parameter"><code>count</code></em>)
  18             are not modified. <em class="parameter"><code>v</code></em> contains the address of an array of floating
  19             point values specifying the
  20             left (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">x</mml:mi></mml:math>),
  21             bottom (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">y</mml:mi></mml:math>),
  22             width (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">w</mml:mi></mml:math>),
  23             and height (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">h</mml:mi></mml:math>)
  24             of each viewport, in that order. <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">x</mml:mi></mml:math>
  25             and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">y</mml:mi></mml:math> give
  26             the location of the viewport's lower left corner, and
  27             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">w</mml:mi></mml:math>
  28             and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">h</mml:mi></mml:math>
  29             give the width and height of the viewport, respectively.
  30             The viewport specifies the affine transformation of
  31             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">x</mml:mi></mml:math>
  32             and
  33             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">y</mml:mi></mml:math>
  34             from
  35             normalized device coordinates to window coordinates.
  36             Let
  37             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  38
  39                 <mml:mfenced open="(" close=")">
  40                     <mml:msub><mml:mi mathvariant="italic">x</mml:mi>
  41                     <mml:mi mathvariant="italic">nd</mml:mi>
  42                     </mml:msub>
  43                     <mml:msub><mml:mi mathvariant="italic">y</mml:mi>
  44                     <mml:mi mathvariant="italic">nd</mml:mi>
  45                     </mml:msub>
  46                 </mml:mfenced>
  47             </mml:math>
  48             be normalized device coordinates.
  49             Then the window coordinates
  50             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  51
  52                 <mml:mfenced open="(" close=")">
  53                     <mml:msub><mml:mi mathvariant="italic">x</mml:mi>
  54                     <mml:mi mathvariant="italic">w</mml:mi>
  55                     </mml:msub>
  56                     <mml:msub><mml:mi mathvariant="italic">y</mml:mi>
  57                     <mml:mi mathvariant="italic">w</mml:mi>
  58                     </mml:msub>
  59                 </mml:mfenced>
  60             </mml:math>
  61             are computed as follows:
  62         </p><p>
  63             </p><div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  64
  65                 <mml:mrow>
  66                     <mml:msub><mml:mi mathvariant="italic">x</mml:mi>
  67                     <mml:mi mathvariant="italic">w</mml:mi>
  68                     </mml:msub>
  69                     <mml:mo>=</mml:mo>
  70                     <mml:mrow>
  71                         <mml:mfenced open="(" close=")">
  72                             <mml:mrow>
  73                                 <mml:msub><mml:mi mathvariant="italic">x</mml:mi>
  74                                 <mml:mi mathvariant="italic">nd</mml:mi>
  75                                 </mml:msub>
  76                                 <mml:mo>+</mml:mo>
  77                                 <mml:mn>1</mml:mn>
  78                             </mml:mrow>
  79                         </mml:mfenced>
  80                         <mml:mo>⁢</mml:mo>
  81                         <mml:mfenced open="(" close=")">
  82                             <mml:mfrac>
  83                                 <mml:mi mathvariant="italic">width</mml:mi>
  84                                 <mml:mn>2</mml:mn>
  85                             </mml:mfrac>
  86                         </mml:mfenced>
  87                         <mml:mo>+</mml:mo>
  88                         <mml:mi mathvariant="italic">x</mml:mi>
  89                     </mml:mrow>
  90                 </mml:mrow>
  91             </mml:math></div><p>
  92         </p><p>
  93             </p><div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  94
  95                 <mml:mrow>
  96                     <mml:msub><mml:mi mathvariant="italic">y</mml:mi>
  97                     <mml:mi mathvariant="italic">w</mml:mi>
  98                     </mml:msub>
  99                     <mml:mo>=</mml:mo>
 100                     <mml:mrow>
 101                         <mml:mfenced open="(" close=")">
 102                             <mml:mrow>
 103                                 <mml:msub><mml:mi mathvariant="italic">y</mml:mi>
 104                                 <mml:mi mathvariant="italic">nd</mml:mi>
 105                                 </mml:msub>
 106                                 <mml:mo>+</mml:mo>
 107                                 <mml:mn>1</mml:mn>
 108                             </mml:mrow>
 109                         </mml:mfenced>
 110                         <mml:mo>⁢</mml:mo>
 111                         <mml:mfenced open="(" close=")">
 112                             <mml:mfrac>
 113                                 <mml:mi mathvariant="italic">height</mml:mi>
 114                                 <mml:mn>2</mml:mn>
 115                             </mml:mfrac>
 116                         </mml:mfenced>
 117                         <mml:mo>+</mml:mo>
 118                         <mml:mi mathvariant="italic">y</mml:mi>
 119                     </mml:mrow>
 120                 </mml:mrow>
 121             </mml:math></div><p>
 122         </p><p>
 123             The location of the viewport's bottom left corner, given by
 124             (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">x</mml:mi></mml:math>, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">y</mml:mi></mml:math>)
 125             is clamped to be within the implementaiton-dependent viewport bounds range.
 126             The viewport bounds range [<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">min</mml:mi></mml:math>, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">max</mml:mi></mml:math>]
 127             can be determined by calling <a href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument
 128             <code class="constant">GL_VIEWPORT_BOUNDS_RANGE</code>.
 129             Viewport width and height are silently clamped
 130             to a range that depends on the implementation.
 131             To query this range, call <a href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument
 132             <code class="constant">GL_MAX_VIEWPORT_DIMS</code>.
 133         </p><p>
 134             The precision with which the GL interprets the floating point viewport bounds is implementation-dependent
 135             and may be determined by querying the impementation-defined constant <code class="constant">GL_VIEWPORT_SUBPIXEL_BITS</code>.
 136         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p>
 137             <code class="constant">GL_INVALID_VALUE</code> is generated if <em class="parameter"><code>first</code></em> is greater than or equal to
 138             the value of <code class="constant">GL_MAX_VIEWPORTS</code>.
 139         </p><p>
 140             <code class="constant">GL_INVALID_VALUE</code> is generated if <em class="parameter"><code>first</code></em> + <em class="parameter"><code>count</code></em>
 141             is greater than or equal to the value of <code class="constant">GL_MAX_VIEWPORTS</code>.
 142         </p><p>
 143             <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.
 144         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="associatedgets"></a><h2>Associated Gets</h2><p>
 145             <a href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument <code class="constant">GL_VIEWPORT</code>
 146         </p><p>
 147             <a href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument <code class="constant">GL_MAX_VIEWPORT_DIMS</code>
 148         </p><p>
 149             <a href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument <code class="constant">GL_VIEWPORT_BOUNDS_RANGE</code>
 150         </p><p>
 151             <a href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument <code class="constant">GL_VIEWPORT_SUBPIXEL_BITS</code>
 152         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
 153             <a href="glDepthRange.xml"><span class="citerefentry"><span class="refentrytitle">glDepthRange</span></span></a>,
 154             <a href="glViewport.xml"><span class="citerefentry"><span class="refentrytitle">glViewport</span></span></a>,
 155             <a href="glViewportIndexed.xml"><span class="citerefentry"><span class="refentrytitle">glViewportIndexed</span></span></a>
 156         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p>
 157             Copyright <span class="trademark"></span>© 2010 Khronos Group.
 158             This material may be distributed subject to the terms and conditions set forth in
 159             the Open Publication License, v 1.0, 8 June 1999.
 160             <a href="http://opencontent.org/openpub/" target="_top">http://opencontent.org/openpub/</a>.
 161         </p></div></div></body></html>