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<?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>glViewportIndexed - 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="glViewportIndexed"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glViewportIndexed — set a specified viewport</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">glViewportIndexedf</b>(</code></td><td>GLuint  </td><td><var class="pdparam">index</var>, </td></tr><tr><td> </td><td>GLfloat  </td><td><var class="pdparam">x</var>, </td></tr><tr><td> </td><td>GLfloat  </td><td><var class="pdparam">y</var>, </td></tr><tr><td> </td><td>GLfloat  </td><td><var class="pdparam">w</var>, </td></tr><tr><td> </td><td>GLfloat  </td><td><var class="pdparam">h</var><code>)</code>;</td></tr></table></div><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><tr><td><code class="funcdef">void <b class="fsfunc">glViewportIndexedfv</b>(</code></td><td>GLuint  </td><td><var class="pdparam">index</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>index</code></em></span></dt><dd><p>
                   Specify the first viewport to set.
                </p></dd><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>
                    For <code class="function">glViewportIndexedf</code>, specifies 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>
                    For <code class="function">glViewportIndexedf</code>, specifies 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><dt><span class="term"><em class="parameter"><code>v</code></em></span></dt><dd><p>
                   For <code class="function">glViewportIndexedfv</code>, specifies the address of an array containing the viewport parameters.
                </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
            <code class="function">glViewportIndexedf</code> and <code class="function">glViewportIndexedfv</code>
            specify the parameters for a single viewport.
            <em class="parameter"><code>index</code></em> specifies the index of the viewport
            to modify.
            <em class="parameter"><code>index</code></em> must be less than the value of <code class="constant">GL_MAX_VIEWPORTS</code>.
            For <code class="function">glViewportIndexedf</code>, <em class="parameter"><code>x</code></em>, <em class="parameter"><code>y</code></em>,
            <em class="parameter"><code>w</code></em>, and <em class="parameter"><code>h</code></em> specify the left, bottom, width and height
            of the viewport in pixels, respectively.
            For <code class="function">glViewportIndexedfv</code>, <em class="parameter"><code>v</code></em> contains the address of an array of floating
            point values specifying the
            left (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">x</mml:mi></mml:math>),
            bottom (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">y</mml:mi></mml:math>),
            width (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">w</mml:mi></mml:math>),
            and height (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">h</mml:mi></mml:math>)
            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>
            and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">y</mml:mi></mml:math> give
            the location of the viewport's lower left corner, and
            <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">w</mml:mi></mml:math>
            and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">h</mml:mi></mml:math>
            give the width and height of the viewport, respectively.
            The viewport 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>
            The location of the viewport's bottom left corner, given by
            (<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>)
            is clamped to be within the implementaiton-dependent viewport bounds range.
            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>]
            can be determined by calling <a href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument
            <code class="constant">GL_VIEWPORT_BOUNDS_RANGE</code>.
            Viewport width and height are silently clamped
            to a range that depends on the implementation.
            To query this range, call <a href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument
            <code class="constant">GL_MAX_VIEWPORT_DIMS</code>.
        </p><p>
            The precision with which the GL interprets the floating point viewport bounds is implementation-dependent
            and may be determined by querying the impementation-defined constant <code class="constant">GL_VIEWPORT_SUBPIXEL_BITS</code>.
        </p><p>
            Calling <code class="function">glViewportIndexedfv</code> is equivalent to calling <a href="glViewportArray.xml"><span class="citerefentry"><span class="refentrytitle">glViewportArray</span></span></a>
            with <em class="parameter"><code>first</code></em> set to <em class="parameter"><code>index</code></em>, <em class="parameter"><code>count</code></em> set to
            1 and <em class="parameter"><code>v</code></em> passsed directly. <code class="function">glViewportIndexedf</code> is equivalent
            to:
        </p><pre class="programlisting">    void glViewportIndexedf(GLuint index, GLfloat x, GLfloat y, GLfloat w, GLfloat h)
    {
        const float v[4]  = { x, y, w, h };
        glViewportArrayv(index, 1, v);
    }</pre></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p>
            <code class="constant">GL_INVALID_VALUE</code> is generated if <em class="parameter"><code>index</code></em> is greater than or equal to
            the value of <code class="constant">GL_MAX_VIEWPORTS</code>.
        </p><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" lang="en" xml:lang="en"><a id="associatedgets"></a><h2>Associated Gets</h2><p>
            <a href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument <code class="constant">GL_VIEWPORT</code>
        </p><p>
            <a href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument <code class="constant">GL_MAX_VIEWPORT_DIMS</code>
        </p><p>
            <a href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument <code class="constant">GL_VIEWPORT_BOUNDS_RANGE</code>
        </p><p>
            <a href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument <code class="constant">GL_VIEWPORT_SUBPIXEL_BITS</code>
        </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
            <a href="glDepthRange.xml"><span class="citerefentry"><span class="refentrytitle">glDepthRange</span></span></a>,
            <a href="glViewport.xml"><span class="citerefentry"><span class="refentrytitle">glViewport</span></span></a>,
            <a href="glViewportArray.xml"><span class="citerefentry"><span class="refentrytitle">glViewportArray</span></span></a>
        </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p>
            Copyright <span class="trademark"></span>© 2010 Khronos Group. 
            This material may be distributed subject to the terms and conditions set forth in 
            the Open Publication License, v 1.0, 8 June 1999.
            <a href="http://opencontent.org/openpub/" target="_top">http://opencontent.org/openpub/</a>.
        </p></div></div></body></html>
