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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" /><title>glCopyTexImage2D</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1" /></head><body><div class="refentry"><a id="glCopyTexImage2D"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glCopyTexImage2D — specify a two-dimensional texture image with pixels from the color buffer</p></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">void <strong class="fsfunc">glCopyTexImage2D</strong>(</code></td><td>GLenum <var class="pdparam">target</var>, </td></tr><tr><td> </td><td>GLint <var class="pdparam">level</var>, </td></tr><tr><td> </td><td>GLenum <var class="pdparam">internalformat</var>, </td></tr><tr><td> </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>, </td></tr><tr><td> </td><td>GLint <var class="pdparam">border</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1"><a id="parameters"></a><h2>Parameters</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term">
                    <em class="parameter"><code>target</code></em>
                </span></dt><dd><p>Specifies the target texture. Must be
                    <code class="constant">GL_TEXTURE_2D</code>.</p></dd><dt><span class="term">
                    <em class="parameter"><code>level</code></em>
                </span></dt><dd><p>Specifies the level-of-detail number. Level 0 is
                    the base image level. Level <em class="parameter"><code>n</code></em>
                    is the <em class="parameter"><code>n</code></em>th mipmap reduction image.</p></dd><dt><span class="term">
                    <em class="parameter"><code>internalformat</code></em>
                </span></dt><dd><p>Specifies the color components of the texture. Must be one
                    of the following symbolic constants:
                    <code class="constant">GL_ALPHA</code>,
                    <code class="constant">GL_LUMINANCE</code>,
                    <code class="constant">GL_LUMINANCE_ALPHA</code>,
                    <code class="constant">GL_RGB</code>, or
                    <code class="constant">GL_RGBA</code>.</p></dd><dt><span class="term">
                <em class="parameter"><code>x</code></em>, <em class="parameter"><code>y</code></em>
                </span></dt><dd><p>Specify the window coordinates of the lower left
                    corner of the rectangular region of pixels to be
                    copied.</p></dd><dt><span class="term">
                    <em class="parameter"><code>width</code></em>
                </span></dt><dd><p>Specifies the width of the texture image. Must be 0 or
                    <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                        <mml:msup><mml:mn>2</mml:mn><mml:mi>n</mml:mi></mml:msup>
                    </mml:math>
                    for some integer <em class="replaceable"><code>n</code></em>.</p></dd><dt><span class="term">
                    <em class="parameter"><code>height</code></em>
                </span></dt><dd><p>Specifies the height of the texture image. Must be 0 or
                    <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                        <mml:msup><mml:mn>2</mml:mn><mml:mi>m</mml:mi></mml:msup>
                    </mml:math>
                    for some integer <em class="replaceable"><code>m</code></em>.</p></dd><dt><span class="term">
                    <em class="parameter"><code>border</code></em>
                </span></dt><dd><p>Specifies the width of the border. Must be 0.</p></dd></dl></div></div><div class="refsect1"><a id="description"></a><h2>Description</h2><p>
        <code class="function">glCopyTexImage2D</code>
        defines a two-dimensional texture image with pixels from the
        color buffer.</p><p>The screen-aligned pixel rectangle with lower left corner
        at (<em class="parameter"><code>x</code></em>, <em class="parameter"><code>y</code></em>)
        and with a width of
        <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
            <mml:mi>width</mml:mi>
        </mml:math>
        and a height of
        <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
            <mml:mi>height</mml:mi>
        </mml:math>
        defines the texture array at the mipmap level specified by
        <em class="parameter"><code>level</code></em>. <em class="parameter"><code>internalformat</code></em>
        specifies the color components of the texture.</p><p>
        The red, green, blue, and alpha
        components of each pixel that is read are converted to an
        internal fixed-point or floating-point format with unspecified precision.
        The conversion maps the largest representable component
        value to 1.0, and component value 0 to 0.0.
        The values are then converted to the texture's internal format for
        storage in the texel array.</p><p><em class="parameter"><code>internalformat</code></em> must be chosen such that
        color buffer components can be dropped during conversion to the
        internal format, but new components cannot be added. For example,
        an <code class="constant">GL_RGB</code> color buffer can be used to create
        <code class="constant">GL_LUMINANCE</code> or <code class="constant">GL_RGB</code>
        textures, but not <code class="constant">GL_ALPHA</code>,
        <code class="constant">GL_LUMINANCE_ALPHA</code> or <code class="constant">GL_RGBA</code>
        textures.</p><p>Pixel ordering is such that lower <em class="parameter"><code>x</code></em>
        and <em class="parameter"><code>y</code></em> screen coordinates correspond to lower
        <em class="parameter"><code>s</code></em> and <em class="parameter"><code>t</code></em> texture
        coordinates.</p><p>If any of the pixels within the specified rectangle of
        the color buffer are outside the window associated with the
        current rendering context, then the values obtained for those
        pixels are undefined.</p></div><div class="refsect1"><a id="notes"></a><h2>Notes</h2><p>An image with height or width of 0 indicates a
        null-texture.</p></div><div class="refsect1"><a id="errors"></a><h2>Errors</h2><p><code class="constant">GL_INVALID_ENUM</code> is generated if
        <em class="parameter"><code>target</code></em> is not
        <code class="constant">GL_TEXTURE_2D</code>.</p><p><code class="constant">GL_INVALID_OPERATION</code> is generated if
        <em class="parameter"><code>internalformat</code></em> is not compatible
        with the color buffer format.</p><p><code class="constant">GL_INVALID_VALUE</code> is generated if
        <em class="parameter"><code>level</code></em> is less than 0.</p><p><code class="constant">GL_INVALID_VALUE</code> may be generated if
        <em class="parameter"><code>level</code></em> is greater than
        <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
            <mml:msub><mml:mo>log</mml:mo><mml:mn>2</mml:mn></mml:msub><mml:mi>max</mml:mi>
        </mml:math>, where
        <em class="replaceable"><code>max</code></em> is the returned value of
        <code class="constant">GL_MAX_TEXTURE_SIZE</code>.</p><p>
        <code class="constant">GL_INVALID_VALUE</code> is generated if
        <em class="parameter"><code>width</code></em> or
        <em class="parameter"><code>height</code></em>
        is less than 0, greater than
        <code class="constant">GL_MAX_TEXTURE_SIZE</code>, or if
        <em class="parameter"><code>width</code></em> or <em class="parameter"><code>height</code></em>
        cannot be represented as
        <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
            <mml:msup><mml:mn>2</mml:mn><mml:mi>k</mml:mi></mml:msup>
        </mml:math>
        for some integer <em class="replaceable"><code>k</code></em>.</p><p><code class="constant">GL_INVALID_VALUE</code> is generated if
        <em class="parameter"><code>border</code></em> is not 0.</p><p>
        <code class="constant">GL_INVALID_ENUM</code> is generated if
        <em class="parameter"><code>internalformat</code></em>
        is not an accepted constant.
        </p></div><div class="refsect1"><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_MAX_TEXTURE_SIZE</code></p></div><div class="refsect1"><a id="seealso"></a><h2>See Also</h2><p>
        <a class="citerefentry" href="glCompressedTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glCompressedTexImage2D</span></span></a>,
        <a class="citerefentry" href="glCopyTexSubImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexSubImage2D</span></span></a>,
        <a class="citerefentry" href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a>,
        <a class="citerefentry" href="glTexEnv.xml"><span class="citerefentry"><span class="refentrytitle">glTexEnv</span></span></a>,
        <a class="citerefentry" href="glTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage2D</span></span></a>,
        <a class="citerefentry" href="glTexSubImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glTexSubImage2D</span></span></a>,
        <a class="citerefentry" href="glTexParameter.xml"><span class="citerefentry"><span class="refentrytitle">glTexParameter</span></span></a>
        </p></div><div class="refsect1"><a id="copyright"></a><h2>Copyright</h2><p>
            Copyright <span class="trademark"></span>© 2003-2004
            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>