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<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE html><html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>glGetCompressedTexImage - OpenGL 4 Reference Pages</title>
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<div class="refentry" id="glGetCompressedTexImage">
<div class="titlepage"/>
<div class="refnamediv">
<h2>Name</h2>
<p>glGetCompressedTexImage — return a compressed texture image</p>
</div>
<div class="refsynopsisdiv">
<h2>C Specification</h2>
<div class="funcsynopsis">
<table style="border: 0; cellspacing: 0; cellpadding: 0;" class="funcprototype-table">
<tr>
<td>
<code class="funcdef">void <strong class="fsfunc">glGetCompressedTexImage</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>GLvoid * <var class="pdparam">pixels</var><code>)</code>;</td>
</tr>
</table>
<div class="funcprototype-spacer"> </div>
<table style="border: 0; cellspacing: 0; cellpadding: 0;" class="funcprototype-table">
<tr>
<td>
<code class="funcdef">void <strong class="fsfunc">glGetnCompressedTexImage</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>GLsizei <var class="pdparam">bufSize</var>, </td>
</tr>
<tr>
<td> </td>
<td>void *<var class="pdparam">pixels</var><code>)</code>;</td>
</tr>
</table>
<div class="funcprototype-spacer"> </div>
<table style="border: 0; cellspacing: 0; cellpadding: 0;" class="funcprototype-table">
<tr>
<td>
<code class="funcdef">void <strong class="fsfunc">glGetCompressedTextureImage</strong>(</code>
</td>
<td>GLuint <var class="pdparam">texture</var>, </td>
</tr>
<tr>
<td> </td>
<td>GLint <var class="pdparam">level</var>, </td>
</tr>
<tr>
<td> </td>
<td>GLsizei <var class="pdparam">bufSize</var>, </td>
</tr>
<tr>
<td> </td>
<td>void *<var class="pdparam">pixels</var><code>)</code>;</td>
</tr>
</table>
<div class="funcprototype-spacer"> </div>
</div>
</div>
<div class="refsect1" id="parameters">
<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 to which the texture is bound for
<code class="function">glGetCompressedTexImage</code> and
<code class="function">glGetnCompressedTexImage</code> functions.
<code class="constant">GL_TEXTURE_1D</code>,
<code class="constant">GL_TEXTURE_1D_ARRAY</code>,
<code class="constant">GL_TEXTURE_2D</code>,
<code class="constant">GL_TEXTURE_2D_ARRAY</code>,
<code class="constant">GL_TEXTURE_3D</code>,
<code class="constant">GL_TEXTURE_CUBE_MAP_ARRAY</code>,
<code class="constant">GL_TEXTURE_CUBE_MAP_POSITIVE_X</code>,
<code class="constant">GL_TEXTURE_CUBE_MAP_NEGATIVE_X</code>,
<code class="constant">GL_TEXTURE_CUBE_MAP_POSITIVE_Y</code>,
<code class="constant">GL_TEXTURE_CUBE_MAP_NEGATIVE_Y</code>,
<code class="constant">GL_TEXTURE_CUBE_MAP_POSITIVE_Z</code>, and
<code class="constant">GL_TEXTURE_CUBE_MAP_NEGATIVE_Z</code>,
<code class="constant">GL_TEXTURE_RECTANGLE</code> are accepted.</p>
</dd>
<dt>
<span class="term">
<em class="parameter">
<code>texture</code>
</em>
</span>
</dt>
<dd>
<p>Specifies the texture object name for
<code class="function">glGetCompressedTextureImage</code> function.</p>
</dd>
<dt>
<span class="term">
<em class="parameter">
<code>level</code>
</em>
</span>
</dt>
<dd>
<p>Specifies the level-of-detail number of the desired image.
Level 0 is the base image level. Level $n$ is the $n$-th mipmap reduction image.</p>
</dd>
<dt>
<span class="term">
<em class="parameter">
<code>bufSize</code>
</em>
</span>
</dt>
<dd>
<p>Specifies the size of the buffer <em class="parameter"><code>pixels</code></em>
for <code class="function">glGetCompressedTextureImage</code> and
<code class="function">glGetnCompressedTexImage</code> functions.</p>
</dd>
<dt>
<span class="term">
<em class="parameter">
<code>pixels</code>
</em>
</span>
</dt>
<dd>
<p>Returns the compressed texture image.</p>
</dd>
</dl>
</div>
</div>
<div class="refsect1" id="description">
<h2>Description</h2>
<p><code class="function">glGetCompressedTexImage</code> and
<code class="function">glGetnCompressedTexImage</code> return the compressed
texture image associated with <em class="parameter"><code>target</code></em> and
<em class="parameter"><code>lod</code></em> into <em class="parameter"><code>pixels</code></em>.
<code class="function">glGetCompressedTextureImage</code> serves the same purpose,
but instead of taking a texture target, it takes the ID of the texture
object. <em class="parameter"><code>pixels</code></em> should be an array of
<em class="parameter"><code>bufSize</code></em> bytes for
<code class="function">glGetnCompresedTexImage</code> and
<code class="function">glGetCompressedTextureImage</code> functions, and of
<code class="constant">GL_TEXTURE_COMPRESSED_IMAGE_SIZE</code> bytes in case of
<code class="function">glGetCompressedTexImage</code>. If the actual data takes
less space than <em class="parameter"><code>bufSize</code></em>, the remaining bytes will
not be touched. <em class="parameter"><code>target</code></em> specifies the texture
target, to which the texture the data the function should extract the data
from is bound to. <em class="parameter"><code>lod</code></em> specifies the level-of-detail
number of the desired image.</p>
<p>If a non-zero named buffer object is bound to the
<code class="constant">GL_PIXEL_PACK_BUFFER</code> target (see <a class="citerefentry" href="glBindBuffer.xhtml"><span class="citerefentry"><span class="refentrytitle">glBindBuffer</span></span></a>) while a texture image is requested,
<em class="parameter"><code>pixels</code></em> is treated as a byte offset into the buffer
object's data store.</p>
<p>To minimize errors, first verify that the texture is compressed by
calling <a class="citerefentry" href="glGetTexLevelParameter.xhtml"><span class="citerefentry"><span class="refentrytitle">glGetTexLevelParameter</span></span></a> with argument
<code class="constant">GL_TEXTURE_COMPRESSED</code>. If the texture is compressed,
you can determine the amount of memory required to store the compressed
texture by calling <a class="citerefentry" href="glGetTexLevelParameter.xhtml"><span class="citerefentry"><span class="refentrytitle">glGetTexLevelParameter</span></span></a> with argument
<code class="constant">GL_TEXTURE_COMPRESSED_IMAGE_SIZE</code>. Finally, retrieve
the internal format of the texture by calling <a class="citerefentry" href="glGetTexLevelParameter.xhtml"><span class="citerefentry"><span class="refentrytitle">glGetTexLevelParameter</span></span></a> with argument
<code class="constant">GL_TEXTURE_INTERNAL_FORMAT</code>. To store the texture for
later use, associate the internal format and size with the retrieved
texture image. These data can be used by the respective texture or
subtexture loading routine used for loading <em class="parameter"><code>target</code></em>
textures.</p>
</div>
<div class="refsect1" id="errors">
<h2>Errors</h2>
<p><code class="constant">GL_INVALID_OPERATION</code> is generated by
<code class="function">glGetCompressedTextureImage</code> if
<em class="parameter"><code>texture</code></em> is not the name of an existing texture
object.</p>
<p><code class="constant">GL_INVALID_VALUE</code> is generated if
<em class="parameter"><code>level</code></em> is less than zero or greater than the maximum
number of LODs permitted by the implementation.</p>
<p><code class="constant">GL_INVALID_OPERATION</code> is generated if
<code class="function">glGetCompressedTexImage</code>,
<code class="function">glGetnCompressedTexImage</code>, and
<code class="function">glGetCompressedTextureImage</code> is used to retrieve a
texture that is in an uncompressed internal format.</p>
<p><code class="constant">GL_INVALID_OPERATION</code> is generated if a non-zero
buffer object name is bound to the
<code class="constant">GL_PIXEL_PACK_BUFFER</code> target, the buffer storage was
not initialized with <code class="function">glBufferStorage</code> using
<code class="constant">GL_MAP_PERSISTENT_BIT</code> flag, and the buffer object's
data store is currently mapped.</p>
<p><code class="constant">GL_INVALID_OPERATION</code> is generated if a non-zero
buffer object name is bound to the
<code class="constant">GL_PIXEL_PACK_BUFFER</code> target and the data would be
packed to the buffer object such that the memory writes required would
exceed the data store size.</p>
</div>
<div class="refsect1" id="associatedgets">
<h2>Associated Gets</h2>
<p><a class="citerefentry" href="glGetTexLevelParameter.xhtml"><span class="citerefentry"><span class="refentrytitle">glGetTexLevelParameter</span></span></a> with argument
<code class="constant">GL_TEXTURE_COMPRESSED</code></p>
<p><a class="citerefentry" href="glGetTexLevelParameter.xhtml"><span class="citerefentry"><span class="refentrytitle">glGetTexLevelParameter</span></span></a> with argument
<code class="constant">GL_TEXTURE_COMPRESSED_IMAGE_SIZE</code></p>
<p><a class="citerefentry" href="glGetTexLevelParameter.xhtml"><span class="citerefentry"><span class="refentrytitle">glGetTexLevelParameter</span></span></a> with argument
<code class="constant">GL_TEXTURE_INTERNAL_FORMAT</code></p>
<p><a class="citerefentry" href="glGet.xhtml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument
<code class="constant">GL_PIXEL_PACK_BUFFER_BINDING</code></p>
</div>
<div class="refsect1" id="versions">
<h2>Version Support</h2>
<div class="informaltable">
<table style="border-collapse: collapse; border-top: 2px solid ; border-bottom: 2px solid ; border-left: 2px solid ; border-right: 2px solid ; ">
<colgroup>
<col style="text-align: left; "/>
<col style="text-align: center; " class="firstvers"/>
<col style="text-align: center; "/>
<col style="text-align: center; "/>
<col style="text-align: center; "/>
<col style="text-align: center; "/>
<col style="text-align: center; "/>
<col style="text-align: center; "/>
<col style="text-align: center; "/>
<col style="text-align: center; "/>
<col style="text-align: center; "/>
<col style="text-align: center; "/>
<col style="text-align: center; " class="lastvers"/>
</colgroup>
<thead>
<tr>
<th style="text-align: left; border-right: 2px solid ; ">
</th>
<th style="text-align: center; border-bottom: 2px solid ; " colspan="12">
<span class="bold"><strong>OpenGL Version</strong></span>
</th>
</tr>
<tr>
<th style="text-align: left; border-right: 2px solid ; border-bottom: 2px solid ; ">
<span class="bold"><strong>Function / Feature Name</strong></span>
</th>
<th style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">
<span class="bold"><strong>2.0</strong></span>
</th>
<th style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">
<span class="bold"><strong>2.1</strong></span>
</th>
<th style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">
<span class="bold"><strong>3.0</strong></span>
</th>
<th style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">
<span class="bold"><strong>3.1</strong></span>
</th>
<th style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">
<span class="bold"><strong>3.2</strong></span>
</th>
<th style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">
<span class="bold"><strong>3.3</strong></span>
</th>
<th style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">
<span class="bold"><strong>4.0</strong></span>
</th>
<th style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">
<span class="bold"><strong>4.1</strong></span>
</th>
<th style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">
<span class="bold"><strong>4.2</strong></span>
</th>
<th style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">
<span class="bold"><strong>4.3</strong></span>
</th>
<th style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">
<span class="bold"><strong>4.4</strong></span>
</th>
<th style="text-align: center; border-bottom: 2px solid ; ">
<span class="bold"><strong>4.5</strong></span>
</th>
</tr>
</thead>
<tbody>
<tr>
<td style="text-align: left; border-right: 2px solid ; border-bottom: 2px solid ; ">
<code class="function">glGetCompressedTexImage</code>
</td>
<td style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">✔</td>
<td style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">✔</td>
<td style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">✔</td>
<td style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">✔</td>
<td style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">✔</td>
<td style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">✔</td>
<td style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">✔</td>
<td style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">✔</td>
<td style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">✔</td>
<td style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">✔</td>
<td style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">✔</td>
<td style="text-align: center; border-bottom: 2px solid ; ">✔</td>
</tr>
<tr>
<td style="text-align: left; border-right: 2px solid ; border-bottom: 2px solid ; ">
<code class="function">glGetCompressedTextureImage</code>
</td>
<td style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">-</td>
<td style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">-</td>
<td style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">-</td>
<td style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">-</td>
<td style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">-</td>
<td style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">-</td>
<td style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">-</td>
<td style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">-</td>
<td style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">-</td>
<td style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">-</td>
<td style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">-</td>
<td style="text-align: center; border-bottom: 2px solid ; ">✔</td>
</tr>
<tr>
<td style="text-align: left; border-right: 2px solid ; ">
<code class="function">glGetnCompressedTexImage</code>
</td>
<td style="text-align: center; border-right: 2px solid ; ">-</td>
<td style="text-align: center; border-right: 2px solid ; ">-</td>
<td style="text-align: center; border-right: 2px solid ; ">-</td>
<td style="text-align: center; border-right: 2px solid ; ">-</td>
<td style="text-align: center; border-right: 2px solid ; ">-</td>
<td style="text-align: center; border-right: 2px solid ; ">-</td>
<td style="text-align: center; border-right: 2px solid ; ">-</td>
<td style="text-align: center; border-right: 2px solid ; ">-</td>
<td style="text-align: center; border-right: 2px solid ; ">-</td>
<td style="text-align: center; border-right: 2px solid ; ">-</td>
<td style="text-align: center; border-right: 2px solid ; ">-</td>
<td style="text-align: center; ">✔</td>
</tr>
</tbody>
</table>
</div>
</div>
<div class="refsect1" id="seealso">
<h2>See Also</h2>
<p><a class="citerefentry" href="glActiveTexture.xhtml"><span class="citerefentry"><span class="refentrytitle">glActiveTexture</span></span></a>, <a class="citerefentry" href="glCompressedTexImage1D.xhtml"><span class="citerefentry"><span class="refentrytitle">glCompressedTexImage1D</span></span></a>, <a class="citerefentry" href="glCompressedTexImage2D.xhtml"><span class="citerefentry"><span class="refentrytitle">glCompressedTexImage2D</span></span></a>, <a class="citerefentry" href="glCompressedTexImage3D.xhtml"><span class="citerefentry"><span class="refentrytitle">glCompressedTexImage3D</span></span></a>, <a class="citerefentry" href="glCompressedTexSubImage1D.xhtml"><span class="citerefentry"><span class="refentrytitle">glCompressedTexSubImage1D</span></span></a>, <a class="citerefentry" href="glCompressedTexSubImage2D.xhtml"><span class="citerefentry"><span class="refentrytitle">glCompressedTexSubImage2D</span></span></a>, <a class="citerefentry" href="glCompressedTexSubImage3D.xhtml"><span class="citerefentry"><span class="refentrytitle">glCompressedTexSubImage3D</span></span></a>, <a class="citerefentry" href="glReadPixels.xhtml"><span class="citerefentry"><span class="refentrytitle">glReadPixels</span></span></a>, <a class="citerefentry" href="glTexImage1D.xhtml"><span class="citerefentry"><span class="refentrytitle">glTexImage1D</span></span></a>, <a class="citerefentry" href="glTexImage2D.xhtml"><span class="citerefentry"><span class="refentrytitle">glTexImage2D</span></span></a>, <a class="citerefentry" href="glTexImage3D.xhtml"><span class="citerefentry"><span class="refentrytitle">glTexImage3D</span></span></a>, <a class="citerefentry" href="glTexParameter.xhtml"><span class="citerefentry"><span class="refentrytitle">glTexParameter</span></span></a>, <a class="citerefentry" href="glTexSubImage1D.xhtml"><span class="citerefentry"><span class="refentrytitle">glTexSubImage1D</span></span></a>, <a class="citerefentry" href="glTexSubImage2D.xhtml"><span class="citerefentry"><span class="refentrytitle">glTexSubImage2D</span></span></a>, <a class="citerefentry" href="glTexSubImage3D.xhtml"><span class="citerefentry"><span class="refentrytitle">glTexSubImage3D</span></span></a></p>
</div>
<div class="refsect1" id="Copyright">
<h2>Copyright</h2>
<p>Copyright <span class="trademark"/>© 1991-2006 Silicon Graphics,
Inc. Copyright <span class="trademark"/>© 2010-2014 Khronos Group.
This document is licensed under the SGI Free Software B License. For
details, see
<a class="link" href="http://opencontent.org/openpub/" target="_top">http://opencontent.org/openpub/</a>.
</p>
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