<div class="refentry"><a id="glCompressedTexImage2D"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glCompressedTexImage2D — specify a two-dimensional texture image in a compressed format</p></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><table class="funcprototype-table" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">void <strong class="fsfunc">glCompressedTexImage2D</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>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>, </td></tr><tr><td> </td><td>GLsizei <var class="pdparam">imageSize</var>, </td></tr><tr><td> </td><td>const GLvoid * <var class="pdparam">data</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 of the active texture unit.

Must be <code class="constant">GL_TEXTURE_2D</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>, or

<code class="constant">GL_TEXTURE_CUBE_MAP_NEGATIVE_Z</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 <span class="emphasis"><em>n</em></span> is the <span class="emphasis"><em>n</em></span>th mipmap reduction image.

</p></dd><dt><span class="term"><em class="parameter"><code>internalformat</code></em></span></dt><dd><p>

Specifies the format of the compressed image data stored at address <em class="parameter"><code>data</code></em>.

</p></dd><dt><span class="term"><em class="parameter"><code>width</code></em></span></dt><dd><p>

Specifies the width of the texture image.

All

implementations support 2D texture images that are at least 64 texels

wide and cube-mapped texture images that are at least 16 texels wide.

</p></dd><dt><span class="term"><em class="parameter"><code>height</code></em></span></dt><dd><p>

Specifies the height of the texture image.

All

implementations support 2D texture images that are at least 64 texels

high and cube-mapped texture images that are at least 16 texels high.

</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><dt><span class="term"><em class="parameter"><code>imageSize</code></em></span></dt><dd><p>

Specifies the number of unsigned bytes of image data starting at the

address specified by <em class="parameter"><code>data</code></em>.

</p></dd><dt><span class="term"><em class="parameter"><code>data</code></em></span></dt><dd><p>

Specifies a pointer to the compressed image data in memory.

</p></dd></dl></div></div><div class="refsect1"><a id="description"></a><h2>Description</h2><p>

Texturing maps a portion of a specified texture image

onto each graphical primitive for which texturing is

active. Texturing is active when the current fragment shader or

vertex shader makes use of built-in texture lookup

functions.

</p><p>

<code class="function">glCompressedTexImage2D</code> defines a two-dimensional texture image

or cube-map texture image using compressed image data from client memory. The texture

image is decoded according to the extension specification defining the specified

<em class="parameter"><code>internalformat</code></em>. OpenGL ES defines no specific compressed

texture formats, but does provide a mechanism to obtain symbolic constants for such

formats provided by extensions. The number of compressed texture formats supported

can be obtained by querying the value of

<code class="constant">GL_NUM_COMPRESSED_TEXTURE_FORMATS</code>. The list of specific

compressed texture formats supported can be obtained by querying the value of

<code class="constant">GL_COMPRESSED_TEXTURE_FORMATS</code>.

</p></div><div class="refsect1"><a id="notes"></a><h2>Notes</h2><p>

A GL implementation may choose to store the texture

array at any internal resolution it chooses.

</p><p>

<code class="function">glCompressedTexImage2D</code>

specifies a two-dimensional or cube-map texture for the current texture unit,

specified with <a class="citerefentry" href="glActiveTexture"><span class="citerefentry"><span class="refentrytitle">glActiveTexture</span></span></a>.

</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>,

<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>, or

<code class="constant">GL_TEXTURE_CUBE_MAP_NEGATIVE_Z</code>.

</p><p>

<code class="constant">GL_INVALID_ENUM</code> is generated if

<em class="parameter"><code>internalformat</code></em> is not a supported format returned in

<code class="constant">GL_COMPRESSED_TEXTURE_FORMATS</code>.

</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

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is the returned value of <code class="constant">GL_MAX_TEXTURE_SIZE</code> when <em class="parameter"><code>target</code></em>

is <code class="constant">GL_TEXTURE_2D</code> or <code class="constant">GL_MAX_CUBE_MAP_TEXTURE_SIZE</code> when

<em class="parameter"><code>target</code></em> is not <code class="constant">GL_TEXTURE_2D</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

or greater than <code class="constant">GL_MAX_TEXTURE_SIZE</code> when <em class="parameter"><code>target</code></em>

is <code class="constant">GL_TEXTURE_2D</code> or <code class="constant">GL_MAX_CUBE_MAP_TEXTURE_SIZE</code> when

<em class="parameter"><code>target</code></em> is not <code class="constant">GL_TEXTURE_2D</code>.

</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_VALUE</code> is generated if <em class="parameter"><code>imageSize</code></em> is not consistent with

the format, dimensions, and contents of the specified compressed image

data.

</p><p>

<code class="constant">GL_INVALID_OPERATION</code> is generated if parameter combinations are not

supported by the specific compressed internal format as specified in the

specific texture compression extension.

</p><p>

Undefined results, including abnormal program termination, are generated if

<em class="parameter"><code>data</code></em> is not encoded in a manner consistent with the extension

specification defining the internal compression format.

</p></div><div class="refsect1"><a id="associatedgets"></a><h2>Associated Gets</h2><p>

<a class="citerefentry" href="glGet"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with arguments

<code class="constant">GL_NUM_COMPRESSED_TEXTURE_FORMATS</code> and

<code class="constant">GL_COMPRESSED_TEXTURE_FORMATS</code>

</p><p>

<a class="citerefentry" href="glGet"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a>

with argument <code class="constant">GL_MAX_TEXTURE_SIZE</code> or

<code class="constant">GL_MAX_CUBE_MAP_TEXTURE_SIZE</code>

</p></div>

{$pipelinestall}{$examples}

<div class="refsect1"><a id="seealso"></a><h2>See Also</h2><p>

<a class="citerefentry" href="glActiveTexture"><span class="citerefentry"><span class="refentrytitle">glActiveTexture</span></span></a>,

<a class="citerefentry" href="glCompressedTexSubImage2D"><span class="citerefentry"><span class="refentrytitle">glCompressedTexSubImage2D</span></span></a>,

<a class="citerefentry" href="glCopyTexImage2D"><span class="citerefentry"><span class="refentrytitle">glCopyTexImage2D</span></span></a>,

<a class="citerefentry" href="glCopyTexSubImage2D"><span class="citerefentry"><span class="refentrytitle">glCopyTexSubImage2D</span></span></a>,

<a class="citerefentry" href="glTexImage2D"><span class="citerefentry"><span class="refentrytitle">glTexImage2D</span></span></a>,

<a class="citerefentry" href="glTexSubImage2D"><span class="citerefentry"><span class="refentrytitle">glTexSubImage2D</span></span></a>,

<a class="citerefentry" href="glTexParameter"><span class="citerefentry"><span class="refentrytitle">glTexParameter</span></span></a>

</p></div><div class="refsect1"><div id="Copyright"><h2>Copyright</h2><p>

Copyright © 1991-2006

Silicon Graphics, Inc. This document is licensed under the SGI

Free Software B License. For details, see

<a class="ulink" href="https://web.archive.org/web/20171022161616/http://oss.sgi.com/projects/FreeB/" target="_top">https://web.archive.org/web/20171022161616/http://oss.sgi.com/projects/FreeB/</a>.

</p></div></div></div>