<div class="refentry" id="glCompressedTexImage2D">

<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 style="border: 0; cellspacing: 0; cellpadding: 0;" class="funcprototype-table">

<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" 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 texture.

Must be <code class="constant">GL_TEXTURE_2D</code>, <code class="constant">GL_PROXY_TEXTURE_2D</code>,

<code class="constant">GL_TEXTURE_1D_ARRAY</code>, <code class="constant">GL_PROXY_TEXTURE_1D_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>,

<code class="constant">GL_TEXTURE_CUBE_MAP_NEGATIVE_Z</code>, or

<code class="constant">GL_PROXY_TEXTURE_CUBE_MAP</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 and cube map texture images that are at least 16384 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 and cube map texture images that are at least 16384 texels high.

</p>

</dd>

<dt>

<span class="term">

<em class="parameter">

<code>border</code>

</em>

</span>

</dt>

<dd>

<p>

This value 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" id="description">

<h2>Description</h2>

<p>

Texturing allows elements of an image array to be read by shaders.

</p>

<p>

<code class="function">glCompressedTexImage2D</code> loads a previously defined, and retrieved, compressed two-dimensional

texture image if <em class="parameter"><code>target</code></em> is <code class="constant">GL_TEXTURE_2D</code>, or one of the

cube map faces such as <code class="constant">GL_TEXTURE_CUBE_MAP_POSITIVE_X</code>.

(see <a class="citerefentry" href="glTexImage2D"><span class="citerefentry"><span class="refentrytitle">glTexImage2D</span></span></a>).

</p>

<p>

If <em class="parameter"><code>target</code></em> is <code class="constant">GL_TEXTURE_1D_ARRAY</code>, <em class="parameter"><code>data</code></em>

is treated as an array of compressed 1D textures.

</p>

<p>

If <em class="parameter"><code>target</code></em> is <code class="constant">GL_PROXY_TEXTURE_2D</code>, <code class="constant">GL_PROXY_TEXTURE_1D_ARRAY</code>

or <code class="constant">GL_PROXY_TEXTURE_CUBE_MAP</code>, no data is read from <em class="parameter"><code>data</code></em>, but

all of the texture image state is recalculated, checked for consistency,

and checked against the implementation's capabilities. If the

implementation cannot handle a texture of the requested texture size, it

sets all of the image state to 0, but does not generate an error (see

<a class="citerefentry" href="glGetError"><span class="citerefentry"><span class="refentrytitle">glGetError</span></span></a>). To query for an entire mipmap array,

use an image array level greater than or equal to 1.

</p>

<p>

<em class="parameter"><code>internalformat</code></em> must be a known compressed image format (such as <code class="constant">GL_RGTC</code>)

or an extension-specified compressed-texture format.

When a texture is loaded with <a class="citerefentry" href="glTexImage2D"><span class="citerefentry"><span class="refentrytitle">glTexImage2D</span></span></a> using a generic compressed

texture format (e.g., <code class="constant">GL_COMPRESSED_RGB</code>), the GL selects from one of

its extensions supporting compressed textures. In order to load the

compressed texture image using <code class="function">glCompressedTexImage2D</code>, query the compressed texture image's

size and format using <a class="citerefentry" href="glGetTexLevelParameter"><span class="citerefentry"><span class="refentrytitle">glGetTexLevelParameter</span></span></a>.

</p>

<p>

If a non-zero named buffer object is bound to the <code class="constant">GL_PIXEL_UNPACK_BUFFER</code> target

(see <a class="citerefentry" href="glBindBuffer"><span class="citerefentry"><span class="refentrytitle">glBindBuffer</span></span></a>) while a texture image is

specified, <em class="parameter"><code>data</code></em> is treated as a byte offset into the buffer object's data store.

</p>

<p>

If the compressed data are arranged into fixed-size blocks of texels, the pixel

storage modes can be used to select a sub-rectangle from a larger containing rectangle.

These pixel storage modes operate in the same way as they do for <a class="citerefentry" href="glTexImage2D"><span class="citerefentry"><span class="refentrytitle">glTexImage2D</span></span></a>.

In the following description, denote by

<math overflow="scroll"><mrow><msub><mi>b</mi><mi>s</mi></msub></mrow></math>,

<math overflow="scroll"><mrow><msub><mi>b</mi><mi>w</mi></msub></mrow></math>,

<math overflow="scroll"><mrow><msub><mi>b</mi><mi>h</mi></msub></mrow></math>, and

<math overflow="scroll"><mrow><msub><mi>b</mi><mi>d</mi></msub></mrow></math>,

the values of pixel storage modes <code class="constant">GL_UNPACK_COMPRESSED_BLOCK_SIZE</code>,

<code class="constant">GL_UNPACK_COMPRESSED_BLOCK_WIDTH</code>, <code class="constant">GL_UNPACK_COMPRESSED_BLOCK_HEIGHT</code>,

and <code class="constant">GL_UNPACK_COMPRESSED_BLOCK_DEPTH</code>, respectively.

<math overflow="scroll"><mrow><msub><mi>b</mi><mi>s</mi></msub></mrow></math> is the compressed block size in bytes;

<math overflow="scroll"><mrow><msub><mi>b</mi><mi>w</mi></msub></mrow></math>,

<math overflow="scroll"><mrow><msub><mi>b</mi><mi>h</mi></msub></mrow></math>, and

<math overflow="scroll"><mrow><msub><mi>b</mi><mi>d</mi></msub></mrow></math> are the compressed block width, height, and depth in pixels.

</p>

<p>

By default the pixel storage modes <code class="constant">GL_UNPACK_ROW_LENGTH</code>,

<code class="constant">GL_UNPACK_SKIP_ROWS</code>, <code class="constant">GL_UNPACK_SKIP_PIXELS</code>,

<code class="constant">GL_UNPACK_IMAGE_HEIGHT</code> and <code class="constant">GL_UNPACK_SKIP_IMAGES</code>

are ignored for compressed images. To enable <code class="constant">GL_UNPACK_SKIP_PIXELS</code>

and <code class="constant">GL_UNPACK_ROW_LENGTH</code>,

<math overflow="scroll"><mrow><msub><mi>b</mi><mi>s</mi></msub></mrow></math>

and

<math overflow="scroll"><mrow><msub><mi>b</mi><mi>w</mi></msub></mrow></math>

must both be non-zero.

To also enable <code class="constant">GL_UNPACK_SKIP_ROWS</code> and <code class="constant">GL_UNPACK_IMAGE_HEIGHT</code>,

<math overflow="scroll"><mrow><msub><mi>b</mi><mi>h</mi></msub></mrow></math>

must be non-zero.

To also enable <code class="constant">GL_UNPACK_SKIP_IMAGES</code>,

<math overflow="scroll"><mrow><msub><mi>b</mi><mi>d</mi></msub></mrow></math>

must be non-zero. All parameters must be consistent with the compressed format to produce the desired results.

</p>

<p>

When selecting a sub-rectangle from a compressed image:

</p>

<div class="itemizedlist">

<ul class="itemizedlist" style="list-style-type: disc; ">

<li class="listitem">

<p>

The value of

<code class="constant">GL_UNPACK_SKIP_PIXELS</code> must be a

multiple of

<math overflow="scroll"><mrow><msub><mi>b</mi><mi>w</mi></msub></mrow></math>;

</p>

</li>

<li class="listitem">

<p>

the value of

<code class="constant">GL_UNPACK_SKIP_ROWS</code> must be a

multiple of

<math overflow="scroll"><mrow><msub><mi>b</mi><mi>w</mi></msub></mrow></math>.

</p>

</li>

</ul>

</div>

<p>

</p>

<p>

<em class="parameter"><code>imageSize</code></em> must be equal to:

</p>

<p>

<math display="block" overflow="scroll">

<mrow>

<msub>

<mi>b</mi>

<mi>s</mi>

</msub>

<mo lspace="2px" rspace="2px">×</mo>

<mfenced open="⌈" close="⌉">

<mfrac>

<mi>width</mi>

<msub>

<mi>b</mi>

<mi>w</mi>

</msub>

</mfrac>

</mfenced>

<mo lspace="2px" rspace="2px">×</mo>

<mfenced open="⌈" close="⌉">

<mfrac>

<mi>height</mi>

<msub>

<mi>b</mi>

<mi>h</mi>

</msub>

</mfrac>

</mfenced>

</mrow>

</math>

</p>

</div>

<div class="refsect1" id="notes">

<h2>Notes</h2>

<p>

The specific compressed internal formats <code class="constant">GL_COMPRESSED_RGB8_ETC2</code>,

<code class="constant">GL_COMPRESSED_SRGB8_ETC2</code>,

<code class="constant">GL_COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2</code>,

<code class="constant">GL_COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2</code>,

<code class="constant">GL_COMPRESSED_RGBA8_ETC2_EAC</code>,

<code class="constant">GL_COMPRESSED_SRGB8_ALPHA8_ETC2_EAC</code>,

<code class="constant">GL_COMPRESSED_R11_EAC</code>,

<code class="constant">GL_COMPRESSED_SIGNED_R11_EAC</code>,

<code class="constant">GL_COMPRESSED_RG11_EAC</code>, and

<code class="constant">GL_COMPRESSED_SIGNED_RG11_EAC</code> are available only if the GL version

is 4.3 or higher.

</p>

</div>

<div class="refsect1" id="errors">

<h2>Errors</h2>

<p>

<code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>internalformat</code></em> is not one of the specific

compressed internal formats:

<code class="constant">GL_COMPRESSED_RED_RGTC1</code>,

<code class="constant">GL_COMPRESSED_SIGNED_RED_RGTC1</code>,

<code class="constant">GL_COMPRESSED_RG_RGTC2</code>,

<code class="constant">GL_COMPRESSED_SIGNED_RG_RGTC2</code>.

<code class="constant">GL_COMPRESSED_RGBA_BPTC_UNORM</code>,

<code class="constant">GL_COMPRESSED_SRGB_ALPHA_BPTC_UNORM</code>,

<code class="constant">GL_COMPRESSED_RGB_BPTC_SIGNED_FLOAT</code>,

<code class="constant">GL_COMPRESSED_RGB_BPTC_UNSIGNED_FLOAT</code>,

<code class="constant">GL_COMPRESSED_RGB8_ETC2</code>,

<code class="constant">GL_COMPRESSED_SRGB8_ETC2</code>,

<code class="constant">GL_COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2</code>,

<code class="constant">GL_COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2</code>,

<code class="constant">GL_COMPRESSED_RGBA8_ETC2_EAC</code>,

<code class="constant">GL_COMPRESSED_SRGB8_ALPHA8_ETC2_EAC</code>,

<code class="constant">GL_COMPRESSED_R11_EAC</code>,

<code class="constant">GL_COMPRESSED_SIGNED_R11_EAC</code>,

<code class="constant">GL_COMPRESSED_RG11_EAC</code>, or

<code class="constant">GL_COMPRESSED_SIGNED_RG11_EAC</code>.

</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_VALUE</code> is generated if <em class="parameter"><code>border</code></em> is not 0.

</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>

<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_UNPACK_BUFFER</code> target 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_UNPACK_BUFFER</code> target and the data would be unpacked from the buffer

object such that the memory reads required would exceed the data store size.

</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" id="associatedgets">

<h2>Associated Gets</h2>

<p>

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

</p>

<p>

<a class="citerefentry" href="glGet"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument <code class="constant">GL_TEXTURE_COMPRESSED</code>

</p>

<p>

<a class="citerefentry" href="glGet"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument <code class="constant">GL_PIXEL_UNPACK_BUFFER_BINDING</code>

</p>

<p>

<a class="citerefentry" href="glGetTexLevelParameter"><span class="citerefentry"><span class="refentrytitle">glGetTexLevelParameter</span></span></a> with arguments <code class="constant">GL_TEXTURE_INTERNAL_FORMAT</code>

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

</p>

</div>

{$pipelinestall}{$examples}

<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 ; ">

<code class="function">glCompressedTexImage2D</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"><span class="citerefentry"><span class="refentrytitle">glActiveTexture</span></span></a>,

<a class="citerefentry" href="glCompressedTexImage1D"><span class="citerefentry"><span class="refentrytitle">glCompressedTexImage1D</span></span></a>,

<a class="citerefentry" href="glCompressedTexImage3D"><span class="citerefentry"><span class="refentrytitle">glCompressedTexImage3D</span></span></a>,

<a class="citerefentry" href="glCompressedTexSubImage1D"><span class="citerefentry"><span class="refentrytitle">glCompressedTexSubImage1D</span></span></a>,

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

<a class="citerefentry" href="glCompressedTexSubImage3D"><span class="citerefentry"><span class="refentrytitle">glCompressedTexSubImage3D</span></span></a>,

<a class="citerefentry" href="glCopyTexImage1D"><span class="citerefentry"><span class="refentrytitle">glCopyTexImage1D</span></span></a>,

<a class="citerefentry" href="glCopyTexSubImage1D"><span class="citerefentry"><span class="refentrytitle">glCopyTexSubImage1D</span></span></a>,

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

<a class="citerefentry" href="glCopyTexSubImage3D"><span class="citerefentry"><span class="refentrytitle">glCopyTexSubImage3D</span></span></a>,

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

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

<a class="citerefentry" href="glTexImage3D"><span class="citerefentry"><span class="refentrytitle">glTexImage3D</span></span></a>,

<a class="citerefentry" href="glTexSubImage1D"><span class="citerefentry"><span class="refentrytitle">glTexSubImage1D</span></span></a>,

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

<a class="citerefentry" href="glTexSubImage3D"><span class="citerefentry"><span class="refentrytitle">glTexSubImage3D</span></span></a>,

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

</p>

</div>

<div class="refsect1" id="Copyright">

<h2>Copyright</h2>

<p>

Copyright © 1991-2006 Silicon Graphics, Inc.

Copyright © 2011-2014 Khronos Group.

This document is licensed under the SGI

Free Software B License. For details, see

<a class="link" 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>