+<?xml version="1.0" encoding="UTF-8"?>
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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>glCompressedTexSubImage2D - 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="glCompressedTexSubImage2D"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glCompressedTexSubImage2D — specify a two-dimensional texture subimage in a compressed format</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">glCompressedTexSubImage2D</b>(</code></td><td>GLenum </td><td><var class="pdparam">target</var>, </td></tr><tr><td> </td><td>GLint </td><td><var class="pdparam">level</var>, </td></tr><tr><td> </td><td>GLint </td><td><var class="pdparam">xoffset</var>, </td></tr><tr><td> </td><td>GLint </td><td><var class="pdparam">yoffset</var>, </td></tr><tr><td> </td><td>GLsizei </td><td><var class="pdparam">width</var>, </td></tr><tr><td> </td><td>GLsizei </td><td><var class="pdparam">height</var>, </td></tr><tr><td> </td><td>GLenum </td><td><var class="pdparam">format</var>, </td></tr><tr><td> </td><td>GLsizei </td><td><var class="pdparam">imageSize</var>, </td></tr><tr><td> </td><td>const GLvoid * </td><td><var class="pdparam">data</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>target</code></em></span></dt><dd><p>
+ Specifies the target texture.
+ 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>xoffset</code></em></span></dt><dd><p>
+ Specifies a texel offset in the x direction within the texture array.
+ </p></dd><dt><span class="term"><em class="parameter"><code>yoffset</code></em></span></dt><dd><p>
+ Specifies a texel offset in the y direction within the texture array.
+ </p></dd><dt><span class="term"><em class="parameter"><code>width</code></em></span></dt><dd><p>
+ Specifies the width of the texture subimage.
+ </p></dd><dt><span class="term"><em class="parameter"><code>height</code></em></span></dt><dd><p>
+ Specifies the height of the texture subimage.
+ </p></dd><dt><span class="term"><em class="parameter"><code>format</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>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" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
+ Texturing allows elements of an image array to be read by shaders.
+ </p><p>
+ <code class="function">glCompressedTexSubImage2D</code> redefines a contiguous subregion of an existing two-dimensional
+ texture image. The texels referenced by <em class="parameter"><code>data</code></em> replace the portion of the
+ existing texture array with x indices <em class="parameter"><code>xoffset</code></em> and
+ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
+
+ <mml:mrow>
+ <mml:mi mathvariant="italic">xoffset</mml:mi>
+ <mml:mo>+</mml:mo>
+ <mml:mi mathvariant="italic">width</mml:mi>
+ <mml:mo>-</mml:mo>
+ <mml:mn>1</mml:mn>
+ </mml:mrow>
+ </mml:math>,
+ and the y indices <em class="parameter"><code>yoffset</code></em> and
+ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
+
+ <mml:mrow>
+ <mml:mi mathvariant="italic">yoffset</mml:mi>
+ <mml:mo>+</mml:mo>
+ <mml:mi mathvariant="italic">height</mml:mi>
+ <mml:mo>-</mml:mo>
+ <mml:mn>1</mml:mn>
+ </mml:mrow>
+ </mml:math>,
+ inclusive.
+ This region may not include any texels
+ outside the range of the texture array as it was originally specified. It
+ is not an error to specify a subtexture with width of 0, but such a
+ specification has no effect.
+ </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.
+ The <em class="parameter"><code>format</code></em> of the compressed texture
+ image is selected by the GL implementation that compressed it (see
+ <a href="glTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage2D</span></span></a>) and should be queried at the time the texture was
+ compressed with <a href="glGetTexLevelParameter.xml"><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 href="glBindBuffer.xml"><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></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p>
+ <code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>internalformat</code></em> is of the generic compressed internal formats:
+ <code class="constant">GL_COMPRESSED_RED</code>,
+ <code class="constant">GL_COMPRESSED_RG</code>,
+ <code class="constant">GL_COMPRESSED_RGB</code>,
+ <code class="constant">GL_COMPRESSED_RGBA</code>.
+ <code class="constant">GL_COMPRESSED_SRGB</code>, or
+ <code class="constant">GL_COMPRESSED_SRGB_ALPHA</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_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" lang="en" xml:lang="en"><a id="associatedgets"></a><h2>Associated Gets</h2><p>
+ <a href="glGetCompressedTexImage.xml"><span class="citerefentry"><span class="refentrytitle">glGetCompressedTexImage</span></span></a>
+ </p><p>
+ <a href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument <code class="constant">GL_TEXTURE_COMPRESSED</code>
+ </p><p>
+ <a href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument <code class="constant">GL_PIXEL_UNPACK_BUFFER_BINDING</code>
+ </p><p>
+ <a href="glGetTexLevelParameter.xml"><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><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
+ <a href="glActiveTexture.xml"><span class="citerefentry"><span class="refentrytitle">glActiveTexture</span></span></a>,
+ <a href="glCompressedTexImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glCompressedTexImage1D</span></span></a>,
+ <a href="glCompressedTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glCompressedTexImage2D</span></span></a>,
+ <a href="glCompressedTexImage3D.xml"><span class="citerefentry"><span class="refentrytitle">glCompressedTexImage3D</span></span></a>,
+ <a href="glCompressedTexSubImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glCompressedTexSubImage1D</span></span></a>,
+ <a href="glCompressedTexSubImage3D.xml"><span class="citerefentry"><span class="refentrytitle">glCompressedTexSubImage3D</span></span></a>,
+ <a href="glCopyTexImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexImage1D</span></span></a>,
+ <a href="glCopyTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexImage2D</span></span></a>,
+ <a href="glCopyTexSubImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexSubImage1D</span></span></a>,
+ <a href="glCopyTexSubImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexSubImage2D</span></span></a>,
+ <a href="glCopyTexSubImage3D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexSubImage3D</span></span></a>,
+ <a href="glPixelStore.xml"><span class="citerefentry"><span class="refentrytitle">glPixelStore</span></span></a>,
+ <a href="glTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage2D</span></span></a>,
+ <a href="glTexImage3D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage3D</span></span></a>,
+ <a href="glTexSubImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glTexSubImage1D</span></span></a>,
+ <a href="glTexSubImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glTexSubImage2D</span></span></a>,
+ <a href="glTexSubImage3D.xml"><span class="citerefentry"><span class="refentrytitle">glTexSubImage3D</span></span></a>,
+ <a href="glTexParameter.xml"><span class="citerefentry"><span class="refentrytitle">glTexParameter</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>© 1991-2006
+ Silicon Graphics, Inc. This document is licensed under the SGI
+ Free Software B License. For details, see
+ <a href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>.
+ </p></div></div></body></html>