upstream-man-pages/man4/xhtml/glCompressedTexSubImage2D.xml

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   4 <?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>
   5                     Specifies the target texture.
   6                     Must be <code class="constant">GL_TEXTURE_2D</code>,
   7                     <code class="constant">GL_TEXTURE_CUBE_MAP_POSITIVE_X</code>,
   8                     <code class="constant">GL_TEXTURE_CUBE_MAP_NEGATIVE_X</code>,
   9                     <code class="constant">GL_TEXTURE_CUBE_MAP_POSITIVE_Y</code>,
  10                     <code class="constant">GL_TEXTURE_CUBE_MAP_NEGATIVE_Y</code>,
  11                     <code class="constant">GL_TEXTURE_CUBE_MAP_POSITIVE_Z</code>, or
  12                     <code class="constant">GL_TEXTURE_CUBE_MAP_NEGATIVE_Z</code>.
  13                 </p></dd><dt><span class="term"><em class="parameter"><code>level</code></em></span></dt><dd><p>
  14                     Specifies the level-of-detail number.
  15                     Level 0 is the base image level.
  16                     Level <span class="emphasis"><em>n</em></span> is the <span class="emphasis"><em>n</em></span>th mipmap reduction image.
  17                 </p></dd><dt><span class="term"><em class="parameter"><code>xoffset</code></em></span></dt><dd><p>
  18                     Specifies a texel offset in the x direction within the texture array.
  19                 </p></dd><dt><span class="term"><em class="parameter"><code>yoffset</code></em></span></dt><dd><p>
  20                     Specifies a texel offset in the y direction within the texture array.
  21                 </p></dd><dt><span class="term"><em class="parameter"><code>width</code></em></span></dt><dd><p>
  22                     Specifies the width of the texture subimage.
  23                 </p></dd><dt><span class="term"><em class="parameter"><code>height</code></em></span></dt><dd><p>
  24                     Specifies the height of the texture subimage.
  25                 </p></dd><dt><span class="term"><em class="parameter"><code>format</code></em></span></dt><dd><p>
  26                     Specifies the format of the compressed image data stored at address <em class="parameter"><code>data</code></em>.
  27                 </p></dd><dt><span class="term"><em class="parameter"><code>imageSize</code></em></span></dt><dd><p>
  28                     Specifies the number of unsigned bytes of image data starting at the
  29                     address specified by <em class="parameter"><code>data</code></em>.
  30                 </p></dd><dt><span class="term"><em class="parameter"><code>data</code></em></span></dt><dd><p>
  31                     Specifies a pointer to the compressed image data in memory.
  32                 </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
  33             Texturing allows elements of an image array to be read by shaders.
  34         </p><p>
  35             <code class="function">glCompressedTexSubImage2D</code> redefines a contiguous subregion of an existing two-dimensional
  36             texture image.  The texels referenced by <em class="parameter"><code>data</code></em> replace the portion of the
  37             existing texture array with x indices <em class="parameter"><code>xoffset</code></em> and
  38             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  39
  40                 <mml:mrow>
  41                     <mml:mi mathvariant="italic">xoffset</mml:mi>
  42                     <mml:mo>+</mml:mo>
  43                     <mml:mi mathvariant="italic">width</mml:mi>
  44                     <mml:mo>-</mml:mo>
  45                     <mml:mn>1</mml:mn>
  46                 </mml:mrow>
  47             </mml:math>,
  48             and the y indices <em class="parameter"><code>yoffset</code></em> and
  49             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  50
  51                 <mml:mrow>
  52                     <mml:mi mathvariant="italic">yoffset</mml:mi>
  53                     <mml:mo>+</mml:mo>
  54                     <mml:mi mathvariant="italic">height</mml:mi>
  55                     <mml:mo>-</mml:mo>
  56                     <mml:mn>1</mml:mn>
  57                 </mml:mrow>
  58             </mml:math>,
  59             inclusive.
  60             This region may not include any texels
  61             outside the range of the texture array as it was originally specified.  It
  62             is not an error to specify a subtexture with width of 0, but such a
  63             specification has no effect.
  64         </p><p>
  65             <em class="parameter"><code>internalformat</code></em> must be a known compressed image format (such as <code class="constant">GL_RGTC</code>)
  66             or an extension-specified compressed-texture format.
  67             The <em class="parameter"><code>format</code></em> of the compressed texture
  68             image is selected by the GL implementation that compressed it (see
  69             <a href="glTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage2D</span></span></a>) and should be queried at the time the texture was
  70             compressed with <a href="glGetTexLevelParameter.xml"><span class="citerefentry"><span class="refentrytitle">glGetTexLevelParameter</span></span></a>.
  71         </p><p>
  72             If a non-zero named buffer object is bound to the <code class="constant">GL_PIXEL_UNPACK_BUFFER</code> target
  73             (see <a href="glBindBuffer.xml"><span class="citerefentry"><span class="refentrytitle">glBindBuffer</span></span></a>) while a texture image is
  74             specified, <em class="parameter"><code>data</code></em> is treated as a byte offset into the buffer object's data store.
  75         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p>
  76           <code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>internalformat</code></em> is of the generic compressed internal formats:
  77           <code class="constant">GL_COMPRESSED_RED</code>,
  78           <code class="constant">GL_COMPRESSED_RG</code>,
  79           <code class="constant">GL_COMPRESSED_RGB</code>,
  80           <code class="constant">GL_COMPRESSED_RGBA</code>.
  81           <code class="constant">GL_COMPRESSED_SRGB</code>, or
  82           <code class="constant">GL_COMPRESSED_SRGB_ALPHA</code>.
  83         </p><p>
  84             <code class="constant">GL_INVALID_VALUE</code> is generated if <em class="parameter"><code>imageSize</code></em> is not consistent with
  85             the format, dimensions, and contents of the specified compressed image
  86             data.
  87         </p><p>
  88             <code class="constant">GL_INVALID_OPERATION</code> is generated if parameter combinations are not
  89             supported by the specific compressed internal format as specified in the
  90             specific texture compression extension.
  91         </p><p>
  92             <code class="constant">GL_INVALID_OPERATION</code> is generated if a non-zero buffer object name is bound to the
  93             <code class="constant">GL_PIXEL_UNPACK_BUFFER</code> target and the buffer object's data store is currently mapped.
  94         </p><p>
  95             <code class="constant">GL_INVALID_OPERATION</code> is generated if a non-zero buffer object name is bound to the
  96             <code class="constant">GL_PIXEL_UNPACK_BUFFER</code> target and the data would be unpacked from the buffer
  97             object such that the memory reads required would exceed the data store size.
  98         </p><p>
  99             Undefined results, including abnormal program termination, are generated if
 100             <em class="parameter"><code>data</code></em> is not encoded in a manner consistent with the extension
 101             specification defining the internal compression format.
 102         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="associatedgets"></a><h2>Associated Gets</h2><p>
 103             <a href="glGetCompressedTexImage.xml"><span class="citerefentry"><span class="refentrytitle">glGetCompressedTexImage</span></span></a>
 104         </p><p>
 105             <a href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument <code class="constant">GL_TEXTURE_COMPRESSED</code>
 106         </p><p>
 107             <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>
 108         </p><p>
 109             <a href="glGetTexLevelParameter.xml"><span class="citerefentry"><span class="refentrytitle">glGetTexLevelParameter</span></span></a> with arguments <code class="constant">GL_TEXTURE_INTERNAL_FORMAT</code>
 110             and <code class="constant">GL_TEXTURE_COMPRESSED_IMAGE_SIZE</code>
 111         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
 112             <a href="glActiveTexture.xml"><span class="citerefentry"><span class="refentrytitle">glActiveTexture</span></span></a>,
 113             <a href="glCompressedTexImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glCompressedTexImage1D</span></span></a>,
 114             <a href="glCompressedTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glCompressedTexImage2D</span></span></a>,
 115             <a href="glCompressedTexImage3D.xml"><span class="citerefentry"><span class="refentrytitle">glCompressedTexImage3D</span></span></a>,
 116             <a href="glCompressedTexSubImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glCompressedTexSubImage1D</span></span></a>,
 117             <a href="glCompressedTexSubImage3D.xml"><span class="citerefentry"><span class="refentrytitle">glCompressedTexSubImage3D</span></span></a>,
 118             <a href="glCopyTexImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexImage1D</span></span></a>,
 119             <a href="glCopyTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexImage2D</span></span></a>,
 120             <a href="glCopyTexSubImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexSubImage1D</span></span></a>,
 121             <a href="glCopyTexSubImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexSubImage2D</span></span></a>,
 122             <a href="glCopyTexSubImage3D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexSubImage3D</span></span></a>,
 123             <a href="glPixelStore.xml"><span class="citerefentry"><span class="refentrytitle">glPixelStore</span></span></a>,
 124             <a href="glTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage2D</span></span></a>,
 125             <a href="glTexImage3D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage3D</span></span></a>,
 126             <a href="glTexSubImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glTexSubImage1D</span></span></a>,
 127             <a href="glTexSubImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glTexSubImage2D</span></span></a>,
 128             <a href="glTexSubImage3D.xml"><span class="citerefentry"><span class="refentrytitle">glTexSubImage3D</span></span></a>,
 129             <a href="glTexParameter.xml"><span class="citerefentry"><span class="refentrytitle">glTexParameter</span></span></a>
 130         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p>
 131             Copyright <span class="trademark"></span>© 1991-2006
 132             Silicon Graphics, Inc. This document is licensed under the SGI
 133             Free Software B License. For details, see
 134             <a href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>.
 135         </p></div></div></body></html>