upstream-doc/man4/xhtml/glCompressedTexImage2D.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>glCompressedTexImage2D - 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="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 border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><tr><td><code class="funcdef">void <b class="fsfunc">glCompressedTexImage2D</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>GLenum  </td><td><var class="pdparam">internalformat</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>GLint  </td><td><var class="pdparam">border</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>, <code class="constant">GL_PROXY_TEXTURE_2D</code>,
   7                     <code class="constant">GL_TEXTURE_1D_ARRAY</code>, <code class="constant">GL_PROXY_TEXTURE_1D_ARRAY</code>,
   8                     <code class="constant">GL_TEXTURE_CUBE_MAP_POSITIVE_X</code>,
   9                     <code class="constant">GL_TEXTURE_CUBE_MAP_NEGATIVE_X</code>,
  10                     <code class="constant">GL_TEXTURE_CUBE_MAP_POSITIVE_Y</code>,
  11                     <code class="constant">GL_TEXTURE_CUBE_MAP_NEGATIVE_Y</code>,
  12                     <code class="constant">GL_TEXTURE_CUBE_MAP_POSITIVE_Z</code>,
  13                     <code class="constant">GL_TEXTURE_CUBE_MAP_NEGATIVE_Z</code>, or
  14                     <code class="constant">GL_PROXY_TEXTURE_CUBE_MAP</code>.
  15                 </p></dd><dt><span class="term"><em class="parameter"><code>level</code></em></span></dt><dd><p>
  16                     Specifies the level-of-detail number.
  17                     Level 0 is the base image level.
  18                     Level <span class="emphasis"><em>n</em></span> is the <span class="emphasis"><em>n</em></span>th mipmap reduction image.
  19                 </p></dd><dt><span class="term"><em class="parameter"><code>internalformat</code></em></span></dt><dd><p>
  20                     Specifies the format of the compressed image data stored at address <em class="parameter"><code>data</code></em>.
  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 image.
  23                     All implementations support 2D texture and cube map texture images that are at least 16384 texels wide.
  24                 </p></dd><dt><span class="term"><em class="parameter"><code>height</code></em></span></dt><dd><p>
  25                     Specifies the height of the texture image.
  26                     All implementations support 2D texture and cube map texture images that are at least 16384 texels high.
  27                 </p></dd><dt><span class="term"><em class="parameter"><code>border</code></em></span></dt><dd><p>
  28                     This value must be 0.
  29                 </p></dd><dt><span class="term"><em class="parameter"><code>imageSize</code></em></span></dt><dd><p>
  30                     Specifies the number of unsigned bytes of image data starting at the
  31                     address specified by <em class="parameter"><code>data</code></em>.
  32                 </p></dd><dt><span class="term"><em class="parameter"><code>data</code></em></span></dt><dd><p>
  33                     Specifies a pointer to the compressed image data in memory.
  34                 </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
  35             Texturing allows elements of an image array to be read by shaders.
  36         </p><p>
  37             <code class="function">glCompressedTexImage2D</code> loads a previously defined, and retrieved, compressed two-dimensional
  38             texture image if <em class="parameter"><code>target</code></em> is <code class="constant">GL_TEXTURE_2D</code>, or one of the
  39             cube map faces such as <code class="constant">GL_TEXTURE_CUBE_MAP_POSITIVE_X</code>.
  40             (see <a href="glTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage2D</span></span></a>).
  41         </p><p>
  42             If <em class="parameter"><code>target</code></em> is <code class="constant">GL_TEXTURE_1D_ARRAY</code>, <em class="parameter"><code>data</code></em>
  43             is treated as an array of compressed 1D textures.
  44         </p><p>
  45             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>
  46             or <code class="constant">GL_PROXY_CUBE_MAP</code>, no data is read from <em class="parameter"><code>data</code></em>, but
  47             all of the texture image state is recalculated, checked for consistency,
  48             and checked against the implementation's capabilities.  If the
  49             implementation cannot handle a texture of the requested texture size, it
  50             sets all of the image state to 0, but does not generate an error (see
  51             <a href="glGetError.xml"><span class="citerefentry"><span class="refentrytitle">glGetError</span></span></a>). To query for an entire mipmap array,
  52             use an image array level greater than or equal to 1.
  53         </p><p>
  54             <em class="parameter"><code>internalformat</code></em> must be a known compressed image format (such as <code class="constant">GL_RGTC</code>)
  55             or an extension-specified compressed-texture format.
  56             When a texture is loaded with <a href="glTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage2D</span></span></a> using a generic compressed
  57             texture format (e.g., <code class="constant">GL_COMPRESSED_RGB</code>), the GL selects from one of
  58             its extensions supporting compressed textures.  In order to load the
  59             compressed texture image using <code class="function">glCompressedTexImage2D</code>, query the compressed texture image's
  60             size and format using <a href="glGetTexLevelParameter.xml"><span class="citerefentry"><span class="refentrytitle">glGetTexLevelParameter</span></span></a>.
  61         </p><p>
  62             If a non-zero named buffer object is bound to the <code class="constant">GL_PIXEL_UNPACK_BUFFER</code> target
  63             (see <a href="glBindBuffer.xml"><span class="citerefentry"><span class="refentrytitle">glBindBuffer</span></span></a>) while a texture image is
  64             specified, <em class="parameter"><code>data</code></em> is treated as a byte offset into the buffer object's data store.
  65         </p><p>
  66             If the compressed data are arranged into fixed-size blocks of texels, the pixel
  67             storage modes can be used to select a sub-rectangle from a larger containing rectangle.
  68             These pixel storage modes operate in the same way as they do for <a href="glTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage2D</span></span></a>.
  69             In the following description, denote by <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mrow><mml:msub><mml:mi>b</mml:mi><mml:mi>s</mml:mi></mml:msub></mml:mrow></mml:math>,
  70             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mrow><mml:msub><mml:mi>b</mml:mi><mml:mi>w</mml:mi></mml:msub></mml:mrow></mml:math>,
  71             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mrow><mml:msub><mml:mi>b</mml:mi><mml:mi>h</mml:mi></mml:msub></mml:mrow></mml:math>, and
  72             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mrow><mml:msub><mml:mi>b</mml:mi><mml:mi>d</mml:mi></mml:msub></mml:mrow></mml:math>,
  73             the values of pixel storage modes <code class="constant">GL_UNPACK_COMPRESSED_BLOCK_SIZE</code>,
  74             <code class="constant">GL_UNPACK_COMPRESSED_BLOCK_WIDTH</code>, <code class="constant">GL_UNPACK_COMPRESSED_BLOCK_HEIGHT</code>,
  75             and <code class="constant">GL_UNPACK_COMPRESSED_BLOCK_DEPTH</code>, respectively.
  76             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mrow><mml:msub><mml:mi>b</mml:mi><mml:mi>s</mml:mi></mml:msub></mml:mrow></mml:math> is
  77             the compressed block size in bytes; <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mrow><mml:msub><mml:mi>b</mml:mi><mml:mi>w</mml:mi></mml:msub></mml:mrow></mml:math>,
  78             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mrow><mml:msub><mml:mi>b</mml:mi><mml:mi>h</mml:mi></mml:msub></mml:mrow></mml:math>,
  79             and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mrow><mml:msub><mml:mi>b</mml:mi><mml:mi>d</mml:mi></mml:msub></mml:mrow></mml:math> are the compressed block width, height, and depth in pixels.
  80         </p><p>
  81             By default the pixel storage modes <code class="constant">GL_UNPACK_ROW_LENGTH</code>,
  82             <code class="constant">GL_UNPACK_SKIP_ROWS</code>, <code class="constant">GL_UNPACK_SKIP_PIXELS</code>,
  83             <code class="constant">GL_UNPACK_IMAGE_HEIGHT</code> and <code class="constant">GL_UNPACK_SKIP_IMAGES</code>
  84             are ignored for compressed images. To enable <code class="constant">GL_UNPACK_SKIP_PIXELS</code>
  85             and <code class="constant">GL_UNPACK_ROW_LENGTH</code>, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mrow><mml:msub><mml:mi>b</mml:mi><mml:mi>s</mml:mi></mml:msub></mml:mrow></mml:math>
  86             and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mrow><mml:msub><mml:mi>b</mml:mi><mml:mi>w</mml:mi></mml:msub></mml:mrow></mml:math> must both be non-zero.
  87             To also enable <code class="constant">GL_UNPACK_SKIP_ROWS</code> and <code class="constant">GL_UNPACK_IMAGE_HEIGHT</code>,
  88             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mrow><mml:msub><mml:mi>b</mml:mi><mml:mi>h</mml:mi></mml:msub></mml:mrow></mml:math> must be non-zero.
  89             To also enable <code class="constant">GL_UNPACK_SKIP_IMAGES</code>, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mrow><mml:msub><mml:mi>b</mml:mi><mml:mi>d</mml:mi></mml:msub></mml:mrow></mml:math>
  90             must be non-zero. All parameters must be consistent with the compressed format to produce the desired results.
  91         </p><p>
  92             When selecting a sub-rectangle from a compressed image:
  93             </p><div class="itemizedlist"><ul type="disc"><li>the value of <code class="constant">GL_UNPACK_SKIP_PIXELS</code> must be a multiple of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mrow><mml:msub><mml:mi>b</mml:mi><mml:mi>w</mml:mi></mml:msub></mml:mrow></mml:math>;</li><li>the value of <code class="constant">GL_UNPACK_SKIP_ROWS</code> must be a multiple of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mrow><mml:msub><mml:mi>b</mml:mi><mml:mi>w</mml:mi></mml:msub></mml:mrow></mml:math>.</li></ul></div><p>
  94         </p><p>
  95             <em class="parameter"><code>imageSize</code></em> must be equal to:
  96         </p><p>
  97 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="block" overflow="scroll">
  98   <mml:mrow>
  99     <mml:msub>
 100       <mml:mi>b</mml:mi>
 101       <mml:mi>s</mml:mi>
 102     </mml:msub>
 103     <mml:mo lspace="2px" rspace="2px">×</mml:mo>
 104     <mml:mfenced open="&#x2308;" close="&#x2309;">
 105       <mml:mfrac>
 106         <mml:mi>width</mml:mi>
 107         <mml:msub>
 108           <mml:mi>b</mml:mi>
 109           <mml:mi>w</mml:mi>
 110         </mml:msub>
 111       </mml:mfrac>
 112     </mml:mfenced>
 113     <mml:mo lspace="2px" rspace="2px">×</mml:mo>
 114     <mml:mfenced open="&#x2308;" close="&#x2309;">
 115       <mml:mfrac>
 116         <mml:mi>height</mml:mi>
 117         <mml:msub>
 118           <mml:mi>b</mml:mi>
 119           <mml:mi>h</mml:mi>
 120         </mml:msub>
 121       </mml:mfrac>
 122     </mml:mfenced>
 123   </mml:mrow>
 124 </mml:math>
 125         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p>
 126             The specific compressed internal formats <code class="constant">GL_COMPRESSED_RGB8_ETC2</code>,
 127           <code class="constant">GL_COMPRESSED_SRGB8_ETC2</code>,
 128           <code class="constant">GL_COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2</code>,
 129           <code class="constant">GL_COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2</code>,
 130           <code class="constant">GL_COMPRESSED_RGBA8_ETC2_EAC</code>,
 131           <code class="constant">GL_COMPRESSED_SRGB8_ALPHA8_ETC2_EAC</code>,
 132           <code class="constant">GL_COMPRESSED_R11_EAC</code>,
 133           <code class="constant">GL_COMPRESSED_SIGNED_R11_EAC</code>,
 134           <code class="constant">GL_COMPRESSED_RG11_EAC</code>, and
 135           <code class="constant">GL_COMPRESSED_SIGNED_RG11_EAC</code> are available only if the GL version
 136           is 4.3 or higher.
 137         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p>
 138           <code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>internalformat</code></em> is not one of the specific
 139           compressed internal formats:
 140           <code class="constant">GL_COMPRESSED_RED_RGTC1</code>,
 141           <code class="constant">GL_COMPRESSED_SIGNED_RED_RGTC1</code>,
 142           <code class="constant">GL_COMPRESSED_RG_RGTC2</code>,
 143           <code class="constant">GL_COMPRESSED_SIGNED_RG_RGTC2</code>.
 144           <code class="constant">GL_COMPRESSED_RGBA_BPTC_UNORM</code>,
 145           <code class="constant">GL_COMPRESSED_SRGB_ALPHA_BPTC_UNORM</code>,
 146           <code class="constant">GL_COMPRESSED_RGB_BPTC_SIGNED_FLOAT</code>,
 147           <code class="constant">GL_COMPRESSED_RGB_BPTC_UNSIGNED_FLOAT</code>,
 148           <code class="constant">GL_COMPRESSED_RGB8_ETC2</code>,
 149           <code class="constant">GL_COMPRESSED_SRGB8_ETC2</code>,
 150           <code class="constant">GL_COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2</code>,
 151           <code class="constant">GL_COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2</code>,
 152           <code class="constant">GL_COMPRESSED_RGBA8_ETC2_EAC</code>,
 153           <code class="constant">GL_COMPRESSED_SRGB8_ALPHA8_ETC2_EAC</code>,
 154           <code class="constant">GL_COMPRESSED_R11_EAC</code>,
 155           <code class="constant">GL_COMPRESSED_SIGNED_R11_EAC</code>,
 156           <code class="constant">GL_COMPRESSED_RG11_EAC</code>, or
 157           <code class="constant">GL_COMPRESSED_SIGNED_RG11_EAC</code>.
 158         </p><p>
 159             <code class="constant">GL_INVALID_VALUE</code> is generated if <em class="parameter"><code>imageSize</code></em> is not consistent with
 160             the format, dimensions, and contents of the specified compressed image
 161             data.
 162         </p><p>
 163             <code class="constant">GL_INVALID_VALUE</code> is generated if <em class="parameter"><code>border</code></em> is not 0.
 164         </p><p>
 165             <code class="constant">GL_INVALID_OPERATION</code> is generated if parameter combinations are not
 166             supported by the specific compressed internal format as specified in the
 167             specific texture compression extension.
 168         </p><p>
 169             <code class="constant">GL_INVALID_OPERATION</code> is generated if a non-zero buffer object name is bound to the
 170             <code class="constant">GL_PIXEL_UNPACK_BUFFER</code> target and the buffer object's data store is currently mapped.
 171         </p><p>
 172             <code class="constant">GL_INVALID_OPERATION</code> is generated if a non-zero buffer object name is bound to the
 173             <code class="constant">GL_PIXEL_UNPACK_BUFFER</code> target and the data would be unpacked from the buffer
 174             object such that the memory reads required would exceed the data store size.
 175         </p><p>
 176             Undefined results, including abnormal program termination, are generated if
 177             <em class="parameter"><code>data</code></em> is not encoded in a manner consistent with the extension
 178             specification defining the internal compression format.
 179         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="associatedgets"></a><h2>Associated Gets</h2><p>
 180             <a href="glGetCompressedTexImage.xml"><span class="citerefentry"><span class="refentrytitle">glGetCompressedTexImage</span></span></a>
 181         </p><p>
 182             <a href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument <code class="constant">GL_TEXTURE_COMPRESSED</code>
 183         </p><p>
 184             <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>
 185         </p><p>
 186             <a href="glGetTexLevelParameter.xml"><span class="citerefentry"><span class="refentrytitle">glGetTexLevelParameter</span></span></a> with arguments <code class="constant">GL_TEXTURE_INTERNAL_FORMAT</code>
 187             and <code class="constant">GL_TEXTURE_COMPRESSED_IMAGE_SIZE</code>
 188         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
 189             <a href="glActiveTexture.xml"><span class="citerefentry"><span class="refentrytitle">glActiveTexture</span></span></a>,
 190             <a href="glCompressedTexImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glCompressedTexImage1D</span></span></a>,
 191             <a href="glCompressedTexImage3D.xml"><span class="citerefentry"><span class="refentrytitle">glCompressedTexImage3D</span></span></a>,
 192             <a href="glCompressedTexSubImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glCompressedTexSubImage1D</span></span></a>,
 193             <a href="glCompressedTexSubImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glCompressedTexSubImage2D</span></span></a>,
 194             <a href="glCompressedTexSubImage3D.xml"><span class="citerefentry"><span class="refentrytitle">glCompressedTexSubImage3D</span></span></a>,
 195             <a href="glCopyTexImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexImage1D</span></span></a>,
 196             <a href="glCopyTexSubImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexSubImage1D</span></span></a>,
 197             <a href="glCopyTexSubImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexSubImage2D</span></span></a>,
 198             <a href="glCopyTexSubImage3D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexSubImage3D</span></span></a>,
 199             <a href="glPixelStore.xml"><span class="citerefentry"><span class="refentrytitle">glPixelStore</span></span></a>,
 200             <a href="glTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage2D</span></span></a>,
 201             <a href="glTexImage3D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage3D</span></span></a>,
 202             <a href="glTexSubImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glTexSubImage1D</span></span></a>,
 203             <a href="glTexSubImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glTexSubImage2D</span></span></a>,
 204             <a href="glTexSubImage3D.xml"><span class="citerefentry"><span class="refentrytitle">glTexSubImage3D</span></span></a>,
 205             <a href="glTexParameter.xml"><span class="citerefentry"><span class="refentrytitle">glTexParameter</span></span></a>
 206         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p>
 207             Copyright <span class="trademark"></span>© 1991-2006
 208             Silicon Graphics, Inc. <span class="trademark"></span>© 2011
 209             Khronos Group. This document is licensed under the SGI
 210             Free Software B License. For details, see
 211             <a href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>.
 212         </p></div></div></body></html>