upstream-doc/man3/glCompressedTexImage2D.xml

   1 <?xml version="1.0" encoding="UTF-8"?>
   2 <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"
   3               "http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">
   4 <refentry id="glCompressedTexImage2D">
   5     <refmeta>
   6         <refmetainfo>
   7             <copyright>
   8                 <year>1991-2006</year>
   9                 <holder>Silicon Graphics, Inc.</holder>
  10             </copyright>
  11         </refmetainfo>
  12         <refentrytitle>glCompressedTexImage2D</refentrytitle>
  13         <manvolnum>3G</manvolnum>
  14     </refmeta>
  15     <refnamediv>
  16         <refname>glCompressedTexImage2D</refname>
  17         <refpurpose>specify a two-dimensional texture image in a compressed format</refpurpose>
  18     </refnamediv>
  19     <refsynopsisdiv><title>C Specification</title>
  20         <funcsynopsis>
  21             <funcprototype>
  22                 <funcdef>void <function>glCompressedTexImage2D</function></funcdef>
  23                 <paramdef>GLenum <parameter>target</parameter></paramdef>
  24                 <paramdef>GLint <parameter>level</parameter></paramdef>
  25                 <paramdef>GLenum <parameter>internalformat</parameter></paramdef>
  26                 <paramdef>GLsizei <parameter>width</parameter></paramdef>
  27                 <paramdef>GLsizei <parameter>height</parameter></paramdef>
  28                 <paramdef>GLint <parameter>border</parameter></paramdef>
  29                 <paramdef>GLsizei <parameter>imageSize</parameter></paramdef>
  30                 <paramdef>const GLvoid * <parameter>data</parameter></paramdef>
  31             </funcprototype>
  32         </funcsynopsis>
  33     </refsynopsisdiv>
  34     <!-- eqn: ignoring delim $$ -->
  35     <refsect1 id="parameters"><title>Parameters</title>
  36         <variablelist>
  37         <varlistentry>
  38             <term><parameter>target</parameter></term>
  39             <listitem>
  40                 <para>
  41                     Specifies the target texture.
  42                     Must be <constant>GL_TEXTURE_2D</constant>, <constant>GL_PROXY_TEXTURE_2D</constant>,
  43                     <constant>GL_TEXTURE_1D_ARRAY</constant>, <constant>GL_PROXY_TEXTURE_1D_ARRAY</constant>,
  44                     <constant>GL_TEXTURE_CUBE_MAP_POSITIVE_X</constant>,
  45                     <constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_X</constant>,
  46                     <constant>GL_TEXTURE_CUBE_MAP_POSITIVE_Y</constant>,
  47                     <constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_Y</constant>,
  48                     <constant>GL_TEXTURE_CUBE_MAP_POSITIVE_Z</constant>,
  49                     <constant>GL_TEXTURE_CUBE_MAP_NEGATIVE_Z</constant>, or
  50                     <constant>GL_PROXY_TEXTURE_CUBE_MAP</constant>.
  51                 </para>
  52             </listitem>
  53         </varlistentry>
  54         <varlistentry>
  55             <term><parameter>level</parameter></term>
  56             <listitem>
  57                 <para>
  58                     Specifies the level-of-detail number.
  59                     Level 0 is the base image level.
  60                     Level <emphasis>n</emphasis> is the <emphasis>n</emphasis>th mipmap reduction image.
  61                 </para>
  62             </listitem>
  63         </varlistentry>
  64         <varlistentry>
  65             <term><parameter>internalformat</parameter></term>
  66             <listitem>
  67                 <para>
  68                     Specifies the format of the compressed image data stored at address <parameter>data</parameter>.
  69                 </para>
  70             </listitem>
  71         </varlistentry>
  72         <varlistentry>
  73             <term><parameter>width</parameter></term>
  74             <listitem>
  75                 <para>
  76                     Specifies the width of the texture image.
  77                     All implementations support 2D texture images that are at least 64 texels
  78                     wide and cube-mapped texture images that are at least 16 texels wide.
  79                 </para>
  80             </listitem>
  81         </varlistentry>
  82         <varlistentry>
  83             <term><parameter>height</parameter></term>
  84             <listitem>
  85                 <para>
  86                     Specifies the height of the texture image.
  87                     All implementations support 2D texture images that are at least 64 texels
  88                     high and cube-mapped texture images that are at least 16 texels high.
  89                 </para>
  90             </listitem>
  91         </varlistentry>
  92         <varlistentry>
  93             <term><parameter>border</parameter></term>
  94             <listitem>
  95                 <para>
  96                     This value must be 0.
  97                 </para>
  98             </listitem>
  99         </varlistentry>
 100         <varlistentry>
 101             <term><parameter>imageSize</parameter></term>
 102             <listitem>
 103                 <para>
 104                     Specifies the number of unsigned bytes of image data starting at the
 105                     address specified by <parameter>data</parameter>.
 106                 </para>
 107             </listitem>
 108         </varlistentry>
 109         <varlistentry>
 110             <term><parameter>data</parameter></term>
 111             <listitem>
 112                 <para>
 113                     Specifies a pointer to the compressed image data in memory.
 114                 </para>
 115             </listitem>
 116         </varlistentry>
 117         </variablelist>
 118     </refsect1>
 119     <refsect1 id="description"><title>Description</title>
 120         <para>
 121             Texturing allows elements of an image array to be read by shaders.
 122         </para>
 123         <para>
 124             <function>glCompressedTexImage2D</function> loads a previously defined, and retrieved, compressed two-dimensional
 125             texture image if <parameter>target</parameter> is <constant>GL_TEXTURE_2D</constant>, or one of the
 126             cube map faces such as <constant>GL_TEXTURE_CUBE_MAP_POSITIVE_X</constant>.
 127             (see <citerefentry><refentrytitle>glTexImage2D</refentrytitle></citerefentry>).
 128         </para>
 129         <para>
 130             If <parameter>target</parameter> is <constant>GL_TEXTURE_1D_ARRAY</constant>, <parameter>data</parameter>
 131             is treated as an array of compressed 1D textures.
 132         </para>
 133         <para>
 134             If <parameter>target</parameter> is <constant>GL_PROXY_TEXTURE_2D</constant>, <constant>GL_PROXY_TEXTURE_1D_ARRAY</constant>
 135             or <constant>GL_PROXY_CUBE_MAP</constant>, no data is read from <parameter>data</parameter>, but
 136             all of the texture image state is recalculated, checked for consistency,
 137             and checked against the implementation's capabilities.  If the
 138             implementation cannot handle a texture of the requested texture size, it
 139             sets all of the image state to 0, but does not generate an error (see
 140             <citerefentry><refentrytitle>glGetError</refentrytitle></citerefentry>). To query for an entire mipmap array,
 141             use an image array level greater than or equal to 1.
 142         </para>
 143         <para>
 144             <parameter>internalformat</parameter> must be a known compressed image format (such as <constant>GL_RGTC</constant>)
 145             or an extension-specified compressed-texture format.
 146             When a texture is loaded with <citerefentry><refentrytitle>glTexImage2D</refentrytitle></citerefentry> using a generic compressed
 147             texture format (e.g., <constant>GL_COMPRESSED_RGB</constant>), the GL selects from one of
 148             its extensions supporting compressed textures.  In order to load the
 149             compressed texture image using <function>glCompressedTexImage2D</function>, query the compressed texture image's
 150             size and format using <citerefentry><refentrytitle>glGetTexLevelParameter</refentrytitle></citerefentry>.
 151         </para>
 152         <para>
 153             If a non-zero named buffer object is bound to the <constant>GL_PIXEL_UNPACK_BUFFER</constant> target
 154             (see <citerefentry><refentrytitle>glBindBuffer</refentrytitle></citerefentry>) while a texture image is
 155             specified, <parameter>data</parameter> is treated as a byte offset into the buffer object's data store.
 156         </para>
 157     </refsect1>
 158     <refsect1 id="errors"><title>Errors</title>
 159         <para>
 160           <constant>GL_INVALID_ENUM</constant> is generated if <parameter>internalformat</parameter> is not one of the generic
 161           compressed internal formats:
 162           <constant>GL_COMPRESSED_RED</constant>,
 163           <constant>GL_COMPRESSED_RG</constant>,
 164           <constant>GL_COMPRESSED_RGB</constant>,
 165           <constant>GL_COMPRESSED_RGBA</constant>.
 166           <constant>GL_COMPRESSED_SRGB</constant>, or
 167           <constant>GL_COMPRESSED_SRGB_ALPHA</constant>.
 168         </para>
 169         <para>
 170             <constant>GL_INVALID_VALUE</constant> is generated if <parameter>imageSize</parameter> is not consistent with
 171             the format, dimensions, and contents of the specified compressed image
 172             data.
 173         </para>
 174         <para>
 175             <constant>GL_INVALID_VALUE</constant> is generated if <parameter>border</parameter> is not 0.
 176         </para>
 177         <para>
 178             <constant>GL_INVALID_OPERATION</constant> is generated if parameter combinations are not
 179             supported by the specific compressed internal format as specified in the
 180             specific texture compression extension.
 181         </para>
 182         <para>
 183             <constant>GL_INVALID_OPERATION</constant> is generated if a non-zero buffer object name is bound to the
 184             <constant>GL_PIXEL_UNPACK_BUFFER</constant> target and the buffer object's data store is currently mapped.
 185         </para>
 186         <para>
 187             <constant>GL_INVALID_OPERATION</constant> is generated if a non-zero buffer object name is bound to the
 188             <constant>GL_PIXEL_UNPACK_BUFFER</constant> target and the data would be unpacked from the buffer
 189             object such that the memory reads required would exceed the data store size.
 190         </para>
 191         <para>
 192             Undefined results, including abnormal program termination, are generated if
 193             <parameter>data</parameter> is not encoded in a manner consistent with the extension
 194             specification defining the internal compression format.
 195         </para>
 196     </refsect1>
 197     <refsect1 id="associatedgets"><title>Associated Gets</title>
 198         <para>
 199             <citerefentry><refentrytitle>glGetCompressedTexImage</refentrytitle></citerefentry>
 200         </para>
 201         <para>
 202             <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_TEXTURE_COMPRESSED</constant>
 203         </para>
 204         <para>
 205             <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_PIXEL_UNPACK_BUFFER_BINDING</constant>
 206         </para>
 207         <para>
 208             <citerefentry><refentrytitle>glGetTexLevelParameter</refentrytitle></citerefentry> with arguments <constant>GL_TEXTURE_INTERNAL_FORMAT</constant>
 209             and <constant>GL_TEXTURE_COMPRESSED_IMAGE_SIZE</constant>
 210         </para>
 211     </refsect1>
 212     <refsect1 id="seealso"><title>See Also</title>
 213         <para>
 214             <citerefentry><refentrytitle>glActiveTexture</refentrytitle></citerefentry>,
 215             <citerefentry><refentrytitle>glCompressedTexImage1D</refentrytitle></citerefentry>,
 216             <citerefentry><refentrytitle>glCompressedTexImage3D</refentrytitle></citerefentry>,
 217             <citerefentry><refentrytitle>glCompressedTexSubImage1D</refentrytitle></citerefentry>,
 218             <citerefentry><refentrytitle>glCompressedTexSubImage2D</refentrytitle></citerefentry>,
 219             <citerefentry><refentrytitle>glCompressedTexSubImage3D</refentrytitle></citerefentry>,
 220             <citerefentry><refentrytitle>glCopyTexImage1D</refentrytitle></citerefentry>,
 221             <citerefentry><refentrytitle>glCopyTexSubImage1D</refentrytitle></citerefentry>,
 222             <citerefentry><refentrytitle>glCopyTexSubImage2D</refentrytitle></citerefentry>,
 223             <citerefentry><refentrytitle>glCopyTexSubImage3D</refentrytitle></citerefentry>,
 224             <citerefentry><refentrytitle>glPixelStore</refentrytitle></citerefentry>,
 225             <citerefentry><refentrytitle>glTexImage2D</refentrytitle></citerefentry>,
 226             <citerefentry><refentrytitle>glTexImage3D</refentrytitle></citerefentry>,
 227             <citerefentry><refentrytitle>glTexSubImage1D</refentrytitle></citerefentry>,
 228             <citerefentry><refentrytitle>glTexSubImage2D</refentrytitle></citerefentry>,
 229             <citerefentry><refentrytitle>glTexSubImage3D</refentrytitle></citerefentry>,
 230             <citerefentry><refentrytitle>glTexParameter</refentrytitle></citerefentry>
 231         </para>
 232     </refsect1>
 233     <refsect1 id="Copyright"><title>Copyright</title>
 234         <para>
 235             Copyright <trademark class="copyright"></trademark> 1991-2006
 236             Silicon Graphics, Inc. This document is licensed under the SGI
 237             Free Software B License. For details, see
 238             <ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>.
 239         </para>
 240     </refsect1>
 241 </refentry>