upstream-man-pages/man3/glBufferData.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="glBufferData">
   5     <refmeta>
   6         <refmetainfo>
   7             <copyright>
   8                 <year>2005</year>
   9                 <holder>Sams Publishing</holder>
  10             </copyright>
  11         </refmetainfo>
  12         <refentrytitle>glBufferData</refentrytitle>
  13         <manvolnum>3G</manvolnum>
  14     </refmeta>
  15     <refnamediv>
  16         <refname>glBufferData</refname>
  17         <refpurpose>creates and initializes a buffer object's data store</refpurpose>
  18     </refnamediv>
  19     <refsynopsisdiv><title>C Specification</title>
  20         <funcsynopsis>
  21             <funcprototype>
  22                 <funcdef>void <function>glBufferData</function></funcdef>
  23                 <paramdef>GLenum <parameter>target</parameter></paramdef>
  24                 <paramdef>GLsizeiptr <parameter>size</parameter></paramdef>
  25                 <paramdef>const GLvoid * <parameter>data</parameter></paramdef>
  26                 <paramdef>GLenum <parameter>usage</parameter></paramdef>
  27             </funcprototype>
  28         </funcsynopsis>
  29     </refsynopsisdiv>
  30     <!-- eqn: ignoring delim $$ -->
  31     <refsect1 id="parameters"><title>Parameters</title>
  32         <variablelist>
  33         <varlistentry>
  34             <term><parameter>target</parameter></term>
  35             <listitem>
  36                 <para>
  37                     Specifies the target buffer object.
  38                     The symbolic constant must be <constant>GL_ARRAY_BUFFER</constant>,
  39                     <constant>GL_COPY_READ_BUFFER</constant>,
  40                     <constant>GL_COPY_WRITE_BUFFER</constant>,
  41                     <constant>GL_ELEMENT_ARRAY_BUFFER</constant>,
  42                     <constant>GL_PIXEL_PACK_BUFFER</constant>,
  43                     <constant>GL_PIXEL_UNPACK_BUFFER</constant>,
  44                     <constant>GL_TEXTURE_BUFFER</constant>,
  45                     <constant>GL_TRANSFORM_FEEDBACK_BUFFER</constant>, or
  46                     <constant>GL_UNIFORM_BUFFER</constant>.
  47                 </para>
  48             </listitem>
  49         </varlistentry>
  50         <varlistentry>
  51             <term><parameter>size</parameter></term>
  52             <listitem>
  53                 <para>
  54                     Specifies the size in bytes of the buffer object's new data store.
  55                 </para>
  56             </listitem>
  57         </varlistentry>
  58         <varlistentry>
  59             <term><parameter>data</parameter></term>
  60             <listitem>
  61                 <para>
  62                     Specifies a pointer to data that will be copied into the data store for initialization,
  63                     or <constant>NULL</constant> if no data is to be copied.
  64                 </para>
  65             </listitem>
  66         </varlistentry>
  67         <varlistentry>
  68             <term><parameter>usage</parameter></term>
  69             <listitem>
  70                 <para>
  71                     Specifies the expected usage pattern of the data store. The symbolic constant must be
  72                     <constant>GL_STREAM_DRAW</constant>, <constant>GL_STREAM_READ</constant>, <constant>GL_STREAM_COPY</constant>,
  73                     <constant>GL_STATIC_DRAW</constant>, <constant>GL_STATIC_READ</constant>, <constant>GL_STATIC_COPY</constant>,
  74                     <constant>GL_DYNAMIC_DRAW</constant>, <constant>GL_DYNAMIC_READ</constant>, or <constant>GL_DYNAMIC_COPY</constant>.
  75                 </para>
  76             </listitem>
  77         </varlistentry>
  78         </variablelist>
  79     </refsect1>
  80     <refsect1 id="description"><title>Description</title>
  81         <para>
  82             <function>glBufferData</function> creates a new data store for the buffer object currently bound to
  83             <parameter>target</parameter>. Any pre-existing data store is deleted. The new data store is created with the
  84             specified <parameter>size</parameter> in bytes and <parameter>usage</parameter>. If <parameter>data</parameter>
  85             is not <constant>NULL</constant>, the data store is initialized with data from this pointer. In its initial
  86             state, the new data store is not mapped, it has a <constant>NULL</constant> mapped pointer, and its mapped access
  87             is <constant>GL_READ_WRITE</constant>.
  88         </para>
  89         <para>
  90             <parameter>usage</parameter> is a hint to the GL implementation as to how a buffer object's data store will be
  91             accessed. This enables the GL implementation to make more intelligent decisions that may significantly
  92             impact buffer object performance. It does not, however, constrain the actual usage of the data store.
  93             <parameter>usage</parameter> can be broken down into two parts: first, the frequency of access (modification
  94             and usage), and second, the nature of that access. The frequency of access may be one of these:
  95         </para>
  96         <variablelist>
  97             <varlistentry>
  98                 <term>STREAM</term>
  99                 <listitem>
 100                     <para>
 101                         The data store contents will be modified once and used at most a few times.
 102                     </para>
 103                 </listitem>
 104             </varlistentry>
 105             <varlistentry>
 106                 <term>STATIC</term>
 107                 <listitem>
 108                     <para>
 109                         The data store contents will be modified once and used many times.
 110                     </para>
 111                 </listitem>
 112             </varlistentry>
 113             <varlistentry>
 114                 <term>DYNAMIC</term>
 115                 <listitem>
 116                     <para>
 117                         The data store contents will be modified repeatedly and used many times.
 118                     </para>
 119                 </listitem>
 120             </varlistentry>
 121         </variablelist>
 122         <para>
 123             The nature of access may be one of these:
 124         </para>
 125         <variablelist>
 126             <varlistentry>
 127                 <term>DRAW</term>
 128                 <listitem>
 129                     <para>
 130                         The data store contents are modified by the application, and used as the source for GL drawing and
 131                         image specification commands.
 132                     </para>
 133                 </listitem>
 134             </varlistentry>
 135             <varlistentry>
 136                 <term>READ</term>
 137                 <listitem>
 138                     <para>
 139                         The data store contents are modified by reading data from the GL, and used to return that data
 140                         when queried by the application.
 141                     </para>
 142                 </listitem>
 143             </varlistentry>
 144             <varlistentry>
 145                 <term>COPY</term>
 146                 <listitem>
 147                     <para>
 148                         The data store contents are modified by reading data from the GL, and used as the source for GL
 149                         drawing and image specification commands.
 150                     </para>
 151                 </listitem>
 152             </varlistentry>
 153         </variablelist>
 154     </refsect1>
 155     <refsect1 id="notes"><title>Notes</title>
 156         <para>
 157             If <parameter>data</parameter> is <constant>NULL</constant>, a data store of the specified size is still created,
 158             but its contents remain uninitialized and thus undefined.
 159         </para>
 160         <para>
 161             Clients must align data elements consistent with the requirements of the client
 162             platform, with an additional base-level requirement that an offset within a buffer to
 163             a datum comprising <inlineequation><mml:math><mml:mi mathvariant="italic">N</mml:mi> bytes be a
 164             multiple of <mml:mi mathvariant="italic">N</mml:mi></mml:math></inlineequation>.
 165         </para>
 166     </refsect1>
 167     <refsect1 id="errors"><title>Errors</title>
 168         <para>
 169             <constant>GL_INVALID_ENUM</constant> is generated if <parameter>target</parameter> is not
 170             one of the accepted buffer targets.
 171         </para>
 172         <para>
 173             <constant>GL_INVALID_ENUM</constant> is generated if <parameter>usage</parameter> is not
 174             <constant>GL_STREAM_DRAW</constant>, <constant>GL_STREAM_READ</constant>, <constant>GL_STREAM_COPY</constant>,
 175             <constant>GL_STATIC_DRAW</constant>, <constant>GL_STATIC_READ</constant>, <constant>GL_STATIC_COPY</constant>,
 176             <constant>GL_DYNAMIC_DRAW</constant>, <constant>GL_DYNAMIC_READ</constant>, or <constant>GL_DYNAMIC_COPY</constant>.
 177         </para>
 178         <para>
 179             <constant>GL_INVALID_VALUE</constant> is generated if <parameter>size</parameter> is negative.
 180         </para>
 181         <para>
 182             <constant>GL_INVALID_OPERATION</constant> is generated if the reserved buffer object name 0 is bound to <parameter>target</parameter>.
 183         </para>
 184         <para>
 185             <constant>GL_OUT_OF_MEMORY</constant> is generated if the GL is unable to create a data store with the specified <parameter>size</parameter>.
 186         </para>
 187     </refsect1>
 188     <refsect1 id="associatedgets"><title>Associated Gets</title>
 189         <para>
 190             <citerefentry><refentrytitle>glGetBufferSubData</refentrytitle></citerefentry>
 191         </para>
 192         <para>
 193             <citerefentry><refentrytitle>glGetBufferParameter</refentrytitle></citerefentry> with argument <constant>GL_BUFFER_SIZE</constant> or <constant>GL_BUFFER_USAGE</constant>
 194         </para>
 195     </refsect1>
 196     <refsect1 id="seealso"><title>See Also</title>
 197         <para>
 198             <citerefentry><refentrytitle>glBindBuffer</refentrytitle></citerefentry>,
 199             <citerefentry><refentrytitle>glBufferSubData</refentrytitle></citerefentry>,
 200             <citerefentry><refentrytitle>glMapBuffer</refentrytitle></citerefentry>,
 201             <citerefentry><refentrytitle>glUnmapBuffer</refentrytitle></citerefentry>
 202         </para>
 203     </refsect1>
 204     <refsect1 id="Copyright"><title>Copyright</title>
 205         <para>
 206             Copyright <trademark class="copyright"></trademark> 2005 Addison-Wesley.
 207             This material may be distributed subject to the terms and conditions set forth in
 208             the Open Publication License, v 1.0, 8 June 1999.
 209             <ulink url="http://opencontent.org/openpub/">http://opencontent.org/openpub/</ulink>.
 210         </para>
 211     </refsect1>
 212 </refentry>