upstream-doc/man2/glBufferSubData.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="glBufferSubData">
   5     <refmeta>
   6         <refmetainfo>
   7             <copyright>
   8                 <year>2005</year>
   9                 <holder>Sams Publishing</holder>
  10             </copyright>
  11         </refmetainfo>
  12         <refentrytitle>glBufferSubData</refentrytitle>
  13         <manvolnum>3G</manvolnum>
  14     </refmeta>
  15     <refnamediv>
  16         <refname>glBufferSubData</refname>
  17         <refpurpose>updates a subset of a buffer object's data store</refpurpose>
  18     </refnamediv>
  19     <refsynopsisdiv><title>C Specification</title>
  20         <funcsynopsis>
  21             <funcprototype>
  22                 <funcdef>void <function>glBufferSubData</function></funcdef>
  23                 <paramdef>GLenum <parameter>target</parameter></paramdef>
  24                 <paramdef>GLintptr <parameter>offset</parameter></paramdef>
  25                 <paramdef>GLsizeiptr <parameter>size</parameter></paramdef>
  26                 <paramdef>const GLvoid * <parameter>data</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_ELEMENT_ARRAY_BUFFER</constant>,
  40                     <constant>GL_PIXEL_PACK_BUFFER</constant>, or
  41                     <constant>GL_PIXEL_UNPACK_BUFFER</constant>.
  42                 </para>
  43             </listitem>
  44         </varlistentry>
  45         <varlistentry>
  46             <term><parameter>offset</parameter></term>
  47             <listitem>
  48                 <para>
  49                     Specifies the offset into the buffer object's data store where data replacement will begin,
  50                     measured in bytes.
  51                 </para>
  52             </listitem>
  53         </varlistentry>
  54         <varlistentry>
  55             <term><parameter>size</parameter></term>
  56             <listitem>
  57                 <para>
  58                     Specifies the size in bytes of the data store region being replaced.
  59                 </para>
  60             </listitem>
  61         </varlistentry>
  62         <varlistentry>
  63             <term><parameter>data</parameter></term>
  64             <listitem>
  65                 <para>
  66                     Specifies a pointer to the new data that will be copied into the data store.
  67                 </para>
  68             </listitem>
  69         </varlistentry>
  70         </variablelist>
  71     </refsect1>
  72     <refsect1 id="description"><title>Description</title>
  73         <para>
  74             <function>glBufferSubData</function> redefines some or all of the data store for the buffer object currently
  75             bound to <parameter>target</parameter>. Data starting at byte offset <parameter>offset</parameter> and
  76             extending for <parameter>size</parameter> bytes is copied to the data store from the memory pointed to by
  77             <parameter>data</parameter>.  An error is thrown if <parameter>offset</parameter> and <parameter>size</parameter>
  78             together define a range beyond the bounds of the buffer object's data store.
  79         </para>
  80     </refsect1>
  81     <refsect1 id="notes"><title>Notes</title>
  82         <para>
  83             <function>glBufferSubData</function> is available only if the GL version is 1.5 or greater.
  84         </para>
  85         <para>
  86             Targets <constant>GL_PIXEL_PACK_BUFFER</constant> and <constant>GL_PIXEL_UNPACK_BUFFER</constant> are available
  87             only if the GL version is 2.1 or greater.
  88         </para>
  89         <para>
  90             When replacing the entire data store, consider using <function>glBufferSubData</function> rather
  91             than completely recreating the data store with <function>glBufferData</function>.  This avoids the cost of
  92             reallocating the data store.
  93         </para>
  94         <para>
  95             Consider using multiple buffer objects to avoid stalling the rendering pipeline during data store updates.
  96             If any rendering in the pipeline makes reference to data in the buffer object being updated by
  97             <function>glBufferSubData</function>, especially from the specific region being updated, that rendering must
  98             drain from the pipeline before the data store can be updated.
  99         </para>
 100         <para>
 101             Clients must align data elements consistent with the requirements of the client
 102             platform, with an additional base-level requirement that an offset within a buffer to
 103             a datum comprising <inlineequation><mml:math><mml:mi mathvariant="italic">N</mml:mi> bytes be a
 104             multiple of <mml:mi mathvariant="italic">N</mml:mi></mml:math></inlineequation>.
 105         </para>
 106     </refsect1>
 107     <refsect1 id="errors"><title>Errors</title>
 108         <para>
 109             <constant>GL_INVALID_ENUM</constant> is generated if <parameter>target</parameter> is not
 110             <constant>GL_ARRAY_BUFFER</constant>, <constant>GL_ELEMENT_ARRAY_BUFFER</constant>,
 111             <constant>GL_PIXEL_PACK_BUFFER</constant>, or <constant>GL_PIXEL_UNPACK_BUFFER</constant>.
 112         </para>
 113         <para>
 114             <constant>GL_INVALID_VALUE</constant> is generated if <parameter>offset</parameter> or
 115             <parameter>size</parameter> is negative, or if together they define a region of memory
 116             that extends beyond the buffer object's allocated data store.
 117         </para>
 118         <para>
 119             <constant>GL_INVALID_OPERATION</constant> is generated if the reserved buffer object name 0 is bound to <parameter>target</parameter>.
 120         </para>
 121         <para>
 122             <constant>GL_INVALID_OPERATION</constant> is generated if the buffer object being updated is mapped.
 123         </para>
 124         <para>
 125             <constant>GL_INVALID_OPERATION</constant> is generated if <function>glBufferSubData</function>
 126             is executed between the execution of
 127             <citerefentry><refentrytitle>glBegin</refentrytitle></citerefentry> and the corresponding execution of
 128             <citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry>.
 129         </para>
 130     </refsect1>
 131     <refsect1 id="associatedgets"><title>Associated Gets</title>
 132         <para>
 133             <citerefentry><refentrytitle>glGetBufferSubData</refentrytitle></citerefentry>
 134         </para>
 135     </refsect1>
 136     <refsect1 id="seealso"><title>See Also</title>
 137         <para>
 138             <citerefentry><refentrytitle>glBindBuffer</refentrytitle></citerefentry>,
 139             <citerefentry><refentrytitle>glBufferData</refentrytitle></citerefentry>,
 140             <citerefentry><refentrytitle>glMapBuffer</refentrytitle></citerefentry>,
 141             <citerefentry><refentrytitle>glUnmapBuffer</refentrytitle></citerefentry>
 142         </para>
 143     </refsect1>
 144     <refsect1 id="Copyright"><title>Copyright</title>
 145         <para>
 146             Copyright <trademark class="copyright"></trademark> 2005 Addison-Wesley.
 147             This material may be distributed subject to the terms and conditions set forth in
 148             the Open Publication License, v 1.0, 8 June 1999.
 149             <ulink url="http://opencontent.org/openpub/">http://opencontent.org/openpub/</ulink>.
 150         </para>
 151     </refsect1>
 152 </refentry>