upstream-man-pages/man4/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
  39                     <constant>GL_ARRAY_BUFFER</constant>,
  40                     <constant>GL_ATOMIC_COUNTER_BUFFER</constant>,
  41                     <constant>GL_COPY_READ_BUFFER</constant>,
  42                     <constant>GL_COPY_WRITE_BUFFER</constant>,
  43                     <constant>GL_DRAW_INDIRECT_BUFFER</constant>,
  44                     <constant>GL_DISPATCH_INDIRECT_BUFFER</constant>,
  45                     <constant>GL_ELEMENT_ARRAY_BUFFER</constant>,
  46                     <constant>GL_PIXEL_PACK_BUFFER</constant>,
  47                     <constant>GL_PIXEL_UNPACK_BUFFER</constant>,
  48                     <constant>GL_SHADER_STORAGE_BUFFER</constant>,
  49                     <constant>GL_TEXTURE_BUFFER</constant>,
  50                     <constant>GL_TRANSFORM_FEEDBACK_BUFFER</constant>, or
  51                     <constant>GL_UNIFORM_BUFFER</constant>.
  52                 </para>
  53             </listitem>
  54         </varlistentry>
  55         <varlistentry>
  56             <term><parameter>offset</parameter></term>
  57             <listitem>
  58                 <para>
  59                     Specifies the offset into the buffer object's data store where data replacement will begin,
  60                     measured in bytes.
  61                 </para>
  62             </listitem>
  63         </varlistentry>
  64         <varlistentry>
  65             <term><parameter>size</parameter></term>
  66             <listitem>
  67                 <para>
  68                     Specifies the size in bytes of the data store region being replaced.
  69                 </para>
  70             </listitem>
  71         </varlistentry>
  72         <varlistentry>
  73             <term><parameter>data</parameter></term>
  74             <listitem>
  75                 <para>
  76                     Specifies a pointer to the new data that will be copied into the data store.
  77                 </para>
  78             </listitem>
  79         </varlistentry>
  80         </variablelist>
  81     </refsect1>
  82     <refsect1 id="description"><title>Description</title>
  83         <para>
  84             <function>glBufferSubData</function> redefines some or all of the data store for the buffer object currently
  85             bound to <parameter>target</parameter>. Data starting at byte offset <parameter>offset</parameter> and
  86             extending for <parameter>size</parameter> bytes is copied to the data store from the memory pointed to by
  87             <parameter>data</parameter>.  An error is thrown if <parameter>offset</parameter> and <parameter>size</parameter>
  88             together define a range beyond the bounds of the buffer object's data store.
  89         </para>
  90     </refsect1>
  91     <refsect1 id="notes"><title>Notes</title>
  92         <para>
  93             When replacing the entire data store, consider using <function>glBufferSubData</function> rather
  94             than completely recreating the data store with <function>glBufferData</function>.  This avoids the cost of
  95             reallocating the data store.
  96         </para>
  97         <para>
  98             Consider using multiple buffer objects to avoid stalling the rendering pipeline during data store updates.
  99             If any rendering in the pipeline makes reference to data in the buffer object being updated by
 100             <function>glBufferSubData</function>, especially from the specific region being updated, that rendering must
 101             drain from the pipeline before the data store can be updated.
 102         </para>
 103         <para>
 104             Clients must align data elements consistent with the requirements of the client
 105             platform, with an additional base-level requirement that an offset within a buffer to
 106             a datum comprising <inlineequation><mml:math><mml:mi mathvariant="italic">N</mml:mi> bytes be a
 107             multiple of <mml:mi mathvariant="italic">N</mml:mi></mml:math></inlineequation>.
 108         </para>
 109         <para>
 110             The <constant>GL_ATOMIC_COUNTER_BUFFER</constant> target is available only if the GL version
 111             is 4.2 or greater.
 112         </para>
 113         <para>
 114             The <constant>GL_DISPATCH_INDIRECT_BUFFER</constant> and <constant>GL_SHADER_STORAGE_BUFFER</constant> targets are available only if the GL version
 115             is 4.3 or greater.
 116         </para>
 117     </refsect1>
 118     <refsect1 id="errors"><title>Errors</title>
 119         <para>
 120             <constant>GL_INVALID_ENUM</constant> is generated if <parameter>target</parameter> is not
 121             one of the accepted buffer targets.
 122         </para>
 123         <para>
 124             <constant>GL_INVALID_VALUE</constant> is generated if <parameter>offset</parameter> or
 125             <parameter>size</parameter> is negative, or if together they define a region of memory
 126             that extends beyond the buffer object's allocated data store.
 127         </para>
 128         <para>
 129             <constant>GL_INVALID_OPERATION</constant> is generated if the reserved buffer object name 0 is bound to <parameter>target</parameter>.
 130         </para>
 131         <para>
 132             <constant>GL_INVALID_OPERATION</constant> is generated if the buffer object being updated is mapped.
 133         </para>
 134     </refsect1>
 135     <refsect1 id="associatedgets"><title>Associated Gets</title>
 136         <para>
 137             <citerefentry><refentrytitle>glGetBufferSubData</refentrytitle></citerefentry>
 138         </para>
 139     </refsect1>
 140     <refsect1 id="seealso"><title>See Also</title>
 141         <para>
 142             <citerefentry><refentrytitle>glBindBuffer</refentrytitle></citerefentry>,
 143             <citerefentry><refentrytitle>glBufferData</refentrytitle></citerefentry>,
 144             <citerefentry><refentrytitle>glMapBuffer</refentrytitle></citerefentry>,
 145             <citerefentry><refentrytitle>glUnmapBuffer</refentrytitle></citerefentry>
 146         </para>
 147     </refsect1>
 148     <refsect1 id="Copyright"><title>Copyright</title>
 149         <para>
 150             Copyright <trademark class="copyright"></trademark> 2005 Addison-Wesley.
 151             This material may be distributed subject to the terms and conditions set forth in
 152             the Open Publication License, v 1.0, 8 June 1999.
 153             <ulink url="http://opencontent.org/openpub/">http://opencontent.org/openpub/</ulink>.
 154         </para>
 155     </refsect1>
 156 </refentry>