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<!DOCTYPE refentry [ <!ENTITY % mathent SYSTEM "math.ent"> %mathent; ]>
<refentry xmlns="http://docbook.org/ns/docbook" version="5.0" xml:id="glBufferData">
<info>
<copyright>
<year>2005</year>
<holder>Sams Publishing</holder>
</copyright>
<copyright>
<year>2010-2014</year>
<holder>Khronos Group</holder>
</copyright>
</info>
<refmeta>
<refentrytitle>glBufferData</refentrytitle>
<manvolnum>3G</manvolnum>
</refmeta>
<refnamediv>
<refname>glBufferData</refname>
<refname>glNamedBufferData</refname>
<refpurpose>creates and initializes a buffer object's data
store</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>C Specification</title>
<funcsynopsis>
<funcprototype>
<funcdef>void <function>glBufferData</function></funcdef>
<paramdef>GLenum <parameter>target</parameter></paramdef>
<paramdef>GLsizeiptr <parameter>size</parameter></paramdef>
<paramdef>const GLvoid * <parameter>data</parameter></paramdef>
<paramdef>GLenum <parameter>usage</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>void <function>glNamedBufferData</function></funcdef>
<paramdef>GLuint <parameter>buffer</parameter></paramdef>
<paramdef>GLsizei <parameter>size</parameter></paramdef>
<paramdef>const void *<parameter>data</parameter></paramdef>
<paramdef>GLenum <parameter>usage</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1 xml:id="parameters">
<title>Parameters</title>
<variablelist>
<varlistentry>
<term><parameter>target</parameter></term>
<listitem>
<para>
Specifies the target to which the buffer object is bound for
<function>glBufferData</function>, which must be one of the
buffer binding targets in the following table:
</para>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="bufferbindings.xml"/>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>buffer</parameter></term>
<listitem>
<para>Specifies the name of the buffer object for
<function>glNamedBufferData</function> function.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>size</parameter></term>
<listitem>
<para>Specifies the size in bytes of the buffer object's new data
store.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>data</parameter></term>
<listitem>
<para>Specifies a pointer to data that will be copied into the data
store for initialization, or <constant>NULL</constant> if no data is
to be copied.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>usage</parameter></term>
<listitem>
<para>Specifies the expected usage pattern of the data store. The
symbolic constant must be <constant>GL_STREAM_DRAW</constant>,
<constant>GL_STREAM_READ</constant>,
<constant>GL_STREAM_COPY</constant>,
<constant>GL_STATIC_DRAW</constant>,
<constant>GL_STATIC_READ</constant>,
<constant>GL_STATIC_COPY</constant>,
<constant>GL_DYNAMIC_DRAW</constant>,
<constant>GL_DYNAMIC_READ</constant>, or
<constant>GL_DYNAMIC_COPY</constant>.</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 xml:id="description">
<title>Description</title>
<para><function>glBufferData</function> and
<function>glNamedBufferData</function> create a new data store for a
buffer object. In case of <function>glBufferData</function>, the buffer
object currently bound to <parameter>target</parameter> is used. For
<function>glNamedBufferData</function>, a buffer object associated with ID
specified by the caller in <parameter>buffer</parameter> will be used
instead.</para>
<para>While creating the new storage, any pre-existing data store is
deleted. The new data store is created with the specified
<parameter>size</parameter> in bytes and <parameter>usage</parameter>. If
<parameter>data</parameter> is not <constant>NULL</constant>, the data
store is initialized with data from this pointer. In its initial state,
the new data store is not mapped, it has a <constant>NULL</constant>
mapped pointer, and its mapped access is
<constant>GL_READ_WRITE</constant>.</para>
<para><parameter>usage</parameter> is a hint to the GL implementation as
to how a buffer object's data store will be accessed. This enables the GL
implementation to make more intelligent decisions that may significantly
impact buffer object performance. It does not, however, constrain the
actual usage of the data store. <parameter>usage</parameter> can be broken
down into two parts: first, the frequency of access (modification and
usage), and second, the nature of that access. The frequency of access may
be one of these:</para>
<variablelist>
<varlistentry>
<term>STREAM</term>
<listitem>
<para>The data store contents will be modified once and used at most
a few times.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>STATIC</term>
<listitem>
<para>The data store contents will be modified once and used many
times.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>DYNAMIC</term>
<listitem>
<para>The data store contents will be modified repeatedly and used
many times.</para>
</listitem>
</varlistentry>
</variablelist>
<para>The nature of access may be one of these:</para>
<variablelist>
<varlistentry>
<term>DRAW</term>
<listitem>
<para>The data store contents are modified by the application, and
used as the source for GL drawing and image specification
commands.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>READ</term>
<listitem>
<para>The data store contents are modified by reading data from the
GL, and used to return that data when queried by the
application.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>COPY</term>
<listitem>
<para>The data store contents are modified by reading data from the
GL, and used as the source for GL drawing and image specification
commands.</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 xml:id="notes"><title>Notes</title>
<para>
If <parameter>data</parameter> is <constant>NULL</constant>, a data store of the specified size is still created,
but its contents remain uninitialized and thus undefined.
</para>
<para>
Clients must align data elements consistently with the requirements of the client
platform, with an additional base-level requirement that an offset within a buffer to
a datum comprising <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">N</mml:mi></mml:math></inlineequation> bytes be a
multiple of <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">N</mml:mi></mml:math></inlineequation>.
</para>
<para>
The <constant>GL_ATOMIC_COUNTER_BUFFER</constant> target is available only if the GL version
is 4.2 or greater.
</para>
<para>
The <constant>GL_DISPATCH_INDIRECT_BUFFER</constant> and <constant>GL_SHADER_STORAGE_BUFFER</constant> targets are available only if the GL version
is 4.3 or greater.
</para>
<para>
The <constant>GL_QUERY_BUFFER</constant> target is available only if the GL version is 4.4 or greater.
</para>
</refsect1>
<refsect1 xml:id="errors">
<title>Errors</title>
<para><constant>GL_INVALID_ENUM</constant> is generated by
<function>glBufferData</function> if <parameter>target</parameter> is not
one of the accepted buffer targets.</para>
<para><constant>GL_INVALID_ENUM</constant> is generated if
<parameter>usage</parameter> is not <constant>GL_STREAM_DRAW</constant>,
<constant>GL_STREAM_READ</constant>, <constant>GL_STREAM_COPY</constant>,
<constant>GL_STATIC_DRAW</constant>, <constant>GL_STATIC_READ</constant>,
<constant>GL_STATIC_COPY</constant>, <constant>GL_DYNAMIC_DRAW</constant>,
<constant>GL_DYNAMIC_READ</constant>, or
<constant>GL_DYNAMIC_COPY</constant>.</para>
<para><constant>GL_INVALID_VALUE</constant> is generated if
<parameter>size</parameter> is negative.</para>
<para><constant>GL_INVALID_OPERATION</constant> is generated by
<function>glBufferData</function> if the reserved buffer object name 0 is
bound to <parameter>target</parameter>.</para>
<para><constant>GL_INVALID_OPERATION</constant> is generated by
<function>glNamedBufferData</function> if buffer is not the name of an
existing buffer object.</para>
<para>
<constant>GL_INVALID_OPERATION</constant> is generated if the
<constant>GL_BUFFER_IMMUTABLE_STORAGE</constant> flag of the buffer
object is <constant>GL_TRUE</constant>.
</para>
<para><constant>GL_OUT_OF_MEMORY</constant> is generated if the GL is
unable to create a data store with the specified
<parameter>size</parameter>.</para>
</refsect1>
<refsect1 xml:id="associatedgets">
<title>Associated Gets</title>
<para>
<citerefentry><refentrytitle>glGetBufferSubData</refentrytitle></citerefentry>
</para>
<para>
<citerefentry><refentrytitle>glGetBufferParameter</refentrytitle></citerefentry>
with argument <constant>GL_BUFFER_SIZE</constant> or <constant>GL_BUFFER_USAGE</constant>
</para>
</refsect1>
<refsect1 xml:id="versions"><title>Version Support</title>
<informaltable>
<tgroup cols="13" align="left">
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apifunchead.xml" xpointer="xpointer(/*/*)"/>
<tbody>
<row>
<entry><function>glBufferData</function></entry>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apiversion.xml" xpointer="xpointer(/*/*[@role='20']/*)"/>
</row>
<row>
<entry><function>glNamedBufferData</function></entry>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apiversion.xml" xpointer="xpointer(/*/*[@role='45']/*)"/>
</row>
</tbody>
</tgroup>
</informaltable>
</refsect1>
<refsect1 xml:id="seealso"><title>See Also</title>
<para>
<citerefentry><refentrytitle>glBindBuffer</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glBufferSubData</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glMapBuffer</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glUnmapBuffer</refentrytitle></citerefentry>
</para>
</refsect1>
<refsect1 xml:id="Copyright"><title>Copyright</title>
<para>
Copyright <trademark class="copyright"/> 2005 Addison-Wesley.
Copyright <trademark class="copyright"/> 2010-2014 Khronos Group.
This material may be distributed subject to the terms and conditions set forth in
the Open Publication License, v 1.0, 8 June 1999.
<link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://opencontent.org/openpub/">http://opencontent.org/openpub/</link>.
</para>
</refsect1>
</refentry>
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