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<refentry id= "glCopyBufferSubData" >
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<refentryinfo >
<copyright >
<year > 2010</year>
<holder > Khronos Group</holder>
</copyright>
</refentryinfo>
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<refmeta >
<refentrytitle > glCopyBufferSubData</refentrytitle>
<manvolnum > 3G</manvolnum>
</refmeta>
<refnamediv >
<refname > glCopyBufferSubData</refname>
<refpurpose > copy part of the data store of a buffer object to the data store of another buffer object</refpurpose>
</refnamediv>
<refsynopsisdiv > <title > C Specification</title>
<funcsynopsis >
<funcprototype >
<funcdef > void <function > glCopyBufferSubData</function> </funcdef>
<paramdef > GLenum <parameter > readtarget</parameter> </paramdef>
<paramdef > GLenum <parameter > writetarget</parameter> </paramdef>
<paramdef > GLintptr <parameter > readoffset</parameter> </paramdef>
<paramdef > GLintptr <parameter > writeoffset</parameter> </paramdef>
<paramdef > GLsizeiptr <parameter > size</parameter> </paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1 id= "parameters" > <title > Parameters</title>
<variablelist >
<varlistentry >
<term > <parameter > readtarget</parameter> </term>
<listitem >
<para >
Specifies the target from whose data store data should be read.
</para>
</listitem>
</varlistentry>
<varlistentry >
<term > <parameter > writetarget</parameter> </term>
<listitem >
<para >
Specifies the target to whose data store data should be written.
</para>
</listitem>
</varlistentry>
<varlistentry >
<term > <parameter > readoffset</parameter> </term>
<listitem >
<para >
Specifies the offset, in basic machine units, within the data store of <parameter > readtarget</parameter> from which data should be read.
</para>
</listitem>
</varlistentry>
<varlistentry >
<term > <parameter > writeoffset</parameter> </term>
<listitem >
<para >
Specifies the offset, in basic machine units, within the data store of <parameter > writetarget</parameter> to which data should be written.
</para>
</listitem>
</varlistentry>
<varlistentry >
<term > <parameter > size</parameter> </term>
<listitem >
<para >
Specifies the size, in basic machine units, of the data to be copied from <parameter > readtarget</parameter> to <parameter > writetarget</parameter> .
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 id= "description" > <title > Description</title>
<para >
<function > glCopyBufferSubData</function> copies part of the data store attached to <parameter > readtarget</parameter> to the
data store attached to <parameter > writetarget</parameter> . The number of basic machine units indicated by <parameter > size</parameter>
is copied from the source, at offset <parameter > readoffset</parameter> to the destination at <parameter > writeoffset</parameter> ,
also in basic machine units.
</para>
<para >
<parameter > readtarget</parameter> and <parameter > writetarget</parameter> must be <constant > GL_ARRAY_BUFFER</constant> ,
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<constant > GL_COPY_READ_BUFFER</constant> , <constant > GL_COPY_WRITE_BUFFER</constant> , <constant > GL_DRAW_INDIRECT_BUFFER</constant> ,
<constant > GL_DISPATCH_INDIRECT_BUFFER</constant> , <constant > GL_ELEMENT_ARRAY_BUFFER</constant> ,
<constant > GL_PIXEL_PACK_BUFFER</constant> , <constant > GL_PIXEL_UNPACK_BUFFER</constant> , <constant > GL_QUERY_BUFFER</constant> ,
<constant > GL_TEXTURE_BUFFER</constant> ,
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<constant > GL_TRANSFORM_FEEDBACK_BUFFER</constant> or <constant > GL_UNIFORM_BUFFER</constant> . Any of these targets may be used,
although the targets <constant > GL_COPY_READ_BUFFER</constant> and <constant > GL_COPY_WRITE_BUFFER</constant> are provided
specifically to allow copies between buffers without disturbing other GL state.
</para>
<para >
<parameter > readoffset</parameter> , <parameter > writeoffset</parameter> and <parameter > size</parameter> must all be greater than or equal to
zero. Furthermore, <parameter > readoffset</parameter> + <parameter > size</parameter> must not exceeed the size of the buffer
object bound to <parameter > readtarget</parameter> , and <parameter > readoffset</parameter> + <parameter > size</parameter> must not exceeed the
size of the buffer bound to <parameter > writetarget</parameter> . If the same buffer object is bound to both <parameter > readtarget</parameter>
and <parameter > writetarget</parameter> , then the ranges specified by <parameter > readoffset</parameter> , <parameter > writeoffset</parameter>
and <parameter > size</parameter> must not overlap.
</para>
</refsect1>
<refsect1 id= "notes" > <title > Notes</title>
<para >
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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.
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</para>
</refsect1>
<refsect1 id= "errors" > <title > Errors</title>
<para >
<constant > GL_INVALID_VALUE</constant> is generated if any of <parameter > readoffset</parameter> , <parameter > writeoffset</parameter>
or <parameter > size</parameter> is negative, if <parameter > readoffset</parameter> + <parameter > size</parameter> exceeds the
size of the buffer object bound to <parameter > readtarget</parameter> or if <parameter > writeoffset</parameter> + <parameter > size</parameter>
exceeds the size of the buffer object bound to <parameter > writetarget</parameter> .
</para>
<para >
<constant > GL_INVALID_VALUE</constant> is generated if the same buffer object is bound to both <parameter > readtarget</parameter>
and <parameter > writetarget</parameter> and the ranges [<parameter > readoffset</parameter> , <parameter > readoffset</parameter> +
<parameter > size</parameter> ) and [<parameter > writeoffset</parameter> , <parameter > writeoffset</parameter> + <parameter > size</parameter> )
overlap.
</para>
<para >
<constant > GL_INVALID_OPERATION</constant> is generated if zero is bound to <parameter > readtarget</parameter> or <parameter > writetarget</parameter> .
</para>
<para >
<constant > GL_INVALID_OPERATION</constant> is generated if the buffer object bound to either <parameter > readtarget</parameter> or <parameter > writetarget</parameter>
is mapped.
</para>
</refsect1>
<refsect1 id= "seealso" > <title > See Also</title>
<para >
<citerefentry > <refentrytitle > glGenBuffers</refentrytitle> </citerefentry> ,
<citerefentry > <refentrytitle > glBindBuffer</refentrytitle> </citerefentry> ,
<citerefentry > <refentrytitle > glBufferData</refentrytitle> </citerefentry> ,
<citerefentry > <refentrytitle > glBufferSubData</refentrytitle> </citerefentry> ,
<citerefentry > <refentrytitle > glGetBufferSubData</refentrytitle> </citerefentry>
</para>
</refsect1>
<refsect1 id= "Copyright" > <title > Copyright</title>
<para >
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Copyright <trademark class= "copyright" > </trademark> 2010-2013 Khronos Group.
This material may be distributed subject to the terms and conditions set forth in
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the Open Publication License, v 1.0, 8 June 1999.
<ulink url= "http://opencontent.org/openpub/" > http://opencontent.org/openpub/</ulink> .
</para>
</refsect1>
</refentry>
