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<refentry xmlns="http://docbook.org/ns/docbook" version="5.0" xml:id="glVertexAttribPointer">
    <info>
        <copyright>
            <year>2003-2005</year>
            <holder>3Dlabs Inc. Ltd.</holder>
        </copyright>
        <copyright>
            <year>2010-2014</year>
            <holder>Khronos Group</holder>
        </copyright>
    </info>
    <refmeta>
        <refentrytitle>glVertexAttribPointer</refentrytitle>
        <manvolnum>3G</manvolnum>
    </refmeta>
    <refnamediv>
        <refname>glVertexAttribPointer</refname>
        <refpurpose>define an array of generic vertex attribute data</refpurpose>
    </refnamediv>
    <refsynopsisdiv>
        <title>C Specification</title>
    <funcsynopsis>
        <funcprototype>
            <funcdef>void <function>glVertexAttribPointer</function></funcdef>
            <paramdef>GLuint <parameter>index</parameter></paramdef>
            <paramdef>GLint <parameter>size</parameter></paramdef>
            <paramdef>GLenum <parameter>type</parameter></paramdef>
            <paramdef>GLboolean <parameter>normalized</parameter></paramdef>
            <paramdef>GLsizei <parameter>stride</parameter></paramdef>
            <paramdef>const GLvoid * <parameter>pointer</parameter></paramdef>
        </funcprototype>
        <funcprototype>
            <funcdef>void <function>glVertexAttribIPointer</function></funcdef>
            <paramdef>GLuint <parameter>index</parameter></paramdef>
            <paramdef>GLint <parameter>size</parameter></paramdef>
            <paramdef>GLenum <parameter>type</parameter></paramdef>
            <paramdef>GLsizei <parameter>stride</parameter></paramdef>
            <paramdef>const GLvoid * <parameter>pointer</parameter></paramdef>
        </funcprototype>
    </funcsynopsis>
    </refsynopsisdiv>
    <refsect1 xml:id="parameters"><title>Parameters</title>
    <variablelist>
        <varlistentry>
        <term><parameter>index</parameter></term>
        <listitem>
            <para>Specifies the index of the generic vertex
            attribute to be modified.</para>
        </listitem>
        </varlistentry>
        <varlistentry>
        <term><parameter>size</parameter></term>
        <listitem>
            <para>Specifies the number of components per
            generic vertex attribute. Must
            be 1, 2, 3, 4. The initial value is 4.</para>
        </listitem>
        </varlistentry>
        <varlistentry>
        <term><parameter>type</parameter></term>
        <listitem>
            <para>Specifies the data type of each component in
            the array. The symbolic constants
            <constant>GL_BYTE</constant>,
            <constant>GL_UNSIGNED_BYTE</constant>,
            <constant>GL_SHORT</constant>,
            <constant>GL_UNSIGNED_SHORT</constant>,
            <constant>GL_INT</constant>, and
            <constant>GL_UNSIGNED_INT</constant> are accepted by both functions. Additionally
            <constant>GL_HALF_FLOAT</constant>,
            <constant>GL_FLOAT</constant>,
            <constant>GL_FIXED</constant>,
            <constant>GL_INT_2_10_10_10_REV</constant>, and
            <constant>GL_UNSIGNED_INT_2_10_10_10_REV</constant> are accepted by <function>glVertexAttribPointer</function>.
            The initial value is <constant>GL_FLOAT</constant>.</para>
        </listitem>
        </varlistentry>
        <varlistentry>
        <term><parameter>normalized</parameter></term>
        <listitem>
            <para>For <function>glVertexAttribPointer</function>, specifies whether fixed-point data values
            should be normalized (<constant>GL_TRUE</constant>)
            or converted directly as fixed-point values
            (<constant>GL_FALSE</constant>) when they are
            accessed. This parameter is ignored if <parameter>type</parameter> is <constant>GL_FIXED</constant>.</para>
        </listitem>
        </varlistentry>
        <varlistentry>
        <term><parameter>stride</parameter></term>
        <listitem>
            <para>
                Specifies the byte offset between consecutive generic vertex
                attributes. If <parameter>stride</parameter> is 0, the
                generic vertex attributes are understood to be tightly
                packed in the array. The initial value is 0.
            </para>
        </listitem>
        </varlistentry>
        <varlistentry>
        <term><parameter>pointer</parameter></term>
        <listitem>
            <para>
                Specifies a pointer to the first generic vertex attribute in
                the array. If a non-zero buffer is currently bound to the
                <constant>GL_ARRAY_BUFFER</constant> target,
                <parameter>pointer</parameter> specifies an offset of into
                the array in the data store of that buffer. The initial
                value is 0.
            </para>
        </listitem>
        </varlistentry>
    </variablelist>
    </refsect1>
    <refsect1 xml:id="description"><title>Description</title>
        <para>
            <function>glVertexAttribPointer</function> and <function>glVertexAttribIPointer</function> specify the
            location and data format of the array of generic vertex attributes at index <parameter>index</parameter>
            to use when rendering. <parameter>size</parameter> specifies the number of components per attribute and
            must be 1, 2, 3 or 4. <parameter>type</parameter> specifies the data type
            of each component, and <parameter>stride</parameter> specifies the byte stride from one attribute to the next,
            allowing vertices and attributes to be packed into a single array or stored in separate arrays.
        </para>
        <para>
            For <function>glVertexAttribPointer</function>, if <parameter>normalized</parameter> is set to <constant>GL_TRUE</constant>,
            it indicates that values stored in an integer format are to be mapped to the range [-1,1] (for signed values) or [0,1] (for
            unsigned values) when they are accessed and converted to floating point. Otherwise, values will
            be converted to floats directly without normalization.
        </para>
        <para>
            For <function>glVertexAttribIPointer</function>, only the integer types <constant>GL_BYTE</constant>,
            <constant>GL_UNSIGNED_BYTE</constant>, <constant>GL_SHORT</constant>, <constant>GL_UNSIGNED_SHORT</constant>,
            <constant>GL_INT</constant>, <constant>GL_UNSIGNED_INT</constant> are accepted. Values are always left as integer values.
        </para>
        <para>
            If a non-zero named buffer object is bound to the <constant>GL_ARRAY_BUFFER</constant> target 
            (see <citerefentry><refentrytitle>glBindBuffer</refentrytitle></citerefentry>),
            <parameter>pointer</parameter> is treated as a byte offset into the buffer object's data store and
            the buffer object binding (<constant>GL_ARRAY_BUFFER_BINDING</constant>) is saved as generic vertex attribute array
            state (<constant>GL_VERTEX_ATTRIB_ARRAY_BUFFER_BINDING</constant>) for index <parameter>index</parameter>.
        </para>
        <para>
            Client vertex arrays (a binding of zero to the <constant>GL_ARRAY_BUFFER</constant> target) are only valid in
            conjunction with the zero named vertex array object. This is provided for backwards compatibility with OpenGL ES 2.0. 
        </para>
        <para>
            When a generic vertex attribute array is specified,
            <parameter>size</parameter>, <parameter>type</parameter>,
            <parameter>normalized</parameter>,
            <parameter>stride</parameter>, and
            <parameter>pointer</parameter> are saved as vertex array
            state, in addition to the current vertex array buffer object binding.
        </para>
        <para>
            To enable and disable a generic vertex attribute array, call
            <citerefentry><refentrytitle>glEnableVertexAttribArray</refentrytitle></citerefentry> and
            <citerefentry><refentrytitle>glDisableVertexAttribArray</refentrytitle></citerefentry> with <parameter>index</parameter>.
            If enabled, the generic vertex attribute array is used when <citerefentry><refentrytitle>glDrawArrays</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glDrawArraysInstanced</refentrytitle></citerefentry>, <citerefentry><refentrytitle>glDrawElements</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glDrawElementsIntanced</refentrytitle></citerefentry>, or  <citerefentry><refentrytitle>glDrawRangeElements</refentrytitle></citerefentry>
            is called.
        </para>
    </refsect1>
    <refsect1 xml:id="notes"><title>Notes</title>
        <para>
            Each generic vertex attribute array is initially disabled and isn't accessed when
            <citerefentry><refentrytitle>glDrawElements</refentrytitle></citerefentry>, <citerefentry><refentrytitle>glDrawRangeElements</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glDrawArrays</refentrytitle></citerefentry>, <citerefentry><refentrytitle>glDrawArraysInstanced</refentrytitle></citerefentry>, or <citerefentry><refentrytitle>glDrawElementsInstanced</refentrytitle></citerefentry>
            is called.
        </para>

    </refsect1>
    <refsect1 xml:id="errors"><title>Errors</title>
        <para>
            <constant>GL_INVALID_VALUE</constant> is generated if
            <parameter>index</parameter> is greater than or equal to
            <constant>GL_MAX_VERTEX_ATTRIBS</constant>.
        </para>
        <para>
            <constant>GL_INVALID_VALUE</constant> is generated if
            <parameter>size</parameter> is not 1, 2, 3 or 4.
        </para>
        <para>
            <constant>GL_INVALID_ENUM</constant> is generated if
            <parameter>type</parameter> is not an accepted value.
        </para>
        <para>
            <constant>GL_INVALID_VALUE</constant> is generated if
            <parameter>stride</parameter> is negative.
        </para>
        <para>
            <constant>GL_INVALID_OPERATION</constant> is generated if
            <parameter>type</parameter> is
            <constant>GL_INT_2_10_10_10_REV</constant> or
            <constant>GL_UNSIGNED_INT_2_10_10_10_REV</constant> and
            <parameter>size</parameter> is not 4.
        </para>
        <para>
            <constant>GL_INVALID_OPERATION</constant> is generated a
            non-zero vertex array object is bound, zero is bound to the
            <constant>GL_ARRAY_BUFFER</constant> buffer object binding point
            and the <parameter>pointer</parameter> argument is not
            <constant>NULL</constant>.
        </para>
    </refsect1>
    <refsect1 xml:id="associatedgets"><title>Associated Gets</title>
        <para><citerefentry><refentrytitle>glGet</refentrytitle></citerefentry>
        with argument <constant>GL_MAX_VERTEX_ATTRIBS</constant></para>
        
        <para><citerefentry><refentrytitle>glGetVertexAttrib</refentrytitle></citerefentry>
        with arguments <parameter>index</parameter> and <constant>GL_VERTEX_ATTRIB_ARRAY_ENABLED</constant></para>
        
        <para><citerefentry><refentrytitle>glGetVertexAttrib</refentrytitle></citerefentry>
        with arguments <parameter>index</parameter> and <constant>GL_VERTEX_ATTRIB_ARRAY_SIZE</constant></para>
        
        <para><citerefentry><refentrytitle>glGetVertexAttrib</refentrytitle></citerefentry>
        with arguments <parameter>index</parameter> and <constant>GL_VERTEX_ATTRIB_ARRAY_TYPE</constant></para>
        
        <para><citerefentry><refentrytitle>glGetVertexAttrib</refentrytitle></citerefentry>
        with arguments <parameter>index</parameter> and <constant>GL_VERTEX_ATTRIB_ARRAY_NORMALIZED</constant></para>
        
        <para><citerefentry><refentrytitle>glGetVertexAttrib</refentrytitle></citerefentry>
        with arguments <parameter>index</parameter> and <constant>GL_VERTEX_ATTRIB_ARRAY_STRIDE</constant></para>
        
        <para><citerefentry><refentrytitle>glGetVertexAttrib</refentrytitle></citerefentry>
        with arguments <parameter>index</parameter> and <constant>GL_VERTEX_ATTRIB_ARRAY_BUFFER_BINDING</constant></para>
        
        <para><citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument 
        <constant>GL_ARRAY_BUFFER_BINDING</constant></para>
        
        <para><citerefentry><refentrytitle>glGetVertexAttribPointerv</refentrytitle></citerefentry>
        with arguments <parameter>index</parameter> and
        <constant>GL_VERTEX_ATTRIB_ARRAY_POINTER</constant></para>
    </refsect1>
    <refsect1 xml:id="versions">
        <title>API Version Support</title>
        <informaltable>
            <tgroup cols="4" align="left">
                <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apifunchead.xml" xpointer="xpointer(/*/*)"/>
                <tbody>
                    <row>
                        <entry><function>glVertexAttribPointer</function></entry>
                        <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apiversion.xml" xpointer="xpointer(/*/*[@role='es20']/*)"/>
                    </row>
                    <row>
                        <entry><function>glVertexAttribIPointer</function></entry>
                        <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apiversion.xml" xpointer="xpointer(/*/*[@role='es30']/*)"/>
                    </row>
                </tbody>
            </tgroup>
        </informaltable>
    </refsect1>
    <refsect1 xml:id="seealso"><title>See Also</title>
        <para>
            <citerefentry><refentrytitle>glBindAttribLocation</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glBindBuffer</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glDisableVertexAttribArray</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glDrawArrays</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glDrawElements</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glDrawRangeElements</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glEnableVertexAttribArray</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glDrawArraysInstanced</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glDrawElementsIntanced</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glVertexAttrib</refentrytitle></citerefentry>
        </para>
    </refsect1>
    <refsect1 xml:id="Copyright"><title>Copyright</title>
        <para>
            Copyright <trademark class="copyright"/> 2003-2005 3Dlabs Inc. Ltd.
            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>
