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<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"
"http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">
<refentry id="glVertexAttribPointer">
<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>
</funcsynopsis>
</refsynopsisdiv>
<refsect1 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, or 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. Symbolic constants
<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>,
<constant>GL_FLOAT</constant>, or
<constant>GL_DOUBLE</constant> are
accepted. The initial value is <constant>GL_FLOAT</constant>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>normalized</parameter></term>
<listitem>
<para>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.</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 component of
the first generic vertex attribute in the array. The initial value is 0.</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 id="description"><title>Description</title>
<para><function>glVertexAttribPointer</function> specifies 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.
If set to <constant>GL_TRUE</constant>,
<parameter>normalized</parameter> 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>If a non-zero named buffer object is bound to the <constant>GL_ARRAY_BUFFER</constant> target
(see <citerefentry><refentrytitle>glBindBuffer</refentrytitle></citerefentry>) while a generic vertex attribute array is
specified, <parameter>pointer</parameter> is treated as a byte offset into the buffer object's data store.
Also, the buffer object binding (<constant>GL_ARRAY_BUFFER_BINDING</constant>) is saved as generic vertex attribute array
client-side state (<constant>GL_VERTEX_ATTRIB_ARRAY_BUFFER_BINDING</constant>) for index <parameter>index</parameter>.</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 client-side
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>glArrayElement</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glDrawArrays</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glMultiDrawArrays</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glDrawElements</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glMultiDrawElements</refentrytitle></citerefentry>, or
<citerefentry><refentrytitle>glDrawRangeElements</refentrytitle></citerefentry>
is called.</para>
</refsect1>
<refsect1 id="notes"><title>Notes</title>
<para><function>glVertexAttribPointer</function> is available
only if the GL version is 2.0 or greater.</para>
<para>Each generic vertex attribute array is initially disabled
and isn't accessed when
<citerefentry><refentrytitle>glArrayElement</refentrytitle></citerefentry>, <citerefentry><refentrytitle>glDrawElements</refentrytitle></citerefentry>, <citerefentry><refentrytitle>glDrawRangeElements</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glDrawArrays</refentrytitle></citerefentry>, <citerefentry><refentrytitle>glMultiDrawArrays</refentrytitle></citerefentry>, or <citerefentry><refentrytitle>glMultiDrawElements</refentrytitle></citerefentry>
is called.</para>
<para>Execution of <function>glVertexAttribPointer</function> is
not allowed between the execution of
<citerefentry><refentrytitle>glBegin</refentrytitle></citerefentry>
and the corresponding execution of
<citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry>,
but an error may or may not be generated. If no error is
generated, the operation is undefined.</para>
<para><function>glVertexAttribPointer</function> is typically
implemented on the client side.</para>
<para>Generic vertex attribute array parameters are client-side
state and are therefore not saved or restored by
<citerefentry><refentrytitle>glPushAttrib</refentrytitle></citerefentry>
and
<citerefentry><refentrytitle>glPopAttrib</refentrytitle></citerefentry>.
Use
<citerefentry><refentrytitle>glPushClientAttrib</refentrytitle></citerefentry>
and
<citerefentry><refentrytitle>glPopClientAttrib</refentrytitle></citerefentry>
instead.</para>
</refsect1>
<refsect1 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>
</refsect1>
<refsect1 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 id="seealso"><title>See Also</title>
<para><citerefentry><refentrytitle>glArrayElement</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glBindAttribLocation</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glBindBuffer</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glColorPointer</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>glEdgeFlagPointer</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glFogCoordPointer</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glIndexPointer</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glInterleavedArrays</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glMultiDrawArrays</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glMultiDrawElements</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glNormalPointer</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glPopClientAttrib</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glPushClientAttrib</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glSecondaryColorPointer</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glTexCoordPointer</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glVertexAttrib</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glVertexPointer</refentrytitle></citerefentry>
</para>
</refsect1>
<refsect1 id="Copyright"><title>Copyright</title>
<para>
Copyright <trademark class="copyright"></trademark> 2003-2005 3Dlabs Inc. Ltd.
This material may be distributed subject to the terms and conditions set forth in
the Open Publication License, v 1.0, 8 June 1999.
<ulink url="http://opencontent.org/openpub/">http://opencontent.org/openpub/</ulink>.
</para>
</refsect1>
</refentry>