
<refentry id="glNormal">
    <refmeta>
        <refmetainfo>
            <copyright>
                <year>1991-2006</year>
                <holder>Silicon Graphics, Inc.</holder>
            </copyright>
        </refmetainfo>
        <refentrytitle>glNormal</refentrytitle>
        <manvolnum>3G</manvolnum>
    </refmeta>
    <refnamediv>
        <refname>glNormal</refname>
        <refpurpose>set the current normal vector</refpurpose>
    </refnamediv>
    <!-- eqn: ignoring delim $$ -->
    <refsynopsisdiv><title>C Specification</title>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glNormal3b</function></funcdef>
                <paramdef>GLbyte <parameter>nx</parameter></paramdef>
                <paramdef>GLbyte <parameter>ny</parameter></paramdef>
                <paramdef>GLbyte <parameter>nz</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glNormal3d</function></funcdef>
                <paramdef>GLdouble <parameter>nx</parameter></paramdef>
                <paramdef>GLdouble <parameter>ny</parameter></paramdef>
                <paramdef>GLdouble <parameter>nz</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glNormal3f</function></funcdef>
                <paramdef>GLfloat <parameter>nx</parameter></paramdef>
                <paramdef>GLfloat <parameter>ny</parameter></paramdef>
                <paramdef>GLfloat <parameter>nz</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glNormal3i</function></funcdef>
                <paramdef>GLint <parameter>nx</parameter></paramdef>
                <paramdef>GLint <parameter>ny</parameter></paramdef>
                <paramdef>GLint <parameter>nz</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glNormal3s</function></funcdef>
                <paramdef>GLshort <parameter>nx</parameter></paramdef>
                <paramdef>GLshort <parameter>ny</parameter></paramdef>
                <paramdef>GLshort <parameter>nz</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
    </refsynopsisdiv>
    <refsect1 id="parameters"><title>Parameters</title>
        <variablelist>
        <varlistentry>
            <term><parameter>nx</parameter></term>
            <term><parameter>ny</parameter></term>
            <term><parameter>nz</parameter></term>
            <listitem>
                <para>
                    Specify the 
                    <inlineequation><mml:math><mml:mi mathvariant="italic">x</mml:mi></mml:math></inlineequation>,
                    <inlineequation><mml:math><mml:mi mathvariant="italic">y</mml:mi></mml:math></inlineequation>,
                    and 
                    <inlineequation><mml:math><mml:mi mathvariant="italic">z</mml:mi></mml:math></inlineequation>
                    coordinates of the new current normal.
                    The initial value of the current normal is the unit vector, (0, 0, 1).
                </para>
                <para>
                </para>
            </listitem>
        </varlistentry>
        </variablelist>
    </refsect1>
    <refsynopsisdiv><title>C Specification</title>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glNormal3bv</function></funcdef>
                <paramdef>const GLbyte * <parameter>v</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glNormal3dv</function></funcdef>
                <paramdef>const GLdouble * <parameter>v</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glNormal3fv</function></funcdef>
                <paramdef>const GLfloat * <parameter>v</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glNormal3iv</function></funcdef>
                <paramdef>const GLint * <parameter>v</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glNormal3sv</function></funcdef>
                <paramdef>const GLshort * <parameter>v</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
    </refsynopsisdiv>
    <refsect1 id="parameters2"><title>Parameters</title>
        <variablelist>
        <varlistentry>
            <term><parameter>v</parameter></term>
            <listitem>
                <para>
                    Specifies a pointer to an array of three elements:
                    the 
                    <inlineequation><mml:math><mml:mi mathvariant="italic">x</mml:mi></mml:math></inlineequation>,
                    <inlineequation><mml:math><mml:mi mathvariant="italic">y</mml:mi></mml:math></inlineequation>,
                    and 
                    <inlineequation><mml:math><mml:mi mathvariant="italic">z</mml:mi></mml:math></inlineequation>
                    coordinates of the new current normal.
                </para>
                <para>
                </para>
            </listitem>
        </varlistentry>
        </variablelist>
    </refsect1>
    <refsect1 id="description"><title>Description</title>
        <para>
            The current normal is set to the given coordinates
            whenever <function>glNormal</function> is issued.
            Byte, short, or integer arguments are converted to floating-point
            format with a linear mapping that maps the most positive representable integer
            value to 1.0
            and the most negative representable integer value to 
            <inlineequation><mml:math>
                <!-- eqn: -1.0:-->
                <mml:mn>-1.0</mml:mn>
            </mml:math></inlineequation>.
        </para>
        <para>
            Normals specified with <function>glNormal</function> need not have unit length.
            If <constant>GL_NORMALIZE</constant> is enabled,
            then normals of any length specified with <function>glNormal</function> are normalized after transformation.
            If <constant>GL_RESCALE_NORMAL</constant> is enabled, normals are scaled by a scaling factor
            derived from the modelview matrix.  <constant>GL_RESCALE_NORMAL</constant> requires that the
            originally specified normals were of unit length, and that the modelview
            matrix contain only uniform scales for proper results.
            To enable and disable normalization, call <citerefentry><refentrytitle>glEnable</refentrytitle></citerefentry> and <citerefentry><refentrytitle>glDisable</refentrytitle></citerefentry>
            with either <constant>GL_NORMALIZE</constant> or <constant>GL_RESCALE_NORMAL</constant>.
            Normalization is initially disabled.
        </para>
    </refsect1>
    <refsect1 id="notes"><title>Notes</title>
        <para>
            The current normal can be updated at any time.
            In particular, <function>glNormal</function> can be called between a call to <citerefentry><refentrytitle>glBegin</refentrytitle></citerefentry> and
            the corresponding call to <citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry>.
        </para>
    </refsect1>
    <refsect1 id="associatedgets"><title>Associated Gets</title>
        <para>
            <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_CURRENT_NORMAL</constant>
        </para>
        <para>
            <citerefentry><refentrytitle>glIsEnabled</refentrytitle></citerefentry> with argument <constant>GL_NORMALIZE</constant>
        </para>
        <para>
            <citerefentry><refentrytitle>glIsEnabled</refentrytitle></citerefentry> with argument <constant>GL_RESCALE_NORMAL</constant>
        </para>
    </refsect1>
    <refsect1 id="seealso"><title>See Also</title>
        <para>
            <citerefentry><refentrytitle>glBegin</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glColor</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glIndex</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glMultiTexCoord</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glNormalPointer</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glTexCoord</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glVertex</refentrytitle></citerefentry>
        </para>
    </refsect1>
    <refsect1 id="Copyright"><title>Copyright</title>
        <para>
            Copyright <trademark class="copyright"></trademark> 1991-2006
            Silicon Graphics, Inc. This document is licensed under the SGI
            Free Software B License. For details, see
            <ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>.
        </para>
    </refsect1>
</refentry>
