
<refentry id="glWindowPos">
    <refmeta>
        <refmetainfo>
            <copyright>
                <year>1991-2006</year>
                <holder>Silicon Graphics, Inc.</holder>
            </copyright>
        </refmetainfo>
        <refentrytitle>glWindowPos</refentrytitle>
        <manvolnum>3G</manvolnum>
    </refmeta>
    <refnamediv>
        <refname>glWindowPos</refname>
        <refpurpose>specify the raster position in window coordinates for pixel operations</refpurpose>
    </refnamediv>
    <refsynopsisdiv><title>C Specification</title>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glWindowPos2s</function></funcdef>
                <paramdef>GLshort <parameter>x</parameter></paramdef>
                <paramdef>GLshort <parameter>y</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glWindowPos2i</function></funcdef>
                <paramdef>GLint <parameter>x</parameter></paramdef>
                <paramdef>GLint <parameter>y</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glWindowPos2f</function></funcdef>
                <paramdef>GLfloat <parameter>x</parameter></paramdef>
                <paramdef>GLfloat <parameter>y</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glWindowPos2d</function></funcdef>
                <paramdef>GLdouble <parameter>x</parameter></paramdef>
                <paramdef>GLdouble <parameter>y</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glWindowPos3s</function></funcdef>
                <paramdef>GLshort <parameter>x</parameter></paramdef>
                <paramdef>GLshort <parameter>y</parameter></paramdef>
                <paramdef>GLshort <parameter>z</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glWindowPos3i</function></funcdef>
                <paramdef>GLint <parameter>x</parameter></paramdef>
                <paramdef>GLint <parameter>y</parameter></paramdef>
                <paramdef>GLint <parameter>z</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glWindowPos3f</function></funcdef>
                <paramdef>GLfloat <parameter>x</parameter></paramdef>
                <paramdef>GLfloat <parameter>y</parameter></paramdef>
                <paramdef>GLfloat <parameter>z</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glWindowPos3d</function></funcdef>
                <paramdef>GLdouble <parameter>x</parameter></paramdef>
                <paramdef>GLdouble <parameter>y</parameter></paramdef>
                <paramdef>GLdouble <parameter>z</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
    </refsynopsisdiv>
    <!-- eqn: ignoring delim $$ -->
    <refsect1 id="parameters"><title>Parameters</title>
        <variablelist>
        <varlistentry>
            <term><parameter>x</parameter></term>
            <term><parameter>y</parameter></term>
            <term><parameter>z</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>,
                    <inlineequation><mml:math><mml:mi mathvariant="italic">z</mml:mi></mml:math></inlineequation>
                    coordinates for the raster position.
                </para>
            </listitem>
        </varlistentry>
        </variablelist>
    </refsect1>
    <refsynopsisdiv><title>C Specification</title>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glWindowPos2sv</function></funcdef>
                <paramdef>const GLshort * <parameter>v</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glWindowPos2iv</function></funcdef>
                <paramdef>const GLint * <parameter>v</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glWindowPos2fv</function></funcdef>
                <paramdef>const GLfloat * <parameter>v</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glWindowPos2dv</function></funcdef>
                <paramdef>const GLdouble * <parameter>v</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glWindowPos3sv</function></funcdef>
                <paramdef>const GLshort * <parameter>v</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glWindowPos3iv</function></funcdef>
                <paramdef>const GLint * <parameter>v</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glWindowPos3fv</function></funcdef>
                <paramdef>const GLfloat * <parameter>v</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glWindowPos3dv</function></funcdef>
                <paramdef>const GLdouble * <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 two or three elements,
                    specifying 
                    <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>,
                    <inlineequation><mml:math><mml:mi mathvariant="italic">z</mml:mi></mml:math></inlineequation>
                    coordinates, respectively.
                </para>
            </listitem>
        </varlistentry>
        </variablelist>
    </refsect1>
    <refsect1 id="description"><title>Description</title>
        <para>
            The GL maintains a 3D position in window coordinates.  This position,
            called the raster position, is used to position pixel and bitmap write
            operations. It is maintained with subpixel accuracy.  See <citerefentry><refentrytitle>glBitmap</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glDrawPixels</refentrytitle></citerefentry>, and <citerefentry><refentrytitle>glCopyPixels</refentrytitle></citerefentry>.
        </para>
        <para>
            <function>glWindowPos2</function> specifies the 
            <inlineequation><mml:math><mml:mi mathvariant="italic">x</mml:mi></mml:math></inlineequation>
            and 
            <inlineequation><mml:math><mml:mi mathvariant="italic">y</mml:mi></mml:math></inlineequation>
            coordinates, while 
            <inlineequation><mml:math><mml:mi mathvariant="italic">z</mml:mi></mml:math></inlineequation>
            is
            implicitly set to 0.  <function>glWindowPos3</function> specifies all three coordinates.
            The 
            <inlineequation><mml:math><mml:mi mathvariant="italic">w</mml:mi></mml:math></inlineequation>
            coordinate of the current raster position is always set to 1.0.
        </para>
        <para>
            <function>glWindowPos</function> directly updates the 
            <inlineequation><mml:math><mml:mi mathvariant="italic">x</mml:mi></mml:math></inlineequation>
            and 
            <inlineequation><mml:math><mml:mi mathvariant="italic">y</mml:mi></mml:math></inlineequation>
            coordinates of the current raster
            position with the values specified.  That is, the values are neither
            transformed by the current modelview and projection matrices, nor by
            the viewport-to-window transform.  The 
            <inlineequation><mml:math><mml:mi mathvariant="italic">z</mml:mi></mml:math></inlineequation>
            coordinate of the current raster
            position is updated in the following manner:
        </para>
        <para>
            <informalequation><mml:math>
                <!-- eqn: z =  left{   lpile {    n above    f above    {n + z * (f - n)} }        lpile { if z <= 0 above if z >= 1 above {roman otherwise} }:-->
                <mml:mrow>
                    <mml:mi mathvariant="italic">z</mml:mi>
                    <mml:mo>=</mml:mo>
                    <mml:mfenced open="{" close="">
                        <mml:mrow>
                            <mml:mtable>
                                <mml:mtr><mml:mtd>
                                    <mml:mi mathvariant="italic">n</mml:mi>
                                </mml:mtd></mml:mtr>
                                <mml:mtr><mml:mtd>
                                    <mml:mi mathvariant="italic">f</mml:mi>
                                </mml:mtd></mml:mtr>
                                <mml:mtr><mml:mtd>
                                    <mml:mfenced open="" close="">
                                        <mml:mrow>
                                            <mml:mi mathvariant="italic">n</mml:mi>
                                            <mml:mo>+</mml:mo>
                                            <mml:mrow>
                                                <mml:mi mathvariant="italic">z</mml:mi>
                                                <mml:mo>&times;</mml:mo>
                                                <mml:mfenced open="(" close=")">
                                                    <mml:mrow>
                                                        <mml:mi mathvariant="italic">f</mml:mi>
                                                        <mml:mo>-</mml:mo>
                                                        <mml:mi mathvariant="italic">n</mml:mi>
                                                    </mml:mrow>
                                                </mml:mfenced>
                                            </mml:mrow>
                                        </mml:mrow>
                                    </mml:mfenced>
                                </mml:mtd></mml:mtr>
                            </mml:mtable>
                            <mml:mo>&it;</mml:mo>
                            <mml:mtable>
                                <mml:mtr><mml:mtd>
                                    <mml:mrow>
                                        <mml:mrow>
                                            <mml:mi mathvariant="italic">if</mml:mi>
                                            <mml:mo>&it;</mml:mo>
                                            <mml:mi mathvariant="italic">z</mml:mi>
                                        </mml:mrow>
                                        <mml:mo>&lt;=</mml:mo>
                                        <mml:mn>0</mml:mn>
                                    </mml:mrow>
                                </mml:mtd></mml:mtr>
                                <mml:mtr><mml:mtd>
                                    <mml:mrow>
                                        <mml:mrow>
                                            <mml:mi mathvariant="italic">if</mml:mi>
                                            <mml:mo>&it;</mml:mo>
                                            <mml:mi mathvariant="italic">z</mml:mi>
                                        </mml:mrow>
                                        <mml:mo>&gt;=</mml:mo>
                                        <mml:mn>1</mml:mn>
                                    </mml:mrow>
                                </mml:mtd></mml:mtr>
                                <mml:mtr><mml:mtd>
                                    <mml:mfenced open="" close="">
                                        <mml:mi mathvariant="normal">otherwise</mml:mi>
                                    </mml:mfenced>
                                </mml:mtd></mml:mtr>
                            </mml:mtable>
                        </mml:mrow>
                    </mml:mfenced>
                </mml:mrow>
            </mml:math></informalequation>
        </para>
        <para>
        </para>
        <para>
            where 
            <inlineequation><mml:math><mml:mi mathvariant="italic">n</mml:mi></mml:math></inlineequation>
            is <constant>GL_DEPTH_RANGE</constant>'s near value, and 
            <inlineequation><mml:math><mml:mi mathvariant="italic">f</mml:mi></mml:math></inlineequation>
            is
            <constant>GL_DEPTH_RANGE</constant>'s far value.  See <citerefentry><refentrytitle>glDepthRange</refentrytitle></citerefentry>.
        </para>
        <para>
            The specified coordinates are not clip-tested, causing the raster position
            to always be valid.
        </para>
        <para>
            The current raster position also includes some associated color data and
            texture coordinates.  If lighting is enabled, then
            <constant>GL_CURRENT_RASTER_COLOR</constant> (in RGBA mode) or <constant>GL_CURRENT_RASTER_INDEX</constant>
            (in color index mode) is set to the color produced by the lighting
            calculation (see <citerefentry><refentrytitle>glLight</refentrytitle></citerefentry>, <citerefentry><refentrytitle>glLightModel</refentrytitle></citerefentry>, and <citerefentry><refentrytitle>glShadeModel</refentrytitle></citerefentry>).
            If lighting is disabled, current color (in RGBA mode, state variable
            <constant>GL_CURRENT_COLOR</constant>) or color index (in color index mode, state variable
            <constant>GL_CURRENT_INDEX</constant>) is used to update the current raster color.
            <constant>GL_CURRENT_RASTER_SECONDARY_COLOR</constant> (in RGBA mode) is likewise updated.
        </para>
        <para>
            Likewise, <constant>GL_CURRENT_RASTER_TEXTURE_COORDS</constant> is updated as a function of
            <constant>GL_CURRENT_TEXTURE_COORDS</constant>, based on the texture matrix and the texture
            generation functions (see <citerefentry><refentrytitle>glTexGen</refentrytitle></citerefentry>).  The
            <constant>GL_CURRENT_RASTER_DISTANCE</constant> is set to the <constant>GL_CURRENT_FOG_COORD</constant>.
        </para>
        <para>
        </para>
    </refsect1>
    <refsect1 id="notes"><title>Notes</title>
        <para>
            <function>glWindowPos</function> is available only if the GL version is 1.4 or greater.
        </para>
        <para>
            The raster position is modified by <citerefentry><refentrytitle>glRasterPos</refentrytitle></citerefentry>, <citerefentry><refentrytitle>glBitmap</refentrytitle></citerefentry>, and
            <function>glWindowPos</function>.
        </para>
        <para>
            Calling <citerefentry><refentrytitle>glDrawElements</refentrytitle></citerefentry>, or <citerefentry><refentrytitle>glDrawRangeElements</refentrytitle></citerefentry> may leave the
            current color or index indeterminate.
            If <function>glWindowPos</function> is executed while the current color or index is indeterminate, the
            current raster color or current raster index remains indeterminate.
        </para>
        <para>
            There are distinct raster texture coordinates for each texture unit. Each
            texture unit's current raster texture coordinates are updated by <function>glWindowPos</function>.
        </para>
    </refsect1>
    <refsect1 id="errors"><title>Errors</title>
        <para>
            <constant>GL_INVALID_OPERATION</constant> is generated if <function>glWindowPos</function>
            is executed between the execution of <citerefentry><refentrytitle>glBegin</refentrytitle></citerefentry>
            and the corresponding execution of <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_RASTER_POSITION</constant>
        </para>
        <para>
            <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_CURRENT_RASTER_POSITION_VALID</constant>
        </para>
        <para>
            <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_CURRENT_RASTER_DISTANCE</constant>
        </para>
        <para>
            <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_CURRENT_RASTER_COLOR</constant>
        </para>
        <para>
            <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_CURRENT_RASTER_SECONDARY_COLOR</constant>
        </para>
        <para>
            <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_CURRENT_RASTER_INDEX</constant>
        </para>
        <para>
            <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_CURRENT_RASTER_TEXTURE_COORDS</constant>
        </para>
    </refsect1>
    <refsect1 id="seealso"><title>See Also</title>
        <para>
            <citerefentry><refentrytitle>glBitmap</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glCopyPixels</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glDrawArrays</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glDrawElements</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glDrawRangeElements</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glDrawPixels</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glMultiTexCoord</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glRasterPos</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glTexCoord</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glTexGen</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>
