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<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>×</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>⁢</mml:mo>
<mml:mtable>
<mml:mtr><mml:mtd>
<mml:mrow>
<mml:mrow>
<mml:mi mathvariant="italic">if</mml:mi>
<mml:mo>⁢</mml:mo>
<mml:mi mathvariant="italic">z</mml:mi>
</mml:mrow>
<mml:mo><=</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>⁢</mml:mo>
<mml:mi mathvariant="italic">z</mml:mi>
</mml:mrow>
<mml:mo>>=</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>