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<?xml-stylesheet type="text/xsl" href="mathml.xsl"?><html xmlns="http://www.w3.org/1999/xhtml" xmlns:pref="http://www.w3.org/2002/Math/preference" pref:renderer="mathplayer-dl"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>gluProject</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1" /></head><body><div class="refentry"><a id="gluProject"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>gluProject — map object coordinates to window coordinates</p></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">GLint <strong class="fsfunc">gluProject</strong>(</code></td><td>GLdouble <var class="pdparam">objX</var>, </td></tr><tr><td> </td><td>GLdouble <var class="pdparam">objY</var>, </td></tr><tr><td> </td><td>GLdouble <var class="pdparam">objZ</var>, </td></tr><tr><td> </td><td>const GLdouble * <var class="pdparam">model</var>, </td></tr><tr><td> </td><td>const GLdouble * <var class="pdparam">proj</var>, </td></tr><tr><td> </td><td>const GLint * <var class="pdparam">view</var>, </td></tr><tr><td> </td><td>GLdouble* <var class="pdparam">winX</var>, </td></tr><tr><td> </td><td>GLdouble* <var class="pdparam">winY</var>, </td></tr><tr><td> </td><td>GLdouble* <var class="pdparam">winZ</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1"><a id="parameters"></a><h2>Parameters</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="parameter"><code>objX</code></em>, </span><span class="term"><em class="parameter"><code>objY</code></em>, </span><span class="term"><em class="parameter"><code>objZ</code></em></span></dt><dd><p>
                    Specify the object coordinates.
                </p></dd><dt><span class="term"><em class="parameter"><code>model</code></em></span></dt><dd><p>
                    Specifies the current modelview matrix (as from a <a class="citerefentry" href="glGetDoublev.xml"><span class="citerefentry"><span class="refentrytitle">glGetDoublev</span></span></a> call).
                </p></dd><dt><span class="term"><em class="parameter"><code>proj</code></em></span></dt><dd><p>
                    Specifies the current projection matrix (as from a <a class="citerefentry" href="glGetDoublev.xml"><span class="citerefentry"><span class="refentrytitle">glGetDoublev</span></span></a> call).
                </p></dd><dt><span class="term"><em class="parameter"><code>view</code></em></span></dt><dd><p>
                    Specifies the current viewport (as from a <a class="citerefentry" href="glGetIntegerv.xml"><span class="citerefentry"><span class="refentrytitle">glGetIntegerv</span></span></a> call).
                </p></dd><dt><span class="term"><em class="parameter"><code>winX</code></em>, </span><span class="term"><em class="parameter"><code>winY</code></em>, </span><span class="term"><em class="parameter"><code>winZ</code></em></span></dt><dd><p>
                    Return the computed window coordinates.
                </p></dd></dl></div></div><div class="refsect1"><a id="description"></a><h2>Description</h2><p>
            <code class="function">gluProject</code> transforms the specified object coordinates into window coordinates
            using <em class="parameter"><code>model</code></em>, <em class="parameter"><code>proj</code></em>, and <em class="parameter"><code>view</code></em>. The result is stored 
            in <em class="parameter"><code>winX</code></em>, <em class="parameter"><code>winY</code></em>, and <em class="parameter"><code>winZ</code></em>. A return value of 
            <code class="constant">GLU_TRUE</code> indicates success, a return value of <code class="constant">GLU_FALSE</code>
            indicates failure.
        </p><p>
            To compute the coordinates,
            let 
            <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                
                <mml:mrow>
                    <mml:mi mathvariant="italic">v</mml:mi>
                    <mml:mo>=</mml:mo>
                    <mml:mfenced open="(" close=")">
                        <mml:mi mathvariant="italic">objX</mml:mi>
                        <mml:mi mathvariant="italic">objY</mml:mi>
                        <mml:mi mathvariant="italic">objZ</mml:mi>
                        <mml:mn>1.0</mml:mn>
                    </mml:mfenced>
                </mml:mrow>
            </mml:math>
            represented as a matrix with 4 rows and 1 column.
            Then <code class="function">gluProject</code> computes 
            <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                
                <mml:msup><mml:mi mathvariant="italic">v</mml:mi>
                <mml:mo>″</mml:mo>
                </mml:msup>
            </mml:math>
            as follows: 
        </p><p>
            </p><div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                
                <mml:mrow>
                    <mml:msup><mml:mi mathvariant="italic">v</mml:mi>
                    <mml:mo>″</mml:mo>
                    </mml:msup>
                    <mml:mo>=</mml:mo>
                    <mml:mrow>
                        <mml:mi mathvariant="italic">P</mml:mi>
                        <mml:mo>×</mml:mo>
                        <mml:mi mathvariant="italic">M</mml:mi>
                        <mml:mo>×</mml:mo>
                        <mml:mi mathvariant="italic">v</mml:mi>
                    </mml:mrow>
                </mml:mrow>
            </mml:math></div><p>
        </p><p>
            where 
            <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">P</mml:mi></mml:math>
            is the current projection matrix <em class="parameter"><code>proj</code></em> and 
            <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">M</mml:mi></mml:math>
            is the current
            modelview matrix <em class="parameter"><code>model</code></em> (both represented as
            <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                
                <mml:mrow>
                    <mml:mn>4</mml:mn>
                    <mml:mo>×</mml:mo>
                    <mml:mn>4</mml:mn>
                </mml:mrow>
            </mml:math>
            matrices in column-major order).
        </p><p>
            The window coordinates are then computed as follows: 
        </p><p>
            </p><div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                
                <mml:mrow>
                    <mml:mi mathvariant="italic">winX</mml:mi>
                    <mml:mo>=</mml:mo>
                    <mml:mrow>
                        <mml:mrow>
                            <mml:mi mathvariant="italic">view</mml:mi>
                            <mml:mo>⁡</mml:mo>
                            <mml:mfenced open="(" close=")">
                                <mml:mn>0</mml:mn>
                            </mml:mfenced>
                        </mml:mrow>
                        <mml:mo>+</mml:mo>
                        <mml:mfrac>
                            <mml:mrow>
                                <mml:mrow>
                                    <mml:mi mathvariant="italic">view</mml:mi>
                                    <mml:mo>⁡</mml:mo>
                                    <mml:mfenced open="(" close=")">
                                        <mml:mn>2</mml:mn>
                                    </mml:mfenced>
                                </mml:mrow>
                                <mml:mo>×</mml:mo>
                                <mml:mfenced open="(" close=")">
                                    <mml:mrow>
                                        <mml:mrow>
                                            <mml:msup><mml:mi mathvariant="italic">v</mml:mi>
                                            <mml:mo>″</mml:mo>
                                            </mml:msup>
                                            <mml:mo>⁡</mml:mo>
                                            <mml:mfenced open="(" close=")">
                                                <mml:mn>0</mml:mn>
                                            </mml:mfenced>
                                        </mml:mrow>
                                        <mml:mo>+</mml:mo>
                                        <mml:mn>1</mml:mn>
                                    </mml:mrow>
                                </mml:mfenced>
                            </mml:mrow>
                            <mml:mn>2</mml:mn>
                        </mml:mfrac>
                    </mml:mrow>
                </mml:mrow>
            </mml:math></div><p>
            </p><p>
                </p><div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                    
                    <mml:mrow>
                        <mml:mi mathvariant="italic">winY</mml:mi>
                        <mml:mo>=</mml:mo>
                        <mml:mrow>
                            <mml:mrow>
                                <mml:mi mathvariant="italic">view</mml:mi>
                                <mml:mo>⁡</mml:mo>
                                <mml:mfenced open="(" close=")">
                                    <mml:mn>1</mml:mn>
                                </mml:mfenced>
                            </mml:mrow>
                            <mml:mo>+</mml:mo>
                            <mml:mfrac>
                                <mml:mrow>
                                    <mml:mrow>
                                        <mml:mi mathvariant="italic">view</mml:mi>
                                        <mml:mo>⁡</mml:mo>
                                        <mml:mfenced open="(" close=")">
                                            <mml:mn>3</mml:mn>
                                        </mml:mfenced>
                                    </mml:mrow>
                                    <mml:mo>×</mml:mo>
                                    <mml:mfenced open="(" close=")">
                                        <mml:mrow>
                                            <mml:mrow>
                                                <mml:msup><mml:mi mathvariant="italic">v</mml:mi>
                                                <mml:mo>″</mml:mo>
                                                </mml:msup>
                                                <mml:mo>⁡</mml:mo>
                                                <mml:mfenced open="(" close=")">
                                                    <mml:mn>1</mml:mn>
                                                </mml:mfenced>
                                            </mml:mrow>
                                            <mml:mo>+</mml:mo>
                                            <mml:mn>1</mml:mn>
                                        </mml:mrow>
                                    </mml:mfenced>
                                </mml:mrow>
                                <mml:mn>2</mml:mn>
                            </mml:mfrac>
                        </mml:mrow>
                    </mml:mrow>
                </mml:math></div><p>
            </p><p>
            </p><p>
                </p><div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                    
                    <mml:mrow>
                        <mml:mi mathvariant="italic">winZ</mml:mi>
                        <mml:mo>=</mml:mo>
                        <mml:mfrac>
                            <mml:mfenced open="(" close=")">
                                <mml:mrow>
                                    <mml:mrow>
                                        <mml:msup><mml:mi mathvariant="italic">v</mml:mi>
                                        <mml:mo>″</mml:mo>
                                        </mml:msup>
                                        <mml:mo>⁡</mml:mo>
                                        <mml:mfenced open="(" close=")">
                                            <mml:mn>2</mml:mn>
                                        </mml:mfenced>
                                    </mml:mrow>
                                    <mml:mo>+</mml:mo>
                                    <mml:mn>1</mml:mn>
                                </mml:mrow>
                            </mml:mfenced>
                            <mml:mn>2</mml:mn>
                        </mml:mfrac>
                    </mml:mrow>
                </mml:math></div><p>
            </p><p>
        </p><p>
        </p></div><div class="refsect1"><a id="seealso"></a><h2>See Also</h2><p>
            <a class="citerefentry" href="gluUnProject.xml"><span class="citerefentry"><span class="refentrytitle">gluUnProject</span></span></a>,
            <a class="citerefentry" href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a>
        </p></div><div class="refsect1"><a id="Copyright"></a><h2>Copyright</h2><p>
            Copyright <span class="trademark"></span>© 1991-2006
            Silicon Graphics, Inc. This document is licensed under the SGI
            Free Software B License. For details, see
            <a class="ulink" href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>.
        </p></div></div></body></html>