| 1 | <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "xhtml1-transitional.dtd"> |
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| 3 | <?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>gluPartialDisk</title><meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="gluPartialDisk"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>gluPartialDisk — draw an arc of a disk</p></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><tr><td><code class="funcdef">void <b class="fsfunc">gluPartialDisk</b>(</code></td><td>GLUquadric* </td><td><var class="pdparam">quad</var>, </td></tr><tr><td> </td><td>GLdouble </td><td><var class="pdparam">inner</var>, </td></tr><tr><td> </td><td>GLdouble </td><td><var class="pdparam">outer</var>, </td></tr><tr><td> </td><td>GLint </td><td><var class="pdparam">slices</var>, </td></tr><tr><td> </td><td>GLint </td><td><var class="pdparam">loops</var>, </td></tr><tr><td> </td><td>GLdouble </td><td><var class="pdparam">start</var>, </td></tr><tr><td> </td><td>GLdouble </td><td><var class="pdparam">sweep</var><code>)</code>;</td></tr></table></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="parameters"></a><h2>Parameters</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>quad</code></em></span></dt><dd><p> |
| 4 | Specifies a quadrics object (created with <a class="citerefentry" href="gluNewQuadric.xml"><span class="citerefentry"><span class="refentrytitle">gluNewQuadric</span></span></a>). |
| 5 | </p></dd><dt><span class="term"><em class="parameter"><code>inner</code></em></span></dt><dd><p> |
| 6 | Specifies the inner radius of the partial disk (can be 0). |
| 7 | </p></dd><dt><span class="term"><em class="parameter"><code>outer</code></em></span></dt><dd><p> |
| 8 | Specifies the outer radius of the partial disk. |
| 9 | </p></dd><dt><span class="term"><em class="parameter"><code>slices</code></em></span></dt><dd><p> |
| 10 | Specifies the number of subdivisions around the <span class="emphasis"><em>z</em></span> axis. |
| 11 | </p></dd><dt><span class="term"><em class="parameter"><code>loops</code></em></span></dt><dd><p> |
| 12 | Specifies the number of concentric rings about the origin into which |
| 13 | the partial disk is subdivided. |
| 14 | </p></dd><dt><span class="term"><em class="parameter"><code>start</code></em></span></dt><dd><p> |
| 15 | Specifies the starting angle, in degrees, of the disk portion. |
| 16 | </p></dd><dt><span class="term"><em class="parameter"><code>sweep</code></em></span></dt><dd><p> |
| 17 | Specifies the sweep angle, in degrees, of the disk portion. |
| 18 | </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p> |
| 19 | <code class="function">gluPartialDisk</code> renders a partial disk on the |
| 20 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> |
| 21 | |
| 22 | <mml:mrow> |
| 23 | <mml:mi mathvariant="italic">z</mml:mi> |
| 24 | <mml:mo>=</mml:mo> |
| 25 | <mml:mn>0</mml:mn> |
| 26 | </mml:mrow> |
| 27 | </mml:math> |
| 28 | plane. A partial disk is |
| 29 | similar to a full disk, except that only the subset of the disk from |
| 30 | <em class="parameter"><code>start</code></em> through <em class="parameter"><code>start</code></em> + <em class="parameter"><code>sweep</code></em> is included (where 0 degrees is along the |
| 31 | +\f2y\f axis, |
| 32 | 90 degrees along the +<span class="emphasis"><em>x</em></span> axis, 180 degrees along the \-<span class="emphasis"><em>y</em></span> axis, and |
| 33 | 270 degrees along the \-<span class="emphasis"><em>x</em></span> axis). |
| 34 | </p><p> |
| 35 | The partial disk has a radius of |
| 36 | <em class="parameter"><code>outer</code></em> and contains a concentric circular hole with a radius |
| 37 | of <em class="parameter"><code>inner</code></em>. If <em class="parameter"><code>inner</code></em> is 0, then no hole is generated. The partial disk is |
| 38 | subdivided around the <span class="emphasis"><em>z</em></span> axis into slices (like pizza slices) and also |
| 39 | about the <span class="emphasis"><em>z</em></span> axis into rings |
| 40 | (as specified by <em class="parameter"><code>slices</code></em> and <em class="parameter"><code>loops</code></em>, respectively). |
| 41 | </p><p> |
| 42 | With respect to orientation, the +<span class="emphasis"><em>z</em></span> |
| 43 | side of the partial disk is considered to |
| 44 | be outside (see <a class="citerefentry" href="gluQuadricOrientation.xml"><span class="citerefentry"><span class="refentrytitle">gluQuadricOrientation</span></span></a>). |
| 45 | This means that if the |
| 46 | orientation is set to <code class="constant">GLU_OUTSIDE</code>, then any normals generated |
| 47 | point along the +<span class="emphasis"><em>z</em></span> axis. Otherwise, they point along the \-<span class="emphasis"><em>z</em></span> |
| 48 | axis. |
| 49 | </p><p> |
| 50 | If texturing is turned on (with <a class="citerefentry" href="gluQuadricTexture.xml"><span class="citerefentry"><span class="refentrytitle">gluQuadricTexture</span></span></a>), texture |
| 51 | coordinates are generated |
| 52 | linearly such that where |
| 53 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> |
| 54 | |
| 55 | <mml:mrow> |
| 56 | <mml:mi mathvariant="italic">r</mml:mi> |
| 57 | <mml:mo>=</mml:mo> |
| 58 | <mml:mi mathvariant="italic">outer</mml:mi> |
| 59 | </mml:mrow> |
| 60 | </mml:math>, |
| 61 | the value at (<span class="emphasis"><em>r</em></span>, 0, 0) is |
| 62 | (1.0, 0.5), at (0, <span class="emphasis"><em>r</em></span>, 0) it is (0.5, 1.0), at (\-<span class="emphasis"><em>r</em></span>, 0, 0) |
| 63 | it is (0.0, 0.5), and |
| 64 | at (0, \-<span class="emphasis"><em>r</em></span>, 0) it is (0.5, 0.0). |
| 65 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p> |
| 66 | <a class="citerefentry" href="gluCylinder.xml"><span class="citerefentry"><span class="refentrytitle">gluCylinder</span></span></a>, |
| 67 | <a class="citerefentry" href="gluDisk.xml"><span class="citerefentry"><span class="refentrytitle">gluDisk</span></span></a>, |
| 68 | <a class="citerefentry" href="gluNewQuadric.xml"><span class="citerefentry"><span class="refentrytitle">gluNewQuadric</span></span></a>, |
| 69 | <a class="citerefentry" href="gluQuadricOrientation.xml"><span class="citerefentry"><span class="refentrytitle">gluQuadricOrientation</span></span></a>, |
| 70 | <a class="citerefentry" href="gluQuadricTexture.xml"><span class="citerefentry"><span class="refentrytitle">gluQuadricTexture</span></span></a>, |
| 71 | <a class="citerefentry" href="gluSphere.xml"><span class="citerefentry"><span class="refentrytitle">gluSphere</span></span></a> |
| 72 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p> |
| 73 | Copyright <span class="trademark"></span>© 1991-2006 |
| 74 | Silicon Graphics, Inc. This document is licensed under the SGI |
| 75 | Free Software B License. For details, see |
| 76 | <a class="ulink" href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>. |
| 77 | </p></div></div></body></html> |