HCoop / clinton / guile-figl.git / blame
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1 | <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "xhtml1-transitional.dtd"> |
| 2 | <!-- saved from url=(0013)about:internet --> | |
| 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>glPolygonMode</title><meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="glPolygonMode"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glPolygonMode — select a polygon rasterization mode</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">glPolygonMode</b>(</code></td><td>GLenum </td><td><var class="pdparam">face</var>, </td></tr><tr><td> </td><td>GLenum </td><td><var class="pdparam">mode</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>face</code></em></span></dt><dd><p> | |
| 4 | Specifies the polygons that <em class="parameter"><code>mode</code></em> applies to. | |
| 5 | Must be | |
| 6 | <code class="constant">GL_FRONT</code> for front-facing polygons, | |
| 7 | <code class="constant">GL_BACK</code> for back-facing polygons, | |
| 8 | or <code class="constant">GL_FRONT_AND_BACK</code> for front- and back-facing polygons. | |
| 9 | </p></dd><dt><span class="term"><em class="parameter"><code>mode</code></em></span></dt><dd><p> | |
| 10 | Specifies how polygons will be rasterized. | |
| 11 | Accepted values are | |
| 12 | <code class="constant">GL_POINT</code>, | |
| 13 | <code class="constant">GL_LINE</code>, and | |
| 14 | <code class="constant">GL_FILL</code>. | |
| 15 | The initial value is <code class="constant">GL_FILL</code> for both front- and back-facing polygons. | |
| 16 | </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p> | |
| 17 | <code class="function">glPolygonMode</code> controls the interpretation of polygons for rasterization. | |
| 18 | <em class="parameter"><code>face</code></em> describes which polygons <em class="parameter"><code>mode</code></em> applies to: | |
| 19 | front-facing polygons (<code class="constant">GL_FRONT</code>), | |
| 20 | back-facing polygons (<code class="constant">GL_BACK</code>), | |
| 21 | or both (<code class="constant">GL_FRONT_AND_BACK</code>). | |
| 22 | The polygon mode affects only the final rasterization of polygons. | |
| 23 | In particular, | |
| 24 | a polygon's vertices are lit and | |
| 25 | the polygon is clipped and possibly culled before these modes are applied. | |
| 26 | </p><p> | |
| 27 | Three modes are defined and can be specified in <em class="parameter"><code>mode</code></em>: | |
| 28 | </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_POINT</code></span></dt><dd><p> | |
| 29 | Polygon vertices that are marked as the start of a boundary edge | |
| 30 | are drawn as points. | |
| 31 | Point attributes such as | |
| 32 | <code class="constant">GL_POINT_SIZE</code> and | |
| 33 | <code class="constant">GL_POINT_SMOOTH</code> control | |
| 34 | the rasterization of the points. | |
| 35 | Polygon rasterization attributes other than <code class="constant">GL_POLYGON_MODE</code> have no effect. | |
| 36 | </p></dd><dt><span class="term"><code class="constant">GL_LINE</code></span></dt><dd><p> | |
| 37 | Boundary edges of the polygon are drawn as line segments. | |
| 38 | They are treated as connected line segments for line stippling; | |
| 39 | the line stipple counter and pattern are not reset between segments | |
| 40 | (see <a class="citerefentry" href="glLineStipple.xml"><span class="citerefentry"><span class="refentrytitle">glLineStipple</span></span></a>). | |
| 41 | Line attributes such as | |
| 42 | <code class="constant">GL_LINE_WIDTH</code> and | |
| 43 | <code class="constant">GL_LINE_SMOOTH</code> control | |
| 44 | the rasterization of the lines. | |
| 45 | Polygon rasterization attributes other than <code class="constant">GL_POLYGON_MODE</code> have no effect. | |
| 46 | </p></dd><dt><span class="term"><code class="constant">GL_FILL</code></span></dt><dd><p> | |
| 47 | The interior of the polygon is filled. | |
| 48 | Polygon attributes such as | |
| 49 | <code class="constant">GL_POLYGON_STIPPLE</code> and | |
| 50 | <code class="constant">GL_POLYGON_SMOOTH</code> control the rasterization of the polygon. | |
| 51 | </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="examples"></a><h2>Examples</h2><p> | |
| 52 | To draw a surface with filled back-facing polygons | |
| 53 | and outlined front-facing polygons, | |
| 54 | call | |
| 55 | </p><pre class="programlisting"> | |
| 56 | glPolygonMode(<code class="constant">GL_FRONT</code>, <code class="constant">GL_LINE</code>); | |
| 57 | </pre><p> | |
| 58 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p> | |
| 59 | Vertices are marked as boundary or nonboundary with an edge flag. | |
| 60 | Edge flags are generated internally by the GL when it decomposes | |
| 61 | polygons; they can be set explicitly using <a class="citerefentry" href="glEdgeFlag.xml"><span class="citerefentry"><span class="refentrytitle">glEdgeFlag</span></span></a>. | |
| 62 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p> | |
| 63 | <code class="constant">GL_INVALID_ENUM</code> is generated if either <em class="parameter"><code>face</code></em> or <em class="parameter"><code>mode</code></em> is not | |
| 64 | an accepted value. | |
| 65 | </p><p> | |
| 66 | <code class="constant">GL_INVALID_OPERATION</code> is generated if <code class="function">glPolygonMode</code> | |
| 67 | is executed between the execution of <a class="citerefentry" href="glBegin.xml"><span class="citerefentry"><span class="refentrytitle">glBegin</span></span></a> | |
| 68 | and the corresponding execution of <a class="citerefentry" href="glEnd.xml"><span class="citerefentry"><span class="refentrytitle">glEnd</span></span></a>. | |
| 69 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="associatedgets"></a><h2>Associated Gets</h2><p> | |
| 70 | <a class="citerefentry" href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument <code class="constant">GL_POLYGON_MODE</code> | |
| 71 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p> | |
| 72 | <a class="citerefentry" href="glBegin.xml"><span class="citerefentry"><span class="refentrytitle">glBegin</span></span></a>, | |
| 73 | <a class="citerefentry" href="glEdgeFlag.xml"><span class="citerefentry"><span class="refentrytitle">glEdgeFlag</span></span></a>, | |
| 74 | <a class="citerefentry" href="glLineStipple.xml"><span class="citerefentry"><span class="refentrytitle">glLineStipple</span></span></a>, | |
| 75 | <a class="citerefentry" href="glLineWidth.xml"><span class="citerefentry"><span class="refentrytitle">glLineWidth</span></span></a>, | |
| 76 | <a class="citerefentry" href="glPointSize.xml"><span class="citerefentry"><span class="refentrytitle">glPointSize</span></span></a>, | |
| 77 | <a class="citerefentry" href="glPolygonStipple.xml"><span class="citerefentry"><span class="refentrytitle">glPolygonStipple</span></span></a> | |
| 78 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p> | |
| 79 | Copyright <span class="trademark"></span>© 1991-2006 | |
| 80 | Silicon Graphics, Inc. This document is licensed under the SGI | |
| 81 | Free Software B License. For details, see | |
| 82 | <a class="ulink" href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>. | |
| 83 | </p></div></div></body></html> |