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1 | <?xml version="1.0" encoding="UTF-8"?> |
2 | <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN" | |
3 | "http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd"> | |
4 | <refentry id="glPolygonMode"> | |
5 | <refmeta> | |
6 | <refmetainfo> | |
7 | <copyright> | |
8 | <year>1991-2006</year> | |
9 | <holder>Silicon Graphics, Inc.</holder> | |
10 | </copyright> | |
11 | </refmetainfo> | |
12 | <refentrytitle>glPolygonMode</refentrytitle> | |
13 | <manvolnum>3G</manvolnum> | |
14 | </refmeta> | |
15 | <refnamediv> | |
16 | <refname>glPolygonMode</refname> | |
17 | <refpurpose>select a polygon rasterization mode</refpurpose> | |
18 | </refnamediv> | |
19 | <refsynopsisdiv><title>C Specification</title> | |
20 | <funcsynopsis> | |
21 | <funcprototype> | |
22 | <funcdef>void <function>glPolygonMode</function></funcdef> | |
23 | <paramdef>GLenum <parameter>face</parameter></paramdef> | |
24 | <paramdef>GLenum <parameter>mode</parameter></paramdef> | |
25 | </funcprototype> | |
26 | </funcsynopsis> | |
27 | </refsynopsisdiv> | |
28 | <refsect1 id="parameters"><title>Parameters</title> | |
29 | <variablelist> | |
30 | <varlistentry> | |
31 | <term><parameter>face</parameter></term> | |
32 | <listitem> | |
33 | <para> | |
34 | Specifies the polygons that <parameter>mode</parameter> applies to. | |
35 | Must be <constant>GL_FRONT_AND_BACK</constant> for front- and back-facing polygons. | |
36 | </para> | |
37 | </listitem> | |
38 | </varlistentry> | |
39 | <varlistentry> | |
40 | <term><parameter>mode</parameter></term> | |
41 | <listitem> | |
42 | <para> | |
43 | Specifies how polygons will be rasterized. | |
44 | Accepted values are | |
45 | <constant>GL_POINT</constant>, | |
46 | <constant>GL_LINE</constant>, and | |
47 | <constant>GL_FILL</constant>. | |
48 | The initial value is <constant>GL_FILL</constant> for both front- and back-facing polygons. | |
49 | </para> | |
50 | </listitem> | |
51 | </varlistentry> | |
52 | </variablelist> | |
53 | </refsect1> | |
54 | <refsect1 id="description"><title>Description</title> | |
55 | <para> | |
56 | <function>glPolygonMode</function> controls the interpretation of polygons for rasterization. | |
57 | <parameter>face</parameter> describes which polygons <parameter>mode</parameter> applies to: | |
58 | both front and back-facing polygons (<constant>GL_FRONT_AND_BACK</constant>). | |
59 | The polygon mode affects only the final rasterization of polygons. | |
60 | In particular, | |
61 | a polygon's vertices are lit and | |
62 | the polygon is clipped and possibly culled before these modes are applied. | |
63 | </para> | |
64 | <para> | |
65 | Three modes are defined and can be specified in <parameter>mode</parameter>: | |
66 | </para> | |
67 | <variablelist> | |
68 | <varlistentry> | |
69 | <term><constant>GL_POINT</constant></term> | |
70 | <listitem> | |
71 | <para> | |
72 | Polygon vertices that are marked as the start of a boundary edge | |
73 | are drawn as points. | |
74 | Point attributes such as | |
75 | <constant>GL_POINT_SIZE</constant> and | |
76 | <constant>GL_POINT_SMOOTH</constant> control | |
77 | the rasterization of the points. | |
78 | Polygon rasterization attributes other than <constant>GL_POLYGON_MODE</constant> have no effect. | |
79 | </para> | |
80 | </listitem> | |
81 | </varlistentry> | |
82 | <varlistentry> | |
83 | <term><constant>GL_LINE</constant></term> | |
84 | <listitem> | |
85 | <para> | |
86 | Boundary edges of the polygon are drawn as line segments. | |
87 | Line attributes such as | |
88 | <constant>GL_LINE_WIDTH</constant> and | |
89 | <constant>GL_LINE_SMOOTH</constant> control | |
90 | the rasterization of the lines. | |
91 | Polygon rasterization attributes other than <constant>GL_POLYGON_MODE</constant> have no effect. | |
92 | </para> | |
93 | </listitem> | |
94 | </varlistentry> | |
95 | <varlistentry> | |
96 | <term><constant>GL_FILL</constant></term> | |
97 | <listitem> | |
98 | <para> | |
99 | The interior of the polygon is filled. | |
100 | Polygon attributes such as <constant>GL_POLYGON_SMOOTH</constant> control the rasterization of the polygon. | |
101 | </para> | |
102 | </listitem> | |
103 | </varlistentry> | |
104 | </variablelist> | |
105 | </refsect1> | |
106 | <refsect1 id="examples"><title>Examples</title> | |
107 | <para> | |
108 | To draw a surface with outlined polygons, | |
109 | call | |
110 | <programlisting> | |
111 | glPolygonMode(<constant>GL_FRONT_AND_BACK</constant>, <constant>GL_LINE</constant>); | |
112 | </programlisting> | |
113 | </para> | |
114 | </refsect1> | |
115 | <refsect1 id="notes"><title>Notes</title> | |
116 | <para> | |
117 | Vertices are marked as boundary or nonboundary with an edge flag. | |
118 | Edge flags are generated internally by the GL when it decomposes | |
119 | triangle stips and fans. | |
120 | </para> | |
121 | </refsect1> | |
122 | <refsect1 id="errors"><title>Errors</title> | |
123 | <para> | |
124 | <constant>GL_INVALID_ENUM</constant> is generated if either <parameter>face</parameter> or <parameter>mode</parameter> is not | |
125 | an accepted value. | |
126 | </para> | |
127 | </refsect1> | |
128 | <refsect1 id="associatedgets"><title>Associated Gets</title> | |
129 | <para> | |
130 | <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_POLYGON_MODE</constant> | |
131 | </para> | |
132 | </refsect1> | |
133 | <refsect1 id="seealso"><title>See Also</title> | |
134 | <para> | |
135 | <citerefentry><refentrytitle>glLineWidth</refentrytitle></citerefentry>, | |
136 | <citerefentry><refentrytitle>glPointSize</refentrytitle></citerefentry> | |
137 | </para> | |
138 | </refsect1> | |
139 | <refsect1 id="Copyright"><title>Copyright</title> | |
140 | <para> | |
141 | Copyright <trademark class="copyright"></trademark> 1991-2006 | |
142 | Silicon Graphics, Inc. This document is licensed under the SGI | |
143 | Free Software B License. For details, see | |
144 | <ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>. | |
145 | </para> | |
146 | </refsect1> | |
147 | </refentry> |