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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="glRenderMode"> | |
5 | <refmeta> | |
6 | <refmetainfo> | |
7 | <copyright> | |
8 | <year>1991-2006</year> | |
9 | <holder>Silicon Graphics, Inc.</holder> | |
10 | </copyright> | |
11 | </refmetainfo> | |
12 | <refentrytitle>glRenderMode</refentrytitle> | |
13 | <manvolnum>3G</manvolnum> | |
14 | </refmeta> | |
15 | <refnamediv> | |
16 | <refname>glRenderMode</refname> | |
17 | <refpurpose>set rasterization mode</refpurpose> | |
18 | </refnamediv> | |
19 | <refsynopsisdiv><title>C Specification</title> | |
20 | <funcsynopsis> | |
21 | <funcprototype> | |
22 | <funcdef>GLint <function>glRenderMode</function></funcdef> | |
23 | <paramdef>GLenum <parameter>mode</parameter></paramdef> | |
24 | </funcprototype> | |
25 | </funcsynopsis> | |
26 | </refsynopsisdiv> | |
27 | <refsect1 id="parameters"><title>Parameters</title> | |
28 | <variablelist> | |
29 | <varlistentry> | |
30 | <term><parameter>mode</parameter></term> | |
31 | <listitem> | |
32 | <para> | |
33 | Specifies the rasterization mode. | |
34 | Three values are accepted: | |
35 | <constant>GL_RENDER</constant>, | |
36 | <constant>GL_SELECT</constant>, and | |
37 | <constant>GL_FEEDBACK</constant>. | |
38 | The initial value is <constant>GL_RENDER</constant>. | |
39 | </para> | |
40 | </listitem> | |
41 | </varlistentry> | |
42 | </variablelist> | |
43 | </refsect1> | |
44 | <refsect1 id="description"><title>Description</title> | |
45 | <para> | |
46 | <function>glRenderMode</function> sets the rasterization mode. | |
47 | It takes one argument, | |
48 | <parameter>mode</parameter>, | |
49 | which can assume one of three predefined values: | |
50 | </para> | |
51 | <variablelist> | |
52 | <varlistentry> | |
53 | <term><constant>GL_RENDER</constant></term> | |
54 | <listitem> | |
55 | <para> | |
56 | Render mode. Primitives are rasterized, | |
57 | producing pixel fragments, | |
58 | which are written into the frame buffer. | |
59 | This is the normal mode | |
60 | and also the default mode. | |
61 | </para> | |
62 | </listitem> | |
63 | </varlistentry> | |
64 | <varlistentry> | |
65 | <term><constant>GL_SELECT</constant></term> | |
66 | <listitem> | |
67 | <para> | |
68 | Selection mode. | |
69 | No pixel fragments are produced, | |
70 | and no change to the frame buffer contents is made. | |
71 | Instead, | |
72 | a record of the names of primitives that would have been drawn | |
73 | if the render mode had been <constant>GL_RENDER</constant> is returned in a select buffer, | |
74 | which must be created (see <citerefentry><refentrytitle>glSelectBuffer</refentrytitle></citerefentry>) before selection mode | |
75 | is entered. | |
76 | </para> | |
77 | </listitem> | |
78 | </varlistentry> | |
79 | <varlistentry> | |
80 | <term><constant>GL_FEEDBACK</constant></term> | |
81 | <listitem> | |
82 | <para> | |
83 | Feedback mode. | |
84 | No pixel fragments are produced, | |
85 | and no change to the frame buffer contents is made. | |
86 | Instead, | |
87 | the coordinates and attributes of vertices that would have been drawn | |
88 | if the render mode had been <constant>GL_RENDER</constant> is returned in a feedback buffer, | |
89 | which must be created (see <citerefentry><refentrytitle>glFeedbackBuffer</refentrytitle></citerefentry>) before feedback mode | |
90 | is entered. | |
91 | </para> | |
92 | </listitem> | |
93 | </varlistentry> | |
94 | </variablelist> | |
95 | <para> | |
96 | The return value of <function>glRenderMode</function> is determined by the render mode at the time | |
97 | <function>glRenderMode</function> is called, | |
98 | rather than by <parameter>mode</parameter>. | |
99 | The values returned for the three render modes are as follows: | |
100 | </para> | |
101 | <variablelist> | |
102 | <varlistentry> | |
103 | <term><constant>GL_RENDER</constant></term> | |
104 | <listitem> | |
105 | <para> | |
106 | 0. | |
107 | </para> | |
108 | </listitem> | |
109 | </varlistentry> | |
110 | <varlistentry> | |
111 | <term><constant>GL_SELECT</constant></term> | |
112 | <listitem> | |
113 | <para> | |
114 | The number of hit records transferred to the select buffer. | |
115 | </para> | |
116 | </listitem> | |
117 | </varlistentry> | |
118 | <varlistentry> | |
119 | <term><constant>GL_FEEDBACK</constant></term> | |
120 | <listitem> | |
121 | <para> | |
122 | The number of values (not vertices) transferred to the feedback buffer. | |
123 | </para> | |
124 | </listitem> | |
125 | </varlistentry> | |
126 | </variablelist> | |
127 | <para> | |
128 | See the <citerefentry><refentrytitle>glSelectBuffer</refentrytitle></citerefentry> and <citerefentry><refentrytitle>glFeedbackBuffer</refentrytitle></citerefentry> reference pages for | |
129 | more details concerning selection and feedback operation. | |
130 | </para> | |
131 | </refsect1> | |
132 | <refsect1 id="notes"><title>Notes</title> | |
133 | <para> | |
134 | If an error is generated, | |
135 | <function>glRenderMode</function> returns 0 regardless of the current render mode. | |
136 | </para> | |
137 | </refsect1> | |
138 | <refsect1 id="errors"><title>Errors</title> | |
139 | <para> | |
140 | <constant>GL_INVALID_ENUM</constant> is generated if <parameter>mode</parameter> is not one of the three | |
141 | accepted values. | |
142 | </para> | |
143 | <para> | |
144 | <constant>GL_INVALID_OPERATION</constant> is generated if <citerefentry><refentrytitle>glSelectBuffer</refentrytitle></citerefentry> is called | |
145 | while the render mode is <constant>GL_SELECT</constant>, | |
146 | or if <function>glRenderMode</function> is called with argument <constant>GL_SELECT</constant> before | |
147 | <citerefentry><refentrytitle>glSelectBuffer</refentrytitle></citerefentry> is called at least once. | |
148 | </para> | |
149 | <para> | |
150 | <constant>GL_INVALID_OPERATION</constant> is generated if <citerefentry><refentrytitle>glFeedbackBuffer</refentrytitle></citerefentry> is called | |
151 | while the render mode is <constant>GL_FEEDBACK</constant>, | |
152 | or if <function>glRenderMode</function> is called with argument <constant>GL_FEEDBACK</constant> before | |
153 | <citerefentry><refentrytitle>glFeedbackBuffer</refentrytitle></citerefentry> is called at least once. | |
154 | </para> | |
155 | <para> | |
156 | <constant>GL_INVALID_OPERATION</constant> is generated if <function>glRenderMode</function> | |
157 | is executed between the execution of <citerefentry><refentrytitle>glBegin</refentrytitle></citerefentry> | |
158 | and the corresponding execution of <citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry>. | |
159 | </para> | |
160 | </refsect1> | |
161 | <refsect1 id="associatedgets"><title>Associated Gets</title> | |
162 | <para> | |
163 | <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_RENDER_MODE</constant> | |
164 | </para> | |
165 | </refsect1> | |
166 | <refsect1 id="seealso"><title>See Also</title> | |
167 | <para> | |
168 | <citerefentry><refentrytitle>glFeedbackBuffer</refentrytitle></citerefentry>, | |
169 | <citerefentry><refentrytitle>glInitNames</refentrytitle></citerefentry>, | |
170 | <citerefentry><refentrytitle>glLoadName</refentrytitle></citerefentry>, | |
171 | <citerefentry><refentrytitle>glPassThrough</refentrytitle></citerefentry>, | |
172 | <citerefentry><refentrytitle>glPushName</refentrytitle></citerefentry>, | |
173 | <citerefentry><refentrytitle>glSelectBuffer</refentrytitle></citerefentry> | |
174 | </para> | |
175 | </refsect1> | |
176 | <refsect1 id="Copyright"><title>Copyright</title> | |
177 | <para> | |
178 | Copyright <trademark class="copyright"></trademark> 1991-2006 | |
179 | Silicon Graphics, Inc. This document is licensed under the SGI | |
180 | Free Software B License. For details, see | |
181 | <ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>. | |
182 | </para> | |
183 | </refsect1> | |
184 | </refentry> |