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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="glGetVertexAttrib"> | |
5 | <refmeta> | |
6 | <refentrytitle>glGetVertexAttrib</refentrytitle> | |
7 | <manvolnum>3G</manvolnum> | |
8 | </refmeta> | |
9 | <refnamediv> | |
10 | <refdescriptor>glGetVertexAttrib</refdescriptor> | |
11 | <refname>glGetVertexAttribdv</refname> | |
12 | <refname>glGetVertexAttribfv</refname> | |
13 | <refname>glGetVertexAttribiv</refname> | |
14 | <refname>glGetVertexAttribIiv</refname> | |
15 | <refname>glGetVertexAttribIuiv</refname> | |
16 | <refname>glGetVertexAttribLdv</refname> | |
17 | <refpurpose>Return a generic vertex attribute parameter</refpurpose> | |
18 | </refnamediv> | |
19 | <refsynopsisdiv><title>C Specification</title> | |
20 | <funcsynopsis> | |
21 | <funcprototype> | |
22 | <funcdef>void <function>glGetVertexAttribdv</function></funcdef> | |
23 | <paramdef>GLuint <parameter>index</parameter></paramdef> | |
24 | <paramdef>GLenum <parameter>pname</parameter></paramdef> | |
25 | <paramdef>GLdouble *<parameter>params</parameter></paramdef> | |
26 | </funcprototype> | |
27 | <funcprototype> | |
28 | <funcdef>void <function>glGetVertexAttribfv</function></funcdef> | |
29 | <paramdef>GLuint <parameter>index</parameter></paramdef> | |
30 | <paramdef>GLenum <parameter>pname</parameter></paramdef> | |
31 | <paramdef>GLfloat *<parameter>params</parameter></paramdef> | |
32 | </funcprototype> | |
33 | <funcprototype> | |
34 | <funcdef>void <function>glGetVertexAttribiv</function></funcdef> | |
35 | <paramdef>GLuint <parameter>index</parameter></paramdef> | |
36 | <paramdef>GLenum <parameter>pname</parameter></paramdef> | |
37 | <paramdef>GLint *<parameter>params</parameter></paramdef> | |
38 | </funcprototype> | |
39 | <funcprototype> | |
40 | <funcdef>void <function>glGetVertexAttribIiv</function></funcdef> | |
41 | <paramdef>GLuint <parameter>index</parameter></paramdef> | |
42 | <paramdef>GLenum <parameter>pname</parameter></paramdef> | |
43 | <paramdef>GLint *<parameter>params</parameter></paramdef> | |
44 | </funcprototype> | |
45 | <funcprototype> | |
46 | <funcdef>void <function>glGetVertexAttribIuiv</function></funcdef> | |
47 | <paramdef>GLuint <parameter>index</parameter></paramdef> | |
48 | <paramdef>GLenum <parameter>pname</parameter></paramdef> | |
49 | <paramdef>GLuint *<parameter>params</parameter></paramdef> | |
50 | </funcprototype> | |
51 | <funcprototype> | |
52 | <funcdef>void <function>glGetVertexAttribLdv</function></funcdef> | |
53 | <paramdef>GLuint <parameter>index</parameter></paramdef> | |
54 | <paramdef>GLenum <parameter>pname</parameter></paramdef> | |
55 | <paramdef>GLdouble *<parameter>params</parameter></paramdef> | |
56 | </funcprototype> | |
57 | </funcsynopsis> | |
58 | </refsynopsisdiv> | |
59 | <refsect1 id="parameters"><title>Parameters</title> | |
60 | <variablelist> | |
61 | <varlistentry> | |
62 | <term><parameter>index</parameter></term> | |
63 | <listitem> | |
64 | <para>Specifies the generic vertex attribute | |
65 | parameter to be queried.</para> | |
66 | </listitem> | |
67 | </varlistentry> | |
68 | <varlistentry> | |
69 | <term><parameter>pname</parameter></term> | |
70 | <listitem> | |
71 | <para>Specifies the symbolic name of the vertex | |
72 | attribute parameter to be queried. Accepted values are | |
73 | <constant>GL_VERTEX_ATTRIB_ARRAY_BUFFER_BINDING</constant>, | |
74 | <constant>GL_VERTEX_ATTRIB_ARRAY_ENABLED</constant>, | |
75 | <constant>GL_VERTEX_ATTRIB_ARRAY_SIZE</constant>, | |
76 | <constant>GL_VERTEX_ATTRIB_ARRAY_STRIDE</constant>, | |
77 | <constant>GL_VERTEX_ATTRIB_ARRAY_TYPE</constant>, | |
78 | <constant>GL_VERTEX_ATTRIB_ARRAY_NORMALIZED</constant>, | |
79 | <constant>GL_VERTEX_ATTRIB_ARRAY_INTEGER</constant>, | |
80 | <constant>GL_VERTEX_ATTRIB_ARRAY_DIVISOR</constant>, or | |
81 | <constant>GL_CURRENT_VERTEX_ATTRIB</constant>.</para> | |
82 | </listitem> | |
83 | </varlistentry> | |
84 | <varlistentry> | |
85 | <term><parameter>params</parameter></term> | |
86 | <listitem> | |
87 | <para>Returns the requested data.</para> | |
88 | </listitem> | |
89 | </varlistentry> | |
90 | </variablelist> | |
91 | </refsect1> | |
92 | <refsect1 id="description"><title>Description</title> | |
93 | <para><function>glGetVertexAttrib</function> returns in | |
94 | <parameter>params</parameter> the value of a generic vertex | |
95 | attribute parameter. The generic vertex attribute to be queried | |
96 | is specified by <parameter>index</parameter>, and the parameter | |
97 | to be queried is specified by <parameter>pname</parameter>.</para> | |
98 | ||
99 | <para>The accepted parameter names are as follows:</para> | |
100 | ||
101 | <variablelist> | |
102 | <varlistentry> | |
103 | <term><constant>GL_VERTEX_ATTRIB_ARRAY_BUFFER_BINDING</constant></term> | |
104 | <listitem> | |
105 | <para> | |
106 | </para> | |
107 | <para> <parameter>params</parameter> returns a | |
108 | single value, the name of the buffer object currently bound to | |
109 | the binding point corresponding to generic vertex attribute array | |
110 | <parameter>index</parameter>. If no buffer object is bound, | |
111 | 0 is returned. The initial value is 0.</para> | |
112 | </listitem> | |
113 | </varlistentry> | |
114 | ||
115 | <varlistentry> | |
116 | <term><constant>GL_VERTEX_ATTRIB_ARRAY_ENABLED</constant></term> | |
117 | <listitem> | |
118 | <para> | |
119 | </para> | |
120 | <para> <parameter>params</parameter> returns a | |
121 | single value that is non-zero (true) if the vertex | |
122 | attribute array for <parameter>index</parameter> is | |
123 | enabled and 0 (false) if it is disabled. The initial | |
124 | value is <constant>GL_FALSE</constant>.</para> | |
125 | </listitem> | |
126 | </varlistentry> | |
127 | ||
128 | <varlistentry> | |
129 | <term><constant>GL_VERTEX_ATTRIB_ARRAY_SIZE</constant></term> | |
130 | <listitem> | |
131 | <para> | |
132 | </para> | |
133 | <para> <parameter>params</parameter> returns a | |
134 | single value, the size of the vertex attribute array | |
135 | for <parameter>index</parameter>. The size is the | |
136 | number of values for each element of the vertex | |
137 | attribute array, and it will be 1, 2, 3, or 4. The | |
138 | initial value is 4.</para> | |
139 | </listitem> | |
140 | </varlistentry> | |
141 | ||
142 | <varlistentry> | |
143 | <term><constant>GL_VERTEX_ATTRIB_ARRAY_STRIDE</constant></term> | |
144 | <listitem> | |
145 | <para> | |
146 | </para> | |
147 | <para> <parameter>params</parameter> returns a | |
148 | single value, the array stride for (number of bytes | |
149 | between successive elements in) the vertex attribute | |
150 | array for <parameter>index</parameter>. A value of 0 | |
151 | indicates that the array elements are stored | |
152 | sequentially in memory. The initial value is 0.</para> | |
153 | </listitem> | |
154 | </varlistentry> | |
155 | ||
156 | <varlistentry> | |
157 | <term><constant>GL_VERTEX_ATTRIB_ARRAY_TYPE</constant></term> | |
158 | <listitem> | |
159 | <para> | |
160 | </para> | |
161 | <para> <parameter>params</parameter> returns a | |
162 | single value, a symbolic constant indicating the | |
163 | array type for the vertex attribute array for | |
164 | <parameter>index</parameter>. Possible values are | |
165 | <constant>GL_BYTE</constant>, | |
166 | <constant>GL_UNSIGNED_BYTE</constant>, | |
167 | <constant>GL_SHORT</constant>, | |
168 | <constant>GL_UNSIGNED_SHORT</constant>, | |
169 | <constant>GL_INT</constant>, | |
170 | <constant>GL_UNSIGNED_INT</constant>, | |
171 | <constant>GL_FLOAT</constant>, and | |
172 | <constant>GL_DOUBLE</constant>. The initial value is | |
173 | <constant>GL_FLOAT</constant>.</para> | |
174 | </listitem> | |
175 | </varlistentry> | |
176 | ||
177 | <varlistentry> | |
178 | <term><constant>GL_VERTEX_ATTRIB_ARRAY_NORMALIZED</constant></term> | |
179 | <listitem> | |
180 | <para> | |
181 | </para> | |
182 | <para> <parameter>params</parameter> returns a | |
183 | single value that is non-zero (true) if fixed-point | |
184 | data types for the vertex attribute array indicated | |
185 | by <parameter>index</parameter> are normalized when | |
186 | they are converted to floating point, and 0 (false) | |
187 | otherwise. The initial value is | |
188 | <constant>GL_FALSE</constant>.</para> | |
189 | </listitem> | |
190 | </varlistentry> | |
191 | ||
192 | <varlistentry> | |
193 | <term><constant>GL_VERTEX_ATTRIB_ARRAY_INTEGER</constant></term> | |
194 | <listitem> | |
195 | <para> | |
196 | </para> | |
197 | <para> <parameter>params</parameter> returns a | |
198 | single value that is non-zero (true) if fixed-point | |
199 | data types for the vertex attribute array indicated | |
200 | by <parameter>index</parameter> have integer data types, and 0 (false) | |
201 | otherwise. The initial value is | |
202 | 0 (<constant>GL_FALSE</constant>).</para> | |
203 | </listitem> | |
204 | </varlistentry> | |
205 | ||
206 | <varlistentry> | |
207 | <term><constant>GL_VERTEX_ATTRIB_ARRAY_DIVISOR</constant></term> | |
208 | <listitem> | |
209 | <para> | |
210 | </para> | |
211 | <para> <parameter>params</parameter> returns a | |
212 | single value that is the frequency divisor used for instanced | |
213 | rendering. See <citerefentry><refentrytitle>glVertexAttribDivisor</refentrytitle></citerefentry>. | |
214 | The initial value is 0.</para> | |
215 | </listitem> | |
216 | </varlistentry> | |
217 | ||
218 | <varlistentry> | |
219 | <term><constant>GL_CURRENT_VERTEX_ATTRIB</constant></term> | |
220 | <listitem> | |
221 | <para> | |
222 | </para> | |
223 | <para> <parameter>params</parameter> returns four | |
224 | values that represent the current value for the | |
225 | generic vertex attribute specified by index. Generic | |
226 | vertex attribute 0 is unique in that it has no | |
227 | current state, so an error will be generated if | |
228 | <parameter>index</parameter> is 0. The initial value | |
229 | for all other generic vertex attributes is | |
230 | (0,0,0,1).</para> | |
231 | <para> | |
232 | <function>glGetVertexAttribdv</function> and <function>glGetVertexAttribfv</function> | |
233 | return the current attribute values as four single-precision floating-point values; | |
234 | <function>glGetVertexAttribiv</function> reads them as floating-point values and | |
235 | converts them to four integer values; <function>glGetVertexAttribIiv</function> and | |
236 | <function>glGetVertexAttribIuiv</function> read and return them as signed or unsigned | |
237 | integer values, respectively; <function>glGetVertexAttribLdv</function> reads and returns | |
238 | them as four double-precision floating-point values. | |
239 | </para> | |
240 | </listitem> | |
241 | </varlistentry> | |
242 | </variablelist> | |
243 | ||
244 | <para>All of the parameters except <constant>GL_CURRENT_VERTEX_ATTRIB</constant> | |
245 | represent state stored in the currently bound vertex array object.</para> | |
246 | ||
247 | </refsect1> | |
248 | <refsect1 id="notes"><title>Notes</title> | |
249 | <para>If an error is generated, no change is made to the | |
250 | contents of <parameter>params</parameter>.</para> | |
251 | </refsect1> | |
252 | <refsect1 id="errors"><title>Errors</title> | |
253 | <para><constant>GL_INVALID_OPERATION</constant> is generated if <parameter>pname</parameter> | |
254 | is not <constant>GL_CURRENT_VERTEX_ATTRIB</constant> and there is no | |
255 | currently bound vertex array object.</para> | |
256 | ||
257 | <para><constant>GL_INVALID_VALUE</constant> is generated if | |
258 | <parameter>index</parameter> is greater than or equal to | |
259 | <constant>GL_MAX_VERTEX_ATTRIBS</constant>.</para> | |
260 | ||
261 | <para><constant>GL_INVALID_ENUM</constant> is generated if | |
262 | <parameter>pname</parameter> is not an accepted value.</para> | |
263 | ||
264 | <para><constant>GL_INVALID_OPERATION</constant> is generated if | |
265 | <parameter>index</parameter> is 0 and | |
266 | <parameter>pname</parameter> is | |
267 | <constant>GL_CURRENT_VERTEX_ATTRIB</constant>.</para> | |
268 | </refsect1> | |
269 | <refsect1 id="associatedgets"><title>Associated Gets</title> | |
270 | <para><citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> | |
271 | with argument <constant>GL_MAX_VERTEX_ATTRIBS</constant></para> | |
272 | ||
273 | <para><citerefentry><refentrytitle>glGetVertexAttribPointerv</refentrytitle></citerefentry> | |
274 | with arguments <parameter>index</parameter> and | |
275 | <constant>GL_VERTEX_ATTRIB_ARRAY_POINTER</constant></para> | |
276 | </refsect1> | |
277 | <refsect1 id="seealso"><title>See Also</title> | |
278 | <para><citerefentry><refentrytitle>glBindAttribLocation</refentrytitle></citerefentry>, | |
279 | <citerefentry><refentrytitle>glBindBuffer</refentrytitle></citerefentry>, | |
280 | <citerefentry><refentrytitle>glDisableVertexAttribArray</refentrytitle></citerefentry>, | |
281 | <citerefentry><refentrytitle>glEnableVertexAttribArray</refentrytitle></citerefentry>, | |
282 | <citerefentry><refentrytitle>glVertexAttrib</refentrytitle></citerefentry>, | |
283 | <citerefentry><refentrytitle>glVertexAttribDivisor</refentrytitle></citerefentry>, | |
284 | <citerefentry><refentrytitle>glVertexAttribPointer</refentrytitle></citerefentry></para> | |
285 | </refsect1> | |
286 | <refsect1 id="Copyright"><title>Copyright</title> | |
287 | <para> | |
288 | Copyright <trademark class="copyright"></trademark> 2003-2005 3Dlabs Inc. Ltd. | |
289 | Copyright <trademark class="copyright"></trademark> 2010 Khronos Group. | |
290 | This material may be distributed subject to the terms and conditions set forth in | |
291 | the Open Publication License, v 1.0, 8 June 1999. | |
292 | <ulink url="http://opencontent.org/openpub/">http://opencontent.org/openpub/</ulink>. | |
293 | </para> | |
294 | </refsect1> | |
295 | </refentry> |