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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="glBufferSubData"> | |
5 | <refmeta> | |
6 | <refmetainfo> | |
7 | <copyright> | |
8 | <year>2005</year> | |
9 | <holder>Sams Publishing</holder> | |
10 | </copyright> | |
11 | </refmetainfo> | |
12 | <refentrytitle>glBufferSubData</refentrytitle> | |
13 | <manvolnum>3G</manvolnum> | |
14 | </refmeta> | |
15 | <refnamediv> | |
16 | <refname>glBufferSubData</refname> | |
17 | <refpurpose>updates a subset of a buffer object's data store</refpurpose> | |
18 | </refnamediv> | |
19 | <refsynopsisdiv><title>C Specification</title> | |
20 | <funcsynopsis> | |
21 | <funcprototype> | |
22 | <funcdef>void <function>glBufferSubData</function></funcdef> | |
23 | <paramdef>GLenum <parameter>target</parameter></paramdef> | |
24 | <paramdef>GLintptr <parameter>offset</parameter></paramdef> | |
25 | <paramdef>GLsizeiptr <parameter>size</parameter></paramdef> | |
26 | <paramdef>const GLvoid * <parameter>data</parameter></paramdef> | |
27 | </funcprototype> | |
28 | </funcsynopsis> | |
29 | </refsynopsisdiv> | |
30 | <!-- eqn: ignoring delim $$ --> | |
31 | <refsect1 id="parameters"><title>Parameters</title> | |
32 | <variablelist> | |
33 | <varlistentry> | |
34 | <term><parameter>target</parameter></term> | |
35 | <listitem> | |
36 | <para> | |
37 | Specifies the target buffer object. | |
38 | The symbolic constant must be | |
39 | <constant>GL_ARRAY_BUFFER</constant>, | |
40 | <constant>GL_ATOMIC_COUNTER_BUFFER</constant>, | |
41 | <constant>GL_COPY_READ_BUFFER</constant>, | |
42 | <constant>GL_COPY_WRITE_BUFFER</constant>, | |
43 | <constant>GL_DRAW_INDIRECT_BUFFER</constant>, | |
44 | <constant>GL_DISPATCH_INDIRECT_BUFFER</constant>, | |
45 | <constant>GL_ELEMENT_ARRAY_BUFFER</constant>, | |
46 | <constant>GL_PIXEL_PACK_BUFFER</constant>, | |
47 | <constant>GL_PIXEL_UNPACK_BUFFER</constant>, | |
48 | <constant>GL_SHADER_STORAGE_BUFFER</constant>, | |
49 | <constant>GL_TEXTURE_BUFFER</constant>, | |
50 | <constant>GL_TRANSFORM_FEEDBACK_BUFFER</constant>, or | |
51 | <constant>GL_UNIFORM_BUFFER</constant>. | |
52 | </para> | |
53 | </listitem> | |
54 | </varlistentry> | |
55 | <varlistentry> | |
56 | <term><parameter>offset</parameter></term> | |
57 | <listitem> | |
58 | <para> | |
59 | Specifies the offset into the buffer object's data store where data replacement will begin, | |
60 | measured in bytes. | |
61 | </para> | |
62 | </listitem> | |
63 | </varlistentry> | |
64 | <varlistentry> | |
65 | <term><parameter>size</parameter></term> | |
66 | <listitem> | |
67 | <para> | |
68 | Specifies the size in bytes of the data store region being replaced. | |
69 | </para> | |
70 | </listitem> | |
71 | </varlistentry> | |
72 | <varlistentry> | |
73 | <term><parameter>data</parameter></term> | |
74 | <listitem> | |
75 | <para> | |
76 | Specifies a pointer to the new data that will be copied into the data store. | |
77 | </para> | |
78 | </listitem> | |
79 | </varlistentry> | |
80 | </variablelist> | |
81 | </refsect1> | |
82 | <refsect1 id="description"><title>Description</title> | |
83 | <para> | |
84 | <function>glBufferSubData</function> redefines some or all of the data store for the buffer object currently | |
85 | bound to <parameter>target</parameter>. Data starting at byte offset <parameter>offset</parameter> and | |
86 | extending for <parameter>size</parameter> bytes is copied to the data store from the memory pointed to by | |
87 | <parameter>data</parameter>. An error is thrown if <parameter>offset</parameter> and <parameter>size</parameter> | |
88 | together define a range beyond the bounds of the buffer object's data store. | |
89 | </para> | |
90 | </refsect1> | |
91 | <refsect1 id="notes"><title>Notes</title> | |
92 | <para> | |
93 | When replacing the entire data store, consider using <function>glBufferSubData</function> rather | |
94 | than completely recreating the data store with <function>glBufferData</function>. This avoids the cost of | |
95 | reallocating the data store. | |
96 | </para> | |
97 | <para> | |
98 | Consider using multiple buffer objects to avoid stalling the rendering pipeline during data store updates. | |
99 | If any rendering in the pipeline makes reference to data in the buffer object being updated by | |
100 | <function>glBufferSubData</function>, especially from the specific region being updated, that rendering must | |
101 | drain from the pipeline before the data store can be updated. | |
102 | </para> | |
103 | <para> | |
104 | Clients must align data elements consistent with the requirements of the client | |
105 | platform, with an additional base-level requirement that an offset within a buffer to | |
106 | a datum comprising <inlineequation><mml:math><mml:mi mathvariant="italic">N</mml:mi> bytes be a | |
107 | multiple of <mml:mi mathvariant="italic">N</mml:mi></mml:math></inlineequation>. | |
108 | </para> | |
109 | <para> | |
110 | The <constant>GL_ATOMIC_COUNTER_BUFFER</constant> target is available only if the GL version | |
111 | is 4.2 or greater. | |
112 | </para> | |
113 | <para> | |
114 | The <constant>GL_DISPATCH_INDIRECT_BUFFER</constant> and <constant>GL_SHADER_STORAGE_BUFFER</constant> targets are available only if the GL version | |
115 | is 4.3 or greater. | |
116 | </para> | |
117 | </refsect1> | |
118 | <refsect1 id="errors"><title>Errors</title> | |
119 | <para> | |
120 | <constant>GL_INVALID_ENUM</constant> is generated if <parameter>target</parameter> is not | |
121 | one of the accepted buffer targets. | |
122 | </para> | |
123 | <para> | |
124 | <constant>GL_INVALID_VALUE</constant> is generated if <parameter>offset</parameter> or | |
125 | <parameter>size</parameter> is negative, or if together they define a region of memory | |
126 | that extends beyond the buffer object's allocated data store. | |
127 | </para> | |
128 | <para> | |
129 | <constant>GL_INVALID_OPERATION</constant> is generated if the reserved buffer object name 0 is bound to <parameter>target</parameter>. | |
130 | </para> | |
131 | <para> | |
132 | <constant>GL_INVALID_OPERATION</constant> is generated if the buffer object being updated is mapped. | |
133 | </para> | |
134 | </refsect1> | |
135 | <refsect1 id="associatedgets"><title>Associated Gets</title> | |
136 | <para> | |
137 | <citerefentry><refentrytitle>glGetBufferSubData</refentrytitle></citerefentry> | |
138 | </para> | |
139 | </refsect1> | |
140 | <refsect1 id="seealso"><title>See Also</title> | |
141 | <para> | |
142 | <citerefentry><refentrytitle>glBindBuffer</refentrytitle></citerefentry>, | |
143 | <citerefentry><refentrytitle>glBufferData</refentrytitle></citerefentry>, | |
144 | <citerefentry><refentrytitle>glMapBuffer</refentrytitle></citerefentry>, | |
145 | <citerefentry><refentrytitle>glUnmapBuffer</refentrytitle></citerefentry> | |
146 | </para> | |
147 | </refsect1> | |
148 | <refsect1 id="Copyright"><title>Copyright</title> | |
149 | <para> | |
150 | Copyright <trademark class="copyright"></trademark> 2005 Addison-Wesley. | |
151 | This material may be distributed subject to the terms and conditions set forth in | |
152 | the Open Publication License, v 1.0, 8 June 1999. | |
153 | <ulink url="http://opencontent.org/openpub/">http://opencontent.org/openpub/</ulink>. | |
154 | </para> | |
155 | </refsect1> | |
156 | </refentry> |