upstream-man-pages/man3/xhtml/glBufferData.xml

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   4 <?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" /><link rel="stylesheet" type="text/css" href="opengl-man.css" /><title>glBufferData</title><meta name="generator" content="DocBook XSL Stylesheets V1.69.1" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="glBufferData"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glBufferData — creates and initializes a buffer object's data store</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">glBufferData</b>(</code></td><td>GLenum  </td><td><var class="pdparam">target</var>, </td></tr><tr><td> </td><td>GLsizeiptr  </td><td><var class="pdparam">size</var>, </td></tr><tr><td> </td><td>const GLvoid *  </td><td><var class="pdparam">data</var>, </td></tr><tr><td> </td><td>GLenum  </td><td><var class="pdparam">usage</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>target</code></em></span></dt><dd><p>
   5                     Specifies the target buffer object.
   6                     The symbolic constant must be <code class="constant">GL_ARRAY_BUFFER</code>,
   7                     <code class="constant">GL_COPY_READ_BUFFER</code>,
   8                     <code class="constant">GL_COPY_WRITE_BUFFER</code>,
   9                     <code class="constant">GL_ELEMENT_ARRAY_BUFFER</code>,
  10                     <code class="constant">GL_PIXEL_PACK_BUFFER</code>,
  11                     <code class="constant">GL_PIXEL_UNPACK_BUFFER</code>,
  12                     <code class="constant">GL_TEXTURE_BUFFER</code>,
  13                     <code class="constant">GL_TRANSFORM_FEEDBACK_BUFFER</code>, or
  14                     <code class="constant">GL_UNIFORM_BUFFER</code>.
  15                 </p></dd><dt><span class="term"><em class="parameter"><code>size</code></em></span></dt><dd><p>
  16                     Specifies the size in bytes of the buffer object's new data store.
  17                 </p></dd><dt><span class="term"><em class="parameter"><code>data</code></em></span></dt><dd><p>
  18                     Specifies a pointer to data that will be copied into the data store for initialization,
  19                     or <code class="constant">NULL</code> if no data is to be copied.
  20                 </p></dd><dt><span class="term"><em class="parameter"><code>usage</code></em></span></dt><dd><p>
  21                     Specifies the expected usage pattern of the data store. The symbolic constant must be
  22                     <code class="constant">GL_STREAM_DRAW</code>, <code class="constant">GL_STREAM_READ</code>, <code class="constant">GL_STREAM_COPY</code>,
  23                     <code class="constant">GL_STATIC_DRAW</code>, <code class="constant">GL_STATIC_READ</code>, <code class="constant">GL_STATIC_COPY</code>,
  24                     <code class="constant">GL_DYNAMIC_DRAW</code>, <code class="constant">GL_DYNAMIC_READ</code>, or <code class="constant">GL_DYNAMIC_COPY</code>.
  25                 </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
  26             <code class="function">glBufferData</code> creates a new data store for the buffer object currently bound to
  27             <em class="parameter"><code>target</code></em>. Any pre-existing data store is deleted. The new data store is created with the
  28             specified <em class="parameter"><code>size</code></em> in bytes and <em class="parameter"><code>usage</code></em>. If <em class="parameter"><code>data</code></em>
  29             is not <code class="constant">NULL</code>, the data store is initialized with data from this pointer. In its initial
  30             state, the new data store is not mapped, it has a <code class="constant">NULL</code> mapped pointer, and its mapped access
  31             is <code class="constant">GL_READ_WRITE</code>.
  32         </p><p>
  33             <em class="parameter"><code>usage</code></em> is a hint to the GL implementation as to how a buffer object's data store will be
  34             accessed. This enables the GL implementation to make more intelligent decisions that may significantly
  35             impact buffer object performance. It does not, however, constrain the actual usage of the data store.
  36             <em class="parameter"><code>usage</code></em> can be broken down into two parts: first, the frequency of access (modification
  37             and usage), and second, the nature of that access. The frequency of access may be one of these:
  38         </p><div class="variablelist"><dl><dt><span class="term">STREAM</span></dt><dd><p>
  39                         The data store contents will be modified once and used at most a few times.
  40                     </p></dd><dt><span class="term">STATIC</span></dt><dd><p>
  41                         The data store contents will be modified once and used many times.
  42                     </p></dd><dt><span class="term">DYNAMIC</span></dt><dd><p>
  43                         The data store contents will be modified repeatedly and used many times.
  44                     </p></dd></dl></div><p>
  45             The nature of access may be one of these:
  46         </p><div class="variablelist"><dl><dt><span class="term">DRAW</span></dt><dd><p>
  47                         The data store contents are modified by the application, and used as the source for GL drawing and
  48                         image specification commands.
  49                     </p></dd><dt><span class="term">READ</span></dt><dd><p>
  50                         The data store contents are modified by reading data from the GL, and used to return that data
  51                         when queried by the application.
  52                     </p></dd><dt><span class="term">COPY</span></dt><dd><p>
  53                         The data store contents are modified by reading data from the GL, and used as the source for GL
  54                         drawing and image specification commands.
  55                     </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p>
  56             If <em class="parameter"><code>data</code></em> is <code class="constant">NULL</code>, a data store of the specified size is still created,
  57             but its contents remain uninitialized and thus undefined.
  58         </p><p>
  59             Clients must align data elements consistent with the requirements of the client
  60             platform, with an additional base-level requirement that an offset within a buffer to
  61             a datum comprising <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">N</mml:mi> bytes be a
  62             multiple of <mml:mi mathvariant="italic">N</mml:mi></mml:math>.
  63         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p>
  64             <code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>target</code></em> is not
  65             one of the accepted buffer targets.
  66         </p><p>
  67             <code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>usage</code></em> is not
  68             <code class="constant">GL_STREAM_DRAW</code>, <code class="constant">GL_STREAM_READ</code>, <code class="constant">GL_STREAM_COPY</code>,
  69             <code class="constant">GL_STATIC_DRAW</code>, <code class="constant">GL_STATIC_READ</code>, <code class="constant">GL_STATIC_COPY</code>,
  70             <code class="constant">GL_DYNAMIC_DRAW</code>, <code class="constant">GL_DYNAMIC_READ</code>, or <code class="constant">GL_DYNAMIC_COPY</code>.
  71         </p><p>
  72             <code class="constant">GL_INVALID_VALUE</code> is generated if <em class="parameter"><code>size</code></em> is negative.
  73         </p><p>
  74             <code class="constant">GL_INVALID_OPERATION</code> is generated if the reserved buffer object name 0 is bound to <em class="parameter"><code>target</code></em>.
  75         </p><p>
  76             <code class="constant">GL_OUT_OF_MEMORY</code> is generated if the GL is unable to create a data store with the specified <em class="parameter"><code>size</code></em>.
  77         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="associatedgets"></a><h2>Associated Gets</h2><p>
  78             <a href="glGetBufferSubData.xml"><span class="citerefentry"><span class="refentrytitle">glGetBufferSubData</span></span></a>
  79         </p><p>
  80             <a href="glGetBufferParameter.xml"><span class="citerefentry"><span class="refentrytitle">glGetBufferParameter</span></span></a> with argument <code class="constant">GL_BUFFER_SIZE</code> or <code class="constant">GL_BUFFER_USAGE</code>
  81         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
  82             <a href="glBindBuffer.xml"><span class="citerefentry"><span class="refentrytitle">glBindBuffer</span></span></a>,
  83             <a href="glBufferSubData.xml"><span class="citerefentry"><span class="refentrytitle">glBufferSubData</span></span></a>,
  84             <a href="glMapBuffer.xml"><span class="citerefentry"><span class="refentrytitle">glMapBuffer</span></span></a>,
  85             <a href="glUnmapBuffer.xml"><span class="citerefentry"><span class="refentrytitle">glUnmapBuffer</span></span></a>
  86         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p>
  87             Copyright <span class="trademark"></span>© 2005 Addison-Wesley.
  88             This material may be distributed subject to the terms and conditions set forth in
  89             the Open Publication License, v 1.0, 8 June 1999.
  90             <a href="http://opencontent.org/openpub/" target="_top">http://opencontent.org/openpub/</a>.
  91         </p></div></div></body></html>