upstream-man-pages/man3/glBlitFramebuffer.xml

   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="glBindVertexArray">
   5     <refmeta>
   6         <refmetainfo>
   7             <copyright>
   8                 <year>2010</year>
   9                 <holder>Khronos Group</holder>
  10             </copyright>
  11         </refmetainfo>
  12         <refentrytitle>glBlitFramebuffer</refentrytitle>
  13         <manvolnum>3G</manvolnum>
  14     </refmeta>
  15     <refnamediv>
  16         <refname>glBlitFramebuffer</refname>
  17         <refpurpose>copy a block of pixels from the read framebuffer to the draw framebuffer</refpurpose>
  18     </refnamediv>
  19     <refsynopsisdiv><title>C Specification</title>
  20         <funcsynopsis>
  21             <funcprototype>
  22                 <funcdef>void <function>glBlitFramebuffer</function></funcdef>
  23                 <paramdef>GLint <parameter>srcX0</parameter></paramdef>
  24                 <paramdef>GLint <parameter>srcY0</parameter></paramdef>
  25                 <paramdef>GLint <parameter>srcX1</parameter></paramdef>
  26                 <paramdef>GLint <parameter>srcY1</parameter></paramdef>
  27                 <paramdef>GLint <parameter>dstX0</parameter></paramdef>
  28                 <paramdef>GLint <parameter>dstY0</parameter></paramdef>
  29                 <paramdef>GLint <parameter>dstX1</parameter></paramdef>
  30                 <paramdef>GLint <parameter>dstY1</parameter></paramdef>
  31                 <paramdef>GLbitfield <parameter>mask</parameter></paramdef>
  32                 <paramdef>GLenum <parameter>filter</parameter></paramdef>
  33             </funcprototype>
  34         </funcsynopsis>
  35     </refsynopsisdiv>
  36     <refsect1 id="parameters"><title>Parameters</title>
  37         <variablelist>
  38         <varlistentry>
  39             <term><parameter>srcX0</parameter></term>
  40             <term><parameter>srcY0</parameter></term>
  41             <term><parameter>srcX1</parameter></term>
  42             <term><parameter>srcY1</parameter></term>
  43             <listitem>
  44                 <para>
  45                     Specify the bounds of the source rectangle within the read buffer of the read framebuffer.
  46                 </para>
  47             </listitem>
  48         </varlistentry>
  49         <varlistentry>
  50             <term><parameter>dstX0</parameter></term>
  51             <term><parameter>dstY0</parameter></term>
  52             <term><parameter>dstX1</parameter></term>
  53             <term><parameter>dstY1</parameter></term>
  54             <listitem>
  55                 <para>
  56                     Specify the bounds of the destination rectangle within the write buffer of the write framebuffer.
  57                 </para>
  58             </listitem>
  59         </varlistentry>
  60         <varlistentry>
  61             <term><parameter>mask</parameter></term>
  62             <listitem>
  63                 <para>
  64                     The bitwise OR of the flags indicating which buffers are to be copied. The allowed flags are
  65                     <constant>GL_COLOR_BUFFER_BIT</constant>, <constant>GL_DEPTH_BUFFER_BIT</constant> and <constant>GL_STENCIL_BUFFER_BIT</constant>.
  66                 </para>
  67             </listitem>
  68         </varlistentry>
  69         <varlistentry>
  70             <term><parameter>filter</parameter></term>
  71             <listitem>
  72                 <para>
  73                     Specifies the interpolation to be applied if the image is stretched. Must be <constant>GL_NEAREST</constant> or <constant>GL_LINEAR</constant>.
  74                 </para>
  75             </listitem>
  76         </varlistentry>
  77         </variablelist>
  78     </refsect1>
  79     <refsect1 id="description"><title>Description</title>
  80         <para>
  81             <function>glBlitFramebuffer</function> transfers a rectangle of pixel values from one region of the read framebuffer to another region in
  82             the draw framebuffer. <parameter>mask</parameter> is the bitwise OR of a number of values indicating which buffers are
  83             to be copied. The values are <constant>GL_COLOR_BUFFER_BIT</constant>, <constant>GL_DEPTH_BUFFER_BIT</constant>, and
  84             <constant>GL_STENCIL_BUFFER_BIT</constant>. The pixels corresponding to these buffers are copied from the source rectangle bounded by the
  85             locations (<parameter>srcX0</parameter>; <parameter>srcY0</parameter>) and (<parameter>srcX1</parameter>; <parameter>srcY1</parameter>)
  86             to the destination rectangle bounded by the locations (<parameter>dstX0</parameter>; <parameter>dstY0</parameter>) and
  87             (<parameter>dstX1</parameter>; <parameter>dstY1</parameter>). The lower bounds of the rectangle are inclusive, while the upper
  88             bounds are exclusive.
  89         </para>
  90         <para>
  91             The actual region taken from the read framebuffer is limited to the intersection of the source buffers being transferred, which may
  92             include the color buffer selected by the read buffer, the depth buffer, and/or the stencil buffer depending on mask. The actual region
  93             written to the draw framebuffer is limited to the intersection of the destination buffers being written, which may include multiple draw
  94             buffers, the depth buffer, and/or the stencil buffer depending on mask. Whether or not the source or destination regions are altered due
  95             to these limits, the scaling and offset applied to pixels being transferred is performed as though no such limits were present.
  96         </para>
  97         <para>
  98             If the sizes of the source and destination rectangles are not equal, <parameter>filter</parameter> specifies the interpolation method that
  99             will be applied to resize the source image , and must be <constant>GL_NEAREST</constant> or <constant>GL_LINEAR</constant>.
 100             <constant>GL_LINEAR</constant> is only a valid interpolation method for the color buffer. If <parameter>filter</parameter> is not
 101             <constant>GL_NEAREST</constant> and <parameter>mask</parameter> includes <constant>GL_DEPTH_BUFFER_BIT</constant> or
 102             <constant>GL_STENCIL_BUFFER_BIT</constant>, no data is transferred and a <constant>GL_INVALID_OPERATION</constant> error is generated.
 103         </para>
 104         <para>
 105             If <parameter>filter</parameter> is <constant>GL_LINEAR</constant> and the source rectangle would require sampling outside the bounds of
 106             the source framebuffer, values are read as if the <constant>GL_CLAMP_TO_EDGE</constant> texture wrapping mode were applied.
 107         </para>
 108         <para>
 109             When the color buffer is transferred, values are taken from the read buffer of the read framebuffer and written to each of the draw
 110             buffers of the draw framebuffer.
 111         </para>
 112         <para>
 113             If the source and destination rectangles overlap or are the same, and the read and draw buffers are the same, the result of the operation
 114             is undefined.
 115         </para>
 116     </refsect1>
 117     <refsect1 id="errors"><title>Errors</title>
 118         <para>
 119             <constant>GL_INVALID_OPERATION</constant> is generated if <parameter>mask</parameter> contains any of the <constant>GL_DEPTH_BUFFER_BIT</constant>
 120             or <constant>GL_STENCIL_BUFFER_BIT</constant> and <parameter>filter</parameter> is not <constant>GL_NEAREST</constant>.
 121         </para>
 122         <para>
 123             <constant>GL_INVALID_OPERATION</constant> is generated if <parameter>mask</parameter> contains <constant>GL_COLOR_BUFFER_BIT</constant>
 124             and any of the following conditions hold:
 125             <itemizedlist>
 126                 <listitem>
 127                 <para>The read buffer contains fixed-point or floating-point values and any draw buffer contains
 128                 neither fixed-point nor floating-point values.</para>
 129                 </listitem>
 130                 <listitem>
 131                 <para>The read buffer contains unsigned integer values and any draw buffer does not contain unsigned
 132                 integer values.</para>
 133                 </listitem>
 134                 <listitem>
 135                 <para>The read buffer contains signed integer values and any draw buffer does not contain signed integer values.</para>
 136                 </listitem>
 137             </itemizedlist>
 138         </para>
 139         <para>
 140             <constant>GL_INVALID_OPERATION</constant> is generated if <parameter>mask</parameter> contains <constant>GL_DEPTH_BUFFER_BIT</constant> or
 141             <constant>GL_STENCIL_BUFFER_BIT</constant> and the source and destination depth and stencil formats do not match.
 142         </para>
 143         <para>
 144             <constant>GL_INVALID_OPERATION</constant> is generated if <parameter>filter</parameter> is <constant>GL_LINEAR</constant> and the read buffer
 145             contains integer data.
 146         </para>
 147         <para>
 148             <constant>GL_INVALID_OPERATION</constant> is generated if the value of <parameter>GL_SAMPLES</parameter> for the read and draw buffers is
 149             not identical.
 150         </para>
 151         <para>
 152             <constant>GL_INVALID_OPERATION</constant> is generated if <parameter>GL_SAMPLE_BUFFERS</parameter> for both read and draw buffers greater than
 153             zero and the dimensions of the source and destination rectangles is not identical.
 154         </para>
 155         <para>
 156             <constant>GL_INVALID_FRAMEBUFFER_OPERATION</constant> is generated if the objects bound to <constant>GL_DRAW_FRAMEBUFFER_BINDING</constant>
 157             or <constant>GL_READ_FRAMEBUFFER_BINDING</constant> are not framebuffer complete.
 158         </para>
 159     </refsect1>
 160     <refsect1 id="seealso"><title>See Also</title>
 161         <para>
 162             <citerefentry><refentrytitle>glReadPixels</refentrytitle></citerefentry>
 163             <citerefentry><refentrytitle>glCheckFramebufferStatus</refentrytitle></citerefentry>,
 164             <citerefentry><refentrytitle>glGenFramebuffers</refentrytitle></citerefentry>
 165             <citerefentry><refentrytitle>glBindFramebuffer</refentrytitle></citerefentry>
 166             <citerefentry><refentrytitle>glDeleteFramebuffers</refentrytitle></citerefentry>
 167         </para>
 168     </refsect1>
 169     <refsect1 id="Copyright"><title>Copyright</title>
 170         <para>
 171             Copyright <trademark class="copyright"></trademark> 2010 Khronos Group.
 172             This material may be distributed subject to the terms and conditions set forth in
 173             the Open Publication License, v 1.0, 8 June 1999.
 174             <ulink url="http://opencontent.org/openpub/">http://opencontent.org/openpub/</ulink>.
 175         </para>
 176     </refsect1>
 177 </refentry>