upstream-doc/man2/xhtml/glCopyConvolutionFilter1D.xml

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   3 <?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" /><title>glCopyConvolutionFilter1D</title><meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="glCopyConvolutionFilter1D"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glCopyConvolutionFilter1D — copy pixels into a one-dimensional convolution filter</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">glCopyConvolutionFilter1D</b>(</code></td><td>GLenum  </td><td><var class="pdparam">target</var>, </td></tr><tr><td> </td><td>GLenum  </td><td><var class="pdparam">internalformat</var>, </td></tr><tr><td> </td><td>GLint  </td><td><var class="pdparam">x</var>, </td></tr><tr><td> </td><td>GLint  </td><td><var class="pdparam">y</var>, </td></tr><tr><td> </td><td>GLsizei  </td><td><var class="pdparam">width</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>
   4                     Must be <code class="constant">GL_CONVOLUTION_1D</code>.
   5                 </p></dd><dt><span class="term"><em class="parameter"><code>internalformat</code></em></span></dt><dd><p>
   6                     The internal format of the convolution filter kernel.
   7                     The allowable values are
   8                     <code class="constant">GL_ALPHA</code>,
   9                     <code class="constant">GL_ALPHA4</code>,
  10                     <code class="constant">GL_ALPHA8</code>,
  11                     <code class="constant">GL_ALPHA12</code>,
  12                     <code class="constant">GL_ALPHA16</code>,
  13                     <code class="constant">GL_LUMINANCE</code>,
  14                     <code class="constant">GL_LUMINANCE4</code>,
  15                     <code class="constant">GL_LUMINANCE8</code>,
  16                     <code class="constant">GL_LUMINANCE12</code>,
  17                     <code class="constant">GL_LUMINANCE16</code>,
  18                     <code class="constant">GL_LUMINANCE_ALPHA</code>,
  19                     <code class="constant">GL_LUMINANCE4_ALPHA4</code>,
  20                     <code class="constant">GL_LUMINANCE6_ALPHA2</code>,
  21                     <code class="constant">GL_LUMINANCE8_ALPHA8</code>,
  22                     <code class="constant">GL_LUMINANCE12_ALPHA4</code>,
  23                     <code class="constant">GL_LUMINANCE12_ALPHA12</code>,
  24                     <code class="constant">GL_LUMINANCE16_ALPHA16</code>,
  25                     <code class="constant">GL_INTENSITY</code>,
  26                     <code class="constant">GL_INTENSITY4</code>,
  27                     <code class="constant">GL_INTENSITY8</code>,
  28                     <code class="constant">GL_INTENSITY12</code>,
  29                     <code class="constant">GL_INTENSITY16</code>,
  30                     <code class="constant">GL_R3_G3_B2</code>,
  31                     <code class="constant">GL_RGB</code>,
  32                     <code class="constant">GL_RGB4</code>,
  33                     <code class="constant">GL_RGB5</code>,
  34                     <code class="constant">GL_RGB8</code>,
  35                     <code class="constant">GL_RGB10</code>,
  36                     <code class="constant">GL_RGB12</code>,
  37                     <code class="constant">GL_RGB16</code>,
  38                     <code class="constant">GL_RGBA</code>,
  39                     <code class="constant">GL_RGBA2</code>,
  40                     <code class="constant">GL_RGBA4</code>,
  41                     <code class="constant">GL_RGB5_A1</code>,
  42                     <code class="constant">GL_RGBA8</code>,
  43                     <code class="constant">GL_RGB10_A2</code>,
  44                     <code class="constant">GL_RGBA12</code>, or
  45                     <code class="constant">GL_RGBA16</code>.
  46                 </p></dd><dt><span class="term"><em class="parameter"><code>x</code></em>, </span><span class="term"><em class="parameter"><code>y</code></em></span></dt><dd><p>
  47                     The window space coordinates of the lower-left coordinate of the
  48                     pixel array to copy.
  49                 </p></dd><dt><span class="term"><em class="parameter"><code>width</code></em></span></dt><dd><p>
  50                     The width of the pixel array to copy.
  51                 </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
  52             <code class="function">glCopyConvolutionFilter1D</code> defines a one-dimensional convolution filter kernel with pixels
  53             from the current <code class="constant">GL_READ_BUFFER</code> (rather than from main memory,
  54             as is the case for <a class="citerefentry" href="glConvolutionFilter1D.xml"><span class="citerefentry"><span class="refentrytitle">glConvolutionFilter1D</span></span></a>).
  55         </p><p>
  56             The screen-aligned pixel rectangle with lower-left corner at (<em class="parameter"><code>x</code></em>,\ <em class="parameter"><code>y</code></em>),
  57             width <em class="parameter"><code>width</code></em> and height 1 is used to define
  58             the convolution filter.  If any pixels within this region are
  59             outside the window that is associated with the GL context, the
  60             values obtained for those pixels are undefined.
  61         </p><p>
  62             The pixels in the rectangle are processed exactly as if <a class="citerefentry" href="glReadPixels.xml"><span class="citerefentry"><span class="refentrytitle">glReadPixels</span></span></a>
  63             had been called with <span class="emphasis"><em>format</em></span>
  64             set to RGBA, but the process stops just before final conversion.
  65             The R, G, B, and A components of each pixel are next scaled by the four
  66             1D <code class="constant">GL_CONVOLUTION_FILTER_SCALE</code> parameters and biased by the
  67             four 1D <code class="constant">GL_CONVOLUTION_FILTER_BIAS</code> parameters.
  68             (The scale and bias parameters are set by <a class="citerefentry" href="glConvolutionParameter.xml"><span class="citerefentry"><span class="refentrytitle">glConvolutionParameter</span></span></a>
  69             using the <code class="constant">GL_CONVOLUTION_1D</code> target and the names
  70             <code class="constant">GL_CONVOLUTION_FILTER_SCALE</code> and <code class="constant">GL_CONVOLUTION_FILTER_BIAS</code>.
  71             The parameters themselves are vectors of four values that are applied to red,
  72             green, blue, and alpha, in that order.)
  73             The R, G, B, and A values are not clamped to [0,1] at any time during this
  74             process.
  75         </p><p>
  76             Each pixel is then converted to the internal format specified by
  77             <em class="parameter"><code>internalformat</code></em>.
  78             This conversion simply maps the component values of the pixel (R, G, B,
  79             and A) to the values included in the internal format (red, green, blue,
  80             alpha, luminance, and intensity).  The mapping is as follows:
  81         </p><p>
  82         </p><div class="informaltable"><table border="1"><colgroup><col align="left" /><col align="center" /><col align="center" /><col align="center" /><col align="center" /><col align="center" /><col align="center" /></colgroup><thead><tr><th align="left"><span class="bold"><strong>
  83                         Internal Format
  84                         </strong></span></th><th align="center"><span class="bold"><strong>
  85                         Red
  86                         </strong></span></th><th align="center"><span class="bold"><strong>
  87                         Green
  88                         </strong></span></th><th align="center"><span class="bold"><strong>
  89                         Blue
  90                         </strong></span></th><th align="center"><span class="bold"><strong>
  91                         Alpha
  92                         </strong></span></th><th align="center"><span class="bold"><strong>
  93                         Luminance
  94                         </strong></span></th><th align="center"><span class="bold"><strong>
  95                         Intensity
  96                         </strong></span></th></tr></thead><tbody><tr><td align="left">
  97                         <code class="constant">GL_ALPHA</code>
  98                         </td><td align="center">
  99                         </td><td align="center">
 100                         </td><td align="center">
 101                         </td><td align="center">
 102                         A
 103                         </td><td align="center">
 104                         </td><td align="center">
 105
 106                         </td></tr><tr><td align="left">
 107                         <code class="constant">GL_LUMINANCE</code>
 108                         </td><td align="center">
 109                         </td><td align="center">
 110                         </td><td align="center">
 111                         </td><td align="center">
 112                         </td><td align="center">
 113                         R
 114                         </td><td align="center">
 115
 116                         </td></tr><tr><td align="left">
 117                         <code class="constant">GL_LUMINANCE_ALPHA</code>
 118                         </td><td align="center">
 119                         </td><td align="center">
 120                         </td><td align="center">
 121                         </td><td align="center">
 122                         A
 123                         </td><td align="center">
 124                         R
 125                         </td><td align="center">
 126
 127                         </td></tr><tr><td align="left">
 128                         <code class="constant">GL_INTENSITY</code>
 129                         </td><td align="center">
 130                         </td><td align="center">
 131                         </td><td align="center">
 132                         </td><td align="center">
 133                         </td><td align="center">
 134                         </td><td align="center">
 135                         R
 136                         </td></tr><tr><td align="left">
 137                         <code class="constant">GL_RGB</code>
 138                         </td><td align="center">
 139                         R
 140                         </td><td align="center">
 141                         G
 142                         </td><td align="center">
 143                         B
 144                         </td><td align="center">
 145                         </td><td align="center">
 146                         </td><td align="center">
 147
 148                         </td></tr><tr><td align="left">
 149                         <code class="constant">GL_RGBA</code>
 150                         </td><td align="center">
 151                         R
 152                         </td><td align="center">
 153                         G
 154                         </td><td align="center">
 155                         B
 156                         </td><td align="center">
 157                         A
 158                         </td><td align="center">
 159                         </td><td align="center">
 160
 161                         </td></tr></tbody></table></div><p>
 162             The red, green, blue, alpha, luminance, and/or intensity components of
 163             the resulting pixels are stored in floating-point rather than integer
 164             format.
 165         </p><p>
 166             Pixel ordering is such that lower x screen coordinates correspond to
 167             lower <span class="emphasis"><em>i</em></span> filter image coordinates.
 168         </p><p>
 169             Note that after a convolution is performed, the resulting color
 170             components are also scaled by their corresponding
 171             <code class="constant">GL_POST_CONVOLUTION_c_SCALE</code> parameters and biased by their
 172             corresponding <code class="constant">GL_POST_CONVOLUTION_c_BIAS</code> parameters (where
 173             <span class="emphasis"><em>c</em></span> takes on the values <span class="bold"><strong>RED</strong></span>, <span class="bold"><strong>GREEN</strong></span>, <span class="bold"><strong>BLUE</strong></span>, and
 174             <span class="bold"><strong>ALPHA</strong></span>).
 175             These parameters are set by <a class="citerefentry" href="glPixelTransfer.xml"><span class="citerefentry"><span class="refentrytitle">glPixelTransfer</span></span></a>.
 176         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p>
 177             <code class="function">glCopyConvolutionFilter1D</code> is present only if <code class="code">ARB_imaging</code> is returned when <a class="citerefentry" href="glGetString.xml"><span class="citerefentry"><span class="refentrytitle">glGetString</span></span></a>
 178             is called with an argument of <code class="constant">GL_EXTENSIONS</code>.
 179         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p>
 180             <code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>target</code></em> is not
 181             <code class="constant">GL_CONVOLUTION_1D</code>.
 182         </p><p>
 183             <code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>internalformat</code></em> is not one of the
 184             allowable values.
 185         </p><p>
 186             <code class="constant">GL_INVALID_VALUE</code> is generated if <em class="parameter"><code>width</code></em> is less than zero or greater
 187             than the maximum supported value.
 188             This value may be queried with <a class="citerefentry" href="glGetConvolutionParameter.xml"><span class="citerefentry"><span class="refentrytitle">glGetConvolutionParameter</span></span></a>
 189             using target <code class="constant">GL_CONVOLUTION_1D</code> and name
 190             <code class="constant">GL_MAX_CONVOLUTION_WIDTH</code>.
 191         </p><p>
 192             <code class="constant">GL_INVALID_OPERATION</code> is generated if <code class="function">glCopyConvolutionFilter1D</code> is executed
 193             between the execution of <a class="citerefentry" href="glBegin.xml"><span class="citerefentry"><span class="refentrytitle">glBegin</span></span></a> and the corresponding
 194             execution of <a class="citerefentry" href="glEnd.xml"><span class="citerefentry"><span class="refentrytitle">glEnd</span></span></a>.
 195         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="associatedgets"></a><h2>Associated Gets</h2><p>
 196             <a class="citerefentry" href="glGetConvolutionParameter.xml"><span class="citerefentry"><span class="refentrytitle">glGetConvolutionParameter</span></span></a>, <a class="citerefentry" href="glGetConvolutionFilter.xml"><span class="citerefentry"><span class="refentrytitle">glGetConvolutionFilter</span></span></a>
 197         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
 198             <a class="citerefentry" href="glConvolutionFilter1D.xml"><span class="citerefentry"><span class="refentrytitle">glConvolutionFilter1D</span></span></a>,
 199             <a class="citerefentry" href="glConvolutionParameter.xml"><span class="citerefentry"><span class="refentrytitle">glConvolutionParameter</span></span></a>,
 200             <a class="citerefentry" href="glPixelTransfer.xml"><span class="citerefentry"><span class="refentrytitle">glPixelTransfer</span></span></a>
 201         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p>
 202             Copyright <span class="trademark"></span>© 1991-2006
 203             Silicon Graphics, Inc. This document is licensed under the SGI
 204             Free Software B License. For details, see
 205             <a class="ulink" href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>.
 206         </p></div></div></body></html>