upstream-man-pages/man2/xhtml/glConvolutionFilter1D.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>glConvolutionFilter1D</title><meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="glConvolutionFilter1D"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glConvolutionFilter1D — define 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">glConvolutionFilter1D</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>GLsizei  </td><td><var class="pdparam">width</var>, </td></tr><tr><td> </td><td>GLenum  </td><td><var class="pdparam">format</var>, </td></tr><tr><td> </td><td>GLenum  </td><td><var class="pdparam">type</var>, </td></tr><tr><td> </td><td>const GLvoid *  </td><td><var class="pdparam">data</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>width</code></em></span></dt><dd><p>
  47                     The width of the pixel array referenced by <em class="parameter"><code>data</code></em>.
  48                 </p></dd><dt><span class="term"><em class="parameter"><code>format</code></em></span></dt><dd><p>
  49                     The format of the pixel data in <em class="parameter"><code>data</code></em>.
  50                     The allowable values are
  51                     <code class="constant">GL_ALPHA</code>,
  52                     <code class="constant">GL_LUMINANCE</code>,
  53                     <code class="constant">GL_LUMINANCE_ALPHA</code>,
  54                     <code class="constant">GL_INTENSITY</code>,
  55                     <code class="constant">GL_RGB</code>, and
  56                     <code class="constant">GL_RGBA</code>.
  57                 </p></dd><dt><span class="term"><em class="parameter"><code>type</code></em></span></dt><dd><p>
  58                     The type of the pixel data in <em class="parameter"><code>data</code></em>.
  59                     Symbolic constants
  60                     <code class="constant">GL_UNSIGNED_BYTE</code>,
  61                     <code class="constant">GL_BYTE</code>,
  62                     <code class="constant">GL_BITMAP</code>,
  63                     <code class="constant">GL_UNSIGNED_SHORT</code>,
  64                     <code class="constant">GL_SHORT</code>,
  65                     <code class="constant">GL_UNSIGNED_INT</code>,
  66                     <code class="constant">GL_INT</code>,
  67                     <code class="constant">GL_FLOAT</code>,
  68                     <code class="constant">GL_UNSIGNED_BYTE_3_3_2</code>,
  69                     <code class="constant">GL_UNSIGNED_BYTE_2_3_3_REV</code>,
  70                     <code class="constant">GL_UNSIGNED_SHORT_5_6_5</code>,
  71                     <code class="constant">GL_UNSIGNED_SHORT_5_6_5_REV</code>,
  72                     <code class="constant">GL_UNSIGNED_SHORT_4_4_4_4</code>,
  73                     <code class="constant">GL_UNSIGNED_SHORT_4_4_4_4_REV</code>,
  74                     <code class="constant">GL_UNSIGNED_SHORT_5_5_5_1</code>,
  75                     <code class="constant">GL_UNSIGNED_SHORT_1_5_5_5_REV</code>,
  76                     <code class="constant">GL_UNSIGNED_INT_8_8_8_8</code>,
  77                     <code class="constant">GL_UNSIGNED_INT_8_8_8_8_REV</code>,
  78                     <code class="constant">GL_UNSIGNED_INT_10_10_10_2</code>, and
  79                     <code class="constant">GL_UNSIGNED_INT_2_10_10_10_REV</code>
  80                     are accepted.
  81                 </p></dd><dt><span class="term"><em class="parameter"><code>data</code></em></span></dt><dd><p>
  82                     Pointer to a one-dimensional array of pixel data that is processed to
  83                     build the convolution filter kernel.
  84                 </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
  85             <code class="function">glConvolutionFilter1D</code> builds a one-dimensional convolution filter kernel from an array of
  86             pixels.
  87         </p><p>
  88             The pixel array specified by <em class="parameter"><code>width</code></em>, <em class="parameter"><code>format</code></em>, <em class="parameter"><code>type</code></em>, and <em class="parameter"><code>data</code></em>
  89             is extracted from memory and
  90             processed just as if <a class="citerefentry" href="glDrawPixels.xml"><span class="citerefentry"><span class="refentrytitle">glDrawPixels</span></span></a> were called, but processing
  91             stops after the final expansion to RGBA is completed.
  92         </p><p>
  93             If a non-zero named buffer object is bound to the <code class="constant">GL_PIXEL_UNPACK_BUFFER</code> target
  94             (see <a class="citerefentry" href="glBindBuffer.xml"><span class="citerefentry"><span class="refentrytitle">glBindBuffer</span></span></a>) while a convolution filter is
  95             specified, <em class="parameter"><code>data</code></em> is treated as a byte offset into the buffer object's data store.
  96         </p><p>
  97             The R, G, B, and A components of each pixel are next scaled by the four
  98             1D <code class="constant">GL_CONVOLUTION_FILTER_SCALE</code> parameters and biased by the
  99             four 1D <code class="constant">GL_CONVOLUTION_FILTER_BIAS</code> parameters.
 100             (The scale and bias parameters are set by <a class="citerefentry" href="glConvolutionParameter.xml"><span class="citerefentry"><span class="refentrytitle">glConvolutionParameter</span></span></a>
 101             using the <code class="constant">GL_CONVOLUTION_1D</code> target and the names
 102             <code class="constant">GL_CONVOLUTION_FILTER_SCALE</code> and <code class="constant">GL_CONVOLUTION_FILTER_BIAS</code>.
 103             The parameters themselves are vectors of four values that are applied to red,
 104             green, blue, and alpha, in that order.)
 105             The R, G, B, and A values are not clamped to [0,1] at any time during this
 106             process.
 107         </p><p>
 108             Each pixel is then converted to the internal format specified by
 109             <em class="parameter"><code>internalformat</code></em>.
 110             This conversion simply maps the component values of the pixel (R, G, B,
 111             and A) to the values included in the internal format (red, green, blue,
 112             alpha, luminance, and intensity).  The mapping is as follows:
 113         </p><p>
 114         </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>
 115                         Internal Format
 116                         </strong></span></th><th align="center"><span class="bold"><strong>
 117                         Red
 118                         </strong></span></th><th align="center"><span class="bold"><strong>
 119                         Green
 120                         </strong></span></th><th align="center"><span class="bold"><strong>
 121                         Blue
 122                         </strong></span></th><th align="center"><span class="bold"><strong>
 123                         Alpha
 124                         </strong></span></th><th align="center"><span class="bold"><strong>
 125                         Luminance
 126                         </strong></span></th><th align="center"><span class="bold"><strong>
 127                         Intensity
 128                         </strong></span></th></tr></thead><tbody><tr><td align="left">
 129                         <code class="constant">GL_ALPHA</code>
 130                         </td><td align="center">
 131                         </td><td align="center">
 132                         </td><td align="center">
 133                         </td><td align="center">
 134                         A
 135                         </td><td align="center">
 136                         </td><td align="center">
 137
 138                         </td></tr><tr><td align="left">
 139                         <code class="constant">GL_LUMINANCE</code>
 140                         </td><td align="center">
 141                         </td><td align="center">
 142                         </td><td align="center">
 143                         </td><td align="center">
 144                         </td><td align="center">
 145                         R
 146                         </td><td align="center">
 147
 148                         </td></tr><tr><td align="left">
 149                         <code class="constant">GL_LUMINANCE_ALPHA</code>
 150                         </td><td align="center">
 151                         </td><td align="center">
 152                         </td><td align="center">
 153                         </td><td align="center">
 154                         A
 155                         </td><td align="center">
 156                         R
 157                         </td><td align="center">
 158
 159                         </td></tr><tr><td align="left">
 160                         <code class="constant">GL_INTENSITY</code>
 161                         </td><td align="center">
 162                         </td><td align="center">
 163                         </td><td align="center">
 164                         </td><td align="center">
 165                         </td><td align="center">
 166                         </td><td align="center">
 167                         R
 168                         </td></tr><tr><td align="left">
 169                         <code class="constant">GL_RGB</code>
 170                         </td><td align="center">
 171                         R
 172                         </td><td align="center">
 173                         G
 174                         </td><td align="center">
 175                         B
 176                         </td><td align="center">
 177                         </td><td align="center">
 178                         </td><td align="center">
 179
 180                         </td></tr><tr><td align="left">
 181                         <code class="constant">GL_RGBA</code>
 182                         </td><td align="center">
 183                         R
 184                         </td><td align="center">
 185                         G
 186                         </td><td align="center">
 187                         B
 188                         </td><td align="center">
 189                         A
 190                         </td><td align="center">
 191                         </td><td align="center">
 192
 193                         </td></tr></tbody></table></div><p>
 194             The red, green, blue, alpha, luminance, and/or intensity components of
 195             the resulting pixels are stored in floating-point rather than integer
 196             format.
 197             They form a one-dimensional filter kernel image indexed with coordinate
 198             <span class="emphasis"><em>i</em></span> such that <span class="emphasis"><em>i</em></span> starts at 0 and increases from left to right.
 199             Kernel location <span class="emphasis"><em>i</em></span> is derived from the <span class="emphasis"><em>i</em></span>th pixel, counting from 0.
 200         </p><p>
 201             Note that after a convolution is performed, the resulting color
 202             components are also scaled by their corresponding
 203             <code class="constant">GL_POST_CONVOLUTION_c_SCALE</code> parameters and biased by their
 204             corresponding <code class="constant">GL_POST_CONVOLUTION_c_BIAS</code> parameters (where
 205             <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
 206             <span class="bold"><strong>ALPHA</strong></span>).
 207             These parameters are set by <a class="citerefentry" href="glPixelTransfer.xml"><span class="citerefentry"><span class="refentrytitle">glPixelTransfer</span></span></a>.
 208         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p>
 209             <code class="function">glConvolutionFilter1D</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>
 210             is called with an argument of <code class="constant">GL_EXTENSIONS</code>.
 211         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p>
 212             <code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>target</code></em> is not
 213             <code class="constant">GL_CONVOLUTION_1D</code>.
 214         </p><p>
 215             <code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>internalformat</code></em> is not one of the
 216             allowable values.
 217         </p><p>
 218             <code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>format</code></em> is not one of the allowable
 219             values.
 220         </p><p>
 221             <code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>type</code></em> is not one of the allowable
 222             values.
 223         </p><p>
 224             <code class="constant">GL_INVALID_VALUE</code> is generated if <em class="parameter"><code>width</code></em> is less than zero or greater
 225             than the maximum supported value.
 226             This value may be queried with <a class="citerefentry" href="glGetConvolutionParameter.xml"><span class="citerefentry"><span class="refentrytitle">glGetConvolutionParameter</span></span></a>
 227             using target <code class="constant">GL_CONVOLUTION_1D</code> and name
 228             <code class="constant">GL_MAX_CONVOLUTION_WIDTH</code>.
 229         </p><p>
 230             <code class="constant">GL_INVALID_OPERATION</code> is generated if <em class="parameter"><code>format</code></em> is one of
 231             <code class="constant">GL_UNSIGNED_BYTE_3_3_2</code>,
 232             <code class="constant">GL_UNSIGNED_BYTE_2_3_3_REV</code>,
 233             <code class="constant">GL_UNSIGNED_SHORT_5_6_5</code>, or
 234             <code class="constant">GL_UNSIGNED_SHORT_5_6_5_REV</code>
 235             and <em class="parameter"><code>type</code></em> is not <code class="constant">GL_RGB</code>.
 236         </p><p>
 237             <code class="constant">GL_INVALID_OPERATION</code> is generated if <em class="parameter"><code>format</code></em> is one of
 238             <code class="constant">GL_UNSIGNED_SHORT_4_4_4_4</code>,
 239             <code class="constant">GL_UNSIGNED_SHORT_4_4_4_4_REV</code>,
 240             <code class="constant">GL_UNSIGNED_SHORT_5_5_5_1</code>,
 241             <code class="constant">GL_UNSIGNED_SHORT_1_5_5_5_REV</code>,
 242             <code class="constant">GL_UNSIGNED_INT_8_8_8_8</code>,
 243             <code class="constant">GL_UNSIGNED_INT_8_8_8_8_REV</code>,
 244             <code class="constant">GL_UNSIGNED_INT_10_10_10_2</code>, or
 245             <code class="constant">GL_UNSIGNED_INT_2_10_10_10_REV</code>
 246             and <em class="parameter"><code>type</code></em> is neither <code class="constant">GL_RGBA</code> nor <code class="constant">GL_BGRA</code>.
 247         </p><p>
 248             <code class="constant">GL_INVALID_OPERATION</code> is generated if a non-zero buffer object name is bound to the
 249             <code class="constant">GL_PIXEL_UNPACK_BUFFER</code> target and the buffer object's data store is currently mapped.
 250         </p><p>
 251             <code class="constant">GL_INVALID_OPERATION</code> is generated if a non-zero buffer object name is bound to the
 252             <code class="constant">GL_PIXEL_UNPACK_BUFFER</code> target and the data would be unpacked from the buffer
 253             object such that the memory reads required would exceed the data store size.
 254         </p><p>
 255             <code class="constant">GL_INVALID_OPERATION</code> is generated if a non-zero buffer object name is bound to the
 256             <code class="constant">GL_PIXEL_UNPACK_BUFFER</code> target and <em class="parameter"><code>data</code></em> is not evenly divisible
 257             into the number of bytes needed to store in memory a datum indicated by <em class="parameter"><code>type</code></em>.
 258         </p><p>
 259             <code class="constant">GL_INVALID_OPERATION</code> is generated if <code class="function">glConvolutionFilter1D</code> is executed
 260             between the execution of <a class="citerefentry" href="glBegin.xml"><span class="citerefentry"><span class="refentrytitle">glBegin</span></span></a> and the corresponding
 261             execution of <a class="citerefentry" href="glEnd.xml"><span class="citerefentry"><span class="refentrytitle">glEnd</span></span></a>.
 262         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="associatedgets"></a><h2>Associated Gets</h2><p>
 263             <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>
 264         </p><p>
 265             <a class="citerefentry" href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument <code class="constant">GL_PIXEL_UNPACK_BUFFER_BINDING</code>
 266         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
 267             <a class="citerefentry" href="glConvolutionFilter2D.xml"><span class="citerefentry"><span class="refentrytitle">glConvolutionFilter2D</span></span></a>,
 268             <a class="citerefentry" href="glSeparableFilter2D.xml"><span class="citerefentry"><span class="refentrytitle">glSeparableFilter2D</span></span></a>,
 269             <a class="citerefentry" href="glConvolutionParameter.xml"><span class="citerefentry"><span class="refentrytitle">glConvolutionParameter</span></span></a>,
 270             <a class="citerefentry" href="glPixelTransfer.xml"><span class="citerefentry"><span class="refentrytitle">glPixelTransfer</span></span></a>
 271         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p>
 272             Copyright <span class="trademark"></span>© 1991-2006
 273             Silicon Graphics, Inc. This document is licensed under the SGI
 274             Free Software B License. For details, see
 275             <a class="ulink" href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>.
 276         </p></div></div></body></html>