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1<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "xhtml1-transitional.dtd">
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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>glGetSeparableFilter</title><meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="glGetSeparableFilter"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glGetSeparableFilter — get separable convolution filter kernel images</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">glGetSeparableFilter</b>(</code></td><td>GLenum  </td><td><var class="pdparam">target</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>GLvoid *  </td><td><var class="pdparam">row</var>, </td></tr><tr><td> </td><td>GLvoid *  </td><td><var class="pdparam">column</var>, </td></tr><tr><td> </td><td>GLvoid *  </td><td><var class="pdparam">span</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 The separable filter to be retrieved.
5 Must be
6 <code class="constant">GL_SEPARABLE_2D</code>.
7 </p></dd><dt><span class="term"><em class="parameter"><code>format</code></em></span></dt><dd><p>
8 Format of the output images.
9 Must be one of
10 <code class="constant">GL_RED</code>,
11 <code class="constant">GL_GREEN</code>,
12 <code class="constant">GL_BLUE</code>,
13 <code class="constant">GL_ALPHA</code>,
14 <code class="constant">GL_RGB</code>,
15 <code class="constant">GL_BGR</code>
16 <code class="constant">GL_RGBA</code>,
17 <code class="constant">GL_BGRA</code>,
18 <code class="constant">GL_LUMINANCE</code>, or
19 <code class="constant">GL_LUMINANCE_ALPHA</code>.
20 </p></dd><dt><span class="term"><em class="parameter"><code>type</code></em></span></dt><dd><p>
21 Data type of components in the output images.
22 Symbolic constants
23 <code class="constant">GL_UNSIGNED_BYTE</code>,
24 <code class="constant">GL_BYTE</code>,
25 <code class="constant">GL_BITMAP</code>,
26 <code class="constant">GL_UNSIGNED_SHORT</code>,
27 <code class="constant">GL_SHORT</code>,
28 <code class="constant">GL_UNSIGNED_INT</code>,
29 <code class="constant">GL_INT</code>,
30 <code class="constant">GL_FLOAT</code>,
31 <code class="constant">GL_UNSIGNED_BYTE_3_3_2</code>,
32 <code class="constant">GL_UNSIGNED_BYTE_2_3_3_REV</code>,
33 <code class="constant">GL_UNSIGNED_SHORT_5_6_5</code>,
34 <code class="constant">GL_UNSIGNED_SHORT_5_6_5_REV</code>,
35 <code class="constant">GL_UNSIGNED_SHORT_4_4_4_4</code>,
36 <code class="constant">GL_UNSIGNED_SHORT_4_4_4_4_REV</code>,
37 <code class="constant">GL_UNSIGNED_SHORT_5_5_5_1</code>,
38 <code class="constant">GL_UNSIGNED_SHORT_1_5_5_5_REV</code>,
39 <code class="constant">GL_UNSIGNED_INT_8_8_8_8</code>,
40 <code class="constant">GL_UNSIGNED_INT_8_8_8_8_REV</code>,
41 <code class="constant">GL_UNSIGNED_INT_10_10_10_2</code>, and
42 <code class="constant">GL_UNSIGNED_INT_2_10_10_10_REV</code>
43 are accepted.
44 </p></dd><dt><span class="term"><em class="parameter"><code>row</code></em></span></dt><dd><p>
45 Pointer to storage for the row filter image.
46 </p></dd><dt><span class="term"><em class="parameter"><code>column</code></em></span></dt><dd><p>
47 Pointer to storage for the column filter image.
48 </p></dd><dt><span class="term"><em class="parameter"><code>span</code></em></span></dt><dd><p>
49 Pointer to storage for the span filter image (currently unused).
50 </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
51 <code class="function">glGetSeparableFilter</code> returns the two one-dimensional filter kernel images for the
52 current separable 2D convolution filter.
53 The row image is placed in <em class="parameter"><code>row</code></em> and the column image is placed in
54 <em class="parameter"><code>column</code></em> according to the specifications in <em class="parameter"><code>format</code></em> and <em class="parameter"><code>type</code></em>.
55 (In the current implementation, <em class="parameter"><code>span</code></em> is not affected in any way.)
56 No pixel transfer operations are performed on the images, but the relevant
57 pixel storage modes are applied.
58 </p><p>
59 If a non-zero named buffer object is bound to the <code class="constant">GL_PIXEL_PACK_BUFFER</code> target
60 (see <a class="citerefentry" href="glBindBuffer.xml"><span class="citerefentry"><span class="refentrytitle">glBindBuffer</span></span></a>) while a separable convolution filter is
61 requested, <em class="parameter"><code>row</code></em>, <em class="parameter"><code>column</code></em>, and <em class="parameter"><code>span</code></em> are treated as a byte offset into the buffer object's data store.
62 </p><p>
63 Color components that are present in <em class="parameter"><code>format</code></em> but not included in the
64 internal format of the filters are returned as zero.
65 The assignments of internal color components to the components of <em class="parameter"><code>format</code></em>
66 are as follows:
67 </p><p>
68 </p><div class="informaltable"><table border="1"><colgroup><col align="center" /><col align="center" /></colgroup><thead><tr><th align="center"><span class="bold"><strong>
69 Internal Component
70 </strong></span></th><th align="center"><span class="bold"><strong>
71 Resulting Component
72 </strong></span></th></tr></thead><tbody><tr><td align="left">
73 Red
74 </td><td align="left">
75 Red
76 </td></tr><tr><td align="left">
77 Green
78 </td><td align="left">
79 Green
80 </td></tr><tr><td align="left">
81 Blue
82 </td><td align="left">
83 Blue
84 </td></tr><tr><td align="left">
85 Alpha
86 </td><td align="left">
87 Alpha
88 </td></tr><tr><td align="left">
89 Luminance
90 </td><td align="left">
91 Red
92 </td></tr><tr><td align="left">
93 Intensity
94 </td><td align="left">
95 Red
96 </td></tr></tbody></table></div><p>
97 </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p>
98 <code class="function">glGetSeparableFilter</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>
99 is called with an argument of <code class="constant">GL_EXTENSIONS</code>.
100 </p><p>
101 Non-separable 2D filters must be retrieved with <a class="citerefentry" href="glGetConvolutionFilter.xml"><span class="citerefentry"><span class="refentrytitle">glGetConvolutionFilter</span></span></a>.
102 </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p>
103 <code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>target</code></em> is not <code class="constant">GL_SEPARABLE_2D</code>.
104 </p><p>
105 <code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>format</code></em> is not one of the allowable
106 values.
107 </p><p>
108 <code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>type</code></em> is not one of the allowable
109 values.
110 </p><p>
111 <code class="constant">GL_INVALID_OPERATION</code> is generated if <em class="parameter"><code>type</code></em> is one of
112 <code class="constant">GL_UNSIGNED_BYTE_3_3_2</code>,
113 <code class="constant">GL_UNSIGNED_BYTE_2_3_3_REV</code>,
114 <code class="constant">GL_UNSIGNED_SHORT_5_6_5</code>, or
115 <code class="constant">GL_UNSIGNED_SHORT_5_6_5_REV</code>
116 and <em class="parameter"><code>format</code></em> is not <code class="constant">GL_RGB</code>.
117 </p><p>
118 <code class="constant">GL_INVALID_OPERATION</code> is generated if <em class="parameter"><code>type</code></em> is one of
119 <code class="constant">GL_UNSIGNED_SHORT_4_4_4_4</code>,
120 <code class="constant">GL_UNSIGNED_SHORT_4_4_4_4_REV</code>,
121 <code class="constant">GL_UNSIGNED_SHORT_5_5_5_1</code>,
122 <code class="constant">GL_UNSIGNED_SHORT_1_5_5_5_REV</code>,
123 <code class="constant">GL_UNSIGNED_INT_8_8_8_8</code>,
124 <code class="constant">GL_UNSIGNED_INT_8_8_8_8_REV</code>,
125 <code class="constant">GL_UNSIGNED_INT_10_10_10_2</code>, or
126 <code class="constant">GL_UNSIGNED_INT_2_10_10_10_REV</code>
127 and <em class="parameter"><code>format</code></em> is neither <code class="constant">GL_RGBA</code> nor <code class="constant">GL_BGRA</code>.
128 </p><p>
129 <code class="constant">GL_INVALID_OPERATION</code> is generated if a non-zero buffer object name is bound to the
130 <code class="constant">GL_PIXEL_PACK_BUFFER</code> target and the buffer object's data store is currently mapped.
131 </p><p>
132 <code class="constant">GL_INVALID_OPERATION</code> is generated if a non-zero buffer object name is bound to the
133 <code class="constant">GL_PIXEL_PACK_BUFFER</code> target and the data would be packed to the buffer
134 object such that the memory writes required would exceed the data store size.
135 </p><p>
136 <code class="constant">GL_INVALID_OPERATION</code> is generated if a non-zero buffer object name is bound to the
137 <code class="constant">GL_PIXEL_PACK_BUFFER</code> target and <em class="parameter"><code>row</code></em> or <em class="parameter"><code>column</code></em> is not evenly divisible
138 into the number of bytes needed to store in memory a datum indicated by <em class="parameter"><code>type</code></em>.
139 </p><p>
140 <code class="constant">GL_INVALID_OPERATION</code> is generated if <code class="function">glGetSeparableFilter</code> is executed
141 between the execution of <a class="citerefentry" href="glBegin.xml"><span class="citerefentry"><span class="refentrytitle">glBegin</span></span></a> and the corresponding
142 execution of <a class="citerefentry" href="glEnd.xml"><span class="citerefentry"><span class="refentrytitle">glEnd</span></span></a>.
143 </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="associatedgets"></a><h2>Associated Gets</h2><p>
144 <a class="citerefentry" href="glGetConvolutionParameter.xml"><span class="citerefentry"><span class="refentrytitle">glGetConvolutionParameter</span></span></a>
145 </p><p>
146 <a class="citerefentry" href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument <code class="constant">GL_PIXEL_PACK_BUFFER_BINDING</code>
147 </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
148 <a class="citerefentry" href="glGetConvolutionFilter.xml"><span class="citerefentry"><span class="refentrytitle">glGetConvolutionFilter</span></span></a>,
149 <a class="citerefentry" href="glConvolutionParameter.xml"><span class="citerefentry"><span class="refentrytitle">glConvolutionParameter</span></span></a>,
150 <a class="citerefentry" href="glSeparableFilter2D.xml"><span class="citerefentry"><span class="refentrytitle">glSeparableFilter2D</span></span></a>
151 </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p>
152 Copyright <span class="trademark"></span>© 1991-2006
153 Silicon Graphics, Inc. This document is licensed under the SGI
154 Free Software B License. For details, see
155 <a class="ulink" href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>.
156 </p></div></div></body></html>