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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="glGetSeparableFilter"> | |
5 | <refmeta> | |
6 | <refmetainfo> | |
7 | <copyright> | |
8 | <year>1991-2006</year> | |
9 | <holder>Silicon Graphics, Inc.</holder> | |
10 | </copyright> | |
11 | </refmetainfo> | |
12 | <refentrytitle>glGetSeparableFilter</refentrytitle> | |
13 | <manvolnum>3G</manvolnum> | |
14 | </refmeta> | |
15 | <refnamediv> | |
16 | <refname>glGetSeparableFilter</refname> | |
17 | <refpurpose>get separable convolution filter kernel images</refpurpose> | |
18 | </refnamediv> | |
19 | <refsynopsisdiv><title>C Specification</title> | |
20 | <funcsynopsis> | |
21 | <funcprototype> | |
22 | <funcdef>void <function>glGetSeparableFilter</function></funcdef> | |
23 | <paramdef>GLenum <parameter>target</parameter></paramdef> | |
24 | <paramdef>GLenum <parameter>format</parameter></paramdef> | |
25 | <paramdef>GLenum <parameter>type</parameter></paramdef> | |
26 | <paramdef>GLvoid * <parameter>row</parameter></paramdef> | |
27 | <paramdef>GLvoid * <parameter>column</parameter></paramdef> | |
28 | <paramdef>GLvoid * <parameter>span</parameter></paramdef> | |
29 | </funcprototype> | |
30 | </funcsynopsis> | |
31 | </refsynopsisdiv> | |
32 | <refsect1 id="parameters"><title>Parameters</title> | |
33 | <variablelist> | |
34 | <varlistentry> | |
35 | <term><parameter>target</parameter></term> | |
36 | <listitem> | |
37 | <para> | |
38 | The separable filter to be retrieved. | |
39 | Must be | |
40 | <constant>GL_SEPARABLE_2D</constant>. | |
41 | </para> | |
42 | </listitem> | |
43 | </varlistentry> | |
44 | <varlistentry> | |
45 | <term><parameter>format</parameter></term> | |
46 | <listitem> | |
47 | <para> | |
48 | Format of the output images. | |
49 | Must be one of | |
50 | <constant>GL_RED</constant>, | |
51 | <constant>GL_GREEN</constant>, | |
52 | <constant>GL_BLUE</constant>, | |
53 | <constant>GL_ALPHA</constant>, | |
54 | <constant>GL_RGB</constant>, | |
55 | <constant>GL_BGR</constant> | |
56 | <constant>GL_RGBA</constant>, | |
57 | <constant>GL_BGRA</constant>, | |
58 | <constant>GL_LUMINANCE</constant>, or | |
59 | <constant>GL_LUMINANCE_ALPHA</constant>. | |
60 | </para> | |
61 | </listitem> | |
62 | </varlistentry> | |
63 | <varlistentry> | |
64 | <term><parameter>type</parameter></term> | |
65 | <listitem> | |
66 | <para> | |
67 | Data type of components in the output images. | |
68 | Symbolic constants | |
69 | <constant>GL_UNSIGNED_BYTE</constant>, | |
70 | <constant>GL_BYTE</constant>, | |
71 | <constant>GL_BITMAP</constant>, | |
72 | <constant>GL_UNSIGNED_SHORT</constant>, | |
73 | <constant>GL_SHORT</constant>, | |
74 | <constant>GL_UNSIGNED_INT</constant>, | |
75 | <constant>GL_INT</constant>, | |
76 | <constant>GL_FLOAT</constant>, | |
77 | <constant>GL_UNSIGNED_BYTE_3_3_2</constant>, | |
78 | <constant>GL_UNSIGNED_BYTE_2_3_3_REV</constant>, | |
79 | <constant>GL_UNSIGNED_SHORT_5_6_5</constant>, | |
80 | <constant>GL_UNSIGNED_SHORT_5_6_5_REV</constant>, | |
81 | <constant>GL_UNSIGNED_SHORT_4_4_4_4</constant>, | |
82 | <constant>GL_UNSIGNED_SHORT_4_4_4_4_REV</constant>, | |
83 | <constant>GL_UNSIGNED_SHORT_5_5_5_1</constant>, | |
84 | <constant>GL_UNSIGNED_SHORT_1_5_5_5_REV</constant>, | |
85 | <constant>GL_UNSIGNED_INT_8_8_8_8</constant>, | |
86 | <constant>GL_UNSIGNED_INT_8_8_8_8_REV</constant>, | |
87 | <constant>GL_UNSIGNED_INT_10_10_10_2</constant>, and | |
88 | <constant>GL_UNSIGNED_INT_2_10_10_10_REV</constant> | |
89 | are accepted. | |
90 | </para> | |
91 | </listitem> | |
92 | </varlistentry> | |
93 | <varlistentry> | |
94 | <term><parameter>row</parameter></term> | |
95 | <listitem> | |
96 | <para> | |
97 | Pointer to storage for the row filter image. | |
98 | </para> | |
99 | </listitem> | |
100 | </varlistentry> | |
101 | <varlistentry> | |
102 | <term><parameter>column</parameter></term> | |
103 | <listitem> | |
104 | <para> | |
105 | Pointer to storage for the column filter image. | |
106 | </para> | |
107 | </listitem> | |
108 | </varlistentry> | |
109 | <varlistentry> | |
110 | <term><parameter>span</parameter></term> | |
111 | <listitem> | |
112 | <para> | |
113 | Pointer to storage for the span filter image (currently unused). | |
114 | </para> | |
115 | </listitem> | |
116 | </varlistentry> | |
117 | </variablelist> | |
118 | </refsect1> | |
119 | <refsect1 id="description"><title>Description</title> | |
120 | <para> | |
121 | <function>glGetSeparableFilter</function> returns the two one-dimensional filter kernel images for the | |
122 | current separable 2D convolution filter. | |
123 | The row image is placed in <parameter>row</parameter> and the column image is placed in | |
124 | <parameter>column</parameter> according to the specifications in <parameter>format</parameter> and <parameter>type</parameter>. | |
125 | (In the current implementation, <parameter>span</parameter> is not affected in any way.) | |
126 | No pixel transfer operations are performed on the images, but the relevant | |
127 | pixel storage modes are applied. | |
128 | </para> | |
129 | <para> | |
130 | If a non-zero named buffer object is bound to the <constant>GL_PIXEL_PACK_BUFFER</constant> target | |
131 | (see <citerefentry><refentrytitle>glBindBuffer</refentrytitle></citerefentry>) while a separable convolution filter is | |
132 | requested, <parameter>row</parameter>, <parameter>column</parameter>, and <parameter>span</parameter> are treated as a byte offset into the buffer object's data store. | |
133 | </para> | |
134 | <para> | |
135 | Color components that are present in <parameter>format</parameter> but not included in the | |
136 | internal format of the filters are returned as zero. | |
137 | The assignments of internal color components to the components of <parameter>format</parameter> | |
138 | are as follows: | |
139 | </para> | |
140 | <para> | |
141 | </para> | |
142 | <informaltable frame="topbot"> | |
143 | <tgroup cols="2" align="left"> | |
144 | <colspec align="center"/> | |
145 | <colspec align="center"/> | |
146 | <thead> | |
147 | <row> | |
148 | <entry rowsep="1" align="center"><emphasis role="bold"> | |
149 | Internal Component | |
150 | </emphasis></entry> | |
151 | <entry rowsep="1" align="center"><emphasis role="bold"> | |
152 | Resulting Component | |
153 | </emphasis></entry> | |
154 | </row> | |
155 | </thead> | |
156 | <tbody> | |
157 | <row> | |
158 | <entry align="left"> | |
159 | Red | |
160 | </entry> | |
161 | <entry align="left"> | |
162 | Red | |
163 | </entry> | |
164 | </row> | |
165 | <row> | |
166 | <entry align="left"> | |
167 | Green | |
168 | </entry> | |
169 | <entry align="left"> | |
170 | Green | |
171 | </entry> | |
172 | </row> | |
173 | <row> | |
174 | <entry align="left"> | |
175 | Blue | |
176 | </entry> | |
177 | <entry align="left"> | |
178 | Blue | |
179 | </entry> | |
180 | </row> | |
181 | <row> | |
182 | <entry align="left"> | |
183 | Alpha | |
184 | </entry> | |
185 | <entry align="left"> | |
186 | Alpha | |
187 | </entry> | |
188 | </row> | |
189 | <row> | |
190 | <entry align="left"> | |
191 | Luminance | |
192 | </entry> | |
193 | <entry align="left"> | |
194 | Red | |
195 | </entry> | |
196 | </row> | |
197 | <row> | |
198 | <entry align="left"> | |
199 | Intensity | |
200 | </entry> | |
201 | <entry align="left"> | |
202 | Red | |
203 | </entry> | |
204 | </row> | |
205 | </tbody> | |
206 | </tgroup> | |
207 | </informaltable> | |
208 | <para> | |
209 | </para> | |
210 | </refsect1> | |
211 | <refsect1 id="notes"><title>Notes</title> | |
212 | <para> | |
213 | <function>glGetSeparableFilter</function> is present only if <code>ARB_imaging</code> is returned when <citerefentry><refentrytitle>glGetString</refentrytitle></citerefentry> | |
214 | is called with an argument of <constant>GL_EXTENSIONS</constant>. | |
215 | </para> | |
216 | <para> | |
217 | Non-separable 2D filters must be retrieved with <citerefentry><refentrytitle>glGetConvolutionFilter</refentrytitle></citerefentry>. | |
218 | </para> | |
219 | </refsect1> | |
220 | <refsect1 id="errors"><title>Errors</title> | |
221 | <para> | |
222 | <constant>GL_INVALID_ENUM</constant> is generated if <parameter>target</parameter> is not <constant>GL_SEPARABLE_2D</constant>. | |
223 | </para> | |
224 | <para> | |
225 | <constant>GL_INVALID_ENUM</constant> is generated if <parameter>format</parameter> is not one of the allowable | |
226 | values. | |
227 | </para> | |
228 | <para> | |
229 | <constant>GL_INVALID_ENUM</constant> is generated if <parameter>type</parameter> is not one of the allowable | |
230 | values. | |
231 | </para> | |
232 | <para> | |
233 | <constant>GL_INVALID_OPERATION</constant> is generated if <parameter>type</parameter> is one of | |
234 | <constant>GL_UNSIGNED_BYTE_3_3_2</constant>, | |
235 | <constant>GL_UNSIGNED_BYTE_2_3_3_REV</constant>, | |
236 | <constant>GL_UNSIGNED_SHORT_5_6_5</constant>, or | |
237 | <constant>GL_UNSIGNED_SHORT_5_6_5_REV</constant> | |
238 | and <parameter>format</parameter> is not <constant>GL_RGB</constant>. | |
239 | </para> | |
240 | <para> | |
241 | <constant>GL_INVALID_OPERATION</constant> is generated if <parameter>type</parameter> is one of | |
242 | <constant>GL_UNSIGNED_SHORT_4_4_4_4</constant>, | |
243 | <constant>GL_UNSIGNED_SHORT_4_4_4_4_REV</constant>, | |
244 | <constant>GL_UNSIGNED_SHORT_5_5_5_1</constant>, | |
245 | <constant>GL_UNSIGNED_SHORT_1_5_5_5_REV</constant>, | |
246 | <constant>GL_UNSIGNED_INT_8_8_8_8</constant>, | |
247 | <constant>GL_UNSIGNED_INT_8_8_8_8_REV</constant>, | |
248 | <constant>GL_UNSIGNED_INT_10_10_10_2</constant>, or | |
249 | <constant>GL_UNSIGNED_INT_2_10_10_10_REV</constant> | |
250 | and <parameter>format</parameter> is neither <constant>GL_RGBA</constant> nor <constant>GL_BGRA</constant>. | |
251 | </para> | |
252 | <para> | |
253 | <constant>GL_INVALID_OPERATION</constant> is generated if a non-zero buffer object name is bound to the | |
254 | <constant>GL_PIXEL_PACK_BUFFER</constant> target and the buffer object's data store is currently mapped. | |
255 | </para> | |
256 | <para> | |
257 | <constant>GL_INVALID_OPERATION</constant> is generated if a non-zero buffer object name is bound to the | |
258 | <constant>GL_PIXEL_PACK_BUFFER</constant> target and the data would be packed to the buffer | |
259 | object such that the memory writes required would exceed the data store size. | |
260 | </para> | |
261 | <para> | |
262 | <constant>GL_INVALID_OPERATION</constant> is generated if a non-zero buffer object name is bound to the | |
263 | <constant>GL_PIXEL_PACK_BUFFER</constant> target and <parameter>row</parameter> or <parameter>column</parameter> is not evenly divisible | |
264 | into the number of bytes needed to store in memory a datum indicated by <parameter>type</parameter>. | |
265 | </para> | |
266 | <para> | |
267 | <constant>GL_INVALID_OPERATION</constant> is generated if <function>glGetSeparableFilter</function> is executed | |
268 | between the execution of <citerefentry><refentrytitle>glBegin</refentrytitle></citerefentry> and the corresponding | |
269 | execution of <citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry>. | |
270 | </para> | |
271 | </refsect1> | |
272 | <refsect1 id="associatedgets"><title>Associated Gets</title> | |
273 | <para> | |
274 | <citerefentry><refentrytitle>glGetConvolutionParameter</refentrytitle></citerefentry> | |
275 | </para> | |
276 | <para> | |
277 | <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_PIXEL_PACK_BUFFER_BINDING</constant> | |
278 | </para> | |
279 | </refsect1> | |
280 | <refsect1 id="seealso"><title>See Also</title> | |
281 | <para> | |
282 | <citerefentry><refentrytitle>glGetConvolutionFilter</refentrytitle></citerefentry>, | |
283 | <citerefentry><refentrytitle>glConvolutionParameter</refentrytitle></citerefentry>, | |
284 | <citerefentry><refentrytitle>glSeparableFilter2D</refentrytitle></citerefentry> | |
285 | </para> | |
286 | </refsect1> | |
287 | <refsect1 id="Copyright"><title>Copyright</title> | |
288 | <para> | |
289 | Copyright <trademark class="copyright"></trademark> 1991-2006 | |
290 | Silicon Graphics, Inc. This document is licensed under the SGI | |
291 | Free Software B License. For details, see | |
292 | <ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>. | |
293 | </para> | |
294 | </refsect1> | |
295 | </refentry> |