| 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> |