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><head><title>glGetSeparableFilter</title><link rel="stylesheet" href="style.css" type="text/css"/><meta name="generator" content="DocBook XSL Stylesheets V1.59.1"/><link rel="home" href="index.xml" title="PyOpenGL 2.0.1.07 Man Pages"/><link rel="up" href="reference-GL.xml" title="GL"/><link rel="previous" href="glGetPolygonStipple.3G.xml" title="glGetPolygonStipple"/><link rel="next" href="glGetString.3G.xml" title="glGetString"/></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">glGetSeparableFilter</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="glGetPolygonStipple.3G.xml">Prev</a> </td><th width="60%" align="center">GL</th><td width="20%" align="right"> <a accesskey="n" href="glGetString.3G.xml">Next</a></td></tr></table><hr/></div><div class="refentry" lang="en"><a name="glGetSeparableFilter.3G"/><div class="titlepage"/><div class="refnamediv"><a name="glGetSeparableFilter.3G-name"/><h2>Name</h2><p>glGetSeparableFilter &#8212; get separable convolution filter kernel images</p></div><div class="refsynopsisdiv"><a name="glGetSeparableFilter.3G-c_spec"/><h2>C Specification</h2><table class="funcprototype" border="0" cellpadding="0" cellspacing="0"><tr><td valign="top"><code>void <tt>glGetSeparableFilter</tt></code></td><td valign="top"><code>(</code></td><td valign="top"><code>GLenum <i><tt>target</tt></i>, GLenum <i><tt>format</tt></i>, GLenum <i><tt>type</tt></i>, GLvoid *<i><tt>row</tt></i>, GLvoid *<i><tt>column</tt></i>, GLvoid *<i><tt>span</tt></i>);</code></td></tr></table></div><div class="refsynopsisdiv"><a name="glGetSeparableFilter.3G-python_spec"/><h2>Python Specification</h2><table class="funcprototype" border="0" cellpadding="0" cellspacing="0"><tr><td valign="top"><code><tt>glGetSeparableFilter</tt></code></td><td valign="top"><code>(</code></td><td valign="top"><code><i><tt>target</tt></i>, <i><tt>format</tt></i>, <i><tt>type</tt></i>, <i><tt>row</tt></i>, <i><tt>column</tt></i>, <i><tt>span</tt></i>) &#8594; <tt>None</tt></code></td></tr></table></div><div class="refsect1" lang="en"><a name="glGetSeparableFilter.3G-parameters"/><h2>Parameters</h2><div class="variablelist"><dl><dt><span class="term"><i><tt>target</tt></i></span></dt><dd>
						The separable filter to be retrieved. Must be <tt>GL_SEPARABLE_2D</tt>.
					</dd><dt><span class="term"><i><tt>format</tt></i></span></dt><dd>
						Format of the output images. Must be one of <tt>GL_RED</tt>, <tt>GL_GREEN</tt>,
						<tt>GL_BLUE</tt>, <tt>GL_ALPHA</tt>, <tt>GL_RGB</tt>,
						<tt>GL_BGR</tt> <tt>GL_RGBA</tt>, <tt>GL_BGRA</tt>,
						<tt>GL_LUMINANCE</tt>, or <tt>GL_LUMINANCE_ALPHA</tt>.
					</dd><dt><span class="term"><i><tt>type</tt></i></span></dt><dd>
						Data type of components in the output images. Symbolic constants <tt>GL_UNSIGNED_BYTE</tt>,
						<tt>GL_BYTE</tt>, <tt>GL_BITMAP</tt>, <tt>GL_UNSIGNED_SHORT</tt>,
						<tt>GL_SHORT</tt>, <tt>GL_UNSIGNED_INT</tt>, <tt>GL_INT</tt>,
						<tt>GL_FLOAT</tt>, <tt>GL_UNSIGNED_BYTE_3_3_2</tt>,
						<tt>GL_UNSIGNED_BYTE_2_3_3_REV</tt>, <tt>GL_UNSIGNED_SHORT_5_6_5</tt>,
						<tt>GL_UNSIGNED_SHORT_5_6_5_REV</tt>, <tt>GL_UNSIGNED_SHORT_4_4_4_4</tt>,
						<tt>GL_UNSIGNED_SHORT_4_4_4_4_REV</tt>, <tt>GL_UNSIGNED_SHORT_5_5_5_1</tt>,
						<tt>GL_UNSIGNED_SHORT_1_5_5_5_REV</tt>, <tt>GL_UNSIGNED_INT_8_8_8_8</tt>,
						<tt>GL_UNSIGNED_INT_8_8_8_8_REV</tt>, <tt>GL_UNSIGNED_INT_10_10_10_2</tt>, and
						<tt>GL_UNSIGNED_INT_2_10_10_10_REV</tt> are accepted.
					</dd><dt><span class="term"><i><tt>row</tt></i></span></dt><dd>
						Pointer to storage for the row filter image.
					</dd><dt><span class="term"><i><tt>column</tt></i></span></dt><dd>
						Pointer to storage for the column filter image.
					</dd><dt><span class="term"><i><tt>span</tt></i></span></dt><dd>
						Pointer to storage for the span filter image (currently unused).
					</dd></dl></div></div><div class="refsect1" lang="en"><a name="glGetSeparableFilter.3G-description"/><h2>Description</h2><p>
			<tt>glGetSeparableFilter</tt> returns the two one-dimensional filter kernel images for the current
			separable 2D convolution filter. The row image is placed in <i><tt>row</tt></i> and the column image is placed
			in <i><tt>column</tt></i> according to the specifications in <i><tt>format</tt></i> and
			<i><tt>type</tt></i>. (In the current implementation, <i><tt>span</tt></i> is not affected in any way.)
			No pixel transfer operations are performed on the images, but the relevant pixel storage modes are applied. Color
			components that are present in <i><tt>format</tt></i> but not included in the internal of the filters are
			returned as zero. The assignments of internal color components to the components of <i><tt>format</tt></i> are
			as follows:
		</p><div class="informaltable"><table border="1"><colgroup><col/><col/></colgroup><tbody><tr><td align="center"><span class="bold"><b>Internal Component</b></span></td><td align="center"><span class="bold"><b>Resulting Component</b></span></td></tr><tr><td>Red</td><td>Red</td></tr><tr><td>Green</td><td>Green</td></tr><tr><td>Blue</td><td>Blue</td></tr><tr><td>Alpha</td><td>Alpha</td></tr><tr><td>Luminance</td><td>Red</td></tr><tr><td>Intensity</td><td>Red</td></tr></tbody></table></div></div><div class="refsect1" lang="en"><a name="glGetSeparableFilter.3G-notes"/><h2>Notes</h2><p>
			<tt>glGetSeparableFilter</tt> is present only if <tt>GL_ARB_imaging</tt> is returned when
			<a href="glGetString.3G.xml"><tt>glGetString</tt></a> is called with an argument of <tt>GL_EXTENSIONS</tt>.
		</p><p>
			Non-separable 2D filters must be retrieved with <a href="glGetConvolutionFilter.3G.xml"><tt>glGetConvolutionFilter</tt></a>.
		</p></div><div class="refsect1" lang="en"><a name="glGetSeparableFilter.3G-errors"/><h2>Errors</h2><p>
			<tt>GL_INVALID_ENUM</tt> is generated if <i><tt>target</tt></i> is not
			<tt>GL_SEPARABLE_2D</tt>.
		</p><p>
			<tt>GL_INVALID_ENUM</tt> is generated if <i><tt>format</tt></i> is not one of the allowable values.
		</p><p>
			<tt>GL_INVALID_ENUM</tt> is generated if <i><tt>type</tt></i> is not one of the allowable values.
		</p><p>
			<tt>GL_INVALID_OPERATION</tt> is generated if <tt>glGetSeparableFilter</tt> is executed between
			the execution of <a href="glBegin.3G.xml"><tt>glBegin</tt></a> and the corresponding execution of <a href="glBegin.3G.xml"><tt>glEnd</tt></a>.
		</p><p>
			<tt>GL_INVALID_OPERATION</tt> is generated if <i><tt>type</tt></i> is one of
			<tt>GL_UNSIGNED_BYTE_3_3_2</tt>, <tt>GL_UNSIGNED_BYTE_2_3_3_REV</tt>,
			<tt>GL_UNSIGNED_SHORT_5_6_5</tt>, or <tt>GL_UNSIGNED_SHORT_5_6_5_REV</tt> and
			<i><tt>format</tt></i> is not <tt>GL_RGB</tt>.
		</p><p>
			<tt>GL_INVALID_OPERATION</tt> is generated if <i><tt>type</tt></i> is one of
			<tt>GL_UNSIGNED_SHORT_4_4_4_4</tt>, <tt>GL_UNSIGNED_SHORT_4_4_4_4_REV</tt>,
			<tt>GL_UNSIGNED_SHORT_5_5_5_1</tt>, <tt>GL_UNSIGNED_SHORT_1_5_5_5_REV</tt>,
			<tt>GL_UNSIGNED_INT_8_8_8_8</tt>, <tt>GL_UNSIGNED_INT_8_8_8_8_REV</tt>,
			<tt>GL_UNSIGNED_INT_10_10_10_2</tt>, or <tt>GL_UNSIGNED_INT_2_10_10_10_REV</tt> and
			<i><tt>format</tt></i> is neither <tt>GL_RGBA</tt> nor <tt>GL_BGRA</tt>.
		</p></div><div class="refsect1" lang="en"><a name="glGetSeparableFilter.3G-associated_gets"/><h2>Associated Gets</h2><p>
			<tt>glGetConvolutionParameter</tt>
		</p></div><div class="refsect1" lang="en"><a name="glGetSeparableFilter.3G-see_also"/><h2>See Also</h2><p>
			<span class="simplelist"><a href="glGetConvolutionFilter.3G.xml">glGetConvolutionFilter</a>, <a href="glConvolutionParameter.3G.xml">glConvolutionParameter</a>, <a href="glSeparableFilter2D.3G.xml">glSeparableFilter2D</a></span>
		</p></div></div><div class="navfooter"><hr/><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="glGetPolygonStipple.3G.xml">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="reference-GL.xml">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="glGetString.3G.xml">Next</a></td></tr><tr><td width="40%" align="left" valign="top">glGetPolygonStipple </td><td width="20%" align="center"><a accesskey="h" href="index.xml">Home</a></td><td width="40%" align="right" valign="top"> glGetString</td></tr></table></div></body></html>