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=
"glGetHistogram">
9 <holder>Silicon Graphics, Inc.
</holder>
12 <refentrytitle>glGetHistogram
</refentrytitle>
13 <manvolnum>3G
</manvolnum>
16 <refname>glGetHistogram
</refname>
17 <refpurpose>get histogram table
</refpurpose>
19 <refsynopsisdiv><title>C Specification
</title>
22 <funcdef>void
<function>glGetHistogram
</function></funcdef>
23 <paramdef>GLenum
<parameter>target
</parameter></paramdef>
24 <paramdef>GLboolean
<parameter>reset
</parameter></paramdef>
25 <paramdef>GLenum
<parameter>format
</parameter></paramdef>
26 <paramdef>GLenum
<parameter>type
</parameter></paramdef>
27 <paramdef>GLvoid *
<parameter>values
</parameter></paramdef>
31 <refsect1 id=
"parameters"><title>Parameters
</title>
34 <term><parameter>target
</parameter></term>
38 <constant>GL_HISTOGRAM
</constant>.
43 <term><parameter>reset
</parameter></term>
46 If
<constant>GL_TRUE
</constant>, each component counter that is actually returned
47 is reset to zero. (Other counters are unaffected.)
48 If
<constant>GL_FALSE
</constant>, none of the counters in the histogram table is modified.
53 <term><parameter>format
</parameter></term>
56 The format of values to be returned in
<parameter>values
</parameter>.
58 <constant>GL_RED
</constant>,
59 <constant>GL_GREEN
</constant>,
60 <constant>GL_BLUE
</constant>,
61 <constant>GL_ALPHA
</constant>,
62 <constant>GL_RGB
</constant>,
63 <constant>GL_BGR
</constant>,
64 <constant>GL_RGBA
</constant>,
65 <constant>GL_BGRA
</constant>,
66 <constant>GL_LUMINANCE
</constant>, or
67 <constant>GL_LUMINANCE_ALPHA
</constant>.
72 <term><parameter>type
</parameter></term>
75 The type of values to be returned in
<parameter>values
</parameter>.
77 <constant>GL_UNSIGNED_BYTE
</constant>,
78 <constant>GL_BYTE
</constant>,
79 <constant>GL_BITMAP
</constant>,
80 <constant>GL_UNSIGNED_SHORT
</constant>,
81 <constant>GL_SHORT
</constant>,
82 <constant>GL_UNSIGNED_INT
</constant>,
83 <constant>GL_INT
</constant>,
84 <constant>GL_FLOAT
</constant>,
85 <constant>GL_UNSIGNED_BYTE_3_3_2
</constant>,
86 <constant>GL_UNSIGNED_BYTE_2_3_3_REV
</constant>,
87 <constant>GL_UNSIGNED_SHORT_5_6_5
</constant>,
88 <constant>GL_UNSIGNED_SHORT_5_6_5_REV
</constant>,
89 <constant>GL_UNSIGNED_SHORT_4_4_4_4
</constant>,
90 <constant>GL_UNSIGNED_SHORT_4_4_4_4_REV
</constant>,
91 <constant>GL_UNSIGNED_SHORT_5_5_5_1
</constant>,
92 <constant>GL_UNSIGNED_SHORT_1_5_5_5_REV
</constant>,
93 <constant>GL_UNSIGNED_INT_8_8_8_8
</constant>,
94 <constant>GL_UNSIGNED_INT_8_8_8_8_REV
</constant>,
95 <constant>GL_UNSIGNED_INT_10_10_10_2
</constant>, and
96 <constant>GL_UNSIGNED_INT_2_10_10_10_REV
</constant>
102 <term><parameter>values
</parameter></term>
105 A pointer to storage for the returned histogram table.
111 <refsect1 id=
"description"><title>Description
</title>
113 <function>glGetHistogram
</function> returns the current histogram table as a one-dimensional image
114 with the same width as the histogram.
115 No pixel transfer operations are performed on this image, but pixel storage
116 modes that are applicable to
1D images are honored.
119 If a non-zero named buffer object is bound to the
<constant>GL_PIXEL_PACK_BUFFER
</constant> target
120 (see
<citerefentry><refentrytitle>glBindBuffer
</refentrytitle></citerefentry>) while a histogram table is
121 requested,
<parameter>values
</parameter> is treated as a byte offset into the buffer object's data store.
124 Color components that are requested in the specified
<parameter>format
</parameter>, but which
125 are not included in the internal format of the histogram, are returned as
127 The assignments of internal color components to the components
128 requested by
<parameter>format
</parameter> are:
130 <informaltable frame=
"topbot">
131 <tgroup cols=
"2" align=
"left">
136 <entry rowsep=
"1" align=
"left"><emphasis role=
"bold">
139 <entry rowsep=
"1" align=
"left"><emphasis role=
"bold">
191 <refsect1 id=
"notes"><title>Notes
</title>
193 <function>glGetHistogram
</function> is present only if
<code>ARB_imaging
</code> is returned when
<citerefentry><refentrytitle>glGetString
</refentrytitle></citerefentry>
194 is called with an argument of
<constant>GL_EXTENSIONS
</constant>.
197 <refsect1 id=
"errors"><title>Errors
</title>
199 <constant>GL_INVALID_ENUM
</constant> is generated if
<parameter>target
</parameter> is not
<constant>GL_HISTOGRAM
</constant>.
202 <constant>GL_INVALID_ENUM
</constant> is generated if
<parameter>format
</parameter> is not one of the allowable
206 <constant>GL_INVALID_ENUM
</constant> is generated if
<parameter>type
</parameter> is not one of the allowable
210 <constant>GL_INVALID_OPERATION
</constant> is generated if
<parameter>type
</parameter> is one of
211 <constant>GL_UNSIGNED_BYTE_3_3_2
</constant>,
212 <constant>GL_UNSIGNED_BYTE_2_3_3_REV
</constant>,
213 <constant>GL_UNSIGNED_SHORT_5_6_5
</constant>, or
214 <constant>GL_UNSIGNED_SHORT_5_6_5_REV
</constant>
215 and
<parameter>format
</parameter> is not
<constant>GL_RGB
</constant>.
218 <constant>GL_INVALID_OPERATION
</constant> is generated if
<parameter>type
</parameter> is one of
219 <constant>GL_UNSIGNED_SHORT_4_4_4_4
</constant>,
220 <constant>GL_UNSIGNED_SHORT_4_4_4_4_REV
</constant>,
221 <constant>GL_UNSIGNED_SHORT_5_5_5_1
</constant>,
222 <constant>GL_UNSIGNED_SHORT_1_5_5_5_REV
</constant>,
223 <constant>GL_UNSIGNED_INT_8_8_8_8
</constant>,
224 <constant>GL_UNSIGNED_INT_8_8_8_8_REV
</constant>,
225 <constant>GL_UNSIGNED_INT_10_10_10_2
</constant>, or
226 <constant>GL_UNSIGNED_INT_2_10_10_10_REV
</constant>
227 and
<parameter>format
</parameter> is neither
<constant>GL_RGBA
</constant> nor
<constant>GL_BGRA
</constant>.
230 <constant>GL_INVALID_OPERATION
</constant> is generated if a non-zero buffer object name is bound to the
231 <constant>GL_PIXEL_PACK_BUFFER
</constant> target and the buffer object's data store is currently mapped.
234 <constant>GL_INVALID_OPERATION
</constant> is generated if a non-zero buffer object name is bound to the
235 <constant>GL_PIXEL_PACK_BUFFER
</constant> target and the data would be packed to the buffer
236 object such that the memory writes required would exceed the data store size.
239 <constant>GL_INVALID_OPERATION
</constant> is generated if a non-zero buffer object name is bound to the
240 <constant>GL_PIXEL_PACK_BUFFER
</constant> target and
<parameter>values
</parameter> is not evenly divisible
241 into the number of bytes needed to store in memory a datum indicated by
<parameter>type
</parameter>.
244 <constant>GL_INVALID_OPERATION
</constant> is generated if
<function>glGetHistogram
</function> is executed
245 between the execution of
<citerefentry><refentrytitle>glBegin
</refentrytitle></citerefentry> and the corresponding
246 execution of
<citerefentry><refentrytitle>glEnd
</refentrytitle></citerefentry>.
249 <refsect1 id=
"associatedgets"><title>Associated Gets
</title>
251 <citerefentry><refentrytitle>glGetHistogramParameter
</refentrytitle></citerefentry>
254 <citerefentry><refentrytitle>glGet
</refentrytitle></citerefentry> with argument
<constant>GL_PIXEL_PACK_BUFFER_BINDING
</constant>
257 <refsect1 id=
"seealso"><title>See Also
</title>
259 <citerefentry><refentrytitle>glHistogram
</refentrytitle></citerefentry>,
260 <citerefentry><refentrytitle>glResetHistogram
</refentrytitle></citerefentry>,
263 <refsect1 id=
"Copyright"><title>Copyright
</title>
265 Copyright
<trademark class=
"copyright"></trademark> 1991-
2006
266 Silicon Graphics, Inc. This document is licensed under the SGI
267 Free Software B License. For details, see
268 <ulink url=
"http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/
</ulink>.