C SPECIFICATION

       void GLAPIENTRY glGetHistogram( GLenum target,
                                       GLboolean rese )

PARAMETERS

       target  Must be GL_HISTOGRAM.

       rese    If GL_TRUE, each component counter that is actually returned is
               reset to zero.  (Other counters are unaffected.)  If  GL_FALSE,
               none of the counters in the histogram table is modified.

       _param3 The format of values to be returned in _param5.  Must be one of
               GL_RED, GL_GREEN, GL_BLUE, GL_ALPHA, GL_RGB,  GL_BGR,  GL_RGBA,
               GL_BGRA, GL_LUMINANCE, or GL_LUMINANCE_ALPHA.

       _param4 The  type  of  values to be returned in _param5.  Symbolic con-
               stants GL_UNSIGNED_BYTE, GL_BYTE, GL_BITMAP, GL_UNSIGNED_SHORT,
               GL_SHORT,        GL_UNSIGNED_INT,       GL_INT,       GL_FLOAT,
               GL_UNSIGNED_BYTE_3_3_2,             GL_UNSIGNED_BYTE_2_3_3_REV,
               GL_UNSIGNED_SHORT_5_6_5,           GL_UNSIGNED_SHORT_5_6_5_REV,
               GL_UNSIGNED_SHORT_4_4_4_4,       GL_UNSIGNED_SHORT_4_4_4_4_REV,
               GL_UNSIGNED_SHORT_5_5_5_1,       GL_UNSIGNED_SHORT_1_5_5_5_REV,
               GL_UNSIGNED_INT_8_8_8_8,           GL_UNSIGNED_INT_8_8_8_8_REV,
               GL_UNSIGNED_INT_10_10_10_2,  and GL_UNSIGNED_INT_2_10_10_10_REV
               are accepted.

       _param5 A pointer to storage for the returned histogram table.

DESCRIPTION

       glGetHistogram returns the current histogram table as a one-dimensional
       image  with  the same width as the histogram.  No pixel transfer opera-
       tions are performed on this image, but pixel  storage  modes  that  are
       applicable to 1D images are honored.

       Color components that are requested in the specified _param3, but which
       are not included in the internal format of the histogram, are  returned
       as zero.













                      Green                Green
                      Blue                 Blue
                      Alpha                Alpha
                      Luminance            Red
                      -----------------------------------------

NOTES

       glGetHistogram is present  only  if  GL_ARB_imaging  is  returned  when
       glGetString is called with an argument of GL_EXTENSIONS.

ERRORS

       GL_INVALID_ENUM is generated if target is not GL_HISTOGRAM.

       GL_INVALID_ENUM  is  generated  if  _param3 is not one of the allowable
       values.

       GL_INVALID_ENUM is generated if _param4 is not  one  of  the  allowable
       values.

       GL_INVALID_OPERATION is generated if glGetHistogram is executed between
       the execution of glBegin and the corresponding execution of glEnd.


       GL_INVALID_OPERATION   is   generated   if   _param4    is    one    of
       GL_UNSIGNED_BYTE_3_3_2,                     GL_UNSIGNED_BYTE_2_3_3_REV,
       GL_UNSIGNED_SHORT_5_6_5, or GL_UNSIGNED_SHORT_5_6_5_REV and _param3  is
       not GL_RGB.

       GL_INVALID_OPERATION    is    generated    if   _param4   is   one   of
       GL_UNSIGNED_SHORT_4_4_4_4,               GL_UNSIGNED_SHORT_4_4_4_4_REV,
       GL_UNSIGNED_SHORT_5_5_5_1,               GL_UNSIGNED_SHORT_1_5_5_5_REV,
       GL_UNSIGNED_INT_8_8_8_8,                   GL_UNSIGNED_INT_8_8_8_8_REV,
       GL_UNSIGNED_INT_10_10_10_2,   or   GL_UNSIGNED_INT_2_10_10_10_REV   and
       _param3 is neither GL_RGBA nor GL_BGRA.

SEE ALSO

       glHistogram, glResetHistogram, glGetHistogramParameter



                                                            GLGETHISTOGRAM(3G)