GLGETHISTOGRAM(3G)														GLGETHISTOGRAM(3G)

NAME

       glGetHistogram - get histogram table

C SPECIFICATION

       void glGetHistogram( GLenum target,
			    GLboolean reset,
			    GLenum format,
			    GLenum type,
			    GLvoid *values )

PARAMETERS

       target  Must be GL_HISTOGRAM.

       reset   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.

       format  The  of values to be returned in values.  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.

       type    The type of values to be returned in values.  Symbolic constants 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.

       values  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
       operations 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 format, but which are not included in the internal	of the histogram, are returned	as
       zero.
       The assignments of internal color components to the components requested by format are:

							-----------------------------------------
							Internal Component   Resulting Component
							-----------------------------------------
							Red		     Red
							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 format is not one of the allowable values.

       GL_INVALID_ENUM is generated if type 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	type  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 format is not GL_RGB.

       GL_INVALID_OPERATION is generated if type 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 format is neither GL_RGBA nor GL_BGRA.

SEE ALSO

       glHistogram(3G), glResetHistogram(3G), glGetHistogramParameter(3G)

																GLGETHISTOGRAM(3G)