glGetMinmax(3G)

NAME
     glGetMinmax - get minimum and maximum pixel values


C SPECIFICATION
     void glGetMinmax( GLenum target,
                       GLboolean reset,
                       GLenum format,
                       GLenum type,
                       GLvoid *values )


PARAMETERS
     target  Must be GL_MINMAX.

     reset   If GL_TRUE, all entries in the minmax table that are actually
             returned are reset to their initial values.  (Other entries are
             unaltered.)  If GL_FALSE, the minmax table is unaltered.

     format  The format of the data 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_ABGR_EXT, GL_LUMINANCE, or GL_LUMINANCE_ALPHA.

     type    The type of the data 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 values.

DESCRIPTION
     glGetMinmax returns the accumulated minimum and maximum pixel values
     (computed on a per-component basis) in a one-dimensional image of width
     2.  The first set of return values are the minima, and the second set of
     return values are the maxima.  The format of the return values is
     determined by format, and their type is determined by type.

     No pixel transfer operations are performed on the return values, but
     pixel storage modes that are applicable to 1-dimensional images are
     performed.  Color components that are requested in the specified format,
     but that are not included in the internal format of the minmax table, are
     returned as zero.  The assignment of internal color components to the
     components requested by format are as follows:

                     ________________________________________
                     Internal Component   Resulting Component
                    _________________________________________
                     Red                  Red
                     Green                Green
                     Blue                 Blue
                     Alpha                Alpha
                     Luminance            Red
                     ________________________________________


     If reset is GL_TRUE, the minmax table entries corresponding to the return
     values are reset to their initial values.  Minimum and maximum values
     that are not returned are not modified, even if reset is GL_TRUE.

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

     GL_ABGR_EXT is valid only if the EXT_abgr extension is supported.

ERRORS
     GL_INVALID_ENUM is generated if target is not GL_MINMAX.

     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 glGetMinmax 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 not GL_RGBA, GL_BGRA or GL_ABGR_EXT.


SEE ALSO
     glMinmax, glResetMinmax, glGetMinmaxParameter