glGetMinmax(3)

NAME

       glGetMinmax - get minimum and maximum pixel values

C SPECIFICATION

       void glGetMinmax( GLenum target,
                         GLboolean reset,
                         GLenum format,
                         GLenum types,
                         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   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_LUMINANCE, or GL_LUMINANCE_ALPHA.

       types   The  type  of the data to be returned in values.  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.

       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  of the return values is deter-
       mined by format, and their type is determined by types.

       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  for-
       mat,  but  that  are not included in the internal  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.

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 val-
       ues.

       GL_INVALID_ENUM is generated if types is not one of the allowable  val-
       ues.

       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    types    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    types    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 for-
       mat is neither GL_RGBA nor GL_BGRA.

SEE ALSO

       glMinmax(3G), glResetMinmax(3G), glGetMinmaxParameter(3G)

                                                               GLGETMINMAX(3G)