GLMINMAX(3G)                                                      GLMINMAX(3G)



NAME
       glinmax - define minmax table


C SPECIFICATION
       void glinmax( GLenum target,
                      GLenum internalformat,
                      GLboolean sink )


PARAMETERS
       target          The  minmax table whose parameters are to be set.  Must
                       be GLMINMAX.

       internalformat  The  of entries in the minmax table.  Must  be  one  of
                       GLALPHA, GLALPHA4, GLALPHA8, GLALPHA12, GLALPHA16,
                       GLUMINANCE,       GLUMINANCE4,       GLUMINANCE8,
                       GLUMINANCE12,   GLUMINANCE16,   GLUMINANCEALPHA,
                       GLUMINANCE4ALPHA4,             GLUMINANCE6ALPHA2,
                       GLUMINANCE8ALPHA8,            GLUMINANCE12ALPHA4,
                       GLUMINANCE12ALPHA12,         GLUMINANCE16ALPHA16,
                       GLR3G3B2,   GLRGB,   GLRGB4,   GLRGB5,   GLRGB8,
                       GLRGB100,  GLRGB12,   GLRGB16,   GLRGBA,   GLRGBA2,
                       GLRGBA4, GLRGB5A1, GLRGBA8, GLRGB100A2, GLRGBA12,
                       or GLRGBA16.

       sink            If GLTRUE, pixels  will  be  consumed  by  the  minmax
                       process  and  no  drawing  or texture loading will take
                       place.  If GLFALSE, pixels will proceed to  the  final
                       conversion process after minmax.

DESCRIPTION
       When  GLMINMAX  is enabled, the RGBA components of incoming pixels are
       compared to the minimum and maximum values for  each  component,  which
       are  stored  in  the 2-element minmax table.  (The first element stores
       the minima, and the second element stores the maxima.)  If a pixel com-
       ponent  is greater than the corresponding component in the maximum ele-
       ment, then the maximum element is  updated  with  the  pixel  component
       value.   If  a pixel component is less than the corresponding component
       in the minimum element, then the minimum element is  updated  with  the
       pixel  component value.  (In both cases, if the internal  of the minmax
       table includes luminance, then the R color component of incoming pixels
       is  used  for  comparison.)   The  contents  of the minmax table may be
       retrieved at a later time by calling glGetinmax.  The minmax operation
       is  enabled or disabled by calling glEnable or glDisable, respectively,
       with an argument of GLMINMAX.

       glinmax redefines the current minmax table  to  have  entries  of  the
       specified  by  internalformat.  The maximum element is initialized with
       the smallest possible component values, and the minimum element is ini-
       tialized with the largest possible component values.  The values in the
       previous minmax table, if any, are lost.  If sink is GLTRUE, then pix-
       els  are  discarded  after  minmax; no further processing of the pixels
       takes place, and no drawing, texture loading, or  pixel  readback  will
       result.


NOTES
       glinmax is present only if GLARBimaging is returned when glGetString
       is called with an argument of GLEXTENSIONS.

ERORS
       GLINVALIDENUM is generated if target is not one of the allowable val-
       ues.

       GLINVALIDENUM is generated if internalformat is not one of the allow-
       able values.

       GLINVALIDOPERATION is generated if glinmax is executed  between  the
       execution of glBegin and the corresponding execution of glEnd.

ASOCIATED GETS
       glGetinmaxParameter

SEE ALSO
       glGetinmax, glResetinmax



                                                                  GLMINMAX(3G)