C SPECIFICATION

       void GLAPIENTRY glMinmax( GLenum target,
                                 GLenum internalforma )

PARAMETERS

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

       internalforma  The format of entries in the minmax table.  Must be  one
                      of    GL_ALPHA,    GL_ALPHA4,   GL_ALPHA8,   GL_ALPHA12,
                      GL_ALPHA16, GL_LUMINANCE, GL_LUMINANCE4,  GL_LUMINANCE8,
                      GL_LUMINANCE12,    GL_LUMINANCE16,   GL_LUMINANCE_ALPHA,
                      GL_LUMINANCE4_ALPHA4,              GL_LUMINANCE6_ALPHA2,
                      GL_LUMINANCE8_ALPHA8,             GL_LUMINANCE12_ALPHA4,
                      GL_LUMINANCE12_ALPHA12,          GL_LUMINANCE16_ALPHA16,
                      GL_R3_G3_B2,    GL_RGB,   GL_RGB4,   GL_RGB5,   GL_RGB8,
                      GL_RGB10,   GL_RGB12,   GL_RGB16,   GL_RGBA,   GL_RGBA2,
                      GL_RGBA4,  GL_RGB5_A1, GL_RGBA8, GL_RGB10_A2, GL_RGBA12,
                      or GL_RGBA16.

       _param3        If GL_TRUE, pixels will be consumed by the  minmax  pro-
                      cess  and no drawing or texture loading will take place.
                      If GL_FALSE, pixels will proceed to the final conversion
                      process after minmax.

DESCRIPTION

       When  GL_MINMAX  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 format 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 glGetMinmax.  The minmax opera-
       tion  is  enabled or disabled by calling glEnable or glDisable, respec-
       tively, with an argument of GL_MINMAX.

       glMinmax redefines the current minmax table to have entries of the for-
       mat  specified  by  internalforma.   The maximum element is initialized
       with the smallest possible component values, and the minimum element is
       initialized  with the largest possible component values.  The values in
       the previous minmax table, if any, are lost.  If  _param3  is  GL_TRUE,
       then  pixels  are  discarded after minmax; no further processing of the
       pixels takes place, and no drawing, texture loading, or pixel  readback
       will result.

ASSOCIATED GETS

       glGetMinmaxParameter

SEE ALSO

       glGetMinmax, glResetMinmax



                                                                  GLMINMAX(3G)