C SPECIFICATION

       void GLAPIENTRY glCopyColorTable( GLenum target,
                                         GLenum internalforma )

       delim $$

PARAMETERS

       target         The   color   table   target.  Must  be  GL_COLOR_TABLE,
                      GL_POST_CONVOLUTION_COLOR_TABLE,                      or
                      GL_POST_COLOR_MATRIX_COLOR_TABLE.

       internalforma  The  internal storage format of the texture image.  Must
                      be one of the following  symbolic  constants:  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_INTENSITY,        GL_INTENSITY4,       GL_INTENSITY8,
                      GL_INTENSITY12,  GL_INTENSITY16,  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, GL_RGBA16.

       _param3        The  x  coordinate of the lower-left corner of the pixel
                      rectangle to be transferred to the color table.

       _param4        The y coordinate of the lower-left corner of  the  pixel
                      rectangle to be transferred to the color table.

       _param5        The width of the pixel rectangle.

DESCRIPTION

       glCopyColorTable  loads  a  color  table  with  pixels from the current
       GL_READ_BUFFER (rather than from  main  memory,  as  is  the  case  for
       glColorTable).

       The   screen-aligned   pixel   rectangle   with  lower-left  corner  at
       (_param3, _param4) having width _param5 and height 1 is loaded into the
       color  table.  If  any pixels within this region are outside the window
       that is associated with the GL context, the values obtained  for  those
       pixels are undefined.

       The  pixels in the rectangle are processed just as if glReadPixels were
       called, with internalforma set to RGBA, but processing stops after  the
       final conversion to RGBA.

       The four scale parameters and the four bias parameters that are defined
       for the table are then used to scale and bias the R, G, B, and A compo-
       nents  of  each pixel. The scale and bias parameters are set by calling
       GL_LUMINANCE                                          R
       GL_LUMINANCE_ALPHA                          A         R
       GL_INTENSITY                                                      R
       GL_RGB                R      G      B
       GL_RGBA               R      G      B       A
       ------------------------------------------------------------------------

       Finally,  the red, green, blue, alpha, luminance, and/or intensity com-
       ponents of the resulting pixels are stored in the  color  table.   They
       form    a   one-dimensional   table   with   indices   in   the   range
       [0, _param5 - 1].

NOTES

       glCopyColorTable is available only if GL_ARB_imaging is  returned  from
       calling glGetString with an argument of GL_EXTENSIONS.

ERRORS

       GL_INVALID_ENUM  is  generated  when target is not one of the allowable
       values.

       GL_INVALID_VALUE is generated if _param5 is less than zero.

       GL_INVALID_VALUE is generated if internalforma is not one of the allow-
       able values.

       GL_TABLE_TOO_LARGE  is  generated  if  the requested color table is too
       large to be supported by the implementation.

       GL_INVALID_OPERATION  is  generated  if  glCopyColorTable  is  executed
       between  the  execution  of  glBegin and the corresponding execution of
       glEnd.

ASSOCIATED GETS

       glGetColorTable, glGetColorTableParameter

SEE ALSO

       glColorTable, glColorTableParameter, glReadPixels



                                                          GLCOPYCOLORTABLE(3G)