C SPECIFICATION

       void glCopyColorTable( GLenum target,
                              GLenum internalformat,
                              GLint x,
                              GLint y,
                              GLsizei width )

PARAMETERS

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

       internalformat  The  internal  storage   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.

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

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

       width           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 (x, y)
       having width width 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  unde-
       fined.

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

       The four scale parameters and the four bias parameters that are defined
        GL_LUMINANCE_ALPHA  A=Alpha, R=Luminance
        GL_INTENSITY        R=Intensity
        GL_RGB              R=Red, G=Green, B=Blue
        GL_RGBA             R=Red, G=Green, B=Blue, A=Alpha


       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, width - 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 width is less than zero.

       GL_INVALID_VALUE  is  generated  if  internalformat  is  not one of the
       allowable 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)