- copy a one-dimensional texture subimage



C SPECIFICATION


PARAMETERS

       _param1  Specifies    the   target   texture.    Must   be
                GL_TEXTURE_1D.

       _param2  Specifies the level-of-detail number.  Level 0 is
                the  base image level.  Level n is the nth mipmap
                reduction image.

       _param3  Specifies the texel  offset  within  the  texture
                array.

       _param4, _param5
                Specify the window coordinates of the left corner
                of the row of pixels to be copied.

       _param6  Specifies the width of the texture subimage.


DESCRIPTION

       glCopyTexSubImage1D replaces a  portion  of  a  one-dimen-
       sional   texture   image  with  pixels  from  the  current
       GL_READ_BUFFER (rather than from main memory,  as  is  the
       case for glTexSubImage1D).

       The   screen-aligned   pixel   row  with  left  corner  at
       (_param4, _param5), and with length _param6  replaces  the
       portion  of  the  texture  array  with  x  indices _param3
       through _eqnparam3+_eqnparam6-1, inclusive.  The  destina-
       tion  in the texture array may not include any texels out-
       side the texture array as it was originally specified.

       The  pixels  in  the  row  are  processed  exactly  as  if
       glCopyPixels  had  been called, but the process stops just
       before final conversion.  At this point all  pixel  compo-
       nent  values are clamped to the range [0, 1] and then con-
       verted to the texture's internal  for storage in the texel
       array.

       It  is  not  an  error  to  specify a subtexture with zero
       width, but such a specification has no effect.  If any  of
       the  pixels  within  the  specified  row  of  the  current
       GL_READ_BUFFER are outside the read window associated with
       the  current  rendering  context, then the values obtained
       for those pixels are undefined.

       No change is made to the internalformat, width, or  border
       parameters of the specified texture array or to texel val-
       ues outside the specified subregion.


ERRORS

       GL_INVALID_ENUM   is   generated   if   _param1   is   not
       GL_TEXTURE_1D.

       GL_INVALID_OPERATION is generated if the texture array has
       not   been   defined   by   a   previous  glTexImage1D  or
       glCopyTexImage1D operation.

       GL_INVALID_VALUE is generated if _param2 is less than 0.

       GL_INVALID_VALUE may be  generated  if  _param2>log2  max,
       where max is the returned value of GL_MAX_TEXTURE_SIZE.

       GL_INVALID_VALUE   is   generated   if  _param5<-b  or  if
       _param6<-b, where b is the border  width  of  the  texture
       array.

       GL_INVALID_VALUE   is   generated   if  _eqnparam3<-b,  or
       (_eqnparam3+_eqnparam6)>(w-b),    where    w    is     the
       GL_TEXTURE_WIDTH,  and  b  is the GL_TEXTURE_BORDER of the
       texture image being modified.  Note that w includes  twice
       the border width.



ASSOCIATED GETS

       glGetTexImage
       glIsEnabled with argument GL_TEXTURE_1D


SEE ALSO

       glCopyPixels,      glCopyTexImage1D,     glCopyTexImage2D,
       glCopyTexSubImage2D,  glCopyTexSubImage3D,   glPixelStore,
       glPixelTransfer,    glReadBuffer,    glTexEnv,   glTexGen,
       glTexImage1D, glTexImage2D, glTexImage3D,  glTexParameter,
       glTexSubImage1D, glTexSubImage2D, glTexSubImage3D



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