C SPECIFICATION

       void GLAPIENTRY glCopyTexSubImage3D( GLenum target,
                                            GLint leve )

PARAMETERS

       target  Specifies the target texture.  Must be GL_TEXTURE_3D

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

       _param3 Specifies a texel offset in the x direction within the  texture
               array.

       _param4 Specifies  a texel offset in the y direction within the texture
               array.

       _param5 Specifies a texel offset in the z direction within the  texture
               array.

       _param6, _param7
               Specify  the window coordinates of the lower left corner of the
               rectangular region of pixels to be copied.

       _param8 Specifies the width of the texture subimage.

       _param9 Specifies the height of the texture subimage.

DESCRIPTION

       glCopyTexSubImage3D replaces a rectangular portion  of  a  three-dimen-
       sional  texture  image  with  pixels  from  the  current GL_READ_BUFFER
       (rather than from main memory, as is the case for glTexSubImage3D).

       The  screen-aligned  pixel  rectangle  with  lower   left   corner   at
       (_param6, _param7)  and  with width _param8 and height _param9 replaces
       the portion of  the  texture  array  with  x  indices  _param3  through
       _param3+_param8-1,   inclusive,   and   y   indices   _param4   through
       _param4+_param9-1, inclusive, at z index  _param5  and  at  the  mipmap
       level specified by leve.

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

       The destination rectangle in the texture array may not include any tex-
       els outside the texture array as it was originally  specified.   It  is
       not  an  error  to  specify a subtexture with zero width or height, but
       such a specification has no effect.


       glPixelStore and glPixelTransfer modes affect texture images in exactly
       the way they affect glDrawPixels.

       When  the  GL_ARB_imaging  extension  is supported, the RGBA components
       copied from the framebuffer may be processed by the  imaging  pipeline,
       as  if  they were a two-dimensional texture.  See glTexImage2D for spe-
       cific details.

ERRORS

       GL_INVALID_ENUM is generated if target is not GL_TEXTURE_3D.

       GL_INVALID_OPERATION is generated if the texture  array  has  not  been
       defined by a previous glTexImage3D or glCopyTexImage3D operation.

       GL_INVALID_VALUE is generated if leve is less than 0.

       GL_INVALID_VALUE  may  be  generated  if  leve is greater than log2max,
       where max is the returned value of GL_MAX_3D_TEXTURE_SIZE.

       GL_INVALID_VALUE is generated if _param6<-b or if _param7<-b,  where  b
       is the border width of the texture array.

       GL_INVALID_VALUE       is       generated       if       _eqnparam3<-b,
       (_param3+_param8)>(w-b),      _param4<-b,      (_param4+_param9)>(h-b),
       _param5<-b, or _param5>(d-b), where w is the GL_TEXTURE_WIDTH, h is the
       GL_TEXTURE_HEIGHT,  d  is  the   GL_TEXTURE_DEPTH,   and   b   is   the
       GL_TEXTURE_BORDER of the texture image being modified.  Note that w, h,
       and d include twice the border width.

       GL_INVALID_OPERATION is generated if  glCopyTexSubImage3D  is  executed
       between  the  execution  of  glBegin and the corresponding execution of
       glEnd.

ASSOCIATED GETS

       glGetTexImage
       glIsEnabled with argument GL_TEXTURE_3D

SEE ALSO

       glCopyPixels, glCopyTexImage1D, glCopyTexImage2D,  glCopyTexSubImage1D,
       glCopyTexSubImage2D,   glPixelStore,   glPixelTransfer,   glReadBuffer,
       glTexEnv,   glTexGen,   glTexImage1D,    glTexImage2D,    glTexImage3D,
       glTexParameter, glTexSubImage1D, glTexSubImage2D, glTexSubImage3D



                                                       GLCOPYTEXSUBIMAGE3D(3G)