fglCopyTexSubImage3D(3G)

NAME
     fglCopyTexSubImage3D - copy a three-dimensional texture subimage


FORTRAN SPECIFICATION
     SUBROUTINE fglCopyTexSubImage3D( INTEGER*4 target,
                                      INTEGER*4 level,
                                      INTEGER*4 xoffset,
                                      INTEGER*4 yoffset,
                                      INTEGER*4 zoffset,
                                      INTEGER*4 x,
                                      INTEGER*4 y,
                                      INTEGER*4 width,
                                      INTEGER*4 height )


PARAMETERS
     target   Specifies the target texture.  Must be GL_TEXTURE_3D

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

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

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

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

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

     width    Specifies the width of the texture subimage.

     height   Specifies the height of the texture subimage.

DESCRIPTION
     fglCopyTexSubImage3D replaces a rectangular portion of a three-
     dimensional texture image with pixels from the current GL_READ_BUFFER
     (rather than from main memory, as is the case for fglTexSubImage3D).

     The screen-aligned pixel rectangle with lower left corner at (x, y) and
     with width width and height height replaces the portion of the texture
     array with x indices xoffset through xoffset + width - 1, inclusive, and
     y indices yoffset through yoffset + height - 1, inclusive, at z index
     zoffset and at the mipmap level specified by level.

     The pixels in the rectangle are processed exactly as if fglCopyPixels 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 texels
     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.

     If any of the pixels within the specified rectangle 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, height, depth, or border
     parameters of the specified texture array or to texel values outside the
     specified subregion.

NOTES
     fglCopyTexSubImage3D is available only if the GL version is 1.2 or
     greater.

     Texturing has no effect in color index mode.

     fglPixelStore and fglPixelTransfer modes affect texture images in exactly
     the way they affect fglDrawPixels.

     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 fglTexImage2D for specific
     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 fglTexImage3D or fglCopyTexImage3D operation.

     GL_INVALID_VALUE is generated if level is less than 0.

     GL_INVALID_VALUE may be generated if level is greater than log max, where
                                                                   2
     max is the returned value of GL_MAX_3D_TEXTURE_SIZE.

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

     GL_INVALID_VALUE is generated if xoffset < -b,
     (xoffset + width) > (w - b), yoffset <  -b, (yoffset + height) > (h - b),
     zoffset <  -b, or zoffset > (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 fglCopyTexSubImage3D is executed
     between the execution of fglBegin and the corresponding execution of
     fglEnd.

ASSOCIATED GETS
     fglGetTexImage
     fglIsEnabled with argument GL_TEXTURE_3D


SEE ALSO
     fglCopyPixels, fglCopyTexImage1D, fglCopyTexImage2D,
     fglCopyTexSubImage1D, fglCopyTexSubImage2D, fglPixelStore,
     fglPixelTransfer, fglReadBuffer, fglTexEnv, fglTexGen, fglTexImage1D,
     fglTexImage2D, fglTexImage3D, fglTexParameter, fglTexSubImage1D,
     fglTexSubImage2D, fglTexSubImage3D