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
glCopyTexSubImage3D 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 glTexSubImage3D).
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
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 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
glCopyTexSubImage3D is available only if the GL version is 1.2 or greater.
Texturing has no effect in color index mode.
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
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 glTexImage3D or glCopyTexImage3D operation.
GL_INVALID_VALUE is generated if level is less than 0.
GL_INVALID_VALUE may be generated if level is greater
than $log sub 2^max$,
where $max$ 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 glCopyTexSubImage3D is executed
between the execution of glBegin and the corresponding
execution of glEnd.
ASSOCIATED GETS
glGetTexImage glIsEnabled with argument GL_TEXTURE_3D
