glCopyTexSubImage3DEXT(3G) OpenGL Reference glCopyTexSubImage3DEXT(3G)
NAME
glCopyTexSubImage3DEXT - copy pixels into a 3D texture subimage
C SPECIFICATION
void glCopyTexSubImage3DEXT( GLenum target,
GLint level,
GLint xoffset,
GLint yoffset,
GLint zoffset,
GLint x,
GLint y,
GLsizei width,
GLsizei height )
PARAMETERS
target The target texture. Must be GLTEXTURE3DEXT
level The level-of-detail number. Level 0 is the base image level.
Level n is the nth mipmap reduction image.
xoffset A texel offset in the x direction within the texture array.
yoffset A texel offset in the y direction within the texture array.
zoffset A texel offset in the z direction within the texture array.
x The x coordinate of the lower-left corner of the pixel rectangle
to be transferred to the texture array.
y The y coordinate of the lower-left corner of the pixel rectangle
to be transferred to the texture array.
width The width of the texture subimage.
height The height of the texture subimage.
DESCRIPTION
glCopyTexSubImage3DEXT replaces a rectangular portion of a three-
dimensional texture image with pixels from the current GLREADBUFFER
(rather than from main memory, as is the case for glTexSubImage3DEXT).
The screen-aligned pixel rectangle with lower-left corner at (x, y)
having width width and height height replaces the rectangular area of the
S-T slice located at zoffset with x indices xoffset through
xoffset+width-1, inclusive, and y indices yoffset through
yoffset+height-1, inclusive (But, see discussion of GLINTERLACESGIX
below).
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glCopyTexSubImage3DEXT(3G) OpenGL Reference glCopyTexSubImage3DEXT(3G)
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 GLINTERLACESGIX is enabled, then every other row of the destination
texture is skipped. That is, only rows (0,2,4,...) of the S-T slice
(where the border is considered part of the slice) are defined. A
complete video frame may be assembled in a slice of the texture array by
invoking glCopyTexSubImage3DEXT on two consecutive video fields, with
yoffset values that differ by one.
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.
If any of the pixels within the specified rectangle of the current
GLREADBUFFER are outside the read window associated with the current
rendering context, then the values obtained for those pixels are
undefined.
NOTES
glCopyTexSubImage3DEXT is part of the EXTcopytexture extension. See
glIntro for more information about using extensions.
ERRORS
GLINVALIDENUM is generated when target is not one of the allowable
values.
GLINVALIDVALUE is generated if level is less than zero or greater than
log (max), where max is the returned value of GLMAXTEXTURESIZE.
2
GLINVALIDVALUE is generated if xoffset<-TEXTURE_BORDER,
(xoffset+width)>(TEXTURE_WIDTH-TEXTURE_BORDER), yoffset<-TEXTURE_BORDER,
(yoffset+interlacexheight)>(TEXTURE_HEIGHT-TEXTURE_BORDER), or if
zoffset<-TEXTURE_BORDER. Where TEXTURE_WIDTH, TEXTURE_HEIGHT, and
TEXTURE_BORDER are the state values of the texture image being modified,
and interlace is 1 if GLINTERLACESGIX is disabled and 2 otherwise.
Note that TEXTURE_WIDTH and TEXTURE_HEIGHT include twice the border
width.
GLINVALIDVALUE is generated if width or height is negative.
GLINVALIDOPERATION is generated when the texture array has not been
defined by a previous glTexImage3D (or equivalent) operation.
GLINVALIDOPERATION is generated if glCopyTexSubImage3DEXT is executed
between the execution of glBegin and the corresponding execution of
glEnd.
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glCopyTexSubImage3DEXT(3G) OpenGL Reference glCopyTexSubImage3DEXT(3G)
ASSOCIATED GETS
glGetTexImage
MACHINE DEPENDENCIES
glCopyTexSubImage3DEXT is not supported on RealityEngine, RealityEngine2,
and VTX systems.
On InfiniteReality systems, there is a performance benefit when the width
of the image to be transferred to texture memory is a multiple of 8.
Texture borders are not supported on InfiniteReality systems.
Applications should use borderless textures and GLCLAMPTOEDGESGIS
wrap mode.
On High Impact and Maximum Impact systems, if the right side of the image
to be transferred to texture memory is not the right side of the texture,
then its index must be a multiple of 32, where index = xoffset+width.
Otherwise it will generate a GLINVALIDVALUE error.
The SGIXinterlace extension is supported only on InfiniteReality
systems, on RealityEngine, RealityEngine2, and VTX systems, and on O2
systems.
SEE ALSO
glTexImage3D, glTexSubImage3DEXT, glCopyPixels.
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