glCopyTexSubImage1D(3G) OpenGL Reference glCopyTexSubImage1D(3G)
NAME
glCopyTexSubImage1D - copy a one-dimensional texture subimage
C SPECIFICATION
void glCopyTexSubImage1D( GLenum target,
GLint level,
GLint xoffset,
GLint x,
GLint y,
GLsizei width )
PARAMETERS
target Specifies the target texture. Must be GLTEXTURE1D.
level Specifies the level-of-detail number. Level 0 is the base image
level. Level n is the nth mipmap reduction image.
xoffset Specifies the texel offset within the texture array.
x, y Specify the window coordinates of the left corner of the row of
pixels to be copied.
width Specifies the width of the texture subimage.
DESCRIPTION
glCopyTexSubImage1D replaces a portion of a one-dimensional texture image
with pixels from the current GLREADBUFFER (rather than from main
memory, as is the case for glTexSubImage1D).
The screen-aligned pixel row with left corner at (x, y), and with length
width replaces the portion of the texture array with x indices xoffset
through xoffset + width - 1, inclusive. The destination in the texture
array may not include any texels outside 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 component values are clamped to the range [0, 1] and then
converted to the texture's internal format 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 GLREADBUFFER 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 values outside the specified
subregion.
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glCopyTexSubImage1D(3G) OpenGL Reference glCopyTexSubImage1D(3G)
NOTES
glCopyTexSubImage1D is available only if the GL version is 1.1 or
greater.
Texturing has no effect in color index mode.
glPixelStore and glPixelTransfer modes affect texture images in exactly
the way they affect glDrawPixels.
ERRORS
GLINVALIDENUM is generated if target is not GLTEXTURE1D.
GLINVALIDOPERATION is generated if the texture array has not been
defined by a previous glTexImage1D or glCopyTexImage1D operation.
GLINVALIDVALUE is generated if level is less than 0.
GLINVALIDVALUE may be generated if level>log max, where max is the
2
returned value of GLMAXTEXTURESIZE.
GLINVALIDVALUE is generated if y < -b or if width < -b, where b is
the border width of the texture array.
GLINVALIDVALUE is generated if xoffset < -b, or
(xoffset + width) > (w-b), where w is the GLTEXTUREWIDTH, and b is the
GLTEXTUREBORDER of the texture image being modified. Note that w
includes twice the border width.
ASSOCIATED GETS
glGetTexImage
glIsEnabled with argument GLTEXTURE1D
MACHINE DEPENDENCIES
glCopyTexSubImage1D and glCopyTexSubImage1DEXT are 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.
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glCopyTexSubImage1D(3G) OpenGL Reference glCopyTexSubImage1D(3G)
SEE ALSO
glCopyPixels, glCopyTexImage1D, glCopyTexImage2D, glCopyTexSubImage2D,
glPixelStore, glPixelTransfer, glTexEnv, glTexGen, glTexImage1D,
glTexImage2D, glTexParameter, glTexSubImage1D, glTexSubImage2D
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