glCopyTexSubImage1DEXT(3G) OpenGL Reference glCopyTexSubImage1DEXT(3G)
NAME
glCopyTexSubImage1DEXT - copy pixels into a 1D texture subimage
C SPECIFICATION
void glCopyTexSubImage1DEXT( GLenum target,
GLint level,
GLint xoffset,
GLint x,
GLint y,
GLsizei width )
PARAMETERS
target The target texture. Must be GLTEXTURE1D
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.
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 pixel rectangle to be transferred to the
texture array.
DESCRIPTION
glCopyTexSubImage1DEXT replaces a rectangular portion of a two-
dimensional texture image with pixels from the current GLREADBUFFER
(rather than from main memory, as is the case for glTexSubImage1DEXT).
The screen-aligned pixel rectangle with lower-left corner at (x, y),
width width and height 1 replaces the portion of the texture array with x
indices xoffset through xoffset+width-1, inclusive. The destination
rectangle in the texture array may not include any texels outside the
texture array as it was originally specified.
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.
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
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.
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glCopyTexSubImage1DEXT(3G) OpenGL Reference glCopyTexSubImage1DEXT(3G)
NOTES
glCopyTexSubImage1DEXT 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, or
(xoffset+width)>(TEXTURE_WIDTH-TEXTURE_BORDER), where TEXTURE_WIDTH and
TEXTURE_BORDER are the state values of the texture image being modified.
Note that TEXTURE_WIDTH includes twice the border width.
GLINVALIDVALUE is generated if width is negative.
GLINVALIDOPERATION is generated when the texture array has not been
defined by a previous glTexImage1D (or equivalent) operation.
GLINVALIDOPERATION is generated if glCopyTexSubImage1DEXT is executed
between the execution of glBegin and the corresponding execution of
glEnd.
ASSOCIATED GETS
glGetTexImage
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.
SEE ALSO
glTexImage1D, glTexSubImage1DEXT, glCopyPixels.
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