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<STRONG>NAME</STRONG>
<STRONG>glCopyTexSubImage1D</STRONG> - copy a one-dimensional texture
subimage
<STRONG>C</STRONG> <STRONG>SPECIFICATION</STRONG>
void <STRONG>glCopyTexSubImage1D</STRONG>( GLenum <EM>target</EM>,
GLint <EM>level</EM>,
GLint <EM>xoffset</EM>,
GLint <EM>x</EM>,
GLint <EM>y</EM>,
GLsizei <EM>width</EM> )
<STRONG>PARAMETERS</STRONG>
<EM>target</EM> Specifies the target texture. Must be
<STRONG>GL_TEXTURE_1D</STRONG>.
<EM>level</EM> Specifies the level-of-detail number. Level 0 is
the base image level. Level <EM>n</EM> is the <EM>n</EM>th mipmap
reduction image.
<EM>xoffset</EM> Specifies the texel offset within the texture
array.
<EM>x</EM>, <EM>y</EM> Specify the window coordinates of the left corner
of the row of pixels to be copied.
<EM>width</EM> Specifies the width of the texture subimage.
<STRONG>DESCRIPTION</STRONG>
<STRONG>glCopyTexSubImage1D</STRONG> replaces a portion of a one-dimensional
texture image with pixels from the current <STRONG>GL_READ_BUFFER</STRONG>
(rather than from main memory, as is the case for
<STRONG>glTexSubImage1D</STRONG>).
The screen-aligned pixel row with left corner at (<EM>x</EM>, <EM>y</EM>), and
with length <EM>width</EM> replaces the portion of the texture array
with x indices <EM>xoffset</EM> 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
<STRONG>glCopyPixels</STRONG> 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
<STRONG>GL_READ_BUFFER</STRONG> 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 <EM>internalformat</EM>, <EM>width</EM>, or <EM>border</EM>
parameters of the specified texture array or to texel values
outside the specified subregion.
<STRONG>NOTES</STRONG>
<STRONG>glCopyTexSubImage1D</STRONG> is available only if the GL version is
1.1 or greater.
Texturing has no effect in color index mode.
<STRONG>glPixelStore</STRONG> and <STRONG>glPixelTransfer</STRONG> modes affect texture images
in exactly the way they affect <STRONG>glDrawPixels</STRONG>.
<STRONG>ERRORS</STRONG>
<STRONG>GL_INVALID_ENUM</STRONG> is generated if <EM>target</EM> is not <STRONG>GL_TEXTURE_1D</STRONG>.
<STRONG>GL_INVALID_OPERATION</STRONG> is generated if the texture array has
not been defined by a previous <STRONG>glTexImage1D</STRONG> or
<STRONG>glCopyTexImage1D</STRONG> operation.
<STRONG>GL_INVALID_VALUE</STRONG> is generated if <EM>level</EM> is less than 0.
<STRONG>GL_INVALID_VALUE</STRONG> may be generated if <EM>level</EM>>log <EM>max</EM>, where
<EM>max</EM> is the returned value of <STRONG>GL_MAX_TEXTURE_SIZE</STRONG>.
<STRONG>GL_INVALID_VALUE</STRONG> is generated if <EM>y</EM> < -b or if <EM>width</EM> < -b,
where b is the border width of the texture array.
<STRONG>GL_INVALID_VALUE</STRONG> is generated if xoffset < -b, or
(xoffset + width) > (w-b), where w is the <STRONG>GL_TEXTURE_WIDTH</STRONG>,
and b is the <STRONG>GL_TEXTURE_BORDER</STRONG> of the texture image being
modified. Note that w includes twice the border width.
<STRONG>ASSOCIATED</STRONG> <STRONG>GETS</STRONG>
<STRONG>glGetTexImage</STRONG>
<STRONG>glIsEnabled</STRONG> with argument <STRONG>GL_TEXTURE_1D</STRONG>
<STRONG>SEE</STRONG> <STRONG>ALSO</STRONG>
<STRONG>glCopyPixels</STRONG>, <STRONG>glCopyTexImage1D</STRONG>, <STRONG>glCopyTexImage2D</STRONG>,
<STRONG>glCopyTexSubImage2D</STRONG>, <STRONG>glPixelStore</STRONG>, <STRONG>glPixelTransfer</STRONG>,
<STRONG>glTexEnv</STRONG>, <STRONG>glTexGen</STRONG>, <STRONG>glTexImage1D</STRONG>, <STRONG>glTexImage2D</STRONG>,
<STRONG>glTexParameter</STRONG>, <STRONG>glTexSubImage1D</STRONG>, <STRONG>glTexSubImage2D</STRONG>
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