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glCopyTexSubImage2D
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glCopyTexSubImage2D: copy a two-dimensional texture subimage.

C Specification | Parameters | Description | Notes | Errors | Associated Gets | See Also

[Up] C Specification

void glCopyTexSubImage2D(
    GLenum	 target,
    GLint	 level,
    GLint	 xoffset,
    GLint	 yoffset,
    GLint	 x,
    GLint	 y,
    GLsizei	 width,
    GLsizei	 height)

[Up] Parameters

target
Specifies the target texture. Must be GL_TEXTURE_2D
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.
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.

[Up] Description

glCopyTexSubImage2D replaces a rectangular portion of a two-dimensional texture image with pixels from the current GL_READ_BUFFER (rather than from main memory, as is the case for glTexSubImage2D).

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 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 format 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, or border parameters of the specified texture array or to texel values outside the specified subregion.

[Up] Notes

glCopyTexSubImage2D 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.

[Up] Errors

[Up] Associated Gets

glGetTexImage
glIsEnabled with argument GL_TEXTURE_2D

[Up] See Also

glCopyPixels,
glCopyTexImage1D,
glCopyTexImage2D,
glCopyTexSubImage1D,
glPixelStore,
glPixelTransfer,
glTexEnv,
glTexGen,
glTexImage1D,
glTexImage2D,
glTexParameter,
glTexSubImage1D,
glTexSubImage2D

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