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# docs.GL

OpenGL 4
OpenGL 3
OpenGL 2
OpenGL ES 3
OpenGL ES 2

# glCopyTexSubImage2D

## Name

glCopyTexSubImage2D — copy a two-dimensional texture subimage

## C Specification

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

## Parameters

`target`

  Specifies the target texture. Must be `GL_TEXTURE_2D`, `GL_TEXTURE_CUBE_MAP_POSITIVE_X`, `GL_TEXTURE_CUBE_MAP_NEGATIVE_X`, `GL_TEXTURE_CUBE_MAP_POSITIVE_Y`, `GL_TEXTURE_CUBE_MAP_NEGATIVE_Y`, `GL_TEXTURE_CUBE_MAP_POSITIVE_Z`, or `GL_TEXTURE_CUBE_MAP_NEGATIVE_Z`.

`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.

## Description

`glCopyTexSubImage2D` replaces a rectangular portion of a two-dimensional texture image or cube-map 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 glReadPixels had been called, but the process stops after conversion to RGBA values. The error `GL_INVALID_OPERATION` is generated if integer RGBA data is required and the format of the current color buffer is not integer; or if floating- or fixed-point RGBA data is required and the format of the current color buffer is integer.

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.

## Notes

glPixelStorei modes affect texture images.

## Errors

`GL_INVALID_ENUM` is generated if `target` is not `GL_TEXTURE_2D`, `GL_TEXTURE_CUBE_MAP_POSITIVE_X`, `GL_TEXTURE_CUBE_MAP_NEGATIVE_X`, `GL_TEXTURE_CUBE_MAP_POSITIVE_Y`, `GL_TEXTURE_CUBE_MAP_NEGATIVE_Y`, `GL_TEXTURE_CUBE_MAP_POSITIVE_Z`, or `GL_TEXTURE_CUBE_MAP_NEGATIVE_Z`.

`GL_INVALID_OPERATION` is generated if the texture array has not been defined by a previous glTexImage2D, glCopyTexImage2D, or glTexStorage2D operation.

`GL_INVALID_VALUE` is generated if `level` is less than 0.

`GL_INVALID_VALUE` may be generated if level > log 2 ⁡ max , where max is the returned value of `GL_MAX_TEXTURE_SIZE`.

`GL_INVALID_VALUE` is generated if xoffset + width > w , or yoffset + height > h , where w is the `GL_TEXTURE_WIDTH`, h is the `GL_TEXTURE_HEIGHT`, of the texture image being modified.

## API Version Support

| OpenGL ES API Version
--- | ---
Function Name | 2.0 | 3.0 | 3.1
glCopyTexSubImage2D | ✔ | ✔ | ✔

## See Also

glCopyTexImage2D, glCopyTexSubImage3D, glPixelStorei, glReadBuffer, glTexImage2D, glTexImage3D, glTexParameter, glTexSubImage2D, glTexSubImage3D

## Copyright

Copyright © 1991-2006 Silicon Graphics, Inc. Copyright © 2010-2014 Khronos Group. This document is licensed under the SGI Free Software B License. For details, see https://web.archive.org/web/20171022161616/http://oss.sgi.com/projects/FreeB/.

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