1991-2006 Silicon Graphics, Inc.
glCopyTexSubImage2D 3G
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 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.

## Notes

`glCopyTexSubImage2D` is available only if the GL version is 1.1 or greater.

`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`, `GL_TEXTURE_CUBE_MAP_NEGATIVE_Z`, or `GL_PROXY_TEXTURE_CUBE_MAP` are available only if the GL version is 1.3 or greater.

Texturing has no effect in color index mode.

glPixelStore and glPixelTransfer modes affect texture images in exactly the way they affect glDrawPixels.

When the `ARB_imaging` extension is supported, the RGBA components read from the framebuffer may be processed by the imaging pipeline. See glTexImage1D for specific details.

## 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 or glCopyTexImage2D 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 < - b , xoffset + width > w - b , yoffset < - b , or yoffset + height > h - b , where w is the `GL_TEXTURE_WIDTH`, h is the `GL_TEXTURE_HEIGHT`, and b is the `GL_TEXTURE_BORDER` of the texture image being modified. Note that w and h include twice the border width.

`GL_INVALID_OPERATION` is generated if `glCopyTexSubImage2D` is executed between the execution of glBegin and the corresponding execution of glEnd.

## Associated Gets

glGetTexImage

glIsEnabled with argument `GL_TEXTURE_2D`

## See Also

glCopyPixels, glCopyTexImage1D, glCopyTexImage2D, glCopyTexSubImage1D, glCopyTexSubImage3D, glPixelStore, glPixelTransfer, glReadBuffer, glTexEnv, glTexGen, glTexImage1D, glTexImage2D, glTexImage3D, glTexParameter, glTexSubImage1D, glTexSubImage2D, glTexSubImage3D

## Copyright

Copyright 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.