1991-2006 Silicon Graphics, Inc.
glCopyTexSubImage1D 3G
glCopyTexSubImage1D copy a one-dimensional texture subimage

## C Specification

void `glCopyTexSubImage1D` GLenum target GLint level GLint xoffset GLint x GLint y GLsizei width

## Parameters

target

  Specifies the target texture. Must be `GL_TEXTURE_1D`.

level

  Specifies the level-of-detail number. Level 0 is the base image level. Level n is the nth mipmap reduction image.

xoffset

  Specifies the texel offset within the texture array.

x
y

  Specify the window coordinates of the left corner of the row of pixels to be copied.

width

  Specifies the width of the texture subimage.

## Description

`glCopyTexSubImage1D` replaces a portion of a one-dimensional texture image with pixels from the current `GL_READ_BUFFER` (rather than from main memory, as is the case for glTexSubImage1D).

The screen-aligned pixel row with left corner at (x,\ y), and with length width replaces the portion of the texture array with x indices xoffset 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 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 row 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, or border parameters of the specified texture array or to texel values outside the specified subregion.

## Notes

`glCopyTexSubImage1D` 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.

When the `ARB_imaging` extension is supported, the RGBA components copied 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_1D`.

`GL_INVALID_OPERATION` is generated if the texture array has not been defined by a previous glTexImage1D or glCopyTexImage1D 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 , or xoffset + width > w - b , where w is the `GL_TEXTURE_WIDTH` and b is the `GL_TEXTURE_BORDER` of the texture image being modified. Note that w includes twice the border width.

## Associated Gets

glGetTexImage

glIsEnabled with argument `GL_TEXTURE_1D`

## See Also

glCopyPixels, glCopyTexImage1D, glCopyTexImage2D, glCopyTexSubImage2D, 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/.