2003-2004 Silicon Graphics, Inc.
glCopyTexImage2D 3G
glCopyTexImage2D specify a two-dimensional texture image with pixels from the color buffer

## C Specification

void `glCopyTexImage2D` GLenum target GLint level GLenum internalformat GLint x GLint y GLsizei width GLsizei height GLint border

## 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.

internalformat

  Specifies the color components of the texture. Must be one of the following symbolic constants: `GL_ALPHA`, `GL_LUMINANCE`, `GL_LUMINANCE_ALPHA`, `GL_RGB`, or `GL_RGBA`.

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 image. Must be 0 or 2 n for some integer n.

height

  Specifies the height of the texture image. Must be 0 or 2 m for some integer m.

border

  Specifies the width of the border. Must be 0.

## Description

`glCopyTexImage2D` defines a two-dimensional texture image with pixels from the color buffer.

The screen-aligned pixel rectangle with lower left corner at (x, y) and with a width of width and a height of height defines the texture array at the mipmap level specified by level. internalformat specifies the color components of the texture.

The red, green, blue, and alpha components of each pixel that is read are converted to an internal fixed-point or floating-point format with unspecified precision. The conversion maps the largest representable component value to 1.0, and component value 0 to 0.0. The values are then converted to the texture's internal format for storage in the texel array.

internalformat must be chosen such that color buffer components can be dropped during conversion to the internal format, but new components cannot be added. For example, an `GL_RGB` color buffer can be used to create `GL_LUMINANCE` or `GL_RGB` textures, but not `GL_ALPHA`, `GL_LUMINANCE_ALPHA` or `GL_RGBA` textures.

Pixel ordering is such that lower x and y screen coordinates correspond to lower s and t texture coordinates.

If any of the pixels within the specified rectangle of the color buffer are outside the window associated with the current rendering context, then the values obtained for those pixels are undefined.

## Notes

An image with height or width of 0 indicates a null-texture.

## Errors

`GL_INVALID_ENUM` is generated if target is not `GL_TEXTURE_2D`.

`GL_INVALID_OPERATION` is generated if internalformat is not compatible with the color buffer format.

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

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

`GL_INVALID_VALUE` is generated if width or height is less than 0, greater than `GL_MAX_TEXTURE_SIZE`, or if width or height cannot be represented as 2 k for some integer k.

`GL_INVALID_VALUE` is generated if border is not 0.

`GL_INVALID_ENUM` is generated if internalformat is not an accepted constant.

## Associated Gets

glGet with argument `GL_MAX_TEXTURE_SIZE`

## See Also

glCompressedTexImage2D, glCopyTexSubImage2D, glGet, glTexEnv, glTexImage2D, glTexSubImage2D, glTexParameter

## Copyright

Copyright 2003-2004 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.