2003-2004 Silicon Graphics, Inc.
glTexSubImage2D 3G
glTexSubImage2D specify a two-dimensional texture subimage

## C Specification

void `glTexSubImage2D` GLenum target GLint level GLint xoffset GLint yoffset GLsizei width GLsizei height GLenum format GLenum type const GLvoid * pixels

## 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.

width

  Specifies the width of the texture subimage.

height

  Specifies the height of the texture subimage.

format

  Specifies the of the pixel data. The following symbolic values are accepted: `GL_ALPHA`, `GL_RGB`, `GL_RGBA`, `GL_LUMINANCE`, and `GL_LUMINANCE_ALPHA`.

type

  Specifies the data type of the pixel data. The following symbolic values are accepted: `GL_UNSIGNED_BYTE`, `GL_UNSIGNED_SHORT_5_6_5`, `GL_UNSIGNED_SHORT_4_4_4_4`, and `GL_UNSIGNED_SHORT_5_5_5_1`.

pixels

  Specifies a pointer to the image data in memory.

## Description

Texturing maps a portion of a specified texture image onto each graphical primitive for which texturing is enabled. To enable and disable two-dimensional texturing, call glEnable and glDisable with argument `GL_TEXTURE_2D`. Two-dimensional texturing is initially disabled.

`glTexSubImage2D` redefines a contiguous subregion of an existing two-dimensional texture image. The texels referenced by pixels replace the portion of the existing texture array with x indices xoffset and xoffset+width-1 , inclusive, and y indices yoffset and yoffset+height-1 , inclusive. This region may not include any texels outside the range of 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.

## Notes

glPixelStorei affects texture images in exactly the way it affects glTexImage2D.

`glTexSubImage2D` specifies a two-dimensional sub texture for the currently bound texture, specified with glBindTexture and current texture unit, specified with glActiveTexture.

## Errors

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

`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 is greater than log 2 max , where max is the returned value of `GL_MAX_TEXTURE_SIZE`.

`GL_INVALID_VALUE` is generated if xoffset<0 , xoffset+width> w , yoffset<0 , or yoffset+height> h , where w is the texture width and h is the texture height.

`GL_INVALID_VALUE` is generated if width or height is less than 0.

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

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

`GL_INVALID_OPERATION` is generated if type is `GL_UNSIGNED_SHORT_5_6_5` and format is not `GL_RGB`.

`GL_INVALID_OPERATION` is generated if type is one of `GL_UNSIGNED_SHORT_4_4_4_4`, or `GL_UNSIGNED_SHORT_5_5_5_1` and format is not `GL_RGBA`.

## Associated Gets

glGet with argument `GL_MAX_TEXTURE_SIZE`

## See Also

glActiveTexture, glBindTexture, glCompressedTexSubImage2D, glCopyTexSubImage2D, glGet, glPixelStorei, glTexEnv, glTexImage2D, 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/.