glCompressedTexSubImage2D

Name

glCompressedTexSubImage2D - specify a two-dimensional compressed texture subimage

C Specification

void glCompressedTexSubImage2D(GLenum target,
    GLint level,
    GLint xoffset,
    GLint yoffset,
    GLsizei width,
    GLsizei height,
    GLenum format,
    GLsizei imageSize,
    const GLvoid * data)

Parameters

target: Specifies the target texture. Must be GL_TEXTURE_2D.
level: Specifies the level-of-detail number.
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 format of the pixel data. Currently, there is no supported format.
imageSize: Specifies the size of the compressed pixel data in bytes.
data: Specifies a pointer to the compressed image data in memory.

Description

glCompressedTexSubImage2D redefines a contiguous subregion of an existing two-dimensional compressed 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.

Currently, there is no supported compressed format for this function.

Notes

glPixelStore has no effect on compressed texture images.

glCompressedTexSubImage2D specifies the two-dimensional sub texture for the currently bound texture, specified with glBindTexture, and the 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 glCompressedTexImage2D operation.

GL_INVALID_VALUE is generated if level is less than 0.

GL_INVALID_VALUE may be generated if level is greater than log₂max, 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 texture width, h is the texture height, and b is the border of the texture image being modified. Note that w and h include twice the border width.

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

GL_INVALID_ENUM is generated if type is not a type 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.

GL_INVALID_OPERATION is generated if none of the above error conditions apply.

Associated Gets

glGet with argument GL_MAX_TEXTURE_SIZE

Copyright

This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.