glCopyTexSubImage2D — copy a two-dimensional texture subimage
void glCopyTexSubImage2D( | GLenum | target, |
GLint | level, | |
GLint | xoffset, | |
GLint | yoffset, | |
GLint | x, | |
GLint | y, | |
GLsizei | width, | |
GLsizei | height) ; |
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.
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
width
and height height
replaces the portion of the
texture array with x indices xoffset
through
yoffset
through
level
.
The pixels in the rectangle are processed exactly as if
glReadPixels had been called, but the process stops just before
final conversion.
At this point, all pixel component values are clamped to the range
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 or height parameters of the specified texture array or to texel values outside the specified subregion.
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
,
GL_TEXTURE_CUBE_MAP_NEGATIVE_Z
, or
GL_TEXTURE_1D_ARRAY
.
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
GL_MAX_TEXTURE_SIZE
.
GL_INVALID_VALUE
is generated if
GL_TEXTURE_WIDTH
, and
GL_TEXTURE_HEIGHT
of the texture image being modified.
glCopyTexImage1D, glCopyTexImage2D, glCopyTexSubImage1D, glCopyTexSubImage3D, glPixelStore, glReadBuffer, glTexImage1D, glTexImage2D, glTexImage3D, glTexParameter, glTexSubImage1D, glTexSubImage2D, glTexSubImage3D
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/.