NAME¶
glCopyTexSubImage2D - copy a two-dimensional texture subimage
C SPECIFICATION¶
void
glCopyTexSubImage2D(GLenum target,
GLint level, GLint xoffset,
GLint yoffset, GLint x,
GLint y, GLsizei width,
GLsizei height);
PARAMETERS¶
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.
DESCRIPTION¶
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 x y and with width
width and height
height replaces the portion of the texture
array with x indices
xoffset through xoffset + width - 1, inclusive,
and y indices
yoffset through yoffset + height - 1, inclusive, at the
mipmap level specified by
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 0 1 and then
converted to the texture's internal format for storage in the texel array.
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,
height, or
border parameters of the specified texture array or to texel values
outside the specified subregion.
NOTES¶
glPixelStore() modes affect texture images.
ERRORS¶
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,
or
GL_TEXTURE_CUBE_MAP_NEGATIVE_Z.
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 > log 2 max, 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
GL_TEXTURE_WIDTH, h is the
GL_TEXTURE_HEIGHT, and b is the
GL_TEXTURE_BORDER of the texture image being modified. Note that w and
h include twice the border width.
ASSOCIATED GETS¶
glGetTexImage()
SEE ALSO¶
glCopyTexImage1D(),
glCopyTexImage2D(),
glCopyTexSubImage1D(),
glCopyTexSubImage3D(),
glPixelStore(),
glReadBuffer(),
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/.
