glCopyTexSubImage2D
- specify a two-dimensional texture subimage with pixels from the color buffer
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
.
level
Specifies the level-of-detail number. Level 0 is the base image level. Level n
is the n
th 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 with pixels from the color buffer.
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 the same way as with glCopyTexImage2D
.
glCopyTexSubImage2D
requires that the internal format of the currently bound texture is such that color buffer components can be dropped during conversion to the internal format, but new components cannot be added. For example, an RGB
color buffer can be used to create LUMINANCE
or RGB
textures, but not ALPHA
, LUMINANCE_ALPHA
or RGBA
textures.
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 color 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.
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 or if the internal format of the currently bound texture 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 log2max, where max is the returned value of GL_MAX_TEXTURE_SIZE
.
GL_INVALID_VALUE
is generated if x < - b, or y < - b, where b is the border of the texture being modified.
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.
glGet
with argument GL_MAX_TEXTURE_SIZE
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/.
glCompressedTexSubImage2D
, glCopyTexImage2D
, glGet
, glTexEnv
, glTexImage2D
, glTexParameter
, glTexSubImage2D