- Method
glCopyTexSubImage2D
void glCopyTexSubImage2D(int target, int level, int xoffset, int yoffset, int x, int y, int width, int height)
- Description
glCopyTexSubImage2D replaces a rectangular portion of a two-dimensional
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
glCopyPixels 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.
- Parameter target
Specifies the target texture.
Must be GL_TEXTURE_2D
- Parameter level
Specifies the level-of-detail number.
Level 0 is the base image level.
Level n is the nth mipmap reduction image.
- Parameter xoffset
Specifies a texel offset in the x direction within the texture array.
- Parameter yoffset
Specifies a texel offset in the y direction within the texture array.
- Parameter x
Specify the window coordinates of the lower left corner
of the rectangular region of pixels to be copied.
- Parameter width
Specifies the width of the texture subimage.
- Parameter height
Specifies the height of the texture subimage.
- Throws
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.
.P
GL_INVALID_VALUE may be generated if level is greater
than log sub 2 max,
where max is the returned value of GL_MAX_TEXTURE_SIZE .
GL_INVALID_VALUE is generated if x ~<~ ~-b or if
y ~<~ ~-b,
where b is the border width of the texture array.
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.
GL_INVALID_OPERATION is generated if glCopyTexSubImage2D is executed
between the execution of glBegin and the corresponding
execution of glEnd .
GL.glCopyTexSubImage1D()