glCopyTexSubImage1D
[New
- Windows 95, OEM Service Release 2]
The glCopyTexSubImage1D
function copies a sub-image of a one-dimensional texture image from the frame
buffer.
void glCopyTexSubImage1D(
|
GLenum target, |
|
|
GLint level, |
|
|
GLint xoffset, |
|
|
GLint x, |
|
|
GLint y, |
|
|
GLsizei width |
|
|
); |
|
Parameters
target
The target to
which the image data will be changed. Must have the value GL_TEXTURE_1D.
level
The
level-of-detail number. Level 0 is the base image. Level n is the nth
mipmap reduction image.
xoffset
The texel
offset within the texture array.
x, y
The window
coordinates of the lower-left corner of the row of pixels to be copied.
width
The width of
the sub-image of the texture image. Specifying a texture sub-image with zero
width has no effect.
Remarks
The glCopyTexSubImage1D
function replaces a portion of a one-dimensional texture image using pixels
from the current frame buffer, rather than from main memory as is the case for glTexSubImage1D.
A row of
pixels beginning with the window coordinates specified by x and y
and with the length width replaces the portion of the texture array with
the indexes xoffset through xoffset + (width - 1). The destination in the texture array cannot include
any texels outside the originally specified texture array.
The glCopyTexSubImage1D
function processes the pixels in a row in the same way as glCopyPixels except that before the
final conversion of the pixels, all pixel component values are clamped to the range
[0, 1] and converted to the texture s internal format for storage in the
texture array. Pixel ordering is determined with lower x coordinates
corresponding to lower texture coordinates. If any of the pixels within a
specified row of the current frame buffer are outside the window associated
with the current rendering context, then their values are undefined.
No change is
made to the internalFormat, width, or border parameter of
the specified texture array or to texel values outside the specified texture
sub-image.
You cannot
include calls to glCopyTexSubImage1D in display lists.
Note The glCopyTexSubImage1D
function is only available in OpenGL version 1.1 or later.
Texturing has
no effect in color-index mode. The glPixelStore and glPixelTransfer functions affect texture
images in exactly the way they affect the way pixels are drawn using glDrawPixels.
The following
functions retrieve information related to glCopyTexSubImage1D:
glGetTexImage
glIsEnabled with argument GL_TEXTURE_1D
Error Codes
The following
are the error codes generated and their conditions.
|
Error
Code |
Condition |
|
GL_INVALID_ENUM
|
target was not an accepted value. |
|
GL_INVALID_VALUE
|
level was less than zero or greater than log sub 2(max),
where max is the returned value of GL_MAX_TEXTURE_SIZE. |
|
GL_INVALID_VALUE |
xoffset was less than border or (xoffset + width)
was greater than (w + border), where w is
GL_TEXTURE_WIDTH and border is GL_TEXTURE_BORDER. Note that w
includes twice the border width. |
|
GL_INVALID_VALUE |
width was less than border or y was less
than border, where border is the border width of the texture
array. |
|
GL_INVALID_OPERATION
|
The texture
array was not defined by a previous glTexImage1D operation. |
|
GL_INVALID_OPERATION
|
glCopyTexSubImage1D was called between a call to glBegin and the
corresponding call to glEnd. |
See Also