GlCopyTexSubImage1D

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_glCopyTexSubImage1D: copy a one-dimensional texture subimage


Syntax

SUB _glCopyTexSubImage1D (BYVAL target AS _UNSIGNED LONG, BYVAL level AS LONG, BYVAL xoffset AS LONG, BYVAL x AS LONG, BYVAL y AS LONG, BYVAL width AS LONG)
void _glCopyTexSubImage1D(GLenum target, GLint level, GLint xoffset, GLint x, GLint y, GLsizei width);


target
Specifies the target texture. Must be _GL_TEXTURE_1D.
level
Specifies the level-of-detail number. Level 0 is the base image level. Level n is the nth mipmap reduction image.
xoffset
Specifies the texel offset within the texture array.
x, y
Specify the window coordinates of the left corner of the row of pixels to be copied.
width
Specifies the width of the texture subimage.


Description

_glCopyTexSubImage1D replaces a portion of a one-dimensional texture image with pixels from the current _GL_READ_BUFFER (rather than from main memory, as is the case for _glTexSubImage1D).

The screen-aligned pixel row with left corner at (x,\ y), and with length width replaces the portion of the texture array with x indices xoffset through xoffset + width - 1, inclusive. The destination in the texture array may not include any texels outside the texture array as it was originally specified.

The pixels in the row 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.

It is not an error to specify a subtexture with zero width, but such a specification has no effect. If any of the pixels within the specified row 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 border parameters of the specified texture array or to texel values outside the specified subregion.


Notes:

The _glPixelStore mode affects texture images.


Errors

_GL_INVALID_ENUM is generated if /target is not _GL_TEXTURE_1D.

_GL_INVALID_OPERATION is generated if the texture array has not been defined by a previous _glTexImage1D or _glCopyTexImage1D operation.

_GL_INVALID_VALUE is generated if level is less than 0.

_GL_INVALID_VALUE may be generated if level is greater than log<sub>2</sub>(max), where max is the returned value of _GL_MAX_TEXTURE_SIZE.

_GL_INVALID_VALUE is generated if xoffset < 0 or xoffset + width > w, where w is the _GL_TEXTURE_WIDTH.


Use With:

_glGetTexImage


See also

_GL _glActiveTexture, _glBindTexture, _glBindFramebuffer, _glCopyImageSubData, _glCopyTexSubImage2D, _glCopyTexSubImage3D, _glCopyTexImage1D, _glReadBuffer


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/.



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