_glCopyTexSubImage1D: copy a one-dimensional texture subimage
- 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);
- Specifies the target texture. Must be _GL_TEXTURE_1D.
- Specifies the level-of-detail number. Level 0 is the base image level. Level n is the nth mipmap reduction image.
- 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.
- Specifies the width of the texture subimage.
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.
The _glPixelStore mode affects texture images.
_GL_INVALID_VALUE is generated if level is less than 0.