GLCOPYTEXSUBIMAGE3DEXT(3gl)GLCOPYTEXSUBIMAGE3DEXT(3gl)NAME
glCopyTexSubImage3DEXT - copy a three-dimensional texture image
C SPECIFICATION
void glCopyTexSubImage3DEXT( GLenum target,
GLint level,
GLint xoffset,
GLint yoffset,
GLint zoffset,
GLint x,
GLint y,
GLsizei width,
GLsizei height)
PARAMETERS
target Specifies the target texture. Must be GL_TEXTURE_3D_EXT.
level Specifies the level-of-detail number. Level 0 is the base
image level. Level n is the nth 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.
zoffset Specifies a texel offset in the z 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.
DESCRIPTION
glCopyTexSubImage3DEXT replaces a rectangular portion of a three-dimen‐
sional texture image with pixels from the current GL_READ_BUFFER
(rather than from main memory, as is the case for glTexSubImage3DEXT).
The screen-aligned pixel rectangle with lower left corner at (x, y) and
with width width and height height replaces the two-dimensional slice
located at (xoffset, yoffset, zoffset) of the three dimensional texture
array. The texels replaced in the two-dimensional slice are at 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 tex‐
els 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 unde‐
fined.
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.
If glCopyTexSubImage3DEXT is called on a constant texture, then a copy
is made internally before executing the call. A texture is a "constant
texture" if at the time of the specification of the texture no copy was
made internally. See glTexImage3DEXT and glPixelStore for details.
NOTES
Texturing has no effect in color index mode.
glPixelStore and glPixelTransfer modes affect texture images in exactly
the way they affect glDrawPixels. In addition, the extension defines
two additional pixel store modes and one additional wrap mode as
defined in glTexImage3DEXT.
One additional pixel transfer operation and one additional table lookup
to texture processing stage is added as specified by glColorTableSGI.
ERRORS
GL_INVALID_ENUM is generated if target is not GL_TEXTURE_3D_EXT.
GL_INVALID_OPERATION is generated if the texture array has not been
defined by a previous glTexImage3DEXT.
GL_INVALID_VALUE is generated if level is less than 0.
GL_INVALID_VALUE is generated if level is less than zero or greater
than log2max, where max is the returned value of GL_MAX_3D_TEX‐
TURE_SIZE_EXT.
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), or zoffset >= (d
- b) where w is the GL_TEXTURE_WIDTH, h is the GL_TEXTURE_HEIGHT, d is
the GL_TEXTURE_DEPTH_EXT and b is the GL_TEXTURE_BORDER of the texture
image being modified. Note that w, h and d include twice the border
width.
GL_INVALID_OPERATION is generated if glCopyTexSubImage3D is executed
between the execution of glBegin and the corresponding execution of
glEnd.
ASSOCIATED GETS
glGetTexImage
glIsEnabled with argument GL_TEXTURE_3D_EXT.
SEE ALSO
glCopyPixels, glCopyTexImage1D, glCopyTexImage2D, glCopyTexSubImage1D,
glPixelStore, glPixelTransfer, glTexEnv, glTexGen, glTexImage1D, glTex‐
Image2D, glTexParameter, glTexSubImage1D, glTexSubImage2D, glTexIm‐
age3DEXT, glTexSubImage3DEXT
15 Mar 97 GLCOPYTEXSUBIMAGE3DEXT(3gl)