NAME

glCopyTexSubImage3D - copy a three-dimensional texture subimage

C SPECIFICATION

void glCopyTexSubImage3D( 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
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

glCopyTexSubImage3D replaces a rectangular portion of a three-dimensional texture image with pixels from the current GL_READ_BUFFER (rather than from main memory, as is the case for glTexSubImage3D).

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 z index zoffset and 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 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, depth, or border parameters of the specified texture array or to texel values outside the specified subregion.

NOTES

glCopyTexSubImage3D is available only if the GL version is 1.2 or greater.

Texturing has no effect in color index mode.

glPixelStore and glPixelTransfer modes affect texture images in exactly the way they affect glDrawPixels.

When the GL_ARB_imaging extension is supported, the RGBA components copied from the framebuffer may be processed by the imaging pipeline, as if they were a two-dimensional texture. See glTexImage2D for specific details.

ERRORS

GL_INVALID_ENUM is generated if target is not GL_TEXTURE_3D.

GL_INVALID_OPERATION is generated if the texture array has not been defined by a previous glTexImage3D operation.

GL_INVALID_VALUE is generated if level is less than 0.

GL_INVALID_VALUE may be generated if level is greater than log2(max), where max is the returned value of GL_MAX_3D_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, (yoffset+height) >(h -b), zoffset< -b, or zoffset >(d -b), where w is the GL_TEXTURE_WIDTH, h is the GL_TEXTURE_HEIGHT, d is the GL_TEXTURE_DEPTH, 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