glCopyTexSubImage2D — copy a two-dimensional texture subimage
Specifies the target texture of the active texture unit. Must be
Specifies the level-of-detail number. Level 0 is the base image level. Level n is the nth mipmap reduction image.
Specifies a texel offset in the x direction within the texture array.
Specifies a texel offset in the y direction within the texture array.
Specify the window coordinates of the lower left corner of the rectangular region of pixels to be copied.
Specifies the width of the texture subimage.
Specifies the height of the texture subimage.
Texturing maps a portion of a specified texture image onto each graphical primitive for which texturing is active. Texturing is active when the current fragment shader or vertex shader makes use of built-in texture lookup functions.
glCopyTexSubImage2D replaces a rectangular portion of a two-dimensional texture image or cube-map texture image with pixels from the current framebuffer (rather than from client memory, as is the case for glTexSubImage2D).
The screen-aligned pixel rectangle with lower left corner at and with width
width and height
height replaces the portion of the texture array with x indices
xoffset through , inclusive, and y indices
yoffset through , inclusive, at the mipmap level specified by
The pixels in the rectangle are processed exactly as if glReadPixels had been called with
format set to
GL_RGBA, but the process stops just after conversion of RGBA values. Subsequent processing is identical to that described for glTexSubImage2D, beginning with the clamping of the R, G, B, and A values to the range and then conversion to the texture's internal format 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 are outside the framebuffer associated with the current rendering context, then the values obtained for those pixels are undefined.
No change is made to the internalformat, width, or height parameters of the specified texture array or to texel values outside the specified subregion.
glCopyTexSubImage2D specifies the two-dimensional or cube-map texture for the current texture unit, specified with glActiveTexture.
GL_INVALID_ENUM is generated if
target is not
GL_INVALID_VALUE is generated if
level is less than 0.
GL_INVALID_VALUE may be generated if , where is the returned value of
GL_INVALID_VALUE is generated if , , , or , where is the width and is the height of the texture image being modified.
GL_INVALID_VALUE is generated if
height is less than 0.
GL_INVALID_OPERATION is generated if the currently bound framebuffer's format does not contain a superset of the components required by the texture's base internal format.
GL_INVALID_FRAMEBUFFER_OPERATION is generated if the currently bound framebuffer is not framebuffer complete (i.e. the return value from glCheckFramebufferStatus is not
glGet with argument
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