The "mirror" texture address mode, identified by the D3DTADDRESS_MIRROR member of the D3DTEXTUREADDRESS enumerated type, causes Direct3D will mirror the texture at every integer boundary. Suppose, for example, your program creates a square primitive and specifies texture coordinates of (0.0,0.0), (0.0,3.0), (3.0,3.0), and (3.0,0.0). Setting the texture addressing mode to D3DTADDRESS_MIRROR will result in the texture being applied three times in both the U and V directions. Every other row and column that it is applied to will be a mirror image of the preceding row or column. This is illustrated in the following figure.
The effects of this texture address mode are similar to, but distinct from, those of the "wrap" mode. For more information, see About the Wrap Texture Address Mode.