Extended Blt Flags

DirectX 9.0 uses the DDBLT_EXTENDED_FLAGS blt flag to extend use of DDBLT_Xxx blt flags that are available in the dwFlags member of the DD_BLTDATA structure. When the DirectX 9.0 runtime calls the display driver's DdBlt function to perform a blt operation, the runtime can combine DDBLT_EXTENDED_FLAGS with DDBLT_Xxx flags using a bitwise OR to create new meanings for the flags. The driver then determines the presence of DDBLT_EXTENDED_FLAGS, reinterprets the meaning of flags, and performs the blt operation accordingly. The driver uses this mechanism when it determines if it should perform gamma correction on a linear color space during a blt from a back buffer to the desktop. The driver also uses extended blt flags to determine if stretch-blit operations are requested.