The RGBA_SETALPHA macro sets the alpha component of an RGBA D3DCOLOR value.
RGBA_SETALPHA(rgba, x) (((x) << 24) | ((rgba) & 0x00ffffff))
The macros returns the RGBA color whose alpha component has been set.
Windows NT: Use version 4.0 or later.
Windows: Use Windows 95 or later. Available as a redistributable for Windows 95.
Windows CE: Unsupported.
Header: Declared in d3dtypes.h.