Color - Introduction to 3D Game Programming with DirectX 9.0 - page 93

operator D3DCOLORVALUE* ();
operator CONST D3DCOLORVALUE* () const;

operator D3DCOLORVALUE& ();
operator CONST D3DCOLORVALUE& () const;

// assignment operators
D3DXCOLOR& operator += ( CONST D3DXCOLOR& );
D3DXCOLOR& operator -= ( CONST D3DXCOLOR& );
D3DXCOLOR& operator *= ( FLOAT );
D3DXCOLOR& operator /= ( FLOAT );

// unary operators
D3DXCOLOR operator + () const;
D3DXCOLOR operator - () const;

// binary operators
D3DXCOLOR operator + ( CONST D3DXCOLOR& ) const;
D3DXCOLOR operator - ( CONST D3DXCOLOR& ) const;
D3DXCOLOR operator * ( FLOAT ) const;
D3DXCOLOR operator / ( FLOAT ) const;

friend D3DXCOLOR operator * (FLOAT, CONST D3DXCOLOR& );

BOOL operator == ( CONST D3DXCOLOR& ) const;
BOOL operator != ( CONST D3DXCOLOR& ) const;

#endif //__cplusplus
FLOAT r, g, b, a;
} D3DXCOLOR, *LPD3DXCOLOR;

Note: Observe that the D3DCOLORVALUE and the D3DXCOLOR struc-
ture both have four floating-point components. This leads to the
common notation of treating a color as a 4D vector ( r , g , b , a ). Color
vectors are added, subtracted, and scaled just like regular vectors. On
the other hand, dot and cross products do not make sense for color
vectors, but component-wise multiplication does make sense for col-
ors. Thus, the color-color multiplication operator in the D3DXCOLOR
class performs component-wise multiplication. The symbol denotes

component-wise multiplication, and it is defined as:
( c 1 , c 2 , c 3 , c 4 ) ( k 1 , k 2 , k 3 , k 4 )=( c 1 k 1 , c 2 k 2 , c 3 k 3 , c 4 k 4 ).

We now update our d3dUtility.h file with the following global color
constants:
namespace d3d
{

.
.
.
const D3DXCOLOR WHITE( D3DCOLOR_XRGB(255, 255, 255) );

const D3DXCOLOR BLACK( D3DCOLOR_XRGB( 0, 0, 0) );

const D3DXCOLOR RED( D3DCOLOR_XRGB(255, 0, 0) );

const D3DXCOLOR GREEN( D3DCOLOR_XRGB( 0, 255, 0) );

const D3DXCOLOR BLUE( D3DCOLOR_XRGB( 0, 0, 255) );