D3DFOGMODE

typedef enum _D3DFOGMODE {

D3DFOG_NONE = 0,

D3DFOG_EXP = 1,

D3DFOG_EXP2 = 2,

D3DFOG_LINEAR = 3

} D3DFOGMODE;

Contains constants describing the fog mode. These values are used by the D3DRENDERSTATE_FOGTABLEMODE render state in the D3DRENDERSTATETYPE enumerated type.

D3DFOG_NONE

No fog effect.

D3DFOG_EXP

The fog effect intensifies exponentially, according to the following formula:

D3DFOG_EXP2

The fog effect intensifies exponentially with the square of the distance, according to the following formula:

D3DFOG_LINEAR

The fog effect intensifies linearly between the start and end points, according to the following formula:

This is the only fog mode supported for DirectX 2.

Note that fog can be considered a measure of visibility—the lower the fog value produced by one of the fog equations, the less visible an object is.