CONST_D3DFOGMODE

The CONST_D3DFOGMODE enumeration contains constants describing the fog mode. These values are used by the D3DRENDERSTATE_FOGTABLEMODE and D3DRENDERSTATE_FOGVERTEXMODE render state in the CONST_D3DRENDERSTATETYPE enumeration.

Enum CONST_D3DFOGMODE
    D3DFOG_NONE   = 0
    D3DFOG_EXP    = 1
    D3DFOG_EXP2   = 2
    D3DFOG_LINEAR = 3 
End Enum

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 currently supported.

Remarks

In monochromatic (ramp) lighting mode, fog works properly only when the fog color is black. (If there is no lighting, any fog color will work, since in this case any fog color is effectively black.)

For more information about fog, see Fog.

Note  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.