TYPE: COP
TITLE: Fog COP

This operator adds a variety of atmospheric effects to an image, including
fog, haze and heat waves. A point or depth plane is required.

Middle click on the dialog '?' help for more help on maskable operations.
Right click on the dialog '?' help for more help on VEX operations. 

Examples:
    Normal Fog   - As distance increases, the pixel color changes to the fog
                   color.
    Additive Fog - The fog color is added to the pixel color. Looks more
                   "cloudy".
    Haze         - As distance increases, the pixel's saturation decreases, so
		   distant pixels appear more grey.
    Heat Waves   - Adds a shimmering heat wave effect to distant pixels.

Parameters
Fog
    Fog Type         - The atmospheric effect. (see above)
    Fog Density      - The density of the atmospheric effect. For
		       each depth unit, this amount is applied.
    Fog Color        - The color of the fog for fog effects.
    Distance Offset  - A constant value added to the per-pixel distance.
    Fog Direction    - The direction the distance is computed in.

Heat (only applicable for Heat Waves):
    Smoothness       - The number of samples taken from the image. '1'
		       produces a grainy effect, while higher values 
		       produce a blurry effect.
    Horizontal Scale - How much horizontal deviation the heat waves cause.
    Vertical Scale   - How much vertical deviation the heat waves cause.
    Time Scale       - How quickly the heat waves change.
    Noise Offset     - The 3D noise offset for the heat waves. Animate the
		       'Y' parameter with $F to see rising heat waves.

Layer
    Layered          - Turns layered fog on, with the fog appearing in the
		       specified area.
    Layer Edge       - Where the fog begins to falloff to zero.
    Layer Falloff    - The size of the falloff region.
    Falloff Function - The interpolation of the falloff region.

Noise
    Use Fog Noise    - If on, the fog is not uniform and has 3D noise
		       variations in it. This takes quite a bit longer to 
		       compute.
    Noise Parameters - The standard parameters for sparse noise.
    Noise Step       - How often the noise is sampled along the way to the
		       final point.

Mask & Plane Scope, Frame Scope
    Overview - See extra help (Middle click on the dialog '?' help).

Local Variables:
    L   - Sequence length
    S   - Start of sequence
    E   - End of sequence
    IL  - Input sequence length
    SR  - Sequence frame rate
    NP  - Number of planes in sequence
    W,H - Width and height of image
    I   - Image index (0 at start frame)
    IT  - Image time (0 at start frame)
    AI  - Current plane array index
    PI  - Current plane index
    PC  - Num of channels in current plane

See Also: Bump, Depth of Field (dof), Lighting (light), Transform (xform)
