Viewport filters (ViewPortFilter) are post-processing effects applied to the viewport that derive from Layer. Some examples of viewport filters are:

• ambient occlusion
• normal map
• depth map
• texture swapper
• depth of field
• tone-mapper
• non-photorealistic rendering

A ViewPortState is used to represent the information about the current viewport state, required by a ViewPortFilter object.

The Mudbox SDK ships with two viewport filters: examples\SampleViewportFilter and examples\TextureSwapperViewportFilter.