List of Bitmap Filter Types
Specifies the type of filtering to perform. One of the following values:
BMM_FILTER_NONE
Specifies no filtering should be performed.
BMM_FILTER_SUM
Specifies summed area filtering.
BMM_FILTER_PYRAMID
Specifies pyramidal filtering.
BMM_FILTER_DUMMY
This is no longer used.
The Pyramidal and Summed Area options provide two methods of pixel averaging that antialias the bitmaps in mapped materials.
Both methods require approximately the same rendering time. Summed-area filtering generally yields superior results but requires much more memory. Pyramidal filtering requires the program to allocate memory equal to approximately 133% of the size of the bitmap. By comparison, summed-area filtering requires the program to allocate approximately 400% of the size of the bitmap.
Use summed-area filtering only for smaller bitmaps, and avoid using any more such bitmaps in a scene than necessary.
Pyramidal filtering is quite adequate for most purposes. However, because it applies filtering as a function of distance, irregular antialiasing may occur on detailed texture maps that are applied to a plane receding into the distance. The effect of pyramidal filtering on extreme perspectives such as this is even more noticeable in animations, where portions of the texture map appear to "swim."