Outcode Clipping
(a.k.a. Cohen-Sutherland Clipping)
The extension of plane partitioning to multiple planes, gives
a simple form of clipping called Cohen-Sutherland Clipping.
This is a rough approach to clipping in that it
only classifies each of its input primitives, rather than forces them to
conform to the viewing window.
A simple 2-D example is shown on the right.
This technique classifies each vertex of a primitive, by generating an
outcode. An outcode identifies the appropriate half space location
of each vertex relative to all of the clipping planes. Outcodes are
usually stored as bit vectors.
By comparing the bit vectors from all of the vertices associated with a primitive we can
develop conclusions about the whole primitive.
|
|
|
