Function GridNode.FilterDiagonalConnections

int FilterDiagonalConnections (

int	conns
NumNeighbours	neighbours
bool	cutCorners

)

Filters diagonal connections based on the non-diagonal ones to prevent corner cutting and similar things.

This involves some complicated bitshifting to calculate which diagonal connections should be active based on the non-diagonal ones. For example a path should not be able to pass from A to B if the #s represent nodes that we cannot traverse.

# B
A #


Additionally if corner cutting is disabled we will also prevent a connection from A to B in this case:

B
A #


If neighbours = 4 then only the 4 axis aligned connections will be enabled.

If neighbours = 6 then only the connections which are valid for hexagonal graphs will be enabled.