//btVector3 PlaneLineIntersection( btPlane &plane, btVector3 p0, btVector3 p1);
//btVector3 PlaneProject( btPlane &plane, btVector3 point);
void ThreePlaneIntersection( ref btPlane p0
, ref btPlane p1
, ref btPlane p2
, out btVector3 result )
{
btVector3 n2n3; p1.normal.cross( ref p2.normal, out n2n3 );
btVector3 n3n1; p2.normal.cross( ref p0.normal, out n3n1 );
btVector3 n1n2; p0.normal.cross( ref p1.normal, out n1n2 );
double quotient = ( p0.normal.dot( ref n2n3 ) );
Debug.Assert( btScalar.btFabs( quotient ) > 0.000001 );
quotient = -1.0 / quotient;
n2n3.Mult( p0.dist, out n2n3 );
n3n1.Mult( p1.dist, out n3n1 );
n1n2.Mult( p2.dist, out n1n2 );
btVector3 potentialVertex;
n2n3.Add( ref n3n1, out potentialVertex );
potentialVertex.Add( ref n3n1, out potentialVertex );
potentialVertex.Add( ref n1n2, out potentialVertex );
potentialVertex.Mult( quotient, out result );
}
PlaneTest SplitTest( ConvexH convex, btPlane plane )
{
PlaneTest flag = 0;
int c = convex.vertices.Count;
btVector3[] array = convex.vertices.InternalArray;
for( int i = 0; i < c; i++ )
{
flag |= DoPlaneTest( ref plane, ref array[i] );
}
return flag;
}
PlaneTest DoPlaneTest( ref btPlane p, ref btVector3 v )
{
double a = v.dot( ref p.normal ) + p.dist;
PlaneTest flag = ( a > planetestepsilon )
? PlaneTest.OVER
: ( ( a < -planetestepsilon )
? PlaneTest.UNDER
: PlaneTest.COPLANAR );
return flag;
}