public List <Intersection> Intersect(LineEdge target, LineEdge tool)
{
var res = new List <Intersection>();
// intersect corresponding lines. 1 or zero intersections
var target_data = target.Data;
var tool_data = tool.Data;
Vector2R target_p0 = new Vector2R(target_data.p0);
Vector2R target_p1 = new Vector2R(target_data.p1);
Vector2R tool_p0 = new Vector2R(tool_data.p0);
Vector2R tool_p1 = new Vector2R(tool_data.p1);
Vector2R dir1 = target_p1 - target_p0;
Vector2R dir2 = tool_p1 - tool_p0;
if (dir1.SqrMagnitude == Rational.FromLong(0) ||
dir2.SqrMagnitude == Rational.FromLong(0)) // one vector is degenerate
{
return(res);
}
if (Vector2R.Cross(dir1, dir2) == new Rational(0)) // parallel or collinear
{
return(res);
}
Rational target_t = Vector2R.Cross(tool_p0 - target_p0, dir2 / Vector2R.Cross(dir1, dir2));
Rational tool_t = Vector2R.Cross(target_p0 - tool_p0, dir1 / Vector2R.Cross(dir2, dir1));
if (target_t >= Rational.FromLong(0) && target_t <= Rational.FromLong(1) &&
tool_t >= Rational.FromLong(0) && tool_t <= Rational.FromLong(1))
{
if (!target.Sense)
{
target_t = Rational.FromLong(1) - target_t;
}
if (!tool.Sense)
{
tool_t = Rational.FromLong(1) - tool_t;
}
Intersection i = new Intersection
{
face_edge_param = target_t,
cut_param = tool_t,
tool_edge_enters = Vector2R.TestLeftHemiplane(dir2, dir1) == (target.Sense == tool.Sense)
};
res.Add(i);
}
return(res);
}