/// <summary>
/// Projects outline of a box from given position to a plane.
/// Returns null if position is inside the box.
/// </summary>
/// <param name="box"></param>
/// <param name="fromPosition"></param>
/// <param name="box2plane">Transformation from world/box-space to plane z=0</param>
public static V2d[] GetOutlineProjected(this Box3d box, V3d fromPosition, M44d box2plane)
{
var ps = box.GetOutlineCornersCW(fromPosition);
if (ps == null)
{
return(null);
}
var qs = ps.Map(p => box2plane.TransformPosProj(p));
var behindPositionCount = 0;
for (var i = 0; i < qs.Length; i++)
{
if (qs[i].Z < 0.0)
{
behindPositionCount++;
}
}
if (behindPositionCount == qs.Length)
{
return(new V2d[0]);
}
if (behindPositionCount > 0)
{
return(null);
}
return(qs.Map(p => p.XY));
}
