public static void TestCrossProduct()
{
var right = Vector3Int.right;
var left = Vector3Int.left;
var down = Vector3Int.down;
var up = Vector3Int.up;
var back = new Vector3Int(0, 0, -1);
var forward = new Vector3Int(0, 0, 1);
Assert.AreEqual(forward, VECTOR3INT.Cross(right, up));
}
/// <summary>
/// Computes the intersection of (1) the line defined by <paramref name="p0"/> and <paramref name="d0"/> and (2) the line defined by <paramref name="p1"/> and <paramref name="d1"/>.
/// </summary>
/// <param name="p0">Any point on the first line.</param>
/// <param name="d0">The direction of the first line.</param>
/// <param name="p1">Any point on the second line.</param>
/// <param name="d1">The direction of second line.</param>
/// <param name="intersection">The point of intersection.</param>
/// <returns>Is there a valid intersection point?</returns>
public static bool LineLineIntersection(Vector3Int p0, Vector3Int d0, Vector3Int p1, Vector3Int d1, out Vector3Int intersection)
{
Vector3Int delta = p1 - p0;
Vector3Int crossVec0and1 = VECTOR3INT.Cross(d0, d1);
Vector3Int crossDeltaAnd1 = VECTOR3INT.Cross(delta, d1);
int planarFactor = VECTOR3INT.Dot(delta, crossVec0and1);
var isCoplanar = planarFactor == 0;
var isParallel = crossVec0and1.sqrMagnitude == 0;
if (isCoplanar && !isParallel)
{
int s = VECTOR3INT.Dot(crossDeltaAnd1, crossVec0and1) / crossVec0and1.sqrMagnitude;
intersection = p0 + s * d0;
return(true);
}
else
{
intersection = Vector3Int.zero;
return(false);
}
}