public void TestCloseMiss()
{
Assert.IsFalse(
Line3Triangle3Collider.FindContacts(
new Vector3(0.0f, 0.5f, 0.0f), Vector3.Right,
Vector3.Zero, Vector3.UnitX, Vector3.UnitX + Vector3.UnitY
).HasContact
);
}
public void TestHitThroughCenter()
{
LineContacts contacts = Line3Triangle3Collider.FindContacts(
new Vector3(-0.25f, -0.5f, -1.0f), Vector3.Normalize(Vector3.One),
Vector3.Zero, Vector3.UnitX, Vector3.UnitX + Vector3.UnitY
);
float contactTime = 1.0f / Vector3.Normalize(Vector3.One).Z;
Assert.That(
contacts.EntryTime,
Is.EqualTo(contactTime).Within(Specifications.MaximumDeviation).Ulps
);
Assert.That(
contacts.ExitTime,
Is.EqualTo(contactTime).Within(Specifications.MaximumDeviation).Ulps
);
}
/// <summary>Determines the contact location between a ray and a triangle</summary>
/// <param name="rayStart">
/// Offset of the ray from the coordinate system's center
/// </param>
/// <param name="rayDirection">Direction of the line</param>
/// <param name="triangleA">
/// First corner point of triangle in counter-clockwise order
/// </param>
/// <param name="triangleB">
/// Second corner point of triangle in counter-clockwise order
/// </param>
/// <param name="triangleC">
/// Third corner point of triangle in counter-clockwise order
/// </param>
/// <returns>The point of intersection of the line with the triangle, if any</returns>
/// <remarks>
/// <para>
/// I saw this algorithm in an article to line/triangle intersections tests
/// by Christopher Bartlett. The material was stated to be free for learning
/// purposes, so I felt free to apply what I've learned here =)
/// </para>
/// <para>
/// There is no special case for when the line precisely touches one of
/// the triangle's corners. It will either enter and exit the triangle or
/// no contacts will be detected at all.
/// </para>
/// </remarks>
internal static LineContacts FindContacts(
Vector3 rayStart, Vector3 rayDirection,
Vector3 triangleA, Vector3 triangleB, Vector3 triangleC
)
{
LineContacts contacts = Line3Triangle3Collider.FindContacts(
rayStart, rayDirection, triangleA, triangleB, triangleC
);
// If the line has entered the triangle before the reference point, this means
// that the ray starts within the triangle and its first contact occurs immediately
if (!float.IsNaN(contacts.EntryTime))
{
if (contacts.EntryTime < 0.0f)
{
return(LineContacts.None);
}
}
return(contacts);
}
