/// <summary>Determines where a ray will hit a triangle, if at all</summary>
/// <param name="rayStart">Starting point of the ray</param>
/// <param name="rayDirection">Direction into which the ray extends</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 intersection points between the ray and the box, if any</returns>
public static LineContacts FindContacts(
Vector2 rayStart, Vector2 rayDirection,
Vector2 triangleA, Vector2 triangleB, Vector2 triangleC
)
{
LineContacts contacts = Line2Triangle2Collider.FindContacts(
rayStart, rayDirection, triangleA, triangleB, triangleC
);
// If the line has entered the box before the reference point, this means
// that the ray starts within the box, thus, its first contact occurs immediately
if (!float.IsNaN(contacts.EntryTime))
{
if (contacts.ExitTime < 0.0f) // Entry & exit before the ray's beginning?
{
return(LineContacts.None);
}
else if (contacts.EntryTime < 0.0f) // Only entry before ray's beginning?
{
contacts.EntryTime = 0.0f;
}
}
return(contacts);
}
public void TestCloseMiss()
{
Assert.IsFalse(
Line2Triangle2Collider.FindContacts(
new Vector2(-0.1f, 0.0f), Vector2.Normalize(Vector2.One),
Vector2.Zero, Vector2.UnitX, Vector2.One
).HasContact
);
}
public void TestHitTopToBottom()
{
LineContacts contacts = Line2Triangle2Collider.FindContacts(
new Vector2(0.5f, 1.0f), -Vector2.UnitY,
Vector2.UnitX, Vector2.One, Vector2.Zero
);
Assert.That(
contacts.EntryTime,
Is.EqualTo(0.5f).Within(Specifications.MaximumDeviation).Ulps
);
Assert.That(
contacts.ExitTime,
Is.EqualTo(1.0f).Within(Specifications.MaximumDeviation).Ulps
);
}
public void TestHitBottomToRight()
{
LineContacts contacts = Line2Triangle2Collider.FindContacts(
new Vector2(0.0f, -0.5f), Vector2.Normalize(Vector2.One),
Vector2.UnitX, Vector2.One, Vector2.Zero
);
float entryTime = 0.5f / Vector2.Normalize(Vector2.One).X;
float exitTime = 1.0f / Vector2.Normalize(Vector2.One).Y;
Assert.That(
contacts.EntryTime,
Is.EqualTo(entryTime).Within(Specifications.MaximumDeviation).Ulps
);
Assert.That(
contacts.ExitTime,
Is.EqualTo(exitTime).Within(Specifications.MaximumDeviation).Ulps
);
}