/// <summary>
/// Checks whether the two boxes collide, generating an intersection containing the collision data.
/// This function can only compare bounding boxes againsts other bounding boxes.
/// </summary>
/// <param name="other">bounding box to check</param>
/// <param name="intersection">the collision data, <code>null</code> if no collision has been detected.</param>
/// <returns></returns>
public override bool Intersects(DBoxCollider other, out Manifold intersection)
{
intersection = null;
//check if one of them is a trigger
if (this.IsTrigger || other.IsTrigger)
{
intersection = new Manifold(this.Body, other.Body);
return(true);
}
// Vector from A to B
Vector2F distance = other.Body.Position - Body.Position;
// Calculate half extents along x axis for each object
Fix32 xEntentA = (max.x - min.x) / (Fix32)2;
Fix32 xExtentB = (other.max.x - other.min.x) / (Fix32)2;
// Calculate overlap on x axis
Fix32 offsetX = xEntentA + xExtentB - Fix32.Abs(distance.x);
// SAT test on x axis
if (offsetX > Fix32.Zero)
{
// Calculate half extents along x axis for each object
Fix32 yExtentA = (max.y - min.y) / (Fix32)2;
Fix32 yExtentB = (other.max.y - other.min.y) / (Fix32)2;
// Calculate overlap on y axis
Fix32 offsetY = yExtentA + yExtentB - Fix32.Abs(distance.y);
// SAT test on y axis
if (offsetY > Fix32.Zero)
{
Vector2F n;
// Find out which axis is axis of least penetration
if (offsetX < offsetY)
{
// Point towards B knowing that n points from A to B
if (distance.x < Fix32.Zero)
{
n = new Vector2F(-1, 0);
}
else
{
n = new Vector2F(1, 0);
}
intersection = new Manifold(Body, other.Body, n, offsetX);
return(true);
}
else
{
// Point toward B knowing that n points from A to B
if (distance.y < Fix32.Zero)
{
n = new Vector2F(0, -1);
}
else
{
n = new Vector2F(0, 1);
}
intersection = new Manifold(Body, other.Body, n, offsetY);
return(true);
}
}
}
return(false);
}