/// <summary>
/// Test whether a <see cref="AABBd"/> intersects this plane.
/// See: Ericson 2005, Real Time Collision Detection, p. 161 - 164
/// </summary>
/// <param name="aabb">The axis aligned bounding box.</param>
public bool Intersects(AABBd aabb)
{
var r = BoxExtendInNormalDirection(aabb);
var s = SignedDistanceFromPoint(aabb.Center);
return(System.Math.Abs(s) <= r);
}
/// <summary>
/// Calculates the bounding box around an existing bounding box and a single point.
/// </summary>
/// <param name="a">The bounding boxes to build the union from.</param>
/// <param name="p">The point to be enclosed by the resulting bounding box</param>
/// <returns>The smallest axis aligned bounding box containing the input box and the point.</returns>
public static AABBd Union(AABBd a, double3 p)
{
AABBd ret;
ret.min.x = (a.min.x < p.x) ? a.min.x : p.x;
ret.min.y = (a.min.y < p.y) ? a.min.y : p.y;
ret.min.z = (a.min.z < p.z) ? a.min.z : p.z;
ret.max.x = (a.max.x > p.x) ? a.max.x : p.x;
ret.max.y = (a.max.y > p.y) ? a.max.y : p.y;
ret.max.z = (a.max.z > p.z) ? a.max.z : p.z;
return(ret);
}
/// <summary>
/// Calculates the bounding box around two existing bounding boxes.
/// </summary>
/// <param name="a">One of the bounding boxes to build the union from</param>
/// <param name="b">The other bounding box to build the union from</param>
/// <returns>The smallest axis aligned bounding box containing both input boxes</returns>
public static AABBd Union(AABBd a, AABBd b)
{
AABBd ret;
ret.min.x = (a.min.x < b.min.x) ? a.min.x : b.min.x;
ret.min.y = (a.min.y < b.min.y) ? a.min.y : b.min.y;
ret.min.z = (a.min.z < b.min.z) ? a.min.z : b.min.z;
ret.max.x = (a.max.x > b.max.x) ? a.max.x : b.max.x;
ret.max.y = (a.max.y > b.max.y) ? a.max.y : b.max.y;
ret.max.z = (a.max.z > b.max.z) ? a.max.z : b.max.z;
return(ret);
}
/// <summary>
/// Test whether a <see cref="AABBd"/> intersects this plane.
/// See: Ericson 2005, Real Time Collision Detection, p. 161 - 164
/// CAREFUL: the definition whats completely inside and outside is flipped in comparison to Ericson,
/// because FUSEE defines a point with a negative signed distance to be inside.
/// </summary>
/// <param name="aabb">The axis aligned bounding box.</param>
public bool InsideOrIntersecting(AABBd aabb)
{
var r = BoxExtendInNormalDirection(aabb);
//Distance from aabb center to plane
var s = SignedDistanceFromPoint(aabb.Center);
//Completely inside
if (s <= -r)
{
return(true);
}
//Completely outside
else if (r <= s)
{
return(false);
}
//else intersecting
return(true);
}
/// <summary>
/// Calculates the projection interval radius of aabb onto line L(t) = aabb.Center + t * plane.Normal (extend (radius) in direction of the plane normal).
/// <param name="aabb">The axis aligned bounding box.</param>
/// </summary>
private double BoxExtendInNormalDirection(AABBd aabb)
{
var boxExtend = aabb.Size * 0.5f;
return(boxExtend.x * System.Math.Abs(Normal.x) + boxExtend.y * System.Math.Abs(Normal.y) + boxExtend.z * System.Math.Abs(Normal.z));
}
/// <summary>
/// Check if a point lies within a AABB
/// </summary>
/// <param name="aabb"></param>
/// <param name="point"></param>
/// <returns></returns>
public static bool Intersects(AABBd aabb, double3 point)
{
return(aabb.Intersects(point));
}
/// <summary>
/// Check if two AABBs intersect each other
/// </summary>
/// <param name="left"></param>
/// <param name="right"></param>
/// <returns></returns>
public static bool Intersects(AABBd left, AABBd right)
{
return(left.Intersects(right));
}
/// <summary>
/// Check if this AABB intersects with another
/// </summary>
/// <param name="b"></param>
/// <returns></returns>
public bool Intersects(AABBd b)
{
return((min.x <= b.max.x && max.x >= b.min.x) &&
(min.y <= b.max.y && max.y >= b.min.y) &&
(min.z <= b.max.z && max.z >= b.min.z));
}