/// <summary>
/// Creates the smallest BoundingSphere that can contain a specified BoundingBox.
/// </summary>
/// <param name="box">The BoundingBox to create the BoundingSphere from.</param><param name="result">[OutAttribute] The created BoundingSphere.</param>
public static void CreateFromBoundingBox(ref BoundingBox box, out BoundingSphere result)
{
// Find the center of the box.
Vector3 center = new Vector3((box.Min.X + box.Max.X) / 2.0f,
(box.Min.Y + box.Max.Y) / 2.0f,
(box.Min.Z + box.Max.Z) / 2.0f);
// Find the distance between the center and one of the corners of the box.
float radius = Vector3.Distance(center, box.Max);
result = new BoundingSphere(center, radius);
}
/// <summary>
/// Checks whether the current BoundingFrustum intersects a BoundingSphere.
/// </summary>
/// <param name="sphere">The BoundingSphere to check for intersection with.</param><param name="result">[OutAttribute] true if the BoundingFrustum and BoundingSphere intersect; false otherwise.</param>
public void Intersects(ref BoundingSphere sphere, out bool result)
{
ContainmentType containment;
Contains(ref sphere, out containment);
result = containment != ContainmentType.Disjoint;
}
/// <summary>
/// Checks whether the current BoundingFrustum contains the specified BoundingSphere.
/// </summary>
/// <param name="sphere">The BoundingSphere to test for overlap.</param><param name="result">[OutAttribute] Enumeration indicating the extent of overlap.</param>
public void Contains(ref BoundingSphere sphere, out ContainmentType result)
{
CreatePlanes();
var intersects = false;
for (var i = 0; i < PlaneCount; ++i)
{
PlaneIntersectionType planeIntersectionType;
sphere.Intersects(ref _planes[i], out planeIntersectionType);
switch (planeIntersectionType)
{
case PlaneIntersectionType.Front:
result = ContainmentType.Disjoint;
return;
case PlaneIntersectionType.Intersecting:
intersects = true;
break;
}
}
result = intersects ? ContainmentType.Intersects : ContainmentType.Contains;
}
public bool Intersects(BoundingSphere sphere)
{
bool result;
Intersects(ref sphere, out result);
return result;
}
public void AssertThat_Inflate_ByNegativeValue_DecreasesRadius()
{
BoundingSphere s = new BoundingSphere(Vector3.Zero, 10);
Assert.AreEqual(5, s.Inflate(-10).Radius);
}
/// <summary>
/// Creates the smallest BoundingBox that will contain the specified BoundingSphere.
/// </summary>
/// <param name="sphere">The BoundingSphere to contain.</param><param name="result">[OutAttribute] The created BoundingBox.</param>
public static void CreateFromSphere(ref BoundingSphere sphere, out BoundingBox result)
{
var corner = new Vector3(sphere.Radius);
result.Min = sphere.Center - corner;
result.Max = sphere.Center + corner;
}
/// <summary>
/// Tests whether the BoundingBox contains a BoundingSphere.
/// </summary>
/// <param name="sphere">The BoundingSphere to test for overlap.</param><param name="result">[OutAttribute] Enumeration indicating the extent of overlap.</param>
public void Contains(ref BoundingSphere sphere, out ContainmentType result)
{
if (sphere.Center.X - Min.X >= sphere.Radius
&& sphere.Center.Y - Min.Y >= sphere.Radius
&& sphere.Center.Z - Min.Z >= sphere.Radius
&& Max.X - sphere.Center.X >= sphere.Radius
&& Max.Y - sphere.Center.Y >= sphere.Radius
&& Max.Z - sphere.Center.Z >= sphere.Radius)
{
result = ContainmentType.Contains;
return;
}
double dmin = 0;
double e = sphere.Center.X - Min.X;
if (e < 0)
{
if (e < -sphere.Radius)
{
result = ContainmentType.Disjoint;
return;
}
dmin += e * e;
}
else
{
e = sphere.Center.X - Max.X;
if (e > 0)
{
if (e > sphere.Radius)
{
result = ContainmentType.Disjoint;
return;
}
dmin += e * e;
}
}
e = sphere.Center.Y - Min.Y;
if (e < 0)
{
if (e < -sphere.Radius)
{
result = ContainmentType.Disjoint;
return;
}
dmin += e * e;
}
else
{
e = sphere.Center.Y - Max.Y;
if (e > 0)
{
if (e > sphere.Radius)
{
result = ContainmentType.Disjoint;
return;
}
dmin += e * e;
}
}
e = sphere.Center.Z - Min.Z;
if (e < 0)
{
if (e < -sphere.Radius)
{
result = ContainmentType.Disjoint;
return;
}
dmin += e * e;
}
else
{
e = sphere.Center.Z - Max.Z;
if (e > 0)
{
if (e > sphere.Radius)
{
result = ContainmentType.Disjoint;
return;
}
dmin += e * e;
}
}
if (dmin <= sphere.Radius * sphere.Radius)
{
result = ContainmentType.Intersects;
return;
}
result = ContainmentType.Disjoint;
}
/// <summary>
/// Creates a BoundingSphere that contains the two specified BoundingSphere instances.
/// </summary>
/// <param name="original">BoundingSphere to be merged.</param><param name="additional">BoundingSphere to be merged.</param><param name="result">[OutAttribute] The created BoundingSphere.</param>
public static void CreateMerged(ref BoundingSphere original, ref BoundingSphere additional, out BoundingSphere result)
{
Vector3 ocenterToaCenter = Vector3.Subtract(additional.Center, original.Center);
float distance = ocenterToaCenter.Length();
if (distance <= original.Radius + additional.Radius)//intersect
{
if (distance <= original.Radius - additional.Radius)//original contain additional
{
result = original;
return;
}
if (distance <= additional.Radius - original.Radius)//additional contain original
{
result = additional;
return;
}
}
//else find center of new sphere and radius
float leftRadius = Math.Max(original.Radius - distance, additional.Radius);
float rightradius = Math.Max(original.Radius + distance, additional.Radius);
ocenterToaCenter = ocenterToaCenter + (((leftRadius - rightradius) / (2 * ocenterToaCenter.Length())) * ocenterToaCenter);//oCenterToResultCenter
result = new BoundingSphere
{
Center = original.Center + ocenterToaCenter,
Radius = (leftRadius + rightradius) / 2
};
}
/// <summary>
/// Expand bounding sphere diameter by distance
/// </summary>
/// <param name="sphere">The sphere to mutate</param>
/// <param name="distance"></param>
/// <returns></returns>
public static void Inflate(ref BoundingSphere sphere, float distance)
{
var r = sphere.Radius + distance / 2;
if (r < 0)
throw new ArgumentOutOfRangeException("distance", "Distance specified to inflate sphere is a negative value larger than the total diameter (this would cause a negative radius!)");
sphere.Radius = r;
}
/// <summary>
/// Checks whether the current Ray intersects a BoundingSphere.
/// </summary>
/// <param name="sphere">The BoundingSphere to check for intersection with.</param><param name="result">[OutAttribute] Distance at which the ray intersects the BoundingSphere or null if there is no intersection.</param>
public void Intersects(ref BoundingSphere sphere, out float? result)
{
// Find the vector between where the ray starts the the sphere's centre
Vector3 difference = sphere.Center - Position;
float differenceLengthSquared = difference.LengthSquared();
float sphereRadiusSquared = sphere.Radius * sphere.Radius;
// If the distance between the ray start and the sphere's centre is less than
// the radius of the sphere, it means we've intersected. N.B. checking the LengthSquared is faster.
if (differenceLengthSquared < sphereRadiusSquared)
{
result = 0.0f;
return;
}
var distanceAlongRay = Vector3.Dot(Direction, difference);
// If the ray is pointing away from the sphere then we don't ever intersect
if (distanceAlongRay < 0)
{
result = null;
return;
}
// Next we kinda use Pythagoras to check if we are within the bounds of the sphere
// if x = radius of sphere
// if y = distance between ray position and sphere centre
// if z = the distance we've travelled along the ray
// if x^2 + z^2 - y^2 < 0, we do not intersect
float dist = sphereRadiusSquared + distanceAlongRay * distanceAlongRay - differenceLengthSquared;
result = (dist < 0) ? null : distanceAlongRay - (float?)Math.Sqrt(dist);
}
/// <summary>
/// Creates a BoundingSphere that contains the two specified BoundingSphere instances.
/// </summary>
/// <param name="original">BoundingSphere to be merged.</param><param name="additional">BoundingSphere to be merged.</param>
public static BoundingSphere CreateMerged(BoundingSphere original, BoundingSphere additional)
{
BoundingSphere result;
CreateMerged(ref original, ref additional, out result);
return result;
}
/// <summary>
/// Checks whether the Ray intersects a specified BoundingSphere.
/// </summary>
/// <param name="sphere">The BoundingSphere to check for intersection with the Ray.</param>
public float? Intersects(BoundingSphere sphere)
{
float? result;
Intersects(ref sphere, out result);
return result;
}
public IEnumerable<string> Intersections(BoundingSphere sphere)
{
return _model
.Model
.SkinningData
.Bounds
.Select((b, i) =>
{
Matrix4x4 transform;
Matrix4x4.Invert(_worldTransforms[i], out transform);
var center = Vector3.Transform(sphere.Center, transform); //Transform sphere center into bone space
var intersects = b.Intersects(new BoundingSphere(center, sphere.Radius)); //Intersect new sphere in bone space
var name = _model.Model.SkinningData.Names[i];
return new KeyValuePair<bool, string>(intersects, name);
})
.Where(a => a.Key)
.Select(a => a.Value);
}
public void AssertThat_Inflate_IncreasesRadius()
{
BoundingSphere s = new BoundingSphere(Vector3.Zero, 10);
Assert.AreEqual(15, s.Inflate(10).Radius);
}
public static void AddBoundingSphere(BoundingSphere sphere, Color color, float life = 0f)
{
// Get a DebugShape we can use to draw the sphere
DebugShape shape = GetShapeForLines(SPHERE_LINE_COUNT, life);
// Iterate our unit sphere vertices
for (int i = 0; i < _unitSphere.Length; i++)
{
// Compute the vertex position by transforming the point by the radius and center of the sphere
Vector3 vertPos = _unitSphere[i] * sphere.Radius + sphere.Center;
// Add the vertex to the shape
shape.Vertices[i] = new VertexPositionColor(vertPos.ToXNA(), color);
}
}
/// <summary>
/// Checks whether the current BoundingSphere contains the specified BoundingSphere.
/// </summary>
/// <param name="sphere">The BoundingSphere to test for overlap.</param><param name="result">[OutAttribute] Enumeration indicating the extent of overlap.</param>
public void Contains(ref BoundingSphere sphere, out ContainmentType result)
{
float sqDistance = Vector3.DistanceSquared(sphere.Center, Center);
if (sqDistance > (sphere.Radius + Radius) * (sphere.Radius + Radius))
result = ContainmentType.Disjoint;
else if (sqDistance <= (Radius - sphere.Radius) * (Radius - sphere.Radius))
result = ContainmentType.Contains;
else
result = ContainmentType.Intersects;
}
/// <summary>
/// Creates the smallest BoundingBox that will contain the specified BoundingSphere.
/// </summary>
/// <param name="sphere">The BoundingSphere to contain.</param>
public static BoundingBox CreateFromSphere(BoundingSphere sphere)
{
BoundingBox result;
CreateFromSphere(ref sphere, out result);
return result;
}
/// <summary>
/// Determines whether the specified BoundingSphere is equal to the current BoundingSphere.
/// </summary>
/// <param name="other">The BoundingSphere to compare with the current BoundingSphere.</param>
public bool Equals(BoundingSphere other)
{
return Radius.Equals(other.Radius) && Center.Equals(other.Center);
}
public ContainmentType Contains(BoundingSphere sphere)
{
ContainmentType result;
Contains(ref sphere, out result);
return result;
}
/// <summary>
/// Checks whether the current BoundingSphere intersects another BoundingSphere.
/// </summary>
/// <param name="sphere">The BoundingSphere to check for intersection with.</param><param name="result">[OutAttribute] true if the BoundingSphere instances intersect; false otherwise.</param>
public void Intersects(ref BoundingSphere sphere, out bool result)
{
float sqDistance = Vector3.DistanceSquared(sphere.Center, Center);
var totalRadius = sphere.Radius + Radius;
result = sqDistance < totalRadius * totalRadius;
}
/// <summary>
/// Creates an instance of BoundingBox around a BoundingSphere
/// </summary>
/// <param name="sphere">The sphere to constain within this box</param>
public BoundingBox(BoundingSphere sphere)
: this(sphere.Center - new Vector3(sphere.Radius), sphere.Center + new Vector3(sphere.Radius))
{
}
/// <summary>
/// Translates and scales the BoundingSphere using a given Matrix.
/// </summary>
/// <param name="matrix">A transformation matrix that might include translation, rotation, or uniform scaling. Note that BoundingSphere.Transform will not return correct results if there are non-uniform scaling, shears, or other unusual transforms in this transformation matrix. This is because there is no way to shear or non-uniformly scale a sphere. Such an operation would cause the sphere to lose its shape as a sphere.</param><param name="result">[OutAttribute] The transformed BoundingSphere.</param>
public void Transform(ref Matrix4x4 matrix, out BoundingSphere result)
{
result.Center = Vector3.Transform(Center, matrix);
result.Radius = Radius * ((float)Math.Sqrt(Math.Max(((matrix.M11 * matrix.M11) + (matrix.M12 * matrix.M12)) + (matrix.M13 * matrix.M13), Math.Max(((matrix.M21 * matrix.M21) + (matrix.M22 * matrix.M22)) + (matrix.M23 * matrix.M23), ((matrix.M31 * matrix.M31) + (matrix.M32 * matrix.M32)) + (matrix.M33 * matrix.M33)))));
}
/// <summary>
/// Checks whether the current BoundingBox intersects a BoundingSphere.
/// </summary>
/// <param name="sphere">The BoundingSphere to check for intersection with.</param><param name="result">[OutAttribute] true if the BoundingBox and BoundingSphere intersect; false otherwise.</param>
public void Intersects(ref BoundingSphere sphere, out bool result)
{
if (sphere.Center.X - Min.X > sphere.Radius
&& sphere.Center.Y - Min.Y > sphere.Radius
&& sphere.Center.Z - Min.Z > sphere.Radius
&& Max.X - sphere.Center.X > sphere.Radius
&& Max.Y - sphere.Center.Y > sphere.Radius
&& Max.Z - sphere.Center.Z > sphere.Radius)
{
result = true;
return;
}
double dmin = 0;
if (sphere.Center.X - Min.X <= sphere.Radius)
dmin += (sphere.Center.X - Min.X) * (sphere.Center.X - Min.X);
else if (Max.X - sphere.Center.X <= sphere.Radius)
dmin += (sphere.Center.X - Max.X) * (sphere.Center.X - Max.X);
if (sphere.Center.Y - Min.Y <= sphere.Radius)
dmin += (sphere.Center.Y - Min.Y) * (sphere.Center.Y - Min.Y);
else if (Max.Y - sphere.Center.Y <= sphere.Radius)
dmin += (sphere.Center.Y - Max.Y) * (sphere.Center.Y - Max.Y);
if (sphere.Center.Z - Min.Z <= sphere.Radius)
dmin += (sphere.Center.Z - Min.Z) * (sphere.Center.Z - Min.Z);
else if (Max.Z - sphere.Center.Z <= sphere.Radius)
dmin += (sphere.Center.Z - Max.Z) * (sphere.Center.Z - Max.Z);
if (dmin <= sphere.Radius * sphere.Radius)
{
result = true;
return;
}
result = false;
}
public void AssertThat_Inflate_ByNegativeValueLargerThanDiameter_Throws()
{
BoundingSphere s = new BoundingSphere(Vector3.Zero, 10);
var result = s.Inflate(-50);
}
