#region License
#endregion
#region Using Statements
using System;
using System.Diagnostics;
using System.Text;
#endregion
namespace Microsoft.Xna.Framework
{
/// <summary>
/// Defines a viewing frustum for intersection operations.
/// </summary>
[DebuggerDisplay("{DebugDisplayString,nq}")]
public class BoundingFrustum : IEquatable<BoundingFrustum>
{
#region Public Properties
/// <summary>
/// Gets or sets the <see cref="Matrix"/> of the frustum.
/// </summary>
public Matrix Matrix
{
get
{
return this.matrix;
}
set
{
this.matrix = value;
this.CreatePlanes();
this.CreateCorners();
}
}
/// <summary>
/// Gets the near plane of the frustum.
/// </summary>
public Plane Near
{
get
{
return this.planes[0];
}
}
/// <summary>
/// Gets the far plane of the frustum.
/// </summary>
public Plane Far
{
get
{
return this.planes[1];
}
}
/// <summary>
/// Gets the left plane of the frustum.
/// </summary>
public Plane Left
{
get
{
return this.planes[2];
}
}
/// <summary>
/// Gets the right plane of the frustum.
/// </summary>
public Plane Right
{
get
{
return this.planes[3];
}
}
/// <summary>
/// Gets the top plane of the frustum.
/// </summary>
public Plane Top
{
get
{
return this.planes[4];
}
}
/// <summary>
/// Gets the bottom plane of the frustum.
/// </summary>
public Plane Bottom
{
get
{
return this.planes[5];
}
}
#endregion
#region Internal Properties
internal string DebugDisplayString
{
get
{
return string.Concat(
"Near( ", planes[0].DebugDisplayString, " ) \r\n",
"Far( ", planes[1].DebugDisplayString, " ) \r\n",
"Left( ", planes[2].DebugDisplayString, " ) \r\n",
"Right( ", planes[3].DebugDisplayString, " ) \r\n",
"Top( ", planes[4].DebugDisplayString, " ) \r\n",
"Bottom( ", planes[5].DebugDisplayString, " ) "
);
}
}
#endregion
#region Public Fields
/// <summary>
/// The number of corner points in the frustum.
/// </summary>
public const int CornerCount = 8;
#endregion
#region Private Fields
private Matrix matrix;
private readonly Vector3[] corners = new Vector3[CornerCount];
private readonly Plane[] planes = new Plane[PlaneCount];
/// <summary>
/// The number of planes in the frustum.
/// </summary>
private const int PlaneCount = 6;
#endregion
#region Public Constructors
/// <summary>
/// Constructs the frustum by extracting the view planes from a matrix.
/// </summary>
/// <param name="value">Combined matrix which usually is (View * Projection).</param>
public BoundingFrustum(Matrix value)
{
this.matrix = value;
this.CreatePlanes();
this.CreateCorners();
}
#endregion
#region Public Methods
/// <summary>
/// Containment test between this <see cref="BoundingFrustum"/> and specified <see cref="BoundingFrustum"/>.
/// </summary>
/// <param name="frustum">A <see cref="BoundingFrustum"/> for testing.</param>
/// <returns>Result of testing for containment between this <see cref="BoundingFrustum"/> and specified <see cref="BoundingFrustum"/>.</returns>
public ContainmentType Contains(BoundingFrustum frustum)
{
if (this == frustum)
{
return ContainmentType.Contains;
}
bool intersects = false;
for (int i = 0; i < PlaneCount; i += 1)
{
PlaneIntersectionType planeIntersectionType;
frustum.Intersects(ref planes[i], out planeIntersectionType);
if (planeIntersectionType == PlaneIntersectionType.Front)
{
return ContainmentType.Disjoint;
}
else if (planeIntersectionType == PlaneIntersectionType.Intersecting)
{
intersects = true;
}
}
return intersects ? ContainmentType.Intersects : ContainmentType.Contains;
}
/// <summary>
/// Containment test between this <see cref="BoundingFrustum"/> and specified <see cref="BoundingBox"/>.
/// </summary>
/// <param name="box">A <see cref="BoundingBox"/> for testing.</param>
/// <returns>Result of testing for containment between this <see cref="BoundingFrustum"/> and specified <see cref="BoundingBox"/>.</returns>
public ContainmentType Contains(BoundingBox box)
{
ContainmentType result = default(ContainmentType);
this.Contains(ref box, out result);
return result;
}
/// <summary>
/// Containment test between this <see cref="BoundingFrustum"/> and specified <see cref="BoundingBox"/>.
/// </summary>
/// <param name="box">A <see cref="BoundingBox"/> for testing.</param>
/// <param name="result">Result of testing for containment between this <see cref="BoundingFrustum"/> and specified <see cref="BoundingBox"/> as an output parameter.</param>
public void Contains(ref BoundingBox box, out ContainmentType result)
{
bool intersects = false;
for (int i = 0; i < PlaneCount; i += 1)
{
PlaneIntersectionType planeIntersectionType = default(PlaneIntersectionType);
box.Intersects(ref this.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;
}
/// <summary>
/// Containment test between this <see cref="BoundingFrustum"/> and specified <see cref="BoundingSphere"/>.
/// </summary>
/// <param name="sphere">A <see cref="BoundingSphere"/> for testing.</param>
/// <returns>Result of testing for containment between this <see cref="BoundingFrustum"/> and specified <see cref="BoundingSphere"/>.</returns>
public ContainmentType Contains(BoundingSphere sphere)
{
ContainmentType result = default(ContainmentType);
this.Contains(ref sphere, out result);
return result;
}
/// <summary>
/// Containment test between this <see cref="BoundingFrustum"/> and specified <see cref="BoundingSphere"/>.
/// </summary>
/// <param name="sphere">A <see cref="BoundingSphere"/> for testing.</param>
/// <param name="result">Result of testing for containment between this <see cref="BoundingFrustum"/> and specified <see cref="BoundingSphere"/> as an output parameter.</param>
public void Contains(ref BoundingSphere sphere, out ContainmentType result)
{
bool intersects = false;
for (int i = 0; i < PlaneCount; i += 1)
{
PlaneIntersectionType planeIntersectionType = default(PlaneIntersectionType);
sphere.Intersects(ref this.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;
}
/// <summary>
/// Containment test between this <see cref="BoundingFrustum"/> and specified <see cref="Vector3"/>.
/// </summary>
/// <param name="point">A <see cref="Vector3"/> for testing.</param>
/// <returns>Result of testing for containment between this <see cref="BoundingFrustum"/> and specified <see cref="Vector3"/>.</returns>
public ContainmentType Contains(Vector3 point)
{
ContainmentType result = default(ContainmentType);
this.Contains(ref point, out result);
return result;
}
/// <summary>
/// Containment test between this <see cref="BoundingFrustum"/> and specified <see cref="Vector3"/>.
/// </summary>
/// <param name="point">A <see cref="Vector3"/> for testing.</param>
/// <param name="result">Result of testing for containment between this <see cref="BoundingFrustum"/> and specified <see cref="Vector3"/> as an output parameter.</param>
public void Contains(ref Vector3 point, out ContainmentType result)
{
bool intersects = false;
for (int i = 0; i < PlaneCount; i += 1)
{
float classifyPoint = (
(point.X * planes[i].Normal.X) +
(point.Y * planes[i].Normal.Y) +
(point.Z * planes[i].Normal.Z) +
planes[i].D
);
if (classifyPoint > 0)
{
result = ContainmentType.Disjoint;
return;
}
else if (classifyPoint == 0)
{
intersects = true;
break;
}
}
result = intersects ? ContainmentType.Intersects : ContainmentType.Contains;
}
/// <summary>
/// Returns a copy of internal corners array.
/// </summary>
/// <returns>The array of corners.</returns>
public Vector3[] GetCorners()
{
return (Vector3[]) this.corners.Clone();
}
/// <summary>
/// Returns a copy of internal corners array.
/// </summary>
/// <param name="corners">The array which values will be replaced to corner values of this instance. It must have size of <see cref="BoundingFrustum.CornerCount"/>.</param>
public void GetCorners(Vector3[] corners)
{
if (corners == null)
{
throw new ArgumentNullException("corners");
}
if (corners.Length < CornerCount)
{
throw new ArgumentOutOfRangeException("corners");
}
this.corners.CopyTo(corners, 0);
}
/// <summary>
/// Gets whether or not a specified <see cref="BoundingFrustum"/> intersects with this <see cref="BoundingFrustum"/>.
/// </summary>
/// <param name="frustum">An other <see cref="BoundingFrustum"/> for intersection test.</param>
/// <returns><c>true</c> if other <see cref="BoundingFrustum"/> intersects with this <see cref="BoundingFrustum"/>; <c>false</c> otherwise.</returns>
public bool Intersects(BoundingFrustum frustum)
{
return (Contains(frustum) != ContainmentType.Disjoint);
}
/// <summary>
/// Gets whether or not a specified <see cref="BoundingBox"/> intersects with this <see cref="BoundingFrustum"/>.
/// </summary>
/// <param name="box">A <see cref="BoundingBox"/> for intersection test.</param>
/// <returns><c>true</c> if specified <see cref="BoundingBox"/> intersects with this <see cref="BoundingFrustum"/>; <c>false</c> otherwise.</returns>
public bool Intersects(BoundingBox box)
{
bool result = false;
this.Intersects(ref box, out result);
return result;
}
/// <summary>
/// Gets whether or not a specified <see cref="BoundingBox"/> intersects with this <see cref="BoundingFrustum"/>.
/// </summary>
/// <param name="box">A <see cref="BoundingBox"/> for intersection test.</param>
/// <param name="result"><c>true</c> if specified <see cref="BoundingBox"/> intersects with this <see cref="BoundingFrustum"/>; <c>false</c> otherwise as an output parameter.</param>
public void Intersects(ref BoundingBox box, out bool result)
{
ContainmentType containment = default(ContainmentType);
this.Contains(ref box, out containment);
result = containment != ContainmentType.Disjoint;
}
/// <summary>
/// Gets whether or not a specified <see cref="BoundingSphere"/> intersects with this <see cref="BoundingFrustum"/>.
/// </summary>
/// <param name="sphere">A <see cref="BoundingSphere"/> for intersection test.</param>
/// <returns><c>true</c> if specified <see cref="BoundingSphere"/> intersects with this <see cref="BoundingFrustum"/>; <c>false</c> otherwise.</returns>
public bool Intersects(BoundingSphere sphere)
{
bool result = default(bool);
this.Intersects(ref sphere, out result);
return result;
}
/// <summary>
/// Gets whether or not a specified <see cref="BoundingSphere"/> intersects with this <see cref="BoundingFrustum"/>.
/// </summary>
/// <param name="sphere">A <see cref="BoundingSphere"/> for intersection test.</param>
/// <param name="result"><c>true</c> if specified <see cref="BoundingSphere"/> intersects with this <see cref="BoundingFrustum"/>; <c>false</c> otherwise as an output parameter.</param>
public void Intersects(ref BoundingSphere sphere, out bool result)
{
ContainmentType containment = default(ContainmentType);
this.Contains(ref sphere, out containment);
result = containment != ContainmentType.Disjoint;
}
/// <summary>
/// Gets type of intersection between specified <see cref="Plane"/> and this <see cref="BoundingFrustum"/>.
/// </summary>
/// <param name="plane">A <see cref="Plane"/> for intersection test.</param>
/// <returns>A plane intersection type.</returns>
public PlaneIntersectionType Intersects(Plane plane)
{
PlaneIntersectionType result;
Intersects(ref plane, out result);
return result;
}
/// <summary>
/// Gets type of intersection between specified <see cref="Plane"/> and this <see cref="BoundingFrustum"/>.
/// </summary>
/// <param name="plane">A <see cref="Plane"/> for intersection test.</param>
/// <param name="result">A plane intersection type as an output parameter.</param>
public void Intersects(ref Plane plane, out PlaneIntersectionType result)
{
result = plane.Intersects(ref corners[0]);
for (int i = 1; i < corners.Length; i += 1)
{
if (plane.Intersects(ref corners[i]) != result)
{
result = PlaneIntersectionType.Intersecting;
}
}
}
/// <summary>
/// Gets the distance of intersection of <see cref="Ray"/> and this <see cref="BoundingFrustum"/> or null if no intersection happens.
/// </summary>
/// <param name="ray">A <see cref="Ray"/> for intersection test.</param>
/// <returns>Distance at which ray intersects with this <see cref="BoundingFrustum"/> or null if no intersection happens.</returns>
public float? Intersects(Ray ray)
{
float? result;
Intersects(ref ray, out result);
return result;
}
/// <summary>
/// Gets the distance of intersection of <see cref="Ray"/> and this <see cref="BoundingFrustum"/> or null if no intersection happens.
/// </summary>
/// <param name="ray">A <see cref="Ray"/> for intersection test.</param>
/// <param name="result">Distance at which ray intersects with this <see cref="BoundingFrustum"/> or null if no intersection happens as an output parameter.</param>
public void Intersects(ref Ray ray, out float? result)
{
ContainmentType ctype;
Contains(ref ray.Position, out ctype);
if (ctype == ContainmentType.Disjoint)
{
result = null;
return;
}
if (ctype == ContainmentType.Contains)
{
result = 0.0f;
return;
}
if (ctype != ContainmentType.Intersects)
{
throw new ArgumentOutOfRangeException("ctype");
}
throw new NotImplementedException();
}
#endregion
#region Private Methods
private void CreateCorners()
{
IntersectionPoint(
ref this.planes[0],
ref this.planes[2],
ref this.planes[4],
out this.corners[0]
);
IntersectionPoint(
ref this.planes[0],
ref this.planes[3],
ref this.planes[4],
out this.corners[1]
);
IntersectionPoint(
ref this.planes[0],
ref this.planes[3],
ref this.planes[5],
out this.corners[2]
);
IntersectionPoint(
ref this.planes[0],
ref this.planes[2],
ref this.planes[5],
out this.corners[3]
);
IntersectionPoint(
ref this.planes[1],
ref this.planes[2],
ref this.planes[4],
out this.corners[4]
);
IntersectionPoint(
ref this.planes[1],
ref this.planes[3],
ref this.planes[4],
out this.corners[5]
);
IntersectionPoint(
ref this.planes[1],
ref this.planes[3],
ref this.planes[5],
out this.corners[6]
);
IntersectionPoint(
ref this.planes[1],
ref this.planes[2],
ref this.planes[5],
out this.corners[7]
);
}
private void CreatePlanes()
{
this.planes[0] = new Plane(
-this.matrix.M13,
-this.matrix.M23,
-this.matrix.M33,
-this.matrix.M43
);
this.planes[1] = new Plane(
this.matrix.M13 - this.matrix.M14,
this.matrix.M23 - this.matrix.M24,
this.matrix.M33 - this.matrix.M34,
this.matrix.M43 - this.matrix.M44
);
this.planes[2] = new Plane(
-this.matrix.M14 - this.matrix.M11,
-this.matrix.M24 - this.matrix.M21,
-this.matrix.M34 - this.matrix.M31,
-this.matrix.M44 - this.matrix.M41
);
this.planes[3] = new Plane(
this.matrix.M11 - this.matrix.M14,
this.matrix.M21 - this.matrix.M24,
this.matrix.M31 - this.matrix.M34,
this.matrix.M41 - this.matrix.M44
);
this.planes[4] = new Plane(
this.matrix.M12 - this.matrix.M14,
this.matrix.M22 - this.matrix.M24,
this.matrix.M32 - this.matrix.M34,
this.matrix.M42 - this.matrix.M44
);
this.planes[5] = new Plane(
-this.matrix.M14 - this.matrix.M12,
-this.matrix.M24 - this.matrix.M22,
-this.matrix.M34 - this.matrix.M32,
-this.matrix.M44 - this.matrix.M42
);
this.NormalizePlane(ref this.planes[0]);
this.NormalizePlane(ref this.planes[1]);
this.NormalizePlane(ref this.planes[2]);
this.NormalizePlane(ref this.planes[3]);
this.NormalizePlane(ref this.planes[4]);
this.NormalizePlane(ref this.planes[5]);
}
private void NormalizePlane(ref Plane p)
{
float factor = 1f / p.Normal.Length();
p.Normal.X *= factor;
p.Normal.Y *= factor;
p.Normal.Z *= factor;
p.D *= factor;
}
#endregion
#region Private Static Methods
private static void IntersectionPoint(
ref Plane a,
ref Plane b,
ref Plane c,
out Vector3 result
) {
Vector3 v1, v2, v3;
Vector3 cross;
Vector3.Cross(ref b.Normal, ref c.Normal, out cross);
float f;
Vector3.Dot(ref a.Normal, ref cross, out f);
f *= -1.0f;
Vector3.Cross(ref b.Normal, ref c.Normal, out cross);
Vector3.Multiply(ref cross, a.D, out v1);
Vector3.Cross(ref c.Normal, ref a.Normal, out cross);
Vector3.Multiply(ref cross, b.D, out v2);
Vector3.Cross(ref a.Normal, ref b.Normal, out cross);
Vector3.Multiply(ref cross, c.D, out v3);
result.X = (v1.X + v2.X + v3.X) / f;
result.Y = (v1.Y + v2.Y + v3.Y) / f;
result.Z = (v1.Z + v2.Z + v3.Z) / f;
}
#endregion
#region Public Static Operators and Override Methods
/// <summary>
/// Compares whether two <see cref="BoundingFrustum"/> instances are equal.
/// </summary>
/// <param name="a"><see cref="BoundingFrustum"/> instance on the left of the equal sign.</param>
/// <param name="b"><see cref="BoundingFrustum"/> instance on the right of the equal sign.</param>
/// <returns><c>true</c> if the instances are equal; <c>false</c> otherwise.</returns>
public static bool operator ==(BoundingFrustum a, BoundingFrustum b)
{
if (object.Equals(a, null))
{
return (object.Equals(b, null));
}
if (object.Equals(b, null))
{
return (object.Equals(a, null));
}
return a.matrix == (b.matrix);
}
/// <summary>
/// Compares whether two <see cref="BoundingFrustum"/> instances are not equal.
/// </summary>
/// <param name="a"><see cref="BoundingFrustum"/> instance on the left of the not equal sign.</param>
/// <param name="b"><see cref="BoundingFrustum"/> instance on the right of the not equal sign.</param>
/// <returns><c>true</c> if the instances are not equal; <c>false</c> otherwise.</returns>
public static bool operator !=(BoundingFrustum a, BoundingFrustum b)
{
return !(a == b);
}
/// <summary>
/// Compares whether current instance is equal to specified <see cref="BoundingFrustum"/>.
/// </summary>
/// <param name="other">The <see cref="BoundingFrustum"/> to compare.</param>
/// <returns><c>true</c> if the instances are equal; <c>false</c> otherwise.</returns>
public bool Equals(BoundingFrustum other)
{
return (this == other);
}
/// <summary>
/// Compares whether current instance is equal to specified <see cref="BoundingFrustum"/>.
/// </summary>
/// <param name="obj">The <see cref="Object"/> to compare.</param>
/// <returns><c>true</c> if the instances are equal; <c>false</c> otherwise.</returns>
public override bool Equals(object obj)
{
BoundingFrustum f = obj as BoundingFrustum;
return (object.Equals(f, null)) ? false : (this == f);
}
/// <summary>
/// Returns a <see cref="String"/> representation of this <see cref="BoundingFrustum"/> in the format:
/// {Near:[nearPlane] Far:[farPlane] Left:[leftPlane] Right:[rightPlane] Top:[topPlane] Bottom:[bottomPlane]}
/// </summary>
/// <returns><see cref="String"/> representation of this <see cref="BoundingFrustum"/>.</returns>
public override string ToString()
{
StringBuilder sb = new StringBuilder(256);
sb.Append("{Near:");
sb.Append(this.planes[0].ToString());
sb.Append(" Far:");
sb.Append(this.planes[1].ToString());
sb.Append(" Left:");
sb.Append(this.planes[2].ToString());
sb.Append(" Right:");
sb.Append(this.planes[3].ToString());
sb.Append(" Top:");
sb.Append(this.planes[4].ToString());
sb.Append(" Bottom:");
sb.Append(this.planes[5].ToString());
sb.Append("}");
return sb.ToString();
}
/// <summary>
/// Gets the hash code of this <see cref="BoundingFrustum"/>.
/// </summary>
/// <returns>Hash code of this <see cref="BoundingFrustum"/>.</returns>
public override int GetHashCode()
{
return this.matrix.GetHashCode();
}
#endregion
}
}
