MonoGame.Framework/BoundingSphere.cs
Rama develop · réplica de lectura del repositorio original.
// MIT License - Copyright (C) The Mono.Xna Team
// This file is subject to the terms and conditions defined in
// file 'LICENSE.txt', which is part of this source code package.
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Runtime.Serialization;
namespace Microsoft.Xna.Framework
{
/// <summary>
/// Describes a sphere in 3D-space for bounding operations.
/// </summary>
[DataContract]
[DebuggerDisplay("{DebugDisplayString,nq}")]
public struct BoundingSphere : IEquatable<BoundingSphere>
{
#region Public Fields
/// <summary>
/// The sphere center.
/// </summary>
[DataMember]
public Vector3 Center;
/// <summary>
/// The sphere radius.
/// </summary>
[DataMember]
public float Radius;
#endregion
#region Internal Properties
internal string DebugDisplayString
{
get
{
return string.Concat(
"Center( ", this.Center.DebugDisplayString, " ) \r\n",
"Radius( ", this.Radius.ToString(), " )"
);
}
}
#endregion
#region Constructors
/// <summary>
/// Constructs a bounding sphere with the specified center and radius.
/// </summary>
/// <param name="center">The sphere center.</param>
/// <param name="radius">The sphere radius.</param>
public BoundingSphere(Vector3 center, float radius)
{
this.Center = center;
this.Radius = radius;
}
#endregion
#region Public Methods
#region Contains
/// <summary>
/// Test if a bounding box is fully inside, outside, or just intersecting the sphere.
/// </summary>
/// <param name="box">The box for testing.</param>
/// <returns>The containment type.</returns>
public ContainmentType Contains(BoundingBox box)
{
//check if all corner is in sphere
bool inside = true;
foreach (Vector3 corner in box.GetCorners())
{
if (this.Contains(corner) == ContainmentType.Disjoint)
{
inside = false;
break;
}
}
if (inside)
return ContainmentType.Contains;
//check if the distance from sphere center to cube face < radius
double dmin = 0;
if (Center.X < box.Min.X)
dmin += (Center.X - box.Min.X) * (Center.X - box.Min.X);
else if (Center.X > box.Max.X)
dmin += (Center.X - box.Max.X) * (Center.X - box.Max.X);
if (Center.Y < box.Min.Y)
dmin += (Center.Y - box.Min.Y) * (Center.Y - box.Min.Y);
else if (Center.Y > box.Max.Y)
dmin += (Center.Y - box.Max.Y) * (Center.Y - box.Max.Y);
if (Center.Z < box.Min.Z)
dmin += (Center.Z - box.Min.Z) * (Center.Z - box.Min.Z);
else if (Center.Z > box.Max.Z)
dmin += (Center.Z - box.Max.Z) * (Center.Z - box.Max.Z);
if (dmin <= Radius * Radius)
return ContainmentType.Intersects;
//else disjoint
return ContainmentType.Disjoint;
}
/// <summary>
/// Test if a bounding box is fully inside, outside, or just intersecting the sphere.
/// </summary>
/// <param name="box">The box for testing.</param>
/// <param name="result">The containment type as an output parameter.</param>
public void Contains(ref BoundingBox box, out ContainmentType result)
{
result = this.Contains(box);
}
/// <summary>
/// Test if a frustum is fully inside, outside, or just intersecting the sphere.
/// </summary>
/// <param name="frustum">The frustum for testing.</param>
/// <returns>The containment type.</returns>
public ContainmentType Contains(BoundingFrustum frustum)
{
//check if all corner is in sphere
bool inside = true;
Vector3[] corners = frustum.GetCorners();
foreach (Vector3 corner in corners)
{
if (this.Contains(corner) == ContainmentType.Disjoint)
{
inside = false;
break;
}
}
if (inside)
return ContainmentType.Contains;
//check if the distance from sphere center to frustrum face < radius
double dmin = 0;
//TODO : calcul dmin
if (dmin <= Radius * Radius)
return ContainmentType.Intersects;
//else disjoint
return ContainmentType.Disjoint;
}
/// <summary>
/// Test if a frustum is fully inside, outside, or just intersecting the sphere.
/// </summary>
/// <param name="frustum">The frustum for testing.</param>
/// <param name="result">The containment type as an output parameter.</param>
public void Contains(ref BoundingFrustum frustum,out ContainmentType result)
{
result = this.Contains(frustum);
}
/// <summary>
/// Test if a sphere is fully inside, outside, or just intersecting the sphere.
/// </summary>
/// <param name="sphere">The other sphere for testing.</param>
/// <returns>The containment type.</returns>
public ContainmentType Contains(BoundingSphere sphere)
{
ContainmentType result;
Contains(ref sphere, out result);
return result;
}
/// <summary>
/// Test if a sphere is fully inside, outside, or just intersecting the sphere.
/// </summary>
/// <param name="sphere">The other sphere for testing.</param>
/// <param name="result">The containment type as an output parameter.</param>
public void Contains(ref BoundingSphere sphere, out ContainmentType result)
{
float sqDistance;
Vector3.DistanceSquared(ref sphere.Center, ref Center, out sqDistance);
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>
/// Test if a point is fully inside, outside, or just intersecting the sphere.
/// </summary>
/// <param name="point">The vector in 3D-space for testing.</param>
/// <returns>The containment type.</returns>
public ContainmentType Contains(Vector3 point)
{
ContainmentType result;
Contains(ref point, out result);
return result;
}
/// <summary>
/// Test if a point is fully inside, outside, or just intersecting the sphere.
/// </summary>
/// <param name="point">The vector in 3D-space for testing.</param>
/// <param name="result">The containment type as an output parameter.</param>
public void Contains(ref Vector3 point, out ContainmentType result)
{
float sqRadius = Radius * Radius;
float sqDistance;
Vector3.DistanceSquared(ref point, ref Center, out sqDistance);
if (sqDistance > sqRadius)
result = ContainmentType.Disjoint;
else if (sqDistance < sqRadius)
result = ContainmentType.Contains;
else
result = ContainmentType.Intersects;
}
#endregion
#region CreateFromBoundingBox
/// <summary>
/// Creates the smallest <see cref="BoundingSphere"/> that can contain a specified <see cref="BoundingBox"/>.
/// </summary>
/// <param name="box">The box to create the sphere from.</param>
/// <returns>The new <see cref="BoundingSphere"/>.</returns>
public static BoundingSphere CreateFromBoundingBox(BoundingBox box)
{
BoundingSphere result;
CreateFromBoundingBox(ref box, out result);
return result;
}
/// <summary>
/// Creates the smallest <see cref="BoundingSphere"/> that can contain a specified <see cref="BoundingBox"/>.
/// </summary>
/// <param name="box">The box to create the sphere from.</param>
/// <param name="result">The new <see cref="BoundingSphere"/> as an output parameter.</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);
}
#endregion
/// <summary>
/// Creates the smallest <see cref="BoundingSphere"/> that can contain a specified <see cref="BoundingFrustum"/>.
/// </summary>
/// <param name="frustum">The frustum to create the sphere from.</param>
/// <returns>The new <see cref="BoundingSphere"/>.</returns>
public static BoundingSphere CreateFromFrustum(BoundingFrustum frustum)
{
return CreateFromPoints(frustum.GetCorners());
}
/// <summary>
/// Creates the smallest <see cref="BoundingSphere"/> that can contain a specified list of points in 3D-space.
/// </summary>
/// <param name="points">List of point to create the sphere from.</param>
/// <returns>The new <see cref="BoundingSphere"/>.</returns>
public static BoundingSphere CreateFromPoints(IEnumerable<Vector3> points)
{
if (points == null )
throw new ArgumentNullException("points");
// From "Real-Time Collision Detection" (Page 89)
var minx = new Vector3(float.MaxValue, float.MaxValue, float.MaxValue);
var maxx = -minx;
var miny = minx;
var maxy = -minx;
var minz = minx;
var maxz = -minx;
// Find the most extreme points along the principle axis.
var numPoints = 0;
foreach (var pt in points)
{
++numPoints;
if (pt.X < minx.X)
minx = pt;
if (pt.X > maxx.X)
maxx = pt;
if (pt.Y < miny.Y)
miny = pt;
if (pt.Y > maxy.Y)
maxy = pt;
if (pt.Z < minz.Z)
minz = pt;
if (pt.Z > maxz.Z)
maxz = pt;
}
if (numPoints == 0)
throw new ArgumentException("You should have at least one point in points.");
var sqDistX = Vector3.DistanceSquared(maxx, minx);
var sqDistY = Vector3.DistanceSquared(maxy, miny);
var sqDistZ = Vector3.DistanceSquared(maxz, minz);
// Pick the pair of most distant points.
var min = minx;
var max = maxx;
if (sqDistY > sqDistX && sqDistY > sqDistZ)
{
max = maxy;
min = miny;
}
if (sqDistZ > sqDistX && sqDistZ > sqDistY)
{
max = maxz;
min = minz;
}
var center = (min + max) * 0.5f;
var radius = Vector3.Distance(max, center);
// Test every point and expand the sphere.
// The current bounding sphere is just a good approximation and may not enclose all points.
// From: Mathematics for 3D Game Programming and Computer Graphics, Eric Lengyel, Third Edition.
// Page 218
float sqRadius = radius * radius;
foreach (var pt in points)
{
Vector3 diff = (pt-center);
float sqDist = diff.LengthSquared();
if (sqDist > sqRadius)
{
float distance = MathF.Sqrt(sqDist); // equal to diff.Length();
Vector3 direction = diff / distance;
Vector3 G = center - radius * direction;
center = (G + pt) / 2;
radius = Vector3.Distance(pt, center);
sqRadius = radius * radius;
}
}
return new BoundingSphere(center, radius);
}
/// <summary>
/// Creates the smallest <see cref="BoundingSphere"/> that can contain two spheres.
/// </summary>
/// <param name="original">First sphere.</param>
/// <param name="additional">Second sphere.</param>
/// <returns>The new <see cref="BoundingSphere"/>.</returns>
public static BoundingSphere CreateMerged(BoundingSphere original, BoundingSphere additional)
{
BoundingSphere result;
CreateMerged(ref original, ref additional, out result);
return result;
}
/// <summary>
/// Creates the smallest <see cref="BoundingSphere"/> that can contain two spheres.
/// </summary>
/// <param name="original">First sphere.</param>
/// <param name="additional">Second sphere.</param>
/// <param name="result">The new <see cref="BoundingSphere"/> as an output parameter.</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.Center = original.Center + ocenterToaCenter;
result.Radius = (leftRadius + Rightradius) / 2;
}
/// <summary>
/// Compares whether current instance is equal to specified <see cref="BoundingSphere"/>.
/// </summary>
/// <param name="other">The <see cref="BoundingSphere"/> to compare.</param>
/// <returns><c>true</c> if the instances are equal; <c>false</c> otherwise.</returns>
public bool Equals(BoundingSphere other)
{
return this.Center == other.Center && this.Radius == other.Radius;
}
/// <summary>
/// Compares whether current instance is equal to specified <see cref="Object"/>.
/// </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)
{
if (obj is BoundingSphere)
return this.Equals((BoundingSphere)obj);
return false;
}
/// <summary>
/// Gets the hash code of this <see cref="BoundingSphere"/>.
/// </summary>
/// <returns>Hash code of this <see cref="BoundingSphere"/>.</returns>
public override int GetHashCode()
{
return this.Center.GetHashCode() + this.Radius.GetHashCode();
}
#region Intersects
/// <summary>
/// Gets whether or not a specified <see cref="BoundingBox"/> intersects with this sphere.
/// </summary>
/// <param name="box">The box for testing.</param>
/// <returns><c>true</c> if <see cref="BoundingBox"/> intersects with this sphere; <c>false</c> otherwise.</returns>
public bool Intersects(BoundingBox box)
{
return box.Intersects(this);
}
/// <summary>
/// Gets whether or not a specified <see cref="BoundingBox"/> intersects with this sphere.
/// </summary>
/// <param name="box">The box for testing.</param>
/// <param name="result"><c>true</c> if <see cref="BoundingBox"/> intersects with this sphere; <c>false</c> otherwise. As an output parameter.</param>
public void Intersects(ref BoundingBox box, out bool result)
{
box.Intersects(ref this, out result);
}
/*
TODO : Make the public bool Intersects(BoundingFrustum frustum) overload
public bool Intersects(BoundingFrustum frustum)
{
if (frustum == null)
throw new NullReferenceException();
throw new NotImplementedException();
}
*/
/// <summary>
/// Gets whether or not the other <see cref="BoundingSphere"/> intersects with this sphere.
/// </summary>
/// <param name="sphere">The other sphere for testing.</param>
/// <returns><c>true</c> if other <see cref="BoundingSphere"/> intersects with this sphere; <c>false</c> otherwise.</returns>
public bool Intersects(BoundingSphere sphere)
{
bool result;
Intersects(ref sphere, out result);
return result;
}
/// <summary>
/// Gets whether or not the other <see cref="BoundingSphere"/> intersects with this sphere.
/// </summary>
/// <param name="sphere">The other sphere for testing.</param>
/// <param name="result"><c>true</c> if other <see cref="BoundingSphere"/> intersects with this sphere; <c>false</c> otherwise. As an output parameter.</param>
public void Intersects(ref BoundingSphere sphere, out bool result)
{
float sqDistance;
Vector3.DistanceSquared(ref sphere.Center, ref Center, out sqDistance);
if (sqDistance > (sphere.Radius + Radius) * (sphere.Radius + Radius))
result = false;
else
result = true;
}
/// <summary>
/// Gets whether or not a specified <see cref="Plane"/> intersects with this sphere.
/// </summary>
/// <param name="plane">The plane for testing.</param>
/// <returns>Type of intersection.</returns>
public PlaneIntersectionType Intersects(Plane plane)
{
var result = default(PlaneIntersectionType);
// TODO: we might want to inline this for performance reasons
this.Intersects(ref plane, out result);
return result;
}
/// <summary>
/// Gets whether or not a specified <see cref="Plane"/> intersects with this sphere.
/// </summary>
/// <param name="plane">The plane for testing.</param>
/// <param name="result">Type of intersection as an output parameter.</param>
public void Intersects(ref Plane plane, out PlaneIntersectionType result)
{
var distance = default(float);
// TODO: we might want to inline this for performance reasons
Vector3.Dot(ref plane.Normal, ref this.Center, out distance);
distance += plane.D;
if (distance > this.Radius)
result = PlaneIntersectionType.Front;
else if (distance < -this.Radius)
result = PlaneIntersectionType.Back;
else
result = PlaneIntersectionType.Intersecting;
}
/// <summary>
/// Gets whether or not a specified <see cref="Ray"/> intersects with this sphere.
/// </summary>
/// <param name="ray">The ray for testing.</param>
/// <returns>Distance of ray intersection or <c>null</c> if there is no intersection.</returns>
public float? Intersects(Ray ray)
{
return ray.Intersects(this);
}
/// <summary>
/// Gets whether or not a specified <see cref="Ray"/> intersects with this sphere.
/// </summary>
/// <param name="ray">The ray for testing.</param>
/// <param name="result">Distance of ray intersection or <c>null</c> if there is no intersection as an output parameter.</param>
public void Intersects(ref Ray ray, out float? result)
{
ray.Intersects(ref this, out result);
}
#endregion
/// <summary>
/// Returns a <see cref="String"/> representation of this <see cref="BoundingSphere"/> in the format:
/// {Center:[<see cref="Center"/>] Radius:[<see cref="Radius"/>]}
/// </summary>
/// <returns>A <see cref="String"/> representation of this <see cref="BoundingSphere"/>.</returns>
public override string ToString()
{
return "{Center:" + this.Center + " Radius:" + this.Radius + "}";
}
#region Transform
/// <summary>
/// Creates a new <see cref="BoundingSphere"/> that contains a transformation of translation and scale from this sphere by the specified <see cref="Matrix"/>.
/// </summary>
/// <param name="matrix">The transformation <see cref="Matrix"/>.</param>
/// <returns>Transformed <see cref="BoundingSphere"/>.</returns>
public BoundingSphere Transform(Matrix matrix)
{
BoundingSphere sphere = new BoundingSphere();
sphere.Center = Vector3.Transform(this.Center, matrix);
sphere.Radius = this.Radius * MathF.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))));
return sphere;
}
/// <summary>
/// Creates a new <see cref="BoundingSphere"/> that contains a transformation of translation and scale from this sphere by the specified <see cref="Matrix"/>.
/// </summary>
/// <param name="matrix">The transformation <see cref="Matrix"/>.</param>
/// <param name="result">Transformed <see cref="BoundingSphere"/> as an output parameter.</param>
public void Transform(ref Matrix matrix, out BoundingSphere result)
{
result.Center = Vector3.Transform(this.Center, matrix);
result.Radius = this.Radius * MathF.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))));
}
#endregion
/// <summary>
/// Deconstruction method for <see cref="BoundingSphere"/>.
/// </summary>
/// <param name="center"></param>
/// <param name="radius"></param>
public void Deconstruct(out Vector3 center, out float radius)
{
center = Center;
radius = Radius;
}
#endregion
#region Operators
/// <summary>
/// Compares whether two <see cref="BoundingSphere"/> instances are equal.
/// </summary>
/// <param name="a"><see cref="BoundingSphere"/> instance on the left of the equal sign.</param>
/// <param name="b"><see cref="BoundingSphere"/> 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 == (BoundingSphere a, BoundingSphere b)
{
return a.Equals(b);
}
/// <summary>
/// Compares whether two <see cref="BoundingSphere"/> instances are not equal.
/// </summary>
/// <param name="a"><see cref="BoundingSphere"/> instance on the left of the not equal sign.</param>
/// <param name="b"><see cref="BoundingSphere"/> 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 != (BoundingSphere a, BoundingSphere b)
{
return !a.Equals(b);
}
#endregion
}
}