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#region License
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/* FNA - XNA4 Reimplementation for Desktop Platforms
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* Copyright 2009-2020 Ethan Lee and the MonoGame Team
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*
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* Released under the Microsoft Public License.
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* See LICENSE for details.
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*/
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/* Derived from code by the Mono.Xna Team (Copyright 2006).
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* Released under the MIT License. See monoxna.LICENSE for details.
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*/
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#endregion
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#region Using Statements
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using System;
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using System.Collections.Generic;
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using System.ComponentModel;
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using System.Diagnostics;
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using Microsoft.Xna.Framework.Design;
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#endregion
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namespace Microsoft.Xna.Framework
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{
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/// <summary>
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/// Describes a sphere in 3D-space for bounding operations.
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/// </summary>
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[Serializable]
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[TypeConverter(typeof(BoundingSphereConverter))]
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[DebuggerDisplay("{DebugDisplayString,nq}")]
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public struct BoundingSphere : IEquatable<BoundingSphere>
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{
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#region Internal Properties
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internal string DebugDisplayString
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{
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get
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{
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return string.Concat(
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"Center( ", Center.DebugDisplayString, " ) \r\n",
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"Radius( ", Radius.ToString(), " ) "
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);
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}
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}
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#endregion
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#region Public Fields
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/// <summary>
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/// The sphere center.
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/// </summary>
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public Vector3 Center;
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/// <summary>
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/// The sphere radius.
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/// </summary>
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public float Radius;
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#endregion
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#region Public Constructors
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/// <summary>
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/// Constructs a bounding sphere with the specified center and radius.
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/// </summary>
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/// <param name="center">The sphere center.</param>
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/// <param name="radius">The sphere radius.</param>
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public BoundingSphere(Vector3 center, float radius)
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{
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this.Center = center;
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this.Radius = radius;
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}
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#endregion
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#region Public Methods
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/// <summary>
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/// Creates a new <see cref="BoundingSphere"/> that contains a transformation of translation and scale from this sphere by the specified <see cref="Matrix"/>.
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/// </summary>
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/// <param name="matrix">The transformation <see cref="Matrix"/>.</param>
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/// <returns>Transformed <see cref="BoundingSphere"/>.</returns>
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public BoundingSphere Transform(Matrix matrix)
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{
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BoundingSphere sphere = new BoundingSphere();
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sphere.Center = Vector3.Transform(this.Center, matrix);
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sphere.Radius = this.Radius *
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(
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(float) Math.Sqrt((double) Math.Max(
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((matrix.M11 * matrix.M11) + (matrix.M12 * matrix.M12)) + (matrix.M13 * matrix.M13),
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Math.Max(
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((matrix.M21 * matrix.M21) + (matrix.M22 * matrix.M22)) + (matrix.M23 * matrix.M23),
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((matrix.M31 * matrix.M31) + (matrix.M32 * matrix.M32)) + (matrix.M33 * matrix.M33))
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)
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)
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);
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return sphere;
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}
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/// <summary>
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/// Creates a new <see cref="BoundingSphere"/> that contains a transformation of translation and scale from this sphere by the specified <see cref="Matrix"/>.
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/// </summary>
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/// <param name="matrix">The transformation <see cref="Matrix"/>.</param>
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/// <param name="result">Transformed <see cref="BoundingSphere"/> as an output parameter.</param>
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public void Transform(ref Matrix matrix, out BoundingSphere result)
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{
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result.Center = Vector3.Transform(this.Center, matrix);
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result.Radius = this.Radius *
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(
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(float) Math.Sqrt((double) Math.Max(
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((matrix.M11 * matrix.M11) + (matrix.M12 * matrix.M12)) + (matrix.M13 * matrix.M13),
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Math.Max(
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((matrix.M21 * matrix.M21) + (matrix.M22 * matrix.M22)) + (matrix.M23 * matrix.M23),
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((matrix.M31 * matrix.M31) + (matrix.M32 * matrix.M32)) + (matrix.M33 * matrix.M33))
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)
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)
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);
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}
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/// <summary>
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/// Test if a bounding box is fully inside, outside, or just intersecting the sphere.
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/// </summary>
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/// <param name="box">The box for testing.</param>
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/// <param name="result">The containment type as an output parameter.</param>
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public void Contains(ref BoundingBox box, out ContainmentType result)
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{
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result = this.Contains(box);
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}
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/// <summary>
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/// Test if a sphere is fully inside, outside, or just intersecting the sphere.
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/// </summary>
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/// <param name="sphere">The other sphere for testing.</param>
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/// <param name="result">The containment type as an output parameter.</param>
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public void Contains(ref BoundingSphere sphere, out ContainmentType result)
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{
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result = Contains(sphere);
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}
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/// <summary>
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/// Test if a point is fully inside, outside, or just intersecting the sphere.
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/// </summary>
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/// <param name="point">The vector in 3D-space for testing.</param>
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/// <param name="result">The containment type as an output parameter.</param>
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public void Contains(ref Vector3 point, out ContainmentType result)
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{
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result = Contains(point);
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}
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/// <summary>
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/// Test if a bounding box is fully inside, outside, or just intersecting the sphere.
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/// </summary>
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/// <param name="box">The box for testing.</param>
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/// <returns>The containment type.</returns>
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public ContainmentType Contains(BoundingBox box)
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{
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// Check if all corners are in sphere.
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bool inside = true;
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foreach (Vector3 corner in box.GetCorners())
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{
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if (this.Contains(corner) == ContainmentType.Disjoint)
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{
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inside = false;
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break;
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}
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}
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if (inside)
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{
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return ContainmentType.Contains;
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}
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// Check if the distance from sphere center to cube face is less than radius.
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double dmin = 0;
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if (Center.X < box.Min.X)
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{
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dmin += (Center.X - box.Min.X) * (Center.X - box.Min.X);
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}
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else if (Center.X > box.Max.X)
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{
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dmin += (Center.X - box.Max.X) * (Center.X - box.Max.X);
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}
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if (Center.Y < box.Min.Y)
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{
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dmin += (Center.Y - box.Min.Y) * (Center.Y - box.Min.Y);
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}
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else if (Center.Y > box.Max.Y)
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{
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dmin += (Center.Y - box.Max.Y) * (Center.Y - box.Max.Y);
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}
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if (Center.Z < box.Min.Z)
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{
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dmin += (Center.Z - box.Min.Z) * (Center.Z - box.Min.Z);
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}
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else if (Center.Z > box.Max.Z)
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{
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dmin += (Center.Z - box.Max.Z) * (Center.Z - box.Max.Z);
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}
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if (dmin <= Radius * Radius)
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{
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return ContainmentType.Intersects;
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}
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// Else disjoint
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return ContainmentType.Disjoint;
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}
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/// <summary>
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/// Test if a frustum is fully inside, outside, or just intersecting the sphere.
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/// </summary>
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/// <param name="box">The box for testing.</param>
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/// <param name="result">The containment type as an output parameter.</param>
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public ContainmentType Contains(BoundingFrustum frustum)
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{
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// Check if all corners are in sphere.
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bool inside = true;
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Vector3[] corners = frustum.GetCorners();
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foreach (Vector3 corner in corners)
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{
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if (this.Contains(corner) == ContainmentType.Disjoint)
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{
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inside = false;
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break;
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}
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}
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if (inside)
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{
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return ContainmentType.Contains;
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}
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// Check if the distance from sphere center to frustrum face is less than radius.
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double dmin = 0;
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// TODO : calcul dmin
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if (dmin <= Radius * Radius)
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{
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return ContainmentType.Intersects;
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}
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// Else disjoint
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return ContainmentType.Disjoint;
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}
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/// <summary>
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/// Test if a sphere is fully inside, outside, or just intersecting the sphere.
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/// </summary>
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/// <param name="sphere">The other sphere for testing.</param>
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/// <returns>The containment type.</returns>
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public ContainmentType Contains(BoundingSphere sphere)
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{
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float sqDistance;
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Vector3.DistanceSquared(ref sphere.Center, ref Center, out sqDistance);
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if (sqDistance > (sphere.Radius + Radius) * (sphere.Radius + Radius))
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{
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return ContainmentType.Disjoint;
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}
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else if (sqDistance <= (Radius - sphere.Radius) * (Radius - sphere.Radius))
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{
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return ContainmentType.Contains;
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}
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return ContainmentType.Intersects;
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}
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/// <summary>
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/// Test if a point is fully inside, outside, or just intersecting the sphere.
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/// </summary>
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/// <param name="point">The vector in 3D-space for testing.</param>
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/// <returns>The containment type.</returns>
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public ContainmentType Contains(Vector3 point)
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{
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float sqRadius = Radius * Radius;
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float sqDistance;
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Vector3.DistanceSquared(ref point, ref Center, out sqDistance);
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if (sqDistance > sqRadius)
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{
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return ContainmentType.Disjoint;
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}
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else if (sqDistance < sqRadius)
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{
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return ContainmentType.Contains;
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}
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return ContainmentType.Intersects;
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}
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/// <summary>
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/// Compares whether current instance is equal to specified <see cref="BoundingSphere"/>.
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/// </summary>
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/// <param name="other">The <see cref="BoundingSphere"/> to compare.</param>
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/// <returns><c>true</c> if the instances are equal; <c>false</c> otherwise.</returns>
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public bool Equals(BoundingSphere other)
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{
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return ( Center == other.Center &&
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Radius == other.Radius );
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}
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#endregion
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#region Public Static Methods
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/// <summary>
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/// Creates the smallest <see cref="BoundingSphere"/> that can contain a specified <see cref="BoundingBox"/>.
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/// </summary>
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/// <param name="box">The box to create the sphere from.</param>
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/// <returns>The new <see cref="BoundingSphere"/>.</returns>
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public static BoundingSphere CreateFromBoundingBox(BoundingBox box)
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{
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BoundingSphere result;
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CreateFromBoundingBox(ref box, out result);
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return result;
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}
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/// <summary>
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/// Creates the smallest <see cref="BoundingSphere"/> that can contain a specified <see cref="BoundingBox"/>.
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/// </summary>
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/// <param name="box">The box to create the sphere from.</param>
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/// <param name="result">The new <see cref="BoundingSphere"/> as an output parameter.</param>
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public static void CreateFromBoundingBox(ref BoundingBox box, out BoundingSphere result)
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{
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// Find the center of the box.
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Vector3 center = new Vector3(
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(box.Min.X + box.Max.X) / 2.0f,
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(box.Min.Y + box.Max.Y) / 2.0f,
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(box.Min.Z + box.Max.Z) / 2.0f
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);
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// Find the distance between the center and one of the corners of the box.
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float radius = Vector3.Distance(center, box.Max);
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result = new BoundingSphere(center, radius);
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}
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/// <summary>
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/// Creates the smallest <see cref="BoundingSphere"/> that can contain a specified <see cref="BoundingFrustum"/>.
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/// </summary>
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/// <param name="frustum">The frustum to create the sphere from.</param>
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/// <returns>The new <see cref="BoundingSphere"/>.</returns>
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public static BoundingSphere CreateFromFrustum(BoundingFrustum frustum)
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{
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return CreateFromPoints(frustum.GetCorners());
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}
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/// <summary>
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/// Creates the smallest <see cref="BoundingSphere"/> that can contain a specified list of points in 3D-space.
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/// </summary>
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/// <param name="points">List of point to create the sphere from.</param>
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/// <returns>The new <see cref="BoundingSphere"/>.</returns>
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public static BoundingSphere CreateFromPoints(IEnumerable<Vector3> points)
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{
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if (points == null)
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{
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throw new ArgumentNullException("points");
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}
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// From "Real-Time Collision Detection" (Page 89)
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Vector3 minx = new Vector3(float.MaxValue, float.MaxValue, float.MaxValue);
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Vector3 maxx = -minx;
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Vector3 miny = minx;
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Vector3 maxy = -minx;
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Vector3 minz = minx;
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Vector3 maxz = -minx;
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// Find the most extreme points along the principle axis.
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int numPoints = 0;
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foreach (Vector3 pt in points)
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{
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numPoints += 1;
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if (pt.X < minx.X)
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{
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minx = pt;
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}
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if (pt.X > maxx.X)
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{
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maxx = pt;
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}
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if (pt.Y < miny.Y)
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{
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miny = pt;
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}
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if (pt.Y > maxy.Y)
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{
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maxy = pt;
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}
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if (pt.Z < minz.Z)
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{
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minz = pt;
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}
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if (pt.Z > maxz.Z)
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{
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maxz = pt;
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}
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}
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if (numPoints == 0)
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{
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throw new ArgumentException(
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"You should have at least one point in points."
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);
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}
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float sqDistX = Vector3.DistanceSquared(maxx, minx);
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float sqDistY = Vector3.DistanceSquared(maxy, miny);
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float sqDistZ = Vector3.DistanceSquared(maxz, minz);
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// Pick the pair of most distant points.
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Vector3 min = minx;
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Vector3 max = maxx;
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if (sqDistY > sqDistX && sqDistY > sqDistZ)
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{
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max = maxy;
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min = miny;
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}
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if (sqDistZ > sqDistX && sqDistZ > sqDistY)
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{
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max = maxz;
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min = minz;
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}
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Vector3 center = (min + max) * 0.5f;
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float radius = Vector3.Distance(max, center);
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// Test every point and expand the sphere.
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// The current bounding sphere is just a good approximation and may not enclose all points.
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// From: Mathematics for 3D Game Programming and Computer Graphics, Eric Lengyel, Third Edition.
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// Page 218
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float sqRadius = radius * radius;
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foreach (Vector3 pt in points)
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{
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Vector3 diff = (pt - center);
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float sqDist = diff.LengthSquared();
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if (sqDist > sqRadius)
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{
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float distance = (float) Math.Sqrt(sqDist); // equal to diff.Length();
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Vector3 direction = diff / distance;
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Vector3 G = center - radius * direction;
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center = (G + pt) / 2;
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radius = Vector3.Distance(pt, center);
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sqRadius = radius * radius;
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}
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}
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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();
|
|
|
|
|
|
// Intersect
|
|
|
if (distance <= original.Radius + additional.Radius)
|
|
|
{
|
|
|
// Original contains additional.
|
|
|
if (distance <= original.Radius - additional.Radius)
|
|
|
{
|
|
|
result = original;
|
|
|
return;
|
|
|
}
|
|
|
|
|
|
// Additional contains original.
|
|
|
if (distance <= additional.Radius - original.Radius)
|
|
|
{
|
|
|
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);
|
|
|
|
|
|
// oCenterToResultCenter
|
|
|
ocenterToaCenter = ocenterToaCenter +
|
|
|
(
|
|
|
((leftRadius - Rightradius) / (2 * ocenterToaCenter.Length()))
|
|
|
* ocenterToaCenter
|
|
|
);
|
|
|
|
|
|
result = new BoundingSphere();
|
|
|
result.Center = original.Center + ocenterToaCenter;
|
|
|
result.Radius = (leftRadius + Rightradius) / 2;
|
|
|
}
|
|
|
|
|
|
/// <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);
|
|
|
}
|
|
|
|
|
|
public bool Intersects(BoundingFrustum frustum)
|
|
|
{
|
|
|
return frustum.Intersects(this);
|
|
|
}
|
|
|
|
|
|
/// <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);
|
|
|
result = !(sqDistance > (sphere.Radius + Radius) * (sphere.Radius + Radius));
|
|
|
}
|
|
|
|
|
|
/// <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);
|
|
|
}
|
|
|
|
|
|
/// <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)
|
|
|
{
|
|
|
PlaneIntersectionType 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)
|
|
|
{
|
|
|
float 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;
|
|
|
}
|
|
|
}
|
|
|
|
|
|
#endregion
|
|
|
|
|
|
#region Public Static Operators and Override Methods
|
|
|
|
|
|
/// <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)
|
|
|
{
|
|
|
return (obj is BoundingSphere) && Equals((BoundingSphere) obj);
|
|
|
}
|
|
|
|
|
|
/// <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();
|
|
|
}
|
|
|
|
|
|
/// <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:" + Center.ToString() +
|
|
|
" Radius:" + Radius.ToString() +
|
|
|
"}"
|
|
|
);
|
|
|
}
|
|
|
|
|
|
/// <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
|
|
|
}
|
|
|
}
|
|
|
|
