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added Circle3, point/circle 2d/3d distances
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4 files changed

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4 files changed

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‎distance/DistPoint2Circle2.cs

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using System;
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using System.Collections.Generic;
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using System.Linq;
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using System.Text;
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namespace g3
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{
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// ported from WildMagic 5's DistPoint3Circle3 (didn't have point2circle2)
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// https://www.geometrictools.com/Downloads/Downloads.html
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public class DistPoint2Circle2
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{
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Vector2d point;
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public Vector2d Point
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{
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get { return point; }
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set { point = value; DistanceSquared = -1.0; }
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}
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Circle2d circle;
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public Circle2d Circle
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{
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get { return circle; }
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set { circle = value; DistanceSquared = -1.0; }
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}
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public double DistanceSquared = -1.0;
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public Vector2d CircleClosest;
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public bool AllCirclePointsEquidistant;
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public DistPoint2Circle2(Vector2d PointIn, Circle2d circleIn )
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{
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point = PointIn; circle = circleIn;
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}
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public DistPoint2Circle2 Compute()
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{
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GetSquared();
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return this;
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}
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public double Get()
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{
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return Math.Sqrt(GetSquared());
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}
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public double GetSquared()
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{
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if (DistanceSquared >= 0)
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return DistanceSquared;
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// Projection of P-C onto plane is Q-C = P-C - Dot(N,P-C)*N.
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Vector2d PmC = point - circle.Center;
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double lengthPmC = PmC.Length;
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if (lengthPmC > 0) {
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CircleClosest = circle.Center + circle.Radius * PmC / lengthPmC;
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AllCirclePointsEquidistant = false;
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} else {
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// All circle points are equidistant from P. Return one of them.
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CircleClosest = circle.Center + circle.Radius;
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AllCirclePointsEquidistant = true;
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}
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Vector2d diff = point - CircleClosest;
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double sqrDistance = diff.Dot(diff);
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// Account for numerical round-off error.
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if (sqrDistance < 0) {
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sqrDistance = 0;
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}
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DistanceSquared = sqrDistance;
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return sqrDistance;
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}
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}
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}

‎distance/DistPoint3Circle3.cs

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using System;
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using System.Collections.Generic;
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using System.Linq;
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using System.Text;
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namespace g3
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{
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// ported from WildMagic 5
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// https://www.geometrictools.com/Downloads/Downloads.html
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public class DistPoint3Circle3
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{
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Vector3d point;
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public Vector3d Point
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{
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get { return point; }
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set { point = value; DistanceSquared = -1.0; }
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}
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Circle3d circle;
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public Circle3d Circle
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{
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get { return circle; }
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set { circle = value; DistanceSquared = -1.0; }
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}
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public double DistanceSquared = -1.0;
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public Vector3d CircleClosest;
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public bool AllCirclePointsEquidistant;
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public DistPoint3Circle3(Vector3d PointIn, Circle3d circleIn )
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{
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point = PointIn; circle = circleIn;
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}
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public DistPoint3Circle3 Compute()
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{
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GetSquared();
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return this;
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}
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public double Get()
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{
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return Math.Sqrt(GetSquared());
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}
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public double GetSquared()
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{
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if (DistanceSquared >= 0)
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return DistanceSquared;
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// Projection of P-C onto plane is Q-C = P-C - Dot(N,P-C)*N.
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Vector3d PmC = point - circle.Center;
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Vector3d QmC = PmC - circle.Normal.Dot(PmC) * circle.Normal;
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double lengthQmC = QmC.Length;
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if (lengthQmC > 0) {
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CircleClosest = circle.Center + circle.Radius * QmC / lengthQmC;
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AllCirclePointsEquidistant = false;
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} else {
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// All circle points are equidistant from P. Return one of them.
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CircleClosest = circle.Center + circle.Radius * circle.AxisX;
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AllCirclePointsEquidistant = true;
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}
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Vector3d diff = point - CircleClosest;
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double sqrDistance = diff.Dot(diff);
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// Account for numerical round-off error.
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if (sqrDistance < 0) {
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sqrDistance = 0;
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}
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DistanceSquared = sqrDistance;
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return sqrDistance;
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}
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}
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}

‎geometry3Sharp.csproj

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<Compile Include="curve\Circle2.cs" />
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<Compile Include="curve\Ellipse2.cs" />
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<Compile Include="curve\NURBSCurve2.cs" />
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<Compile Include="distance\DistPoint3Circle3.cs" />
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<Compile Include="implicit\ImplicitField.cs" />
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<Compile Include="implicit\ImplicitOperators.cs" />
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<Compile Include="implicit\MarchingQuads.cs" />
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<Compile Include="intersection\IntrLine3Box3.cs" />
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<Compile Include="intersection\IntrSegment3Box3.cs" />
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<Compile Include="intersection\IntrRay3Box3.cs" />
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<Compile Include="shapes3\Circle3.cs" />
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<Compile Include="spatial\DMeshAABBTree.cs" />
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<Compile Include="spatial\MeshProjectionTarget.cs" />
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<Compile Include="spatial\SpatialInterfaces.cs" />

‎shapes3/Circle3.cs

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using System;
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namespace g3
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{
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public class Circle3d
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{
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// The plane containing the circle is Dot(N,X-C) = 0, where X is any point
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// in the plane. Vectors U, V, and N form an orthonormal right-handed set
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// (matrix [U V N] is orthonormal and has determinant 1). The circle
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// within the plane is parameterized by X = C + R*(cos(t)*U + sin(t)*V),
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// where t is an angle in [-pi,pi).
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public Vector3d Center;
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public Vector3d Normal;
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public Vector3d AxisX, AxisY;
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public double Radius;
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public bool IsReversed; // use ccw orientation instead of cw
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public Circle3d(Vector3d center, Vector3d axis0, Vector3d axis1, Vector3d normal, double radius)
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{
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IsReversed = false;
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Center = center;
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Normal = normal;
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AxisX = axis0;
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AxisY = axis1;
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Radius = radius;
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}
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public bool IsClosed {
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get { return true; }
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}
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public void Reverse() {
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IsReversed = ! IsReversed;
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}
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// angle in range [0,360] (but works for any value, obviously)
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public Vector3d SampleDeg(double degrees)
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{
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double theta = degrees * MathUtil.Deg2Rad;
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double c = Math.Cos(theta), s = Math.Sin(theta);
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return Center + c * Radius * AxisX + s * Radius * AxisY;
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}
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// angle in range [0,2pi] (but works for any value, obviously)
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public Vector3d SampleRad(double radians)
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{
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double c = Math.Cos(radians), s = Math.Sin(radians);
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return Center + c * Radius * AxisX + s * Radius * AxisY;
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}
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public double ParamLength {
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get { return 1.0f; }
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}
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// t in range[0,1] spans circle [0,2pi]
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public Vector3d SampleT(double t) {
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double theta = (IsReversed) ? -t*MathUtil.TwoPI : t*MathUtil.TwoPI;
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double c = Math.Cos(theta), s = Math.Sin(theta);
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return Center + c * Radius * AxisX + s * Radius * AxisY;
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}
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public bool HasArcLength { get {return true;} }
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public double ArcLength {
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get {
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return MathUtil.TwoPI * Radius;
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}
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}
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public Vector3d SampleArcLength(double a) {
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double t = a / ArcLength;
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double theta = (IsReversed) ? -t*MathUtil.TwoPI : t*MathUtil.TwoPI;
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double c = Math.Cos(theta), s = Math.Sin(theta);
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return Center + c * Radius * AxisX + s * Radius * AxisY;
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}
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public double Circumference {
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get { return MathUtil.TwoPI * Radius; }
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}
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public double Diameter {
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get { return 2 * Radius; }
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}
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public double Area {
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get { return Math.PI * Radius * Radius; }
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}
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}
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}

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