333 lines
11 KiB
C#
333 lines
11 KiB
C#
using UnityEngine;
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using System.Collections;
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namespace RootMotion.FinalIK {
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/// <summary>
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/// Using a spherical polygon to limit the range of rotation on universal and ball-and-socket joints. A reach cone is specified as a spherical polygon
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/// on the surface of a a reach sphere that defines all positions the longitudinal segment axis beyond the joint can take.
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///
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/// This class is based on the "Fast and Easy Reach-Cone Joint Limits" paper by Jane Wilhelms and Allen Van Gelder.
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/// Computer Science Dept., University of California, Santa Cruz, CA 95064. August 2, 2001
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/// http://users.soe.ucsc.edu/~avg/Papers/jtl.pdf
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///
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/// </summary>
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[HelpURL("http://www.root-motion.com/finalikdox/html/page14.html")]
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[AddComponentMenu("Scripts/RootMotion.FinalIK/Rotation Limits/Rotation Limit Polygonal")]
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public class RotationLimitPolygonal : RotationLimit {
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// Open the User Manual URL
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[ContextMenu("User Manual")]
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private void OpenUserManual() {
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Application.OpenURL("http://www.root-motion.com/finalikdox/html/page14.html");
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}
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// Open the Script Reference URL
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[ContextMenu("Scrpt Reference")]
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private void OpenScriptReference() {
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Application.OpenURL("http://www.root-motion.com/finalikdox/html/class_root_motion_1_1_final_i_k_1_1_rotation_limit_polygonal.html");
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}
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// Link to the Final IK Google Group
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[ContextMenu("Support Group")]
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void SupportGroup() {
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Application.OpenURL("https://groups.google.com/forum/#!forum/final-ik");
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}
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// Link to the Final IK Asset Store thread in the Unity Community
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[ContextMenu("Asset Store Thread")]
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void ASThread() {
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Application.OpenURL("http://forum.unity3d.com/threads/final-ik-full-body-ik-aim-look-at-fabrik-ccd-ik-1-0-released.222685/");
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}
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#region Main Interface
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/// <summary>
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/// Limit of twist rotation around the main axis.
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/// </summary>
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[Range(0f, 180f)] public float twistLimit = 180;
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/// <summary>
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/// The number of smoothing iterations applied to the polygon.
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/// </summary>
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[Range(0, 3)] public int smoothIterations = 0;
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/// <summary>
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/// Sets the limit points and recalculates the reach cones.
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/// </summary>
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/// <param name='_points'>
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/// _points.
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/// </param>
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public void SetLimitPoints(LimitPoint[] points) {
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if (points.Length < 3) {
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LogWarning("The polygon must have at least 3 Limit Points.");
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return;
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}
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this.points = points;
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BuildReachCones();
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}
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#endregion Main Interface
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/*
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* Limits the rotation in the local space of this instance's Transform.
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* */
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protected override Quaternion LimitRotation(Quaternion rotation) {
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if (reachCones.Length == 0) Start();
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// Subtracting off-limits swing
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Quaternion swing = LimitSwing(rotation);
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// Apply twist limits
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return LimitTwist(swing, axis, secondaryAxis, twistLimit);
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}
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/*
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* Tetrahedron composed of 2 Limit points, the origin and an axis point.
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* */
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[System.Serializable]
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public class ReachCone {
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public Vector3[] tetrahedron;
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public float volume;
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public Vector3 S, B;
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public Vector3 o { get { return tetrahedron[0]; }}
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public Vector3 a { get { return tetrahedron[1]; }}
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public Vector3 b { get { return tetrahedron[2]; }}
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public Vector3 c { get { return tetrahedron[3]; }}
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public ReachCone(Vector3 _o, Vector3 _a, Vector3 _b, Vector3 _c) {
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this.tetrahedron = new Vector3[4];
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this.tetrahedron[0] = _o; // Origin
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this.tetrahedron[1] = _a; // Axis
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this.tetrahedron[2] = _b; // Limit Point 1
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this.tetrahedron[3] = _c; // Limit Point 2
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this.volume = 0;
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this.S = Vector3.zero;
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this.B = Vector3.zero;
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}
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public bool isValid { get { return volume > 0; }}
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public void Calculate() {
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Vector3 crossAB = Vector3.Cross(a, b);
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volume = Vector3.Dot(crossAB, c) / 6.0f;
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S = Vector3.Cross(a, b).normalized;
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B = Vector3.Cross(b, c).normalized;
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}
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}
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/*
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* The points defining the polygon
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* */
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[System.Serializable]
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public class LimitPoint {
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public Vector3 point;
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public float tangentWeight;
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public LimitPoint() {
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this.point = Vector3.forward;
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this.tangentWeight = 1;
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}
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}
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[SerializeField][HideInInspector] public LimitPoint[] points;
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[SerializeField][HideInInspector] public Vector3[] P;
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[SerializeField][HideInInspector] public ReachCone[] reachCones = new ReachCone[0];
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void Start() {
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if (points.Length < 3) ResetToDefault();
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// Check if Limit Points are valid
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for (int i = 0; i < reachCones.Length; i++) {
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if (!reachCones[i].isValid) {
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if (smoothIterations <= 0) {
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int nextPoint = 0;
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if (i < reachCones.Length - 1) nextPoint = i + 1;
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else nextPoint = 0;
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LogWarning("Reach Cone {point " + i + ", point " + nextPoint + ", Origin} has negative volume. Make sure Axis vector is in the reachable area and the polygon is convex.");
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} else LogWarning("One of the Reach Cones in the polygon has negative volume. Make sure Axis vector is in the reachable area and the polygon is convex.");
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}
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}
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axis = axis.normalized;
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}
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#region Precalculations
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/*
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* Apply the default initial setup of 4 Limit Points
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* */
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public void ResetToDefault() {
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points = new LimitPoint[4];
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for (int i = 0; i < points.Length; i++) points[i] = new LimitPoint();
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Quaternion swing1Rotation = Quaternion.AngleAxis(45, Vector3.right);
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Quaternion swing2Rotation = Quaternion.AngleAxis(45, Vector3.up);
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points[0].point = (swing1Rotation * swing2Rotation) * axis;
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points[1].point = (Quaternion.Inverse(swing1Rotation) * swing2Rotation) * axis;
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points[2].point = (Quaternion.Inverse(swing1Rotation) * Quaternion.Inverse(swing2Rotation)) * axis;
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points[3].point = (swing1Rotation * Quaternion.Inverse(swing2Rotation)) * axis;
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BuildReachCones();
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}
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/*
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* Recalculate reach cones if the Limit Points have changed
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* */
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public void BuildReachCones() {
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smoothIterations = Mathf.Clamp(smoothIterations, 0, 3);
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// Make another array for the points so that they could be smoothed without changing the initial points
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P = new Vector3[points.Length];
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for (int i = 0; i < points.Length; i++) P[i] = points[i].point.normalized;
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for (int i = 0; i < smoothIterations; i++) P = SmoothPoints();
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// Calculating the reach cones
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reachCones = new ReachCone[P.Length];
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for (int i = 0; i < reachCones.Length - 1; i++) {
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reachCones[i] = new ReachCone(Vector3.zero, axis.normalized, P[i], P[i + 1]);
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}
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reachCones[P.Length - 1] = new ReachCone(Vector3.zero, axis.normalized, P[P.Length - 1], P[0]);
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for (int i = 0; i < reachCones.Length; i++) reachCones[i].Calculate();
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}
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/*
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* Automatically adds virtual limit points to smooth the polygon
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* */
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private Vector3[] SmoothPoints() {
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// Create the new point array with double length
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Vector3[] Q = new Vector3[P.Length * 2];
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float scalar = GetScalar(P.Length); // Get the constant used for interpolation
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// Project all the existing points on a plane that is tangent to the unit sphere at the Axis point
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for (int i = 0; i < Q.Length; i+= 2) Q[i] = PointToTangentPlane(P[i / 2], 1);
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// Interpolate the new points
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for (int i = 1; i < Q.Length; i+= 2) {
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Vector3 minus2 = Vector3.zero;
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Vector3 plus1 = Vector3.zero;
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Vector3 plus2 = Vector3.zero;
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if (i > 1 && i < Q.Length - 2) {
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minus2 = Q[i - 2];
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plus2 = Q[i + 1];
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} else if (i == 1) {
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minus2 = Q[Q.Length - 2];
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plus2 = Q[i + 1];
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} else if (i == Q.Length - 1) {
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minus2 = Q[i - 2];
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plus2 = Q[0];
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}
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if (i < Q.Length - 1) plus1 = Q[i + 1];
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else plus1 = Q[0];
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int t = Q.Length / points.Length;
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// Interpolation
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Q[i] = (0.5f * (Q[i - 1] + plus1)) + (scalar * points[i / t].tangentWeight * (plus1 - minus2)) + (scalar * points[i / t].tangentWeight * (Q[i - 1] - plus2));
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}
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// Project the points from tangent plane to the sphere
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for (int i = 0; i < Q.Length; i++) Q[i] = TangentPointToSphere(Q[i], 1);
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return Q;
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}
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/*
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* Returns scalar values used for interpolating smooth positions between limit points
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* */
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private float GetScalar(int k) {
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// Values k (number of points) == 3, 4 and 6 are calculated by analytical geometry, values 5 and 7 were estimated by interpolation
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if (k <= 3) return .1667f;
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if (k == 4) return .1036f;
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if (k == 5) return .0850f;
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if (k == 6) return .0773f;
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if (k == 7) return .0700f;
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return .0625f; // Cubic spline fit
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}
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/*
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* Project a point on the sphere to a plane that is tangent to the unit sphere at the Axis point
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* */
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private Vector3 PointToTangentPlane(Vector3 p, float r) {
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float d = Vector3.Dot(axis, p);
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float u = (2 * r * r) / ((r * r) + d);
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return (u * p) + ((1 - u) * -axis);
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}
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/*
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* Project a point on the tangent plane to the sphere
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* */
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private Vector3 TangentPointToSphere(Vector3 q, float r) {
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float d = Vector3.Dot(q - axis, q - axis);
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float u = (4 * r * r) / ((4 * r * r) + d);
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return (u * q) + ((1 - u) * -axis);
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}
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#endregion Precalculations
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#region Runtime calculations
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/*
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* Applies Swing limit to the rotation
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* */
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private Quaternion LimitSwing(Quaternion rotation) {
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if (rotation == Quaternion.identity) return rotation; // Assuming initial rotation is in the reachable area
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Vector3 L = rotation * axis; // Test this vector against the reach cones
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int r = GetReachCone(L); // Get the reach cone to test against (can be only 1)
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// Just in case we are running our application with invalid reach cones
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if (r == -1) {
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if (!Warning.logged) LogWarning("RotationLimitPolygonal reach cones are invalid.");
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return rotation;
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}
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// Dot product of cone normal and rotated axis
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float v = Vector3.Dot(reachCones[r].B, L);
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if (v > 0) return rotation; // Rotation is reachable
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// Find normal for a plane defined by origin, axis, and rotated axis
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Vector3 rotationNormal = Vector3.Cross(axis, L);
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// Find the line where this plane intersects with the reach cone plane
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L = Vector3.Cross(-reachCones[r].B, rotationNormal);
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// Rotation from current(illegal) swing rotation to the limited(legal) swing rotation
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Quaternion toLimits = Quaternion.FromToRotation(rotation * axis, L);
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// Subtract the illegal rotation
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return toLimits * rotation;
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}
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/*
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* Finding the reach cone to test against
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* */
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private int GetReachCone(Vector3 L) {
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float p = 0;
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float p1 = Vector3.Dot(reachCones[0].S, L);
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for (int i = 0; i < reachCones.Length; i++) {
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p = p1;
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if (i < reachCones.Length - 1) p1 = Vector3.Dot(reachCones[i + 1].S, L);
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else p1 = Vector3.Dot(reachCones[0].S, L);
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if (p >= 0 && p1 < 0) return i;
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}
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return -1;
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}
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#endregion Runtime calculations
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}
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}
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