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582 lines
18 KiB
C#
582 lines
18 KiB
C#
using UnityEngine;
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using System.Collections;
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using System;
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namespace RootMotion.FinalIK {
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/// <summary>
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/// A chain of bones in IKSolverFullBody.
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/// </summary>
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[System.Serializable]
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public class FBIKChain {
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#region Main Interface
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/// <summary>
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/// Linear constraint between child chains of a FBIKChain.
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/// </summary>
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[System.Serializable]
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public class ChildConstraint {
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/// <summary>
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/// The push elasticity.
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/// </summary>
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public float pushElasticity = 0f;
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/// <summary>
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/// The pull elasticity.
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/// </summary>
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public float pullElasticity = 0f;
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/// <summary>
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/// The first bone.
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/// </summary>
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[SerializeField] private Transform bone1;
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/// <summary>
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/// The second bone.
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/// </summary>
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[SerializeField] private Transform bone2;
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// Gets the nominal (animated) distance between the two bones.
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public float nominalDistance { get; private set; }
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// The constraint is rigid if both push and pull elasticity are 0.
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public bool isRigid { get; private set; }
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// The crossFade value between the connected chains
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private float crossFade, inverseCrossFade;
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private int chain1Index;
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private int chain2Index;
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/*
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* Constructor
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* */
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public ChildConstraint(Transform bone1, Transform bone2, float pushElasticity = 0f, float pullElasticity = 0f) {
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this.bone1 = bone1;
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this.bone2 = bone2;
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this.pushElasticity = pushElasticity;
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this.pullElasticity = pullElasticity;
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}
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/*
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* Initiating the constraint
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* */
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public void Initiate(IKSolverFullBody solver) {
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chain1Index = solver.GetChainIndex(bone1);
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chain2Index = solver.GetChainIndex(bone2);
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OnPreSolve(solver);
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}
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/*
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* Updating nominal distance because it might have changed in the animation
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* */
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public void OnPreSolve(IKSolverFullBody solver) {
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nominalDistance = Vector3.Distance(solver.chain[chain1Index].nodes[0].transform.position, solver.chain[chain2Index].nodes[0].transform.position);
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isRigid = pushElasticity <= 0 && pullElasticity <= 0;
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// CrossFade
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if (isRigid) {
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float offset = solver.chain[chain1Index].pull - solver.chain[chain2Index].pull;
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crossFade = 1f - (0.5f + (offset * 0.5f));
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} else crossFade = 0.5f;
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inverseCrossFade = 1f - crossFade;
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}
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/*
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* Solving the constraint
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* */
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public void Solve(IKSolverFullBody solver) {
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if (pushElasticity >= 1 && pullElasticity >= 1) return;
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Vector3 direction = solver.chain[chain2Index].nodes[0].solverPosition - solver.chain[chain1Index].nodes[0].solverPosition;
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float distance = direction.magnitude;
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if (distance == nominalDistance) return;
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if (distance == 0f) return;
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float force = 1f;
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if (!isRigid) {
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float elasticity = distance > nominalDistance? pullElasticity: pushElasticity;
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force = 1f - elasticity;
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}
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force *= 1f - nominalDistance / distance;
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Vector3 offset = direction * force;
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solver.chain[chain1Index].nodes[0].solverPosition += offset * crossFade;
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solver.chain[chain2Index].nodes[0].solverPosition -= offset * inverseCrossFade;
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}
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}
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[System.Serializable]
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public enum Smoothing {
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None,
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Exponential,
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Cubic
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}
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/// <summary>
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/// The pin weight. If closer to 1, the chain will be less influenced by child chains.
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/// </summary>
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[Range(0f, 1f)]
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public float pin;
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/// <summary>
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/// The weight of pulling the parent chain.
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/// </summary>
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[Range(0f, 1f)]
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public float pull = 1f;
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/// <summary>
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/// The weight of the end-effector pushing the shoulder/thigh when the end-effector is close to it.
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/// </summary>
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[Range(0f, 1f)]
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public float push;
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/// <summary>
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/// The amount of push force transferred to the parent (from hand or foot to the body).
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/// </summary>
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[Range(-1f, 1f)]
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public float pushParent;
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/// <summary>
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/// Only used in 3 segmented chains, pulls the first node closer to the third node.
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/// </summary>
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[Range(0f, 1f)]
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public float reach = 0.1f;
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/// <summary>
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/// Smoothing the effect of the Reach with the expense of some accuracy.
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/// </summary>
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public Smoothing reachSmoothing = Smoothing.Exponential;
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/// <summary>
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/// Smoothing the effect of the Push.
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/// </summary>
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public Smoothing pushSmoothing = Smoothing.Exponential;
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/// <summary>
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/// The nodes in this chain.
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/// </summary>
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public IKSolver.Node[] nodes = new IKSolver.Node[0];
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/// <summary>
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/// The child chains.
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/// </summary>
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public int[] children = new int[0];
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/// <summary>
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/// The child constraints are used for example for fixing the distance between left upper arm and right upper arm
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/// </summary>
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public ChildConstraint[] childConstraints = new ChildConstraint[0];
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/// <summary>
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/// Gets the bend constraint (if this chain has 3 segments).
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/// </summary>
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/// <value>The bend constraint.</value>
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public IKConstraintBend bendConstraint = new IKConstraintBend();
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#endregion Main Interface
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private float rootLength;
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private bool initiated;
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private float length;
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private float distance;
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private IKSolver.Point p;
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private float reachForce;
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private float pullParentSum;
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private float[] crossFades;
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private float sqrMag1, sqrMag2, sqrMagDif;
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private const float maxLimbLength = 0.99999f;
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public FBIKChain() {}
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public FBIKChain (float pin, float pull, params Transform[] nodeTransforms) {
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this.pin = pin;
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this.pull = pull;
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SetNodes(nodeTransforms);
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children = new int[0];
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}
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/*
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* Set nodes to the following bone transforms.
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* */
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public void SetNodes(params Transform[] boneTransforms) {
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nodes = new IKSolver.Node[boneTransforms.Length];
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for (int i = 0; i < boneTransforms.Length; i++) {
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nodes[i] = new IKSolver.Node(boneTransforms[i]);
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}
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}
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public int GetNodeIndex(Transform boneTransform) {
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for (int i = 0; i < nodes.Length; i++) {
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if (nodes[i].transform == boneTransform) return i;
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}
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return -1;
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}
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/*
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* Check if this chain is valid or not.
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* */
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public bool IsValid(ref string message) {
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if (nodes.Length == 0) {
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message = "FBIK chain contains no nodes.";
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return false;
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}
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foreach (IKSolver.Node node in nodes) if (node.transform == null) {
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message = "Node transform is null in FBIK chain.";
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return false;
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}
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return true;
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}
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/*
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* Initiating the chain.
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* */
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public void Initiate(IKSolverFullBody solver) {
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initiated = false;
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foreach (IKSolver.Node node in nodes) {
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node.solverPosition = node.transform.position;
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}
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// Calculating bone lengths
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CalculateBoneLengths(solver);
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// Initiating child constraints
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foreach (ChildConstraint c in childConstraints) c.Initiate(solver as IKSolverFullBody);
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// Initiating the bend constraint
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if (nodes.Length == 3) {
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bendConstraint.SetBones(nodes[0].transform, nodes[1].transform, nodes[2].transform);
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bendConstraint.Initiate(solver as IKSolverFullBody);
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}
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crossFades = new float[children.Length];
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initiated = true;
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}
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/*
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* Before updating the chain
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* */
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public void ReadPose(IKSolverFullBody solver, bool fullBody) {
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if (!initiated) return;
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for (int i = 0; i < nodes.Length; i++) {
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nodes[i].solverPosition = nodes[i].transform.position + nodes[i].offset;
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}
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// Calculating bone lengths
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CalculateBoneLengths(solver);
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if (fullBody) {
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// Pre-update child constraints
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for (int i = 0; i < childConstraints.Length; i++) childConstraints[i].OnPreSolve(solver);
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if (children.Length > 0) {
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// PullSum
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float pullSum = nodes[nodes.Length - 1].effectorPositionWeight;
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for (int i = 0; i < children.Length; i++) pullSum += solver.chain[children[i]].nodes[0].effectorPositionWeight * solver.chain[children[i]].pull;
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pullSum = Mathf.Clamp(pullSum, 1f, Mathf.Infinity);
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// CrossFades
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for (int i = 0; i < children.Length; i++) {
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crossFades[i] = (solver.chain[children[i]].nodes[0].effectorPositionWeight * solver.chain[children[i]].pull) / pullSum;
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}
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}
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// Finding the total pull force by all child chains
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pullParentSum = 0f;
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for (int i = 0; i < children.Length; i++) pullParentSum += solver.chain[children[i]].pull;
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pullParentSum = Mathf.Clamp(pullParentSum, 1f, Mathf.Infinity);
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// Reach force
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if (nodes.Length == 3) {
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reachForce = reach * Mathf.Clamp(nodes[2].effectorPositionWeight, 0f, 1f);
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} else reachForce = 0f;
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if (push > 0f && nodes.Length > 1) distance = Vector3.Distance(nodes[0].transform.position, nodes[nodes.Length - 1].transform.position);
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}
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}
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// Calculates all bone lengths as well as lenghts between the chains
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private void CalculateBoneLengths(IKSolverFullBody solver) {
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// Calculating bone lengths
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length = 0f;
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for (int i = 0; i < nodes.Length - 1; i++) {
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nodes[i].length = Vector3.Distance(nodes[i].transform.position, nodes[i + 1].transform.position);
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length += nodes[i].length;
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if (nodes[i].length == 0) {
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Warning.Log("Bone " + nodes[i].transform.name + " - " + nodes[i + 1].transform.name + " length is zero, can not solve.", nodes[i].transform);
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return;
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}
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}
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for (int i = 0; i < children.Length; i++) {
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solver.chain[children[i]].rootLength = (solver.chain[children[i]].nodes[0].transform.position - nodes[nodes.Length - 1].transform.position).magnitude;
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if (solver.chain[children[i]].rootLength == 0f) {
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return;
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}
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}
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if (nodes.Length == 3) {
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// Square magnitude of the limb lengths
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sqrMag1 = nodes[0].length * nodes[0].length;
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sqrMag2 = nodes[1].length * nodes[1].length;
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sqrMagDif = sqrMag1 - sqrMag2;
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}
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}
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#region Recursive Methods
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/*
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* Reaching limbs
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* */
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public void Reach(IKSolverFullBody solver) {
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if (!initiated) return;
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// Solve children first
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for (int i = 0; i < children.Length; i++) solver.chain[children[i]].Reach(solver);
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if (reachForce <= 0f) return;
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Vector3 solverDirection = nodes[2].solverPosition - nodes[0].solverPosition;
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if (solverDirection == Vector3.zero) return;
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float solverLength = solverDirection.magnitude;
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//Reaching
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Vector3 straight = (solverDirection / solverLength) * length;
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float delta = Mathf.Clamp(solverLength / length, 1 - reachForce, 1 + reachForce) - 1f;
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delta = Mathf.Clamp(delta + reachForce, -1f, 1f);
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// Smoothing the effect of Reach with the expense of some accuracy
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switch (reachSmoothing) {
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case Smoothing.Exponential:
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delta *= delta;
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break;
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case Smoothing.Cubic:
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delta *= delta * delta;
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break;
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}
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Vector3 offset = straight * Mathf.Clamp(delta, 0f, solverLength);
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nodes[0].solverPosition += offset * (1f - nodes[0].effectorPositionWeight);
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nodes[2].solverPosition += offset;
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}
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/*
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* End-effectors pushing the first nodes
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* */
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public Vector3 Push(IKSolverFullBody solver) {
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Vector3 sum = Vector3.zero;
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// Get the push from the children
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for (int i = 0; i < children.Length; i++) {
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sum += solver.chain[children[i]].Push(solver) * solver.chain[children[i]].pushParent;
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}
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// Apply the push from a child
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nodes[nodes.Length - 1].solverPosition += sum;
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// Calculating the push of THIS chain (passed on to the parent as we're in a recursive method)
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if (nodes.Length < 2) return Vector3.zero;
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if (push <= 0f) return Vector3.zero;
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Vector3 solverDirection = nodes[2].solverPosition - nodes[0].solverPosition;
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float solverLength = solverDirection.magnitude;
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if (solverLength == 0f) return Vector3.zero;
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// Get the push force factor
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float f = 1f - (solverLength / distance);
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if (f <= 0f) return Vector3.zero;
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// Push smoothing
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switch (pushSmoothing) {
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case Smoothing.Exponential:
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f *= f;
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break;
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case Smoothing.Cubic:
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f *= f * f;
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break;
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}
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// The final push force
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Vector3 p = -solverDirection * f * push;
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nodes[0].solverPosition += p;
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return p;
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}
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/*
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* Applying trigonometric IK solver on the 3 segmented chains to relieve tension from the solver and increase accuracy.
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* */
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public void SolveTrigonometric(IKSolverFullBody solver, bool calculateBendDirection = false) {
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if (!initiated) return;
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// Solve children first
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for (int i = 0; i < children.Length; i++) solver.chain[children[i]].SolveTrigonometric(solver, calculateBendDirection);
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if (nodes.Length != 3) return;
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// Direction of the limb in solver
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Vector3 solverDirection = nodes[2].solverPosition - nodes[0].solverPosition;
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// Distance between the first and the last node solver positions
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float solverLength = solverDirection.magnitude;
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if (solverLength == 0f) return;
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// Maximim stretch of the limb
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float maxMag = Mathf.Clamp(solverLength, 0f, length * maxLimbLength);
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Vector3 direction = (solverDirection / solverLength) * maxMag;
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// Get the general world space bending direction
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Vector3 bendDirection = calculateBendDirection && bendConstraint.initiated? bendConstraint.GetDir(solver): nodes[1].solverPosition - nodes[0].solverPosition;
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// Get the direction to the trigonometrically solved position of the second node
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Vector3 toBendPoint = GetDirToBendPoint(direction, bendDirection, maxMag);
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// Position the second node
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nodes[1].solverPosition = nodes[0].solverPosition + toBendPoint;
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}
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/*
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* Stage 1 of the FABRIK algorithm
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* */
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public void Stage1(IKSolverFullBody solver) {
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// Stage 1
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for (int i = 0; i < children.Length; i++) solver.chain[children[i]].Stage1(solver);
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// If is the last chain in this hierarchy, solve immediatelly and return
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if (children.Length == 0) {
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ForwardReach(nodes[nodes.Length - 1].solverPosition);
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return;
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}
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Vector3 centroid = nodes[nodes.Length - 1].solverPosition;
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// Satisfying child constraints
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SolveChildConstraints(solver);
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// Finding the centroid position of all child chains according to their individual pull weights
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for (int i = 0; i < children.Length; i++) {
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Vector3 childPosition = solver.chain[children[i]].nodes[0].solverPosition;
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if (solver.chain[children[i]].rootLength > 0) {
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childPosition = SolveFABRIKJoint(nodes[nodes.Length - 1].solverPosition, solver.chain[children[i]].nodes[0].solverPosition, solver.chain[children[i]].rootLength);
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}
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if (pullParentSum > 0) centroid += (childPosition - nodes[nodes.Length - 1].solverPosition) * (solver.chain[children[i]].pull / pullParentSum);
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}
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// Forward reach to the centroid (unless pinned)
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ForwardReach(Vector3.Lerp(centroid, nodes[nodes.Length - 1].solverPosition, pin));
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}
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/*
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* Stage 2 of the FABRIK algorithm.
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* */
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public void Stage2(IKSolverFullBody solver, Vector3 position) {
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// Stage 2
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BackwardReach(position);
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int it = Mathf.Clamp(solver.iterations, 2, 4);
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// Iterating child constraints and child chains to make sure they are not conflicting
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if (childConstraints.Length > 0) {
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for (int i = 0; i < it; i++) SolveConstraintSystems(solver);
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}
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// Stage 2 for the children
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for (int i = 0; i < children.Length; i++) solver.chain[children[i]].Stage2(solver, nodes[nodes.Length - 1].solverPosition);
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}
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/*
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* Iterating child constraints and child chains to make sure they are not conflicting
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* */
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public void SolveConstraintSystems(IKSolverFullBody solver) {
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// Satisfy child constraints
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SolveChildConstraints(solver);
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for (int i = 0; i < children.Length; i++) {
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SolveLinearConstraint(nodes[nodes.Length - 1], solver.chain[children[i]].nodes[0], crossFades[i], solver.chain[children[i]].rootLength);
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}
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}
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#endregion Recursive Methods
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/*
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* Interpolates the joint position to match the bone's length
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*/
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private Vector3 SolveFABRIKJoint(Vector3 pos1, Vector3 pos2, float length) {
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return pos2 + (pos1 - pos2).normalized * length;
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}
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/*
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* Calculates the bend direction based on the law of cosines (from IKSolverTrigonometric).
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* */
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protected Vector3 GetDirToBendPoint(Vector3 direction, Vector3 bendDirection, float directionMagnitude) {
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float x = ((directionMagnitude * directionMagnitude) + sqrMagDif) / 2f / directionMagnitude;
|
|
float y = (float)Math.Sqrt(Mathf.Clamp(sqrMag1 - x * x, 0, Mathf.Infinity));
|
|
|
|
if (direction == Vector3.zero) return Vector3.zero;
|
|
return Quaternion.LookRotation(direction, bendDirection) * new Vector3(0f, y, x);
|
|
}
|
|
|
|
/*
|
|
* Satisfying child constraints
|
|
* */
|
|
private void SolveChildConstraints(IKSolverFullBody solver) {
|
|
for (int i = 0; i < childConstraints.Length; i++) {
|
|
childConstraints[i].Solve(solver);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Solve simple linear constraint
|
|
* */
|
|
private void SolveLinearConstraint(IKSolver.Node node1, IKSolver.Node node2, float crossFade, float distance) {
|
|
Vector3 dir = node2.solverPosition - node1.solverPosition;
|
|
|
|
float mag = dir.magnitude;
|
|
|
|
if (distance == mag) return;
|
|
if (mag == 0f) return;
|
|
|
|
Vector3 offset = dir * (1f - distance / mag);
|
|
|
|
node1.solverPosition += offset * crossFade;
|
|
node2.solverPosition -= offset * (1f - crossFade);
|
|
}
|
|
|
|
/*
|
|
* FABRIK Forward reach
|
|
* */
|
|
public void ForwardReach(Vector3 position) {
|
|
// Lerp last node's solverPosition to position
|
|
nodes[nodes.Length - 1].solverPosition = position;
|
|
|
|
for (int i = nodes.Length - 2; i > -1; i--) {
|
|
// Finding joint positions
|
|
nodes[i].solverPosition = SolveFABRIKJoint(nodes[i].solverPosition, nodes[i + 1].solverPosition, nodes[i].length);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* FABRIK Backward reach
|
|
* */
|
|
private void BackwardReach(Vector3 position) {
|
|
// Solve forst node only if it already hasn't been solved in SolveConstraintSystems
|
|
if (rootLength > 0) position = SolveFABRIKJoint(nodes[0].solverPosition, position, rootLength);
|
|
nodes[0].solverPosition = position;
|
|
|
|
// Finding joint positions
|
|
for (int i = 1; i < nodes.Length; i++) {
|
|
nodes[i].solverPosition = SolveFABRIKJoint(nodes[i].solverPosition, nodes[i - 1].solverPosition, nodes[i - 1].length);
|
|
}
|
|
}
|
|
}
|
|
} |