initial upload

Unity-Master/Assets/Plugins/RootMotion/FinalIK/IK Solvers/FABRIKChain.cs

@@ -0,0 +1,122 @@
+using UnityEngine;
+using System.Collections;
+
+	namespace RootMotion.FinalIK {
+		
+	/// <summary>
+	/// Branch of FABRIK components in the FABRIKRoot hierarchy.
+	/// </summary>
+	[System.Serializable]
+	public class FABRIKChain {
+		
+		#region Main Interface
+		
+		/// <summary>
+		/// The FABRIK component.
+		/// </summary>
+		public FABRIK ik;
+		/// <summary>
+		/// Parent pull weight.
+		/// </summary>
+		[Range(0f, 1f)]
+		public float pull = 1f;
+		/// <summary>
+		/// Resistance to being pulled by child chains.
+		/// </summary>
+		[Range(0f, 1f)]
+		public float pin = 1f;
+		/// <summary>
+		/// The child chain indexes.
+		/// </summary>
+		public int[] children = new int[0];
+		
+		/// <summary>
+		/// Checks whether this FABRIKChain is valid.
+		/// </summary>
+		public bool IsValid(ref string message) {
+			if (ik == null) {
+				message = "IK unassigned in FABRIKChain.";
+				return false;
+			}
+			
+			if (!ik.solver.IsValid(ref message)) return false;
+
+			return true;
+		}
+
+		#endregion Main Interface
+		
+		/*
+		 * Initiate the chain
+		 * */
+		public void Initiate() {
+			ik.enabled = false;
+		}
+	
+		/*
+		 * Solving stage 1 of the FABRIK algorithm from end effectors towards the root.
+		 * */
+		public void Stage1(FABRIKChain[] chain) {
+			// Solving children first
+			for (int i = 0; i < children.Length; i++) chain[children[i]].Stage1(chain);
+			
+			// The last chains
+			if (children.Length == 0) {
+				ik.solver.SolveForward(ik.solver.GetIKPosition());
+				return;
+			}
+
+			ik.solver.SolveForward(GetCentroid(chain));
+		}
+
+		/*
+		 * Solving stage 2 of the FABRIK algoright from the root to the end effectors.
+		 * */
+		public void Stage2(Vector3 rootPosition, FABRIKChain[] chain) {
+			// Solve this chain backwards
+			ik.solver.SolveBackward(rootPosition);
+			
+			// Solve child chains
+			for (int i = 0; i < children.Length; i++) {
+				chain[children[i]].Stage2(ik.solver.bones[ik.solver.bones.Length - 1].transform.position, chain);
+			}
+		}
+
+		// Calculate the centroid of child positions
+		private Vector3 GetCentroid(FABRIKChain[] chain) {
+			Vector3 position = ik.solver.GetIKPosition();
+			
+			// The chain is pinned, ignore the children
+			if (pin >= 1f) return position;
+			
+			// Get the sum of the pull values of all the children
+			float pullSum = 0f;
+			for (int i = 0; i < children.Length; i++) pullSum += chain[children[i]].pull;
+			
+			// All pull values are zero
+			if (pullSum <= 0f) return position;
+			
+			if (pullSum < 1f) pullSum = 1f;
+			
+			// Calculating the centroid
+			Vector3 centroid = position;
+			
+			for (int i = 0; i < children.Length; i++) {
+				// Vector from IKPosition to the first bone of the child
+				Vector3 toChild = chain[children[i]].ik.solver.bones[0].solverPosition - position;
+
+				// Weight of the child
+				float childWeight = chain[children[i]].pull / pullSum;
+
+				// Adding to the centroid
+				centroid += toChild * childWeight;
+			}
+			
+			// No pinning
+			if (pin <= 0f) return centroid;
+			
+			// Pinning
+			return centroid + (position - centroid) * pin; 
+		}
+	}
+}