FishingPole

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

[RequireComponent(typeof(SkinnedMeshRenderer))]
public class FishingPole : MonoBehaviour
{
	// FishingPole is Singleton
	private static FishingPole _instance;

	public static FishingPole Instance
	{
		get
		{
			return _instance;
		}
	}

	public Vector3 PoleTipPosition
	{
		get
		{
			return tip.position;
		}
	}

	public float length
	{
		get
		{
			return (bones[0].position - tip.position).magnitude;
		}
	}

	List<Transform> bones = new List<Transform>();

	public float m_forceModule = 0;	

	private Transform lastBone;

	public Vector3 m_forceSource;

	[SerializeField]
	public int m_steps = 20;

	public Material material;
	public Space space;

	private int segments = 5;
	private Transform tip;

	private void Awake()
	{
		if (_instance != null)
		{
			Destroy(this);
			return;
		}
		
		_instance = this;

		if (GetComponent<SkinnedMeshRenderer>().sharedMesh != null)
			GetComponent<SkinnedMeshRenderer>().sharedMesh.Clear();

		GenerateMesh();

		this.gameObject.SetActive(false);
	}

	public void GenerateMesh()
	{
		Transform transform = this.transform;

		Matrix4x4 toLocal = transform.worldToLocalMatrix;

		SkinnedMeshRenderer skinnedMeshRenderer = GetComponent<SkinnedMeshRenderer>();

		List<Vector3> points = new List<Vector3>();
		List<BoneWeight> weights = new List<BoneWeight>();
		List<Matrix4x4> poses = new List<Matrix4x4>();

		int index = 0;

		Transform t = new GameObject("joint " + index).transform;
		t.parent = this.transform;
		t.localRotation = Quaternion.identity;
		t.localPosition = new Vector3(0, 0, 0);

		Vector3 a = toLocal.MultiplyPoint(transform.position);

		points.Add(a);
		bones.Add(t);
		poses.Add(t.worldToLocalMatrix * transform.localToWorldMatrix);

		while (++index < m_steps)
		{
			a = a + new Vector3(0, 1, 0) / (float)Mathf.Sqrt(index);

			t = new GameObject("joint " + index).transform;
			t.parent = bones[index - 1];
			t.localRotation = Quaternion.identity;
			t.localPosition = new Vector3(0, 1, 0) / (float)Mathf.Sqrt(index);

			points.Add(a);
			bones.Add(t);
			poses.Add(t.worldToLocalMatrix * transform.localToWorldMatrix);
		}

		tip = new GameObject("tip").transform;
		tip.parent = bones[index - 1];
		tip.localRotation = Quaternion.identity;
		tip.localPosition = new Vector3(0, 1, 0) / (float)Mathf.Sqrt(index);

		a = a + new Vector3(0, 1, 0) / (float)Mathf.Sqrt(index);
		points.Add(a);

		List<int> indices = new List<int>();
		List<Vector3> vertices = new List<Vector3>();

		int counter = 0;

		Vector3[] p = new Vector3[segments];

		for (int s = 0; s < segments; s++)
		{
			p[s] = new Vector3(Mathf.Cos((float)s * Mathf.PI * 2 / (float)segments), 0, Mathf.Sin((float)s * Mathf.PI * 2 / (float)segments));
			p[s] *= 0.05f;
		}

		for (int i = 0; i < bones.Count; i++)
		{
			for (int s = 0; s < segments; s++)
			{
				vertices.Add(points[i] + p[s] / (float)Mathf.Sqrt(i + 1.0f) );
				indices.Add(counter++);
				weights.Add(new BoneWeight() { boneIndex0 = i, weight0 = 1 });

				vertices.Add(points[i + 1] + p[s] / (float)Mathf.Sqrt(i + 2.0f));
				indices.Add(counter++);
				weights.Add(new BoneWeight() { boneIndex0 = (i < bones.Count - 1) ? i + 1 : bones.Count - 1, weight0 = 1 });

				vertices.Add(points[i] + p[(s + 1) % segments] / (float)Mathf.Sqrt(i + 1.0f));
				indices.Add(counter++);
				weights.Add(new BoneWeight() { boneIndex0 = i, weight0 = 1 });

				vertices.Add(points[i] + p[(s + 1) % segments] / (float)Mathf.Sqrt(i + 1.0f));
				indices.Add(counter++);
				weights.Add(new BoneWeight() { boneIndex0 = i, weight0 = 1 });

				vertices.Add(points[i + 1] + p[s] / (float)Mathf.Sqrt(i + 2.0f));
				indices.Add(counter++);
				weights.Add(new BoneWeight() { boneIndex0 = (i < bones.Count - 1) ? i + 1 : bones.Count - 1, weight0 = 1 });

				vertices.Add(points[i + 1] + p[(s + 1) % segments] / (float)Mathf.Sqrt(i + 2.0f));
				indices.Add(counter++);
				weights.Add(new BoneWeight() { boneIndex0 = (i < bones.Count - 1) ? i + 1 : bones.Count - 1, weight0 = 1 });
			}
		}

		Mesh mesh = new Mesh();
		mesh.vertices = vertices.ToArray();
		mesh.triangles = indices.ToArray();
		mesh.RecalculateNormals();
		mesh.boneWeights = weights.ToArray();
		mesh.bindposes = poses.ToArray();

		skinnedMeshRenderer.bones = bones.ToArray();
		skinnedMeshRenderer.sharedMesh = mesh;
		skinnedMeshRenderer.sharedMaterial = material;

		lastBone = bones[bones.Count - 1];
	}

	public void UpdateMesh()
	{
		for (int i = 0; i < bones.Count; i++)
		{
			Vector3 f = bones[i].parent.worldToLocalMatrix.MultiplyPoint(m_forceSource).normalized;
			Vector3 up = bones[i].worldToLocalMatrix.MultiplyVector(bones[i].parent.up).normalized;

			Vector3 v  = f / ((float)m_steps - i) * m_forceModule;
			Vector3 d = (up + v).normalized;

			Quaternion rotation = Quaternion.FromToRotation(up, d);

			bones[i].localRotation = rotation;
		} 
		return;
	}
}