LineGraph.cs

using System.Collections.Generic;
using UnityEngine;

public class LineGraph : MonoBehaviour {
	class Point {
		public int id;
		public Vector3 pos;
	}

	readonly List<List<Point>> links = new List<List<Point>>();
	readonly List<Point> points = new List<Point>();

	public Mesh mesh;
	public float a, b, c;
	public float segmentLength;

	public float ringUpAmount;
	public float ringDownAmount;
	public float ringHorizontalAmount;

	public float swingHorizontalAmount;
	public float swingSpeedScale;

	readonly List<Vector3> verts = new List<Vector3>();
	readonly List<int> tris = new List<int>();
	readonly List<float> swing = new List<float>();

	float GetValue(float x) {
		return a * x * x + b * x + c;
	}

	void OnEnable() {
		mesh = GetComponent<MeshFilter>().mesh;

//		AddPoint(new Vector3(0, 0, 0));
//
//		for (int i = 0; i < 200; i += 1) {
//			AddPoint(new Vector3(10, 0, i * .5f));
//			CreateLink(0, i + 1);
//		}

//		RebuildMesh();
	}

	public int AddPoint(Vector3 pos) {
		int id = points.Count;
		points.Add(new Point{id = id, pos = pos});
		links.Add(new List<Point>());
		swing.Add(Random.Range(0, 1000));
		return id;
	}

	public void DelinkPoint(int id) {
		var ptr = points[id];
		foreach (var edges in links) {
			edges.Remove(ptr);
		}
		links[id].Clear();
		RebuildMesh();
	}

	public void CreateLink(int fromId, int toId) {
		links[fromId].Add(points[toId]);
		RebuildMesh();
	}

	public void DeleteLink(int fromId, int toId) {
		links[fromId].Remove(points[toId]);
		RebuildMesh();
	}

	void RebuildMesh() {
		verts.Clear();
		tris.Clear();

		var ringUpShift = new Vector3(0, ringUpAmount, 0);

		for (int i = 0, count = links.Count; i < count; i += 1) {
			var start = points[i];
			foreach (var end in links[i]) {
				var startPos = start.pos;
				var endPos = end.pos;
				var direction = endPos - startPos;

				var ringRightShift = Vector3.Cross(direction, Vector3.up).normalized * ringHorizontalAmount;
				var ringLeftShift = -ringRightShift;
				ringRightShift.y -= ringDownAmount;
				ringLeftShift.y -= ringDownAmount;

				float length = Vector3.Distance(startPos, endPos);
				int segments = (int)(length / segmentLength);
				for (var j = 0; j <= segments; j += 1) {
					float t = (float)j / segments;
					var pos = startPos + direction * t;
					pos.y += GetValue(t);

					int vertStart = verts.Count - 3;

					var up = pos + ringUpShift;
					var right = pos + ringRightShift;
					var left = pos + ringLeftShift;

					verts.Add(up);
					verts.Add(right);
					verts.Add(left);

					if (j > 0) {
						tris.Add(vertStart + 0); tris.Add(vertStart + 4); tris.Add(vertStart + 3);
						tris.Add(vertStart + 0); tris.Add(vertStart + 1); tris.Add(vertStart + 4);
						tris.Add(vertStart + 1); tris.Add(vertStart + 2); tris.Add(vertStart + 5);
						tris.Add(vertStart + 1); tris.Add(vertStart + 5); tris.Add(vertStart + 4);
						tris.Add(vertStart + 2); tris.Add(vertStart + 3); tris.Add(vertStart + 5);
						tris.Add(vertStart + 2); tris.Add(vertStart + 0); tris.Add(vertStart + 3);
					}
				}
			}
		}

		mesh.vertices = verts.ToArray();
		mesh.triangles = tris.ToArray();
		mesh.RecalculateNormals();
	}

	void RebuildVertices() {
		verts.Clear();

		var ringUpShift = new Vector3(0, ringUpAmount, 0);

		for (int i = 0, count = links.Count; i < count; i += 1) {
			var start = points[i];
			foreach (var end in links[i]) {
				float swingAmount = Mathf.Sin(swing[i] + swing[end.id]) * swingHorizontalAmount;

				var startPos = start.pos;
				var endPos = end.pos;
				var direction = endPos - startPos;

				var right = Vector3.Cross(direction, Vector3.up).normalized;
				var swingRight = right * swingAmount;
				var ringRightShift = right * ringHorizontalAmount;
				var ringLeftShift = -ringRightShift;
				ringRightShift.y -= ringDownAmount;
				ringLeftShift.y -= ringDownAmount;

				float length = Vector3.Distance(startPos, endPos);
				int segments = (int)(length / segmentLength);
				for (var j = 0; j <= segments; j += 1) {
					float t = (float)j / segments;
					var pos = startPos + direction * t;
					pos.y += GetValue(t);
					pos += swingRight * (-4 * t * t + 4 * t);

					var u = pos + ringUpShift;
					var r = pos + ringRightShift;
					var l = pos + ringLeftShift;

					verts.Add(u);
					verts.Add(r);
					verts.Add(l);
				}
			}
		}

		mesh.vertices = verts.ToArray();
		mesh.triangles = tris.ToArray();
		mesh.RecalculateNormals();
	}

	void Update() {
		for (int i = 0, count = swing.Count; i < count; i += 1) {
			swing[i] += Time.deltaTime * swingSpeedScale;
		}

		RebuildVertices();
	}
}