Spline mesh

SplineMesh.cs

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

public class SplineMesh : MonoBehaviour
{
    [System.Serializable]
    public class Node
    {
        public Vector3 position;
        
        public Node(Vector3 position)
        {
            this.position = position;
        }
    }
    
    public struct Segment
    {
        public Node start;
        public Node end;
        
        public Segment(Node previous, Node next)
        {
            this.start = previous;
            this.end = next;
        }
        
        public Vector3 Direction {get {return end.position - start.position;}}
        public Vector3 Normal {get {Vector3 direction = Direction.normalized; return new Vector3(-direction.y, direction.x, 0.0f);}}
    }
    
    [SerializeField] protected Node[] m_Nodes;
    [SerializeField] protected int m_Divisions = 8;
    
    [SerializeField] protected float m_Height = 1.0f;
    [SerializeField] protected float m_Depth = 1.0f;
    [SerializeField] protected float m_BaselineOffset = 1.0f;
    [SerializeField] protected Vector2 m_UVTiling = Vector2.one;
    [SerializeField] protected Vector2 m_UVOffset = Vector2.zero;
    [SerializeField] protected bool m_LengthAffectsU = true;
    
    public Node GetNode(int index)
    {
        return m_Nodes[index];
    }
    
    protected void Reset()
    {
        m_Nodes = new Node[] {new Node(new Vector3(-1, 0, 0)), new Node(new Vector3(1, 0, 0))};
    }
    
#region Properties
    public IEnumerable<Node> Nodes {get {return m_Nodes;}}
    
    public IEnumerable<Segment> Segments
    {
        get
        {
            var previousNode = m_Nodes.First();
            foreach(var node in m_Nodes.Skip(1))
            {
                yield return new Segment(previousNode, node);
                previousNode = node;
            }
        }
    }
    
    public IEnumerable<Node> Spline
    {
        get
        {
            if(m_Nodes.Length > 2)
                yield return m_Nodes[0];
            
            Vector3 p2 = m_Nodes[0].position;
            
            for(int nodeIndex = 1; nodeIndex < m_Nodes.Length - 1; ++nodeIndex)
            {
                Vector3 previousNode = m_Nodes[nodeIndex - 1].position;
                Vector3 thisNode = m_Nodes[nodeIndex + 0].position;
                Vector3 nextNode = m_Nodes[nodeIndex + 1].position;
                
                Vector3 p0 = (previousNode + thisNode) * 0.5f;
                Vector3 p1 = thisNode;
                p2 = (thisNode + nextNode) * 0.5f;

                foreach(var vertex in QuadraticSplinePieceVertices(p0, p1, p2, m_Divisions))
                    yield return new Node(vertex);
            }
            
            yield return new Node(p2);
            yield return m_Nodes[m_Nodes.Length - 1];
        }
    }
    
    public static IEnumerable<Vector3> QuadraticSplinePieceVertices(Vector3 point0, Vector3 point1, Vector3 point2, int divisions)
    {
        for(int i = 0; i < divisions; i++)
        {
            float t = (float)i / divisions;
            float oneMinusT = 1.0f - t;
            
            yield return oneMinusT * oneMinusT * point0 + 2 * oneMinusT * t * point1 + t * t * point2;
        }
    }
    
    public IEnumerable<Segment> SplineSegments
    {
        get
        {
            var spline = Spline;
            var previousNode = spline.First();
            foreach(var node in spline.Skip(1))
            {
//              Debug.Log(string.Format("Segment {0} - {1}", previousNode.position, node.position));
                yield return new Segment(previousNode, node);
                previousNode = node;
            }
        }
    }
    
    public int CountNodes {get {return (m_Nodes != null ? m_Nodes.Length : 0);}}
    public int CountSplineDivisions
    {
        get
        {
            int numNodes = CountNodes;
            return 2 + (numNodes > 2 ? 1 : 0) + (numNodes - 2) * m_Divisions;
        }
    }
    
//  public float Height {get {return m_Height;}}
//  public float Depth {get {return m_Depth;}}
#endregion
}