Failed setting triangles. Some indices are referencing out of bounds vertices.

Unity Engine
1

In the code below at line 25 I get this error:
Failed setting triangles. Some indices are referencing out of bounds vertices.
UnityEngine.Mesh:set_triangles(Int32[ ])

Why do I get this error and how can I fix it?

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

public class CreateMesh : MonoBehaviour {

    private Mesh mesh;

    void Start () {
        GenerateMesh ();
    }

    void GenerateMesh () {
        mesh = new Mesh ();

        List<Vector3> vertices = new List<Vector3>();
        List<int> triangles = new List<int>();
        List<Vector2> uv = new List<Vector2>();


        GeneratePlane (Vector3.zero, Vector3.up, Vector3.right, vertices, triangles, uv);
        GeneratePlane (Vector3.forward, Vector3.up, -Vector3.forward, vertices, triangles, uv);

        mesh.vertices = vertices.ToArray();
        mesh.triangles = triangles.ToArray();
        mesh.uv = uv.ToArray();
        mesh.RecalculateBounds();
        mesh.RecalculateNormals();

        GetComponent<MeshFilter>().mesh = mesh;
    }

    void GeneratePlane (Vector3 corner, Vector3 up, Vector3 right, List<Vector3> verts, List<int> tris, List<Vector2> uvs) {
        verts.Add (corner);
        verts.Add (corner + up);
        verts.Add (corner + up + right);
        verts.Add (corner + right);

        int index = tris.Count;
        tris.Add(index + 0); tris.Add(index + 1); tris.Add(index + 2);
        tris.Add(index + 2); tris.Add(index + 3); tris.Add(index + 0);

        uvs.Add(new Vector2(0, 0));
        uvs.Add(new Vector2(0, 1));
        uvs.Add(new Vector2(1, 1));
        uvs.Add(new Vector2(1, 0));
    }
}
2

The indices in the triangles need to refer to the appropriate vertices; using tris.Count will not work. Using verts.Count would, I think, but you’d have to do that first.

–Eric

1 Like
3

Thank you!
It works!