Create a sphere that a 360-video (or still image) texture can be applied to. This is the same as LatLonSphere.cs, except that the vertex order is tweaked so that the sphere will be visible from the inside, rather than outside.

360VideoSphere.cs

/*
 Create Unity mesh data for a sphere, which can be used with a video (or still) texture from a 360-camera.
 The mesh is created so that it will be visible when the viewer is inside, rather than outside, of the sphere, with Unity's default backface-culling mode.
 Texture coordinates are based on latitude & longitude (ie an equirectangular map projection) which matches the images from the 360-cameras that we use.
*/
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class LatLonSphere : MonoBehaviour
{
    public int latRes=20, lonRes=40;

    void Start()
        {
        Vector3[] myVerts = new Vector3[latRes*lonRes];
        Vector2[] myUV = new Vector2[latRes*lonRes];
        int index=0;
        for (int j=0; j < latRes; j++)
            {
            for (int i=0; i < lonRes; i++)
                {
                float lat = (j*Mathf.PI)/(latRes-1) - Mathf.PI/2;
                float lon = (i*Mathf.PI*2)/(lonRes-1) - Mathf.PI;
                myVerts[index] = new Vector3(Mathf.Cos(lat)*Mathf.Sin(lon), Mathf.Sin(lat), -Mathf.Cos(lat)*Mathf.Cos(lon));
                myUV[index] = new Vector2(i/(lonRes-1.0f), j/(latRes-1.0f));
                index++;
                }
            }
        int[] myTris = new int[(latRes-1)*(lonRes-1)*2*3];
        index=0;
        for (int j=0; j < latRes-1; j++)
            {
            for (int i=0; i < lonRes-1; i++)
                {
                int corner = i + j*lonRes;
                myTris[index++] = corner;
                myTris[index++] = corner+1;
                myTris[index++] = corner+lonRes;
                myTris[index++] = corner+lonRes;
                myTris[index++] = corner+1;
                myTris[index++] = corner+lonRes+1;
                }
            }
        Mesh myMesh = gameObject.GetComponent<MeshFilter>().mesh;
        myMesh.Clear();
        myMesh.vertices = myVerts;
        myMesh.uv = myUV;
        myMesh.triangles = myTris;
        myMesh.normals = myVerts;
        }

}