OBJGenerator.cs

using Dummiesman;
using System.IO;
using System.Text;
using UnityEngine;
using UnityEngine.Networking;
using System.Collections;


public class OBJGenerator : MonoBehaviour
{
    public Transform transform;
    // Copy several hardcoded components from this
    public GameObject sourceObject;
    public PhysicMaterial material;

    public string uri;

    private void Start()
    {
        this.makeOBJ();
    }

    public void makeOBJ()
    {
        // https://raw.githubusercontent.com/gyng/raytracer-assets/master/models/teapot.obj
        // https://raw.githubusercontent.com/gyng/raytracer-assets/master/models/bunny.obj
        // https://raw.githubusercontent.com/gyng/raytracer-assets/master/models/cow.obj
        // https://raw.githubusercontent.com/gyng/raytracer-assets/master/models/tachikoma.obj
        // https://people.sc.fsu.edu/~jburkardt/data/obj/lamp.obj
        var defaultObjects = new string[] {
            "https://raw.githubusercontent.com/gyng/raytracer-assets/master/models/teapot.obj",
            "https://raw.githubusercontent.com/gyng/raytracer-assets/master/models/bunny.obj",
            // "https://raw.githubusercontent.com/gyng/raytracer-assets/master/models/cow.obj",
            // "https://raw.githubusercontent.com/gyng/raytracer-assets/master/models/tachikoma.obj"
            // "https://people.sc.fsu.edu/~jburkardt/data/obj/lamp.obj"
        };
        var initialUrl = defaultObjects[Random.Range(0, defaultObjects.Length)];

        var requestUri = uri == null ? uri : initialUrl;
        StartCoroutine(GetRequest(requestUri));
    }

    private IEnumerator GetRequest(string uri)
    {
        using (UnityWebRequest webRequest = UnityWebRequest.Get(uri))
        {
            yield return webRequest.SendWebRequest();
            switch (webRequest.result)
            {
                case UnityWebRequest.Result.Success:
                    initObject(webRequest.downloadHandler.text);
                    break;
            }
        }
    }

    private void initObject(string text)
    {
        var textStream = new MemoryStream(Encoding.UTF8.GetBytes(text));
        var go = new OBJLoader().Load(textStream);

        // CopyComponent<Rigidbody>(sourceObject.GetComponent<Rigidbody>(), go);

        go.AddComponent<Rigidbody>();

        var sourceSize = sourceObject.GetComponent<MeshRenderer>().bounds.size;
        var child = go.transform.GetChild(0);
        var mesh = child.GetComponent<MeshRenderer>();

        float resizeX = sourceSize.x / mesh.bounds.size.x;
        float resizeY = sourceSize.y / mesh.bounds.size.y;
        float resizeZ = sourceSize.z / mesh.bounds.size.z;
        resizeX *= mesh.transform.localScale.x;
        resizeY *= mesh.transform.localScale.y;
        resizeZ *= mesh.transform.localScale.z;
        float minResize = Mathf.Min(Mathf.Min(resizeX, resizeY), resizeZ);
        mesh.transform.localScale = new Vector3(minResize, minResize, minResize);

        var collider = go.AddComponent<MeshCollider>();
        var meshFilter = child.GetComponent<MeshFilter>();
        collider.sharedMesh = meshFilter.mesh;
        collider.convex = true; // OVRGrabbable needs this
        collider.material = material;

        // var sphereCollider = CopyComponent<SphereCollider>(sourceObject.GetComponent<SphereCollider>(), go);
        // sphereCollider.isTrigger = true; // Extra collider for easier grabbing

        var grab = CopyComponent<OVRGrabbable>(sourceObject.GetComponent<OVRGrabbable>(), go);
        grab.m_grabPoints = new Collider[] { collider };
        grab.enabled = true;

        Instantiate(go, transform);
    }

    private static T CopyComponent<T>(T original, GameObject destination) where T : Component
    {
        System.Type type = original.GetType();
        Component copy = destination.AddComponent(type);
        System.Reflection.FieldInfo[] fields = type.GetFields();
        foreach (System.Reflection.FieldInfo field in fields)
        {
            field.SetValue(copy, field.GetValue(original));
        }
        return copy as T;
    }
}