AR core loading prefabs dynamically in unity - unity3d

Question

I have recently started dabbling in Unity with ARcore, I am using the HelloARController.cs that comes with ARcore 1.5 but I want to load a bundle from my server, I have two scripts
one called LoadAsset.cs which loads a bundle from a webserver and I have another called HelloARcontroller.cs which is basically the main part of the app, this allows me to preset prefabs that will be loaded when the screen is clicked
What I would like to do instead of loading one of the "Andy" objects is for it to pull a prefab from the webserver and use that instead
I have managed so far to load a prefab from my server at runtime but placing it is another matter
namespace GoogleARCore.Examples.HelloAR
{
using System.Collections.Generic;
using GoogleARCore;
using GoogleARCore.Examples.Common;
using UnityEngine;
using System;
using System.Collections;
#if UNITY_EDITOR
// Set up touch input propagation while using Instant Preview in the editor.
using Input = InstantPreviewInput;
#endif
/// <summary>
/// Controls the HelloAR example.
/// </summary>
public class HelloARController : MonoBehaviour
{
public string BundleURL; // -->
http://Myserver/public_http/Assets/AssetBundles/cube_prefab (path to the AssetBundle)
public string AssetName; // --> Cube_pref (name of the Asset prefab)
public int version;
/// <summary>
/// The first-person camera being used to render the passthrough camera image (i.e. AR background).
/// </summary>
public Camera FirstPersonCamera;
/// <summary>
/// A prefab for tracking and visualizing detected planes.
/// </summary>
public GameObject DetectedPlanePrefab;
/// <summary>
/// A model to place when a raycast from a user touch hits a plane.
/// </summary>
public GameObject AndyPlanePrefab;
/// <summary>
/// A model to place when a raycast from a user touch hits a feature point.
/// </summary>
public GameObject AndyPointPrefab;
/// <summary>
/// A gameobject parenting UI for displaying the "searching for planes" snackbar.
/// </summary>
public GameObject SearchingForPlaneUI;
/// <summary>
/// The rotation in degrees need to apply to model when the Andy model is placed.
/// </summary>
private const float k_ModelRotation = 180.0f;
/// <summary>
/// A list to hold all planes ARCore is tracking in the current frame. This object is used across
/// the application to avoid per-frame allocations.
/// </summary>
private List<DetectedPlane> m_AllPlanes = new List<DetectedPlane>();
/// <summary>
/// True if the app is in the process of quitting due to an ARCore connection error, otherwise false.
/// </summary>
private bool m_IsQuitting = false;
/// <summary>
/// The Unity Update() method.
/// </summary>
void Start()
{
StartCoroutine(DownloadAndCache());
}
IEnumerator DownloadAndCache()
{
// Load the AssetBundle file from Cache if it exists with the same version or download and store it in the cache
using (WWW www = WWW.LoadFromCacheOrDownload(BundleURL, version))
{
yield return www;
if (www.error != null)
throw new Exception("WWW download had an error:" + www.error);
AssetBundle bundle = www.assetBundle;
GameObject testing = bundle.LoadAsset(AssetName) as GameObject;
// Unload the AssetBundles compressed contents to conserve memory
bundle.Unload(false);
} // memory is freed from the web stream (www.Dispose() gets called implicitly)
}
I've declared all my variables and managed to get the Prefab to load up to this point ^^^^^
public void Update()
{
_UpdateApplicationLifecycle();
// Hide snackbar when currently tracking at least one plane.
Session.GetTrackables<DetectedPlane>(m_AllPlanes);
bool showSearchingUI = true;
for (int i = 0; i < m_AllPlanes.Count; i++)
{
if (m_AllPlanes[i].TrackingState == TrackingState.Tracking)
{
showSearchingUI = false;
break;
}
}
SearchingForPlaneUI.SetActive(showSearchingUI);
// If the player has not touched the screen, we are done with this update.
Touch touch;
if (Input.touchCount < 1 || (touch = Input.GetTouch(0)).phase != TouchPhase.Began)
{
return;
}
// Raycast against the location the player touched to search for planes.
TrackableHit hit;
TrackableHitFlags raycastFilter = TrackableHitFlags.PlaneWithinPolygon |
TrackableHitFlags.FeaturePointWithSurfaceNormal;
if (Frame.Raycast(touch.position.x, touch.position.y, raycastFilter, out hit))
{
// Use hit pose and camera pose to check if hittest is from the
// back of the plane, if it is, no need to create the anchor.
if ((hit.Trackable is DetectedPlane) &&
Vector3.Dot(FirstPersonCamera.transform.position - hit.Pose.position,
hit.Pose.rotation * Vector3.up) < 0)
{
Debug.Log("Hit at back of the current DetectedPlane");
}
else
{
This is where it loads the Andy prefabs, what I would like to do is swap the andy prefab out for the asset bundle
// Choose the Andy model for the Trackable that got hit.
GameObject prefab;
if (hit.Trackable is FeaturePoint)
{
prefab = AndyPlanePrefab;
}
else
{
prefab = AndyPointPrefab;
}
// Instantiate Andy model at the hit pose.
var andyObject = Instantiate(prefab, hit.Pose.position, hit.Pose.rotation);
// Compensate for the hitPose rotation facing away from the raycast (i.e. camera).
andyObject.transform.Rotate(0, k_ModelRotation, 0, Space.Self);
// Create an anchor to allow ARCore to track the hitpoint as understanding of the physical
// world evolves.
var anchor = hit.Trackable.CreateAnchor(hit.Pose);
// Make Andy model a child of the anchor.
andyObject.transform.parent = anchor.transform;
}
}
}
/// <summary>
/// Check and update the application lifecycle.
/// </summary>
private void _UpdateApplicationLifecycle()
{
// Exit the app when the 'back' button is pressed.
if (Input.GetKey(KeyCode.Escape))
{
Application.Quit();
}
// Only allow the screen to sleep when not tracking.
if (Session.Status != SessionStatus.Tracking)
{
const int lostTrackingSleepTimeout = 15;
Screen.sleepTimeout = lostTrackingSleepTimeout;
}
else
{
Screen.sleepTimeout = SleepTimeout.NeverSleep;
}
if (m_IsQuitting)
{
return;
}
// Quit if ARCore was unable to connect and give Unity some time for the toast to appear.
if (Session.Status == SessionStatus.ErrorPermissionNotGranted)
{
_ShowAndroidToastMessage("Camera permission is needed to run this application.");
m_IsQuitting = true;
Invoke("_DoQuit", 0.5f);
}
else if (Session.Status.IsError())
{
_ShowAndroidToastMessage("ARCore encountered a problem connecting. Please start the app again.");
m_IsQuitting = true;
Invoke("_DoQuit", 0.5f);
}
}
/// <summary>
/// Actually quit the application.
/// </summary>
private void _DoQuit()
{
Application.Quit();
}
/// <summary>
/// Show an Android toast message.
/// </summary>
/// <param name="message">Message string to show in the toast.</param>
private void _ShowAndroidToastMessage(string message)
{
AndroidJavaClass unityPlayer = new AndroidJavaClass("com.unity3d.player.UnityPlayer");
AndroidJavaObject unityActivity = unityPlayer.GetStatic<AndroidJavaObject>("currentActivity");
if (unityActivity != null)
{
AndroidJavaClass toastClass = new AndroidJavaClass("android.widget.Toast");
unityActivity.Call("runOnUiThread", new AndroidJavaRunnable(() =>
{
AndroidJavaObject toastObject = toastClass.CallStatic<AndroidJavaObject>("makeText", unityActivity,
message, 0);
toastObject.Call("show");
}));
}
}
}
}
My plan is to change the URL dynamically as thats just a public variable so that I can load a different prefab once the app is running, then change the url and load a different prefab.
Any help, advice greatly appreciated.