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Object Tracker iOS Tutorial

1. Overview
2. iOS Development
2.1 Create Instants
2.2 Start / Stop Tracker
2.3 Use Tracking Information
2.4 Set Map
2.5 Add / Replace Map
2.6 Change Tracking Mode
3. Reference
3.1 API Reference
3.2 Sample


1. Overview

Start developing MAXST ARSDK Object Tracker on iOS Platform. Refer to Object Tracker Introduction for detailed information.

Refer to Tracker Coordinate System to better understand 3D coordinate system of Object tracker.

Generate 3D Mapfile of the target for Object Tracker via Visual SLAM Tool. The Object Tracker loads the map file and renders 3D object on it. Refer to Visual SLAM Learning Guide to create a map more precisely while scanning 3D space.

Prerequisites
Object Tracker Introduction
Visual SLAM Tool
Tracker Coordinate System
Visual SLAM Learning Guide

2. iOS Development

Start developing on xCode using Objective-C. Refer to Requirements & Supports to find out which devices are supported.

ARSDK has to properly integrate on iOS UIViewController. Refer to Life Cycle documents for detail.


2.1 Create Instants

ObjectTrackerViewController.mm

- (void)viewDidLoad
{
    ...
    trackingManager = [[MasTrackerManager alloc] init];
    cameraDevice = [[MasCameraDevice alloc] init];
}

2.2 Starting / Stopping the Tracker

To start / stop the tracker after loading the map, refer to the following code.

※ To change the tracker, destroyTracker() should be called before

ObjectTrackerViewController.mm

- (void)resumeAR
{
    ...
    [trackingManager startTracker:TRACKER_TYPE_OBJECT];
}

- (void)pauseAR
{
    [trackingManager stopTracker];
    ...
}

2.3 Use Tracking Information

To use the Tracking information, refer to the following code.

※ startTracker() should be called before

ObjectTrackerViewController.mm

- (void)glkView:(GLKView *)view drawInRect:(CGRect)rect
{
    ...
    MasTrackingState *trackingState = [trackingManager updateTrackingState];
    MasTrackingResult *result = [trackingState getTrackingResult];
    
   MasTrackedImage *trackedImage = [trackingState getImage];
    [backgroundCameraQuad draw:trackedImage projectionMatrix:[cameraDevice getBackgroundPlaneProjectionMatrix]];
    
    glEnable(GL_DEPTH_TEST);
    matrix_float4x4 projectionMatrix = [cameraDevice getProjectionMatrix];
    
    for (int i = 0; i < [result getCount]; i++)
    {
        MasTrackable *trackable = [result getTrackable:i];
        
        [texturedCube setProjectionMatrix:projectionMatrix];
        [texturedCube setPoseMatrix:[trackable getPose]];
        [texturedCube setTranslation:0.0f y:0.0f z:-0.0005f];
        [texturedCube setScale:0.4f y:0.4f z:0.001f];
        [texturedCube draw];
    }
    ...
}

2.4 Set Map

By calling function addTrackerData to register the map file and calling function loadTrackerData, Space can be tracked. To set a map, refer to the following code.

ObjectTrackerViewController.mm

- (void)startEngine
{
    ...
    [trackingManager addTrackerData:objectTrackerMapPath];
    [trackingManager loadTrackerData];
}

2.5 Add / Replace Map

※ You can add multiple 3Dmaps to recognize one of multiple objects. We recommend to add up to three maps.

  1. Create a map file refer to Visual SLAM Tool.

  2. Copy the received map file to the desired path.

  3. Set a map.

  4. If you have an existing map file, call function 'addTrackerData' and function 'loadTrackerData' after calling [trackingManager removeTrackerData]


2.6 Change Tracking Mode

2 Tracking Modes of Object Tracker:

  • NORMAL_TRACKING
  • EXTENDED_TRACKING
  • EXTENDED_TRACKING: Default Setting. Track surrounded environment beyond a trained object.
[trackingManager setTrackingOption: EXTENDED_TRACKING];
  • NORMAL_TRACKING: Track only a trained object.
[trackingManager setTrackingOption: NORMAL_TRACKING];

3. References

These are additional references to develop Object Tracker


3.1 API Reference

Following documents explain classes and functions used to run Object Tracker.

MaxstAR Class

TrackerManager Class

CameraDevice Class


3.2 Sample

For information regarding sample build and run of Object Tracker, refer to Sample

ObjectTrackerViewController.mm