ofxARCore

Addon for openFrameworks to use ARCore on Android devices.

About

This addon is based on the work of HalfdanJ. I added these APIs :

- Point cloud

- Augmented Images

- Hit testing

- Planes

Developer guide

To use the addon, you need the development branch of openFrameworks from github. Follow the Android Studio guide to learn how to get started with openFrameworks and Android.

To add the addon, add ofxARCore to addons.make in your project, or through the project generator. Additionally you will need to add the following two lines to the end of settings.gradle of your project:

What is implemented

Anchor

// ofApp.h

ofxARCore arcore;
vector<ofMatrix4x4> anchors;

// ofApp.cpp

void ofApp::setup() {
  arcore.setup();
}

void ofApp::update() {
  anchors.push_back(arcore.getViewMatrix().getInverse());
}

void RafalleApp::draw() {

  for (int i = 0; i < anchors.size(); i++) {

    ofMatrix4x4 anchor = anchors[i];
    ofPushMatrix();
    ofMultMatrix(anchor);

    ofDrawBox(ofVec3f(0,0,0), 0.05); // Draws a 5cm box at anchor location

    ofPopMatrix();
  }


  ofDisableDepthTest();

}

Point Cloud

// ofApp.h

vector<float> point_cloud;
ofVbo vbo_pointcloud;

// ofApp.cpp

void ofApp::setup() {
  for(int i = 0; i < point_cloud.size(); i++) {
    point_color.push_back(ofColor::red);
  }
  vbo_pointcloud.setVertexData(&point_cloud[0], 3, 1000, GL_DYNAMIC_DRAW);
  vbo_pointcloud.setColorData(&point_color[0], 1000, GL_DYNAMIC_DRAW);
  point_color.clear();
}

void ofApp::update() {
  point_cloud = arcore->getPointCloud();
  if (point_cloud.size() > 1) {
    for (int i = 0; i < point_cloud.size(); i++)
    point_color.push_back(ofColor::red);

    vbo_pointcloud.updateVertexData(&point_cloud[0], (int) point_cloud.size() * 2);
    vbo_pointcloud.updateColorData(&point_color[0], (int) point_color.size() * 2);
  }

  for (int i = 0; i < point_cloud.size(); i+=3) {
    ofVec3f pos(point_cloud[i], point_cloud[i+1], point_cloud[i+2]);
    points.push_back(pos);
  }
}

for (int i = 0; i < points.size(); i+=3) {
  ofDrawBox(points[i], 0.01); // Draws a 1cm box at each point of point cloud
}

Augmented Images

// ofApp.cpp

void ofApp::draw() {

  vector<ofAugmentedImage*> augmented_images = arcore->getImageMatrices();

  // draw a box above each detected image
  for (int i = 0; i < augmented_images.size(); i++) {

    if (augmented_images[i]->is_tracking == true) {

      // get AugmentedImage position
      ofMatrix4x4 anchor = augmented_images[i]->matrix;
      ofPushMatrix();
      // translate to AugmentedImage position
      ofMultMatrix(anchor);

      ofBoxPrimitive box;

      // set box dimentions according to arcore image width estimation
      box.set(augmented_images[i]->width, 0.01, augmented_images[i]->height);
      box.setPosition(0,0,0);

      // draw box above the image
      box.draw();


      ofPopMatrix();
    }
  }

}

Hit testing

void ofApp::touchDown(int x, int y, int id) {

  ofHitPose *hitPose = arcore->getHitPose(x, y);

  if (pose != NULL) {
    ofMatrix4x4 pose = hitPose->pose;
    float distance   = hitPose->distance;

    // translate to the hit location
    ofPushMatrix();
    ofMultMatrix(pose);

    // draw a box at the hit location
    ofDrawBox(0,0,0, 0.1);

  }

}

Planes

void ofApp::draw() {

    vector<ofARPlane*> planes = arcore->getPlanes();

    // for each plane
    for (int i = 0; i < planes.size(); i++) {

        // translate to it's center
        ofARPlane *plane= planes[i];
        ofPushMatrix();
        ofMultMatrix(plane->center);

        // draw a red box on it's center
        ofSetColor(255,0,0,100);
        ofDrawBox(0,0.025,0, 0.2, 0.05, 0.1);

        // draw the plane
        ofSetColor(0,255,0,100);
        plane->mesh.draw();

        // draw the path (contours)
        ofSetColor(0,0,255,100);
        plane->path.draw();

        ofPopMatrix();
    }

Utils

Camera FOV

// ofApp.cpp

arcore.getCameraFOV();

Screen DPI

// ofApp.cpp

arcore.getDpi();