get 3d objects name by touching using min3d android

Question

i need to add features of my android project, to get each name of the 3d objects. The objects are irregular and it can be rotate based on the user's gesture. I have lots of reading on openGL ray picking but still cant figure out how to make it work. I am using 3d min to load the .obj file. Thanks for advance.

Answer 1

The creator of min3d has deprecated the library and has an updated version called Rajawali built off of the same principles which you can find here.

Setting up your scene/project will be very similar if not the same. Better performance too.

As for getting 3d objects name after touching the object, do this:

In your main activity;

    public boolean onTouch(View v, MotionEvent event) {
    if(event.getAction() == MotionEvent.ACTION_DOWN)
    {
        mRenderer.getObjectAt(event.getX(), event.getY());
    }
    return super.onTouchEvent(event);
}

In your renderer, you have to register the "selectable" objects in the initScene;

    public class Renderer extends RajawaliRenderer implements OnObjectPickedListener {
private PointLight mLight;
private BaseObject3D object1, object2;
private ObjectColorPicker mPicker;

public RajawaliObjectPickingRenderer(Context context) {
    super(context);
    setFrameRate(60);
}

protected void initScene() {
    mPicker = new ObjectColorPicker(this);
    mPicker.setOnObjectPickedListener(this);
    mLight = new PointLight();
    mLight.setPosition(-2, 1, 4);
    mLight.setPower(1.5f);
    mCamera.setPosition(0, 0, 7);

        object1 = new BaseObject3D(serializedMonkey);
        object1.addLight(mLight);
        object1.setScale(.7f);
        object1.setPosition(-1, 1, 0);
        object1.setRotY(0);
        addChild(object1);

        object2 = object1.clone();
        object2.addLight(mLight);
        object2.setScale(.7f);
        object2.setPosition(1, 1, 0);
        object2.setRotY(45);
        addChild(object2);


        mPicker.registerObject(mMonkey3);
        mPicker.registerObject(mMonkey4);

}



public void getObjectAt(float x, float y) {
    mPicker.getObjectAt(x, y);
}

public void onObjectPicked(BaseObject3D object) {
    //Do whatever you want here once the object is touched
    if object.picked == mObject1{
        //print line here or toast
        //just an example, not legit code
    }
}
    }

If you have any issues, feel free to ask. I've been using Rajawali since way back when min3d was created. ;)