Interacting with world

Goals

• Have our cube interact with the room
• Learn how to use the tap gesture in the Unity editor

1. Make the cube a physics object

1. Click the Cube game object
2. Click Add Component
3. Search for and add Rigidbody

If you play now, you will see the cube fall. If you move the cube to be where the room would be on load, it will land in the room.

Easy, right? Let's make it a little bit interactive

2. Throw cube around the room

We will add a script so that whenever you use the Tap gesture, the cube will be thrown in the direction you face.

Note: This is a quick script to demonstrate physical response for the spatial map - we will cover input in greater detail later.

1. Add a Scripts folder to your assets
2. Create a new script, call it ThrowAtWall (Important: Do not add the .cs file extension)
3. Click the Cube game object
4. Click Add Component
5. Search for and add ThrowAtWall
6. Right-click the script and choose Edit Script

This will launch Visual Studio with the script projects - handy! You can open this in any code editor you like - in the end it will be compiled by Unity, not your IDE.

Edit the file to look like this:

using HoloToolkit.Unity.InputModule;
using UnityEngine;

public class ThrowAtWall : MonoBehaviour, IInputClickHandler
{
    public GameObject ThrowSource;
    public Rigidbody RigidBody;

    void Start()
    {
        InputManager.Instance.AddGlobalListener(gameObject);
    }

    public void OnInputClicked(InputClickedEventData eventData)
    {
        gameObject.transform.position = ThrowSource.transform.position;
        RigidBody.velocity = ThrowSource.transform.rotation * Vector3.forward * 10;
        RigidBody.angularVelocity = Vector3.forward * 4;
    }
}

A quick rundown:

1. Has an input for the throw source (ours will be the camera), and the rigid body. These will be exposed in the Unity editor
2. The Start() method (called when the object is started) registers this script with HoloToolkit's InputManager singleton
3. This is being registered as a global Click handler - which translates to tap in our gesture world
4. When the event is clicked, we:
   1. Set the position of the cube to the throw source
   2. Set the velocity of the rigid body to a multiple of the throw source's "look" vector (positive z).
   3. Put some angular velocity on so it tumbles through the air and looks freakin' amazing

3. Set up the throw source and rigid body

With the cube selected in the editor, under the ThrowAtWall script component

1. Drag the "camera" game object to the Throw Source parameter
2. Select the Rigid Body component for the Rigid Body parameter
3. Reduce the cube size to 20cm (set scale transform to 0.2, 0.2, 0.2)

4. Test it out

Run! With the default key bindings, here is how you tap. You will likely be holding down the Right Mouse Button at the same time for mouselook. It's a little awkward, honestly.

1. Hold Space to put your right hand into view
2. Hold Left Mouse Button to lower your finger
3. Release Left Mouse Button to raise again

You'll need to be careful you're not inside a wall at the time, as that tends to mess things up.

Next: Placing Objects

Prev: Spatial Mapper