Cardboard VR Projects for Android

Table of Contents

Cardboard VR Projects for Android

Credits

About the Authors

About the Reviewers

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eBooks, discount offers, and more

Why subscribe?

Preface

What this book covers

What you need for this book

Who this book is for

Conventions

Reader feedback

Customer support

Downloading the example code

Downloading the color images of this book

Errata

Piracy

Questions

1. Virtual Reality for Everyone

Why is it called Cardboard?

The spectrum of VR devices

Old fashioned stereoscopes

Cardboard is mobile VR

Desktop VR and beyond

A gateway to VR

The value of low-end VR

Cardware!

Configuring your Cardboard viewer

Developing apps for Cardboard

Using Unity

Going native

An overview to VR best practices

Summary

2. The Skeleton Cardboard Project

What's in an Android app?

APK files

A Gradle build process

A Java compiler

The Android project structure

Getting started with Android Studio

Installing Android Studio

The Android Studio user interface

Creating a new Cardboard project

Adding the Cardboard Java SDK

The AndroidManifest.xml file

The activity_main.xml file

The MainActivity class

Default onCreate

Building and running

Summary

3. Cardboard Box

Creating a new project

Hello, triangle!

Introducing geometry

Triangle variables

onSurfaceCreated

Introducing OpenGL ES 2.0

Simple shaders

The compileShaders method

The prepareRenderingTriangle method

onDrawEye

Building and running

3D camera, perspective, and head rotation

Welcome to the matrix

The MVP vertex shader

Setting up the perspective viewing matrices

Render in perspective

Building and running

Repositioning the triangle

Hello, cube!

The cube model data

Cube code

Lighting and shading

Adding shaders

Cube normals and colors

Preparing the vertex buffers

Preparing the shaders

Adding a light source

Building and running the app

Spinning the cube

Hello, floor!

Shaders

Floor model data

Variables

onCreate

onSurfaceCreated

initializeScene

prepareRenderingFloor

onDrawEye

drawFloor

Hey, look at this!

The isLookingAtObject method

Summary

4. Launcher Lobby

Creating a new project

Adding Hello Virtual World text overlay

A simple text overlay

Center the text using a child view

Create stereoscopic views for each eye

Controlling the overlay view from MainActivity

Using a virtual screen

Responding to head look

Adding an icon to the view

Listing installed Cardboard apps

Queries for Cardboard apps

Create the Shortcut class for apps

Add shortcuts to OverlayView

Using view lists in OverlayEye

Highlighting the current shortcut

Using the trigger to pick and launch the app

Further enhancements

Summary

5. RenderBox Engine

Introducing RenderBox – a graphics engine

Creating a new project

Creating the RenderBox package folder

Creating an empty RenderBox class

Adding the IRenderBox interface

Materials, textures, and shaders

Abstract material

The Math package

MathUtils

Matrix4

Quaternion

Vector2

Vector3

The Transform class

Parent methods

Position methods

Rotation methods

Scale methods

Transform to matrix and draw

The Component class

The RenderObject component

The Cube RenderObject component

Vertex color material and shaders

Vertex color shaders

VertexColorMaterial

The Camera component

RenderBox methods

A simple box scene

Cube with face normals

The Light component

Vertex color lighting material and shaders

Time for animation

Detect looking at objects

Exporting the RenderBox package

Building the RenderBoxLib module

The RenderBox test app

Using RenderBox in future projects

Summary

6. Solar System

Setting up a new project

Creating a Sphere component

A solid color lighted sphere

Solid color lighting shaders

Solid color lighting material

Adding a Material to a Sphere

Viewing the Sphere

Adding the Earth texture material

Loading a texture file

Diffuse lighting shaders

Diffuse lighting material

Adding diffuse lighting texture to a Sphere component

Viewing the Earth

Changing the camera position

Day and night material

Day/night shader

The DayNightMaterial class

Rendering with day/night

Creating the Sun

Unlit texture shaders

Unlit texture material

Rendering with an unlit texture

Adding the Sun

Creating a Planet class

Formation of the Solar System

Setting up planets in MainActivity

Camera's planet view

Animating the heavenly bodies

A starry sky dome

Fine tuning the Earth

The night texture

Axis tilt and wobble

Changing the camera location

Possible enhancements

Updating the RenderBox library

Summary

7. 360-Degree Gallery

Setting up the new project

Viewing a 360-degree photo

Viewing a sample photosphere

Using the background image

Viewing a regular photo

Defining the Plane component and allocating buffers

Adding materials to the Plane component

Adding an image screen to the scene

Putting a border frame on the image

Border shaders

The border material

Using the border material

Loading and displaying a photo image

Defining the image class

Reading images into the app

Image load texture

Showing an image on the screen

Rotating to the correct orientation

Dimensions to correct the width and height

Sample image down to size

Loading and displaying a photosphere image

The image gallery user interface

Positioning the photo screen on the left

Displaying thumbnails in a grid

The thumbnail image

The Thumbnail class

The thumbnail grid

Gaze to load

Gaze-based highlights

Selecting and showing photos

Queue events

Using a vibrator

Enable scrolling

Creating the Triangle component

Adding triangles to the UI

Interacting with the scroll buttons

Implementing the scrolling method

Stay responsive and use threads

An explanation of threading and virtual reality

Launch with an intent

Showing/hiding the grid with tilt-up gestures

Spherical thumbnails

Add a sphere to the Thumbnail class

Updating the RenderBox library

Further possible enhancements

Summary

8. 3D Model Viewer

Setting up a new project

Understanding the OBJ file format

Creating the ModelObject class

Parse OBJ models

buildBuffers

Model extents, scaling, and center

I'm a little teapot

I'm a little rotating teapot

Thread safe

Launch with intent

Practical and production ready

Summary

9. Music Visualizer

Setting up a new project

Capturing audio data

A VisualizerBox architecture

Waveform data capture

A basic geometric visualization

2D texture-based visualization

Texture generator and loader

Waveform shaders

Basic waveform material

Waveform visualization

FFT visualization

Capture the FFT audio data

FFT shaders

Basic FFT material

FFT visualization

Trippy trails mode

Multiple simultaneous visualizations

Random visualizations

Further enhancements

A community invite

Summary

Onward to the future

Index

Cardboard VR Projects for Android

Cardboard VR Projects for Android

Copyright © 2016 Packt Publishing

All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.

Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the authors, nor Packt Publishing, and its dealers and distributors will be held liable for any damages caused or alleged to be caused directly or indirectly by this book.

Packt Publishing has endeavored to provide trademark information about all of the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information.

First published: May 2016

Production reference: 1120516

Published by Packt Publishing Ltd.

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ISBN 978-1-78588-787-1

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Credits for the Cover Image:

Custom Illustration designed by eLearning Mind, LLC., www.eLearningMind.com, ELM creates interactive learning experiences using modern brain science and intuitively stunning design.

The DIY Virtual Reality article: http://elearningmind.com/diy-virtual-reality-world-of-warcraft-thinks-inside-the-box-at-comic-con-2015/

Credits

Authors

Jonathan Linowes

Matt Schoen

Reviewers

Scott Dolim

Oleksandr Popov

Commissioning Editor

Edward Gordon

Acquisition Editor

Reshma Raman

Content Development Editor

Sachin Karnani

Technical Editor

Siddhi Rane

Copy Editor

Rashmi Sawant

Project Coordinator

Nikhil Nair

Proofreader

Safis Editing

Indexer

Hemangini Bari

Graphics

Kirk D'Penha

Production Coordinator

Shantanu N. Zagade

Cover Work

Shantanu N. Zagade

About the Authors

Jonathan Linowes is the owner of Parkerhill Reality Labs, a start-up VR/AR consultancy firm. He is a VR and 3D graphics enthusiast, full-stack web developer, software engineer, successful entrepreneur, and teacher. He has a fine arts degree from Syracuse University and a master's degree from the MIT Media Lab. He has founded several successful start-ups and held technical leadership positions at major corporations, including Autodesk Inc. He is also the author of the Unity Virtual Reality Projects book by Packt Publishing.

Matt Schoen is the cofounder of Defective Studios and has been making VR apps since the early DK1 days. Still in the early stages of his career, he spent most of his time working on Unity apps and games, some for hire and some of his own design. He studied computer engineering at Boston University and graduated with a BS in 2010, at which point he founded Defective with Jono Forbes, a high-school friend. He has been making games and apps ever since. Matt was the technical lead on Defective's debut game, CosmoKnots, and remains involved in Jono's pet project, Archean. This is his first foray into authorship, but he brings with him his experience as an instructor and curriculum designer for Digital Media Academy. Jono and Matt have recently joined Unity's VR Labs division, where they will be helping to create experimental new features which will shape the VR landscape for years to come.

About the Reviewers

Scott Dolim has worked on and off in 3D computer graphics for over 20 years, including a 5-year stint at Walt Disney Feature Animation in the 1990s. More recently, for the last 5 years, he has been actively involved in virtual reality development, mostly with Unity 3D. Scott currently works at Google where he is the lead engineer of the Cardboard SDK for Unity.

Oleksandr Popov is a developer of numerous 3D apps, mainly live wallpapers, for Android devices. His first experience with 3D for Android started in 2012 when with the release of Android 2.2, it became possible to create live wallpapers. Since then, he has released about 15 of them in collaboration with his brother, Dmytro, who is responsible for creating 3D scenes. After releasing each app, he gained more and more experience in OpenGL ES. Basically, he tried almost every new feature of Android where 3D and OpenGL can be applied. He started with live wallpapers in Android 2.2, then he added support of the daydream mode for them in 4.2. He started using some of the features of OpenGL ES 3.0 introduced in Android 4.3. And as soon as Google added support of custom watch faces for Android Wear 5.0, he and his brother created a set of 3D watch faces for smart watches too. Of course, after Google announced Cardboard, he immediately decided to create VR apps for this platform as well.

He and his brother are also coauthors of the Deconstructing Google Cardboard Apps book by Bleeding Edge Press.

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Preface

Google Cardboard is a low-cost, entry-level medium used for experiencing virtual 3D environments. Its applications are as broad and varied as mobile smartphone applications themselves. This book gives you the opportunity to implement a variety of interesting projects for Google Cardboard using the native Java SDK. The idea is to educate you with best practices and methodologies to make Cardboard-compatible mobile VR apps and guide you through making quality content appropriate for the device and its intended users.

What this book covers

Chapter 1, Virtual Reality for Everyone, defines Google Cardboard, explores it, and discusses how it's used and how it fits in the spectrum of VR devices.

Chapter 2, The Skeleton Cardboard Project, examines the structure of a Cardboard app for Android, takes a tour of Android Studio, and helps you build a starter Cardboard project by introducing the Cardboard Java SDK.

Chapter 3, Cardboard Box, discusses how to build a Cardboard Android app from scratch (based on Google's Treasure Hunt sample) with a 3D cube model, transformations, stereoscopic camera views, and head rotations. This chapter also includes discussions of 3D geometry, Open GL ES, shaders, matrix math, and the rendering pipeline.

Chapter 4, Launcher Lobby, helps you build an app to launch other Cardboard apps on your phone. Rather than using 3D graphics, this project simulates stereoscopic views in screen space and implements gaze-based selections.

Chapter 5, RenderBox Engine, shows you how to create a small graphics engine used to build new Cardboard VR apps by abstracting the low-level OpenGL ES API calls into a suite of the Material, RenderObject, Component, and Transform classes. The library will be used and further developed in subsequent projects.

Chapter 6, Solar System, builds a Solar System simulation science project by adding a sunlight source, spherical planets with texture mapped materials and shaders, animating in their solar orbits, and a Milky Way star field.

Chapter 7, 360-Degree Gallery, helps you build a media viewer for regular and 360-degree photos, and helps you load the phone's camera folder pictures into a grid of thumbnail images and use gaze-based selections to choose the ones to view. It also discusses how to add process threading for improved user experience and support Android intents to view images from other apps.

Chapter 8, 3D Model Viewer, helps you build a viewer for 3D models in the OBJ file format, rendered using our RenderBox library. It also shows you how to interactively control the view of the model as you move your head.

Chapter 9, Music Visualizer, builds a VR music visualizer that animates based on waveform and FFT data from the phone's current audio player. We implement a general architecture used to add new visualizations, including geometric animations and dynamic texture shaders. Then, we add a trippy trails mode and multiple concurrent visualizations that transition in and out randomly.

What you need for this book

Throughout the book, we use the Android Studio IDE development environment to write and build Android applications. You can download Android Studio for free, as explained in Chapter 2, The Skeleton Cardboard Project. You will need an Android phone to run and test your projects. And it's strongly recommended that you have a Google Cardboard viewer to experience your apps in stereoscopic virtual reality.

Who this book is for

This book is for Android developers who are interested in learning about and developing Google Cardboard apps using the Google Cardboard native SDK. We assume that the reader has some knowledge of Android development and the Java language, but may be new to 3D graphics, virtual reality, and Google Cardboard. Novice developers, or those unfamiliar with the Android SDK, may find it hard to get started with this book. Those who aren't coming from an Android background may be better served by creating cardboard apps with a game engine like Unity.

Conventions

In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning.

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: Edit the MainActivity Java class so that it extends CardboardActivity and implements CardboardView.StereoRenderer.

A block of code is set as follows:

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        CardboardView cardboardView = (CardboardView) findViewById(R.id.cardboard_view);

        cardboardView.setRenderer(this);

        setCardboardView(cardboardView);

    }

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        CardboardView cardboardView = (CardboardView) findViewById(R.id.cardboard_view);

        cardboardView.setRenderer(this);         setCardboardView(cardboardView);

    }

Any command-line input or output is written as follows:

git clone https://github.com/googlesamples/cardboard-java.git

New terms and important words are shown in bold. Words that you see on the screen, for example, in menus or dialog boxes, appear in the text like this: In Android Studio, select File | New | New Module…. Select Import .JAR/.AAR Package.

Note

Warnings or important notes appear in a box like this.

Tip

Tips and tricks appear like this.

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Chapter 1. Virtual Reality for Everyone

Welcome to the exciting new world of virtual reality! We're sure that, as an Android developer, you want to jump right in and start building cool stuff that can be viewed using Google Cardboard. Your users can then just slip their smartphone into a viewer and step into your virtual creations. Before we get up to our elbows in the code and tech stuff throughout the rest of this book, let's take an outside-in tour of VR, Google Cardboard, and its Android SDK to see how they all fit together. We will discuss the following topics in this chapter:

Why is it called Cardboard?

The spectrum of virtual reality devices

A gateway to VR

The value of low-end VR

Cardware

Configuring your Cardboard viewer

Developing apps for Cardboard

An overview of VR best practices

Why is it called Cardboard?

It all started in early 2014 when Google employees, David Coz and Damien Henry, in their spare time, built a simple and cheap stereoscopic viewer for the Android smartphones. They designed a device that can be constructed from ordinary cardboard, plus a couple of lenses for your eyes, and a mechanism to trigger a button click. The viewer is literally made from cardboard. They wrote software that renders a 3D scene with a split screen: one view for the left eye, and another view, with offset, for the right eye. Peering through the device, you get a real sense of 3D immersion into the computer generated scene. It worked! The project was then proposed and approved as a 20% project (where employees may dedicate one day a week for innovations), funded, and joined by other employees.

Note

Two sources of canonical facts about the story behind how Cardboard came into existence are as follows:

http://www.wired.com/2015/06/inside-story-googles-unlikely-leap-cardboard-vr/

https://en.wikipedia.org/wiki/Google_Cardboard

In fact, Cardboard worked so well that Google decided to go forward, taking the project to the next level and releasing it to the public a few months later at Google I/O 2014. The following figure shows a typical unassembled Google Cardboard kit:

Since its inception, Google Cardboard has been accessible to hackers, hobbyists, and professional developers alike. Google open sourced the viewer design for anyone to download the schematics and make their own, from a pizza box or from whatever they had lying around. One can even go into business selling precut kits directly to consumers. An assembled Cardboard viewer is shown in the following image:

The Cardboard project also includes a software development kit (SDK) that makes it easy to build VR apps. Google has released continuous improvements to the software, including both a native Java SDK as well as a plugin for the Unity 3D game engine (https://unity3d.com/).

Since the release of Cardboard, a huge number of applications have been developed and made available on the Google Play Store. At Google I/O 2015, Version 2.0 introduced an upgraded design, improved software, and support for Apple iOS.

Google Cardboard has rapidly evolved in the eye of the market from an almost laughable toy into a serious new media device for certain types of 3D content and VR experiences. Google's own Cardboard demo app has been downloaded millions of times from the Google Play Store. The New York Times distributed about a million cardboard viewers with its November 8, Sunday issue back in 2015.

Cardboard is useful for viewing 360-degree photos and playing low-fidelity 3D VR games. It is universally accessible to almost anyone because it runs on any Android or iOS smartphone.

Developers are now integrating 3D VR content directly into Android apps. Google Cardboard is a way of experiencing virtual reality that is here to stay.

The spectrum of VR devices

As with most technologies, there is a spectrum of products for virtual reality ranging from the simplest and least expensive to the very advanced.

Old fashioned stereoscopes

Cardboard is at the low end of the VR device spectrum. Well, you could even go lower if you consider the ViewMaster that you may have played with as a child, or even the historic stereoscope viewer from 1876 (B.W. Kilborn & Co, Littleton, New Hampshire), as shown in the following image:

In these old fashioned viewers, a pair of photographs display two separate views for the left and right eyes that are slightly offset to create parallax. This fools the brain into thinking that it's seeing a truly three-dimensional view. The device contains separate lenses for each eye that allow you to easily focus on the photo close up.

Similarly, rendering these side-by-side stereo views is the first job of a Google Cardboard application. (Leveraging their legacy, Mattel recently released a Cardboard-compatible ViewMaster brand VR viewer that uses a smartphone, which can be found at http://www.view-master.com/).

Cardboard is mobile VR

Cardboard's obvious advantages over stereoscopic viewers are like the advantages of digital photographs over traditional ones. Digital media can be dynamically stored, loaded, and manipulated right within our smartphones. That's a powerful leap on its own.

On top of that, Cardboard uses the motion sensors in the phone in such a way that when you turn your head left-right or up-down, the image is adjusted accordingly, effectively obliterating the traditional frame edges of the image. Framing the image is a very important part of traditional visual media, such as painting, photography, and cinematography. For centuries, artists and directors have established a visual language using this rectangular frame.

However, not so much in VR. When you move your head in VR your view direction changes, and the scene is updated as if the camera is rotating along with you, providing a fully immersive view. You can rotate it horizontally 360 degrees as you look side to side and 180 degrees up and down. In other words, you can look anywhere you want. There is no frame in VR! (Albeit your peripheral vision might be limited by the optics and display size, which determine the device's field of view or FOV). In this way, the design considerations may be more akin to sculpture, theatre-in-the-round, or even architectural design. We need to think about the whole space that immerses the visitor.

The Google Cardboard device is simply a casing for you to slip your smartphone into. It uses the smartphone's technology, including the following:

Display

CPU (the main processor)

GPU (the graphics processor)

IMU (the motion sensor)

Magnetometer and/or touchscreen (the trigger sensor)

We'll talk more about how all this works a little later.

Using a mobile smartphone for VR means great things, such as ease of use, but also annoying constraints, such as limited battery life, slower graphics processing, and lower accuracy/higher latency motion sensors.

The Samsung Gear VR is a mobile VR headset that is smarter than a simple Cardboard viewer. Android-based but not compatible with Cardboard apps (and only works with specific models of Samsung phones), it has a separate built-in higher precision IMU (motion sensor), which increases the accuracy of the head motion tracking and helps reduce the motion-to-pixel latency when updating the display. It's also ergonomically designed for more extended use and it includes a strap.

Desktop VR and beyond

At the higher end of consumer virtual reality devices are the Oculus Rift, HTC Vive, and Sony PlayStation VR, among others. These products go beyond what Cardboard can do because they're not limited by the capabilities of a smartphone. Sometimes referred to as desktop VR, these devices are head-mounted displays (HMD) tethered to an external PC or console.

On desktop VR, the desktop's powerful CPU and GPU do the actual computation and graphics rendering and send the results to the HMD. Furthermore, the HMD has higher quality motion sensors and other features that help reduce the latency when updating the display at, say, 90 frames per second (FPS). We'll learn throughout this book that reducing latency and maintaining high FPS are important concerns for all VR development and the comfort of your users on all VR devices, including Cardboard.

Desktop VR devices also add positional tracking. The Cardboard device can detect the rotational movement on any of the X, Y, and Z axes, but it unfortunately cannot detect the positional movement (for example, sliding along any of these axes). The Rift, Vive, and PSVR can. The Rift, for example, uses an external camera to track the position using infrared lights on the HMD (outside-in tracking). The Vive, on the other hand, uses sensors on the HMD to track a pair of laser emitters placed strategically in the room (inside-out tracking). The Vive also uses this system to track the position and rotation of a pair of hand controllers. Both strategies achieve similar results. The user has a greater freedom to move around within the tracked space while experiencing moving around within the virtual space. Cardboard cannot do this.

Note that innovations are continually being introduced. Very likely, at some point, positional tracking will be included with the Cardboard arsenal. For example, we know that Google's Project Tango implements visual-inertial odometry, or VIO, using sensors, gyroscopes, and awareness of the physical space to provide motion and positional tracking to mobile apps. Refer to https://developers.google.com/project-tango/overview/concepts. Mobile device companies, such as LG and Samsung, are working hard to figure out how to do mobile positional tracking, but (at the time of this writing) a universal, low-latency solution does not yet exist. Google's Project Tango shows some promise but cannot yet achieve the time-to-pixel latency required for a smooth, comfortable VR experience. Too much latency and you get sick!

At the