Node.js and Cloud NoSQL Databases: Azure Cosmos DB

Azure Cosmos DB Quickstart

Learn how to access a cloud-based NoSQL database from Node.js. The Azure Cosmos DB stores documents (e.g., JSON) and allows scaling for improved performance plus geo-redundancy with one click. The access interface also allows well-known SQL queries.

This guide uses the latest Azure Cosmos DB JavaScript module (released as final version just 17 days ago). Additionally, this article is based on the ES 2017 standard. The async / await syntax makes the code short and readable. In contrast to many other tutorials, this article focuses on the minimum code required to understand the concepts.

The complete source code of this article is available on GitHub.

Continue reading “Node.js and Cloud NoSQL Databases: Azure Cosmos DB”

Asynchronous JavaScript with Promises & Async/Await in JavaScript

From the perspective of a C# developer, the introduction of Async and Await into the latest JavaScript version (ECMAScript 2017+) is a welcome addition. It makes asynchronous code a lot cleaner and more readable.

However, a lot of legacy libraries and code snippets are out there. It’s usually difficult to go all-in with async/await. This article is a short intro to error handling and the evolution of asynchronous development in JavaScript.

Error Handling in JavaScript

Most asynchronous operations like web requests can cause an error. Thus, let’s spend a minute reviewing the basics of the code flow.

Continue reading “Asynchronous JavaScript with Promises & Async/Await in JavaScript”

Basics of AR: SLAM – Simultaneous Localization and Mapping

How HoloLens sees the World

In the first part, we took a look at how an algorithm identifies keypoints in camera frames. These are the base for tracking & recognizing the environment.

For Augmented Reality, the device has to know more: its 3D position in the world. It calculates this through the spatial relationship between itself and multiple keypoints. This process is called “Simultaneous Localization and Mapping” – SLAM for short.

Sensors for Perceiving the World

The high-level view: when you first start an AR app using Google ARCore, Apple ARKit or Microsoft Mixed Reality, the system doesn’t know much about the environment. It starts processing data from various sources – mostly the camera. To improve accuracy, the device combines data from other useful sensors like the accelerometer and the gyroscope.

Based on this data, the algorithm has two aims:

  1. Build a map of the environment
  2. Locate the device within that environment
Continue reading “Basics of AR: SLAM – Simultaneous Localization and Mapping”

Basics of AR: Anchors, Keypoints & Feature Detection

Detected Anchors by Google ARCore

Creating apps that work well with Augmented Reality requires some background knowledge of the image processing algorithms that work behind the scenes. One of the most fundamental concepts involves anchors. These rely on keypoints and their descriptors, detected in the recording of the real world.

Anchor Virtual Objects to the Real World

AR development APIs hide much of the complexity. As a developer, you simply anchor virtual objects to the world. This ensures that the hologram stays glued to the physical location where you put it. Continue reading “Basics of AR: Anchors, Keypoints & Feature Detection”

Mixed Reality @ Microsoft Insider Dev Tour

Microsoft Insider Dev Tour

On June 20th, the Microsoft Insider Dev Tour will come to Vienna, Austria. It’s a world-wide event series for developers, organized by Microsoft together with Microsoft Developer MVPs.

You’ll learn about the latest trends for developers – including artificial intelligence, progressive web apps and more. Of course, Mixed Reality is also on the agenda!

As a Microsoft MVP for Windows Development, I’ll take over the Mixed Reality session. You’ll see live demos of getting started with both VR headsets, as well as the Microsoft HoloLens. 150 attendees have signed up – so it’ll certainly be a great event!

In addition, Microsoft has released amazing hands-on labs for everyone to follow up and dive deeper into the content presented at the sessions. The Mixed Reality Lab includes controllers, spatial sound and spatial mapping. It’s a great way to get started with some of the most exciting features of MR. Check it out!

 

How to Record a Video from a Unity ARCore App on Android

ARCore Recorded Video converted to an Animated GIF

A video is a great way to showcase your Unity app. To capture the full visual fidelity of your app, you need to record at the highest possible quality with a smooth frame rate.

Several screen recording apps are available in the Google Play Store. However, there’s an easy and completely free way that provides the highest possible quality.

This short guide demonstrates how to record the screen with an APK file generated by Unity. Of course, it works for both AR and Non-AR Apps. Continue reading “How to Record a Video from a Unity ARCore App on Android”

Remote ARCore with Unity’s Experimental ARInterface

Overall, the AR ecosystem is still small. Nevertheless, it’s fragmented. Google develops ARCore, Apple creates ARKit and Microsoft is working on the Mixed Reality Toolkit. Fortunately, Unity started unifying these APIs with the ARInterface.

At Unite Austin, two of the Unity engineers introduced the new experimental ARInterface. In November 2017, they released it to the public via GitHub. It looks like this will be integrated into Unity 2018 – the new features of Unity 2018.1 include “AR Crossplatfom Kit (ARCore/ARKit API)“.

Remote Testing of AR Apps

The traditional mobile AR app development cycle includes compiling and deploying apps to a real device. That takes a long time and is tedious for quick testing iterations.

A big advantage of ARKit so far has been the ARKit Unity Remote feature. The iPhone runs a simple “tracking” app. It transmits its captured live data to the PC. Your actual AR app is running directly in the Unity Editor on the PC, based on the data it gets from the device. Through this approach, you can run the app by simply pressing the Play-button in Unity, without native compilation.

This is similar to the Holographic Emulation for the Microsoft HoloLens, which has been available for Unity for some time.

The great news is that the new Unity ARInterface finally adds a similar feature to Google ARCore: ARRemoteInterface. It’s available cross-platform for ARKit and ARCore.

ARInterface Demo App

In this article, I’ll explain the steps to get AR Remote running on Google ARCore. For reference: “Pirates Just AR” also posted a helpful short video on YouTube. Continue reading “Remote ARCore with Unity’s Experimental ARInterface”

NFC Tags, NDEF and Android (with Kotlin)

Android: Launch App through NFC Tags

In this article, you will learn how to add NFC tag reading to an Android app. It registers for auto-starting when the user taps a specific NDEF NFC tag with the phone. In addition, the app reads the NDEF records from the tag.

NFC & NDEF

Apple added support for reading NFC tags with iOS 11 in September 2017. All iPhones starting with the iPhone 7 offer an API to read NFC tags. While Android included NFC support for many years, this was the final missing piece to bring NFC tag scenarios to the masses. Continue reading “NFC Tags, NDEF and Android (with Kotlin)”

How To: RecyclerView with a Kotlin-Style Click Listener in Android

Android RecyclerView - Click Listener - Flow

In this article, we add a click listener to a RecyclerView on Android. Advanced language features of Kotlin make it far easier than it has been with Java. However, you need to understand a few core concepts of the Kotlin language.

To get started with the RecyclerView, follow the steps in the previous article or check out the finished project on GitHub. Continue reading “How To: RecyclerView with a Kotlin-Style Click Listener in Android”

Kotlin & RecyclerView for High Performance Lists in Android

Android: RecyclerView - Adapter Flow

RecyclerView is the best approach to show scrolling lists on Android. It ensures high performance & smooth scrolling, while providing list elements with flexible layouts. Combined with modern language features of Kotlin, the code overhead of the RecyclerView is greatly reduced compared to the traditional Java approach.

Sample Project: PartsList – Getting Started

In this article, we’ll walk through a sample scenario: a scrolling list for a maintenance app, listing machine parts: “PartsList”. However, this scenario only affects the strings we use – you can copy this approach for any use case you need. Continue reading “Kotlin & RecyclerView for High Performance Lists in Android”