Articles

Blink a LED on a Raspberry Pi With Vaadin

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As I’m becoming a senior developer in terms of age, I’ve transitioned from one language to another. One of my main interests has always been clean, easy-to-understand UIs (User Interface). That journey started for me with Director (to create multimedia CD-ROMs), Flash website animation, and Flex Rich Internet Applications (= « Flash on steroids »). When I started developing with Java over 10 years ago, we had some projects with the early versions of Vaadin and JavaFX. As I went on with serverside applications, I only continued with JavaFX for some personal and side projects and loved the way you can create a UI both with XML (FXML actually) and code, exactly the same approach I loved with Flex. Since then, my love for Java and JavaFX only grew and it’s still my major programming environment.

But JavaFX has one missing piece: running it in the browser… Yes, JPRO can do this, but it needs a license and a dedicated server. And yes, there are some projects ongoing to bring JavaFX fully to the browser, but they are ongoing and not mature yet… Let’s look at another approach: Vaadin Flow and run it on a Raspberry Pi to control a LED and show the state of a button.

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AWS Lambda Aliases: A Practical Approach

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Lambda functions are a fundamental component of the AWS serverless model. They provide a simple, cost-effective, and easily scalable programming model based on FaaS (functions as a service).

Lambda ARNs

Lambda functions can be referenced by their ARN (Amazon Resource Name). For example, the ARN to reference a ‘helloworld‘ function in the ‘us-east-2‘ region in account ‘3445435‘ would be:

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Coordinating Threads Using CountDownLatch

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Since Java 5, the core Java APIs have been enhanced with more features for handling coordination between threads in concurrent programming. In this post, we discuss a class in the java.util.concurrent package that aids in this purpose: the CountDownLatch.

Introduction

The CountDownLatch class enables us to coordinate threads by introducing awareness of the number of threads that are carrying out related tasks and keeping track of the number of threads that have completed their task. 

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A Beginner’s Guide to High-Performance Computing in Python

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Ever since the Python programming language was born, its core philosophy has always been to maximize the readability and simplicity of code. In fact, the reach for readability and simplicity is so deep within Python’s root that, if you type import this in a Python console, it will recite a little poem:

    Beautiful is better than ugly. Explicit is better than implicit. Simple is better than complex. The complex is better than complicated. The flat is better than nested. Sparse is better than dense. Readability counts…

Simple is better than complex. Readability counts. No doubt, Python has indeed been quite successful at achieving these goals: it is by far the most friendly language to learn, and an average Python program is often 5 to 10 times shorter than equivalent C++ code. Unfortunately, there is a catch: Python’s simplicity comes at the cost of reduced performance. In fact, it is almost never surprising for a Python program to be 10 to 100 times slower than its C++ counterpart. It thus appears that there is a perpetual trade-off between speed and simplicity, and no programming language shall ever possess both.
But, don’t you worry, all hope is not lost.

Taichi: Best of Both Worlds

The Taichi Programming Language is an attempt to extend the Python programming language with constructs that enable general-purpose, high-performance computing. It is seamlessly embedded in Python, yet can summon every ounce of computing power in a machine — the multi-core CPU, and more importantly, the GPU.
We’ll show an example program written using taichi. The program uses the GPU to run a real-time physical simulation of a piece of cloth falling onto a sphere and simultaneously renders the result.
Writing a real-time GPU physics simulator is rarely an easy task, but the Taichi source code behind this program is surprisingly simple. The remainder of this article will walk you through the entire implementation, so you can get a taste of the functionalities that taichi provides, and just how powerful and friendly they are.
Before we begin, take a guess of how many lines of code this program consists of. You will find the answer at the end of the article.

Algorithmic Overview

Our program will model the piece of cloth as a mass-spring system. More specifically, we will represent the piece of cloth as an N by N grid of point-masses, where adjacent points are linked by springs. The following image, provided by Matthew Fisher, illustrates this structure:
The motion of this mass-spring system is affected by 4 factors:
  • Gravity
  • Internal forces of the springs
  • Damping
  • Collision with the red ball in the middle
For the simplicity of this blog, we ignore the self-collisions of the cloth. Our program begins at the time t = 0. Then, at each step of the simulation, it advances time by a small constant dt. The program estimates what happens to the system in this small period of time by evaluating the effect of each of the 4 factors above, and updates the position and velocity of each mass point at the end of the timestep. The updated positions of mass points are then used to update the image rendered on the screen.

Getting Started

Although Taichi is a programming language in its own right, it exists in the form of a Python package and can be installed by simply running pip install taichi.
To start using Taichi in a python program, import it under the alias ti:
import taichi as ti
The performance of a Taichi program is maximized if your machine has a CUDA-enabled Nvidia GPU. If this is the case, add the following line of code after the import: ti.init(arch=ti.cuda)

If you don’t have a CUDA GPU, Taichi can still interact with your GPU via other graphics APIs, such as ti.metal, ti.vulkan, and ti.opengl. However, Taichi’s support for these APIs is not as complete as its CUDA support, so, for now, use the CPU backend: ti.init(arch=ti.cpu)And don’t worry, Taichi is blazing fast even if it only runs on the CPU. Having initialized Taichi, we can start declaring the data structures used to describe the mass-spring cloth. We add the following lines of code:

Python

  

 N = 128 x = ti.Vector.field(3, float, (N, N)) v = ti.Vector.field(3, float, (N, N))

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8 Top Metrics for Measuring Your Technical Debt in 2022

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Much like running up bills on your credit card, technical debt can easily get out of hand. To avoid this happening, you need to keep track of how much debt you’re building up.

Technical debt metrics are designed to help you make sense of all the data you collect. There are many different metrics to choose from nowadays, and plenty of tools for recording the data.

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Why a Developer Should Be a Bit of a Cloud Engineer: The Need for Cloud Services

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A Short Background

I characterize myself as a slothful engineer due to the specificity of my behavior: rather than duplicating, mentioning different issues in my project, and setting up new appliances to be more efficient, I would be grateful for the opportunity and get back on my way.

My first job as a professional started in the entertainment industry where I had to do my projects really quickly before the deadline was over; moreover, it was not possible to use high-end tools or spend a lot of time researching and integrating peculiar properties. That is the reason why I decided to spend some overtime hours researching and showing my teammates how a few specific tools could improve the process, and show how to have a greater impact in solving technical problems.

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How to Prepare for the Immersive Web

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Websites as we know them are going to change very soon. The days of text, images, and basic interactions in a 2D browser window have served us well, but virtual, augmented, and mixed reality experiences are getting better all the time. Developers and designers need to think beyond the browser window and prepare for an immersive future.

Many have been very skeptical about VR and AR in the past because despite grand promises about what they would achieve, they’ve mostly failed to deliver on the scale that the industry hoped for.

But it’s different this time: industry leaders like Meta, Apple, and Microsoft are pursuing a range of different mixed reality projects; they see the opportunity and are dropping hints about what’s next.

In a survey from Perkins Coie LLP and the XR Association, nearly 9 in 10 respondents said that by the year 2025, immersive technologies—including augmented reality, virtual reality, and mixed reality — will be as ubiquitous as mobile devices.

That’s a bold prediction, but it could be our new reality.

Use Cases

VR and AR aren’t a logical fit for every website, and that’s fine. There’s no need to force an immersive experience on something better suited to a standard viewing experience.

But when they’re done right, 3D experiences can add a lot to your website. Check out the demo experience from Mozilla, the 3D tours from Matterport, and the immersive storytelling from Within.

Here are a few areas where these technologies shine:

  • Retail – VR can be used to provide a virtual showroom where customers browse through products. AR can even bring the products into your home by showing you how a piece of furniture will fit in your room, what a painting will look like on your wall, or in Apple’s case, how a product will look on your desk.
  • News – Coverage of events can be enriched by providing a 360-degree view and placing viewers in the center of the story.
  • Training – AR can generate virtual overlays over physical equipment so employees can have hands-on training that’s more effective.

Define Your Platform

Adding immersive experiences to your website will require various skills based on what you’re trying to create. Whether you’re new to web development or are a seasoned developer with many years of experience, the main difference from classic web development is that you’re switching from a 2D to a 3D experience. Development in VR/AR is much closer to developing 3D video games than creating web applications.

First of all, you need to decide on the hardware that you’re building for. Are your viewers mainly using computers, smartphones, or a headset like the Oculus Quest? Each hardware category offers a different set of capabilities for what’s possible.

Next, when we look at 3D engines and frameworks on the market, some big names like Unity, Unreal Engine, and CRYENGINE stand out. Most of these engines were spun out of game development and are based on programming languages like C, C++, or C#. While very powerful, they’re overkill for anyone trying to create a basic immersive web experience.

The good news for web developers is that the WebXR Device API is an open standard specified by the W3C with a JavaScript API that makes immersive experiences possible in the browser. So if you already have a background in web development, you can use your knowledge of JavaScript to get started.

There are some useful frameworks and platforms that make working with WebXR more convenient:

  • A-Frame – A web framework for building 3D experiences.
  • React 360 – A framework for the creation of interactive 360-degree experiences that run in the web browser. As the name already suggests, it builds on React and reuses the concepts you already know.
  • Amazon Sumerian – A managed service that lets you create and run 3D, AR, and VR applications. Since it’s integrated into the AWS ecosystem, it’s also possible to add AI-enabled elements into your generated world.

Create Your Content

No one wants to read long blocks of text in 3D. Since we’re talking about visual experiences, it’s logical that the emphasis should be on creating content that is pleasing to the eye and interesting to look at. What works on a normal website probably isn’t going to feel natural in a 3D environment, so you need to decide what visuals you should create to suit the format.

What high-resolution images and assets do you need? Can you add videos? How about 360-degree videos? Will viewers just be looking at something, or will they be able to interact with it?

You also can’t forget about sound because it’s a critical part of immersive experiences. What music and sounds should you create to make the content come alive?

Not everyone is going to have the latest and greatest device or 5G coverage. The requirements for bandwidth and transmission quality are much higher with 3D content. A few milliseconds of latency can go unnoticed on a typical website, but in a VR/AR setting, it can make the experience laggy or unusable.

Try to optimize your content to be the highest quality it can be within a reasonable file size. If the experience starts to suffer from too many assets downloading at the same time, it’s better to create a more streamlined experience that maintains a high performance rate.

It’s important to consider your hosting infrastructure, as well. This shouldn’t be a big problem, but it is worth mentioning that you need to add new content types to your configurations, and your CDN needs to support these new types, too.

Make Your Content Flexible

When we’re talking about getting your website ready for immersive experiences, we’re not just talking about having people scroll through your regular website in VR. That isn’t compelling for your audience.

The idea is to take some content that’s already on your website and separate it from the presentation layer so you can use it in a 3D environment or any other platform that you want. Classic content management takes place in silos, which means you cannot easily reuse the content from your website.

This separation can be achieved by using a classic database, but if you want developers and content teams to collaborate, a headless CMS is front-end agnostic and more user friendly.

Start Experimenting Today

Building 3D content experiences may seem intimidating, but as we’ve seen, you likely already have the web development skills necessary to get started and try out some different ideas.

What you build today will prepare you for the 3D future of tomorrow.

 

Featured image via Pexels.

Source

The post How to Prepare for the Immersive Web first appeared on Webdesigner Depot.

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Revisiting Switch and If-then-else

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In computer science, there is nothing more fundamental and intuitive than control structures. Every student learned about them in the first few weeks of any computer science program. We could not code without them, period. But they are not set in stone: we did get rid of the infamous GOTO in the 80s!

At the pre-ALGOL meeting held in 1959 Heinz Zemanek explicitly threw doubt on the necessity for GOTO statements; at the time no one paid attention to his remark, including Edsger W. Dijkstra, who later became the iconic opponent of GOTO.[3] The 1970s and 1980s saw a decline in the use of GOTO statements in favor of the « structured programming » paradigm, with goto criticized as leading to « unmaintainable spaghetti code« 

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C# Errors by Example: Checking the DotNetNuke CMS

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Today, we discuss C# code quality and a variety of errors by the example of CMS DotNetNuke. We’re going to dig into its source code. You’re going to need a cup of coffee…

DotNetNuke

DotNetNuke is an open-source content management system (CMS) written mainly in C#. The source code is available on GitHub. The project is part of the .NET Foundation.

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