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If you’re familiar with the demo-scene, you’ve probably seen the plasma effect: In this article, you’ll learn how to implement plasma effects of your own. The Algorithm To generate a plasma effect, you iterate the pixels in the screen buffer. For each pixel: Apply a function to the pixel’s coordinate producing some value \(v\). Use \(v\) to calculate the new RGB value of the pixel. Update the pixel’s RGB value in the screen buffer. Repeat steps (1)-(3) until you have processed the entire image frame. Display the updated frame. Applying these steps at a high frequency creates the plasma animation. As you’ll see, the choice of function determines the shape and scale of the output image. ...

Port scanning is the name given to the process of discovering open ports on a remote host. In this article, you’ll explore the design and implementation of a basic port scanner written in Rust. Starting with a Ping Utilities with port scanning capabilities often start by sending a ping to the target. For example, nmap pings the target before scanning. This ensures the target is reachable. To send a ping or an ICMP packet, you need to create a raw socket which requires the CAP_NET_RAW capability. A regular user doesn’t have CAP_NET_RAW capability meaning a ping requires sudo or elevated privileges. Luckily, modern Linux provides unpriviledged ping. The unpriviledged ping uses a dgram socket rather than a raw socket. ...

A previous article explored writing rsbot, a scriptable auto clicker meant to automate training the most repetitive skills in RuneScape. As a recap, that bot would take as input a script defining click events where each click event includes an ID, click box, and delay range. The bot would continuously execute each event. Executing an event means randomly clicking within the click box and waiting a random amount of time within the delay range. Bonus points, rsbot mouse movements look human. ...

Have you been away from your PC and wished you could login and start a job or view a file? Do you run Linux on your PC and use an Android phone? If you answered yes to these questions, you came to the right place. In this article, you’ll see how to connect to and control your Linux PC from anywhere in the world using your Android phone. Required Software On your Linux PC, install the following packages using your distro’s package manager: ...

Virtual Network Computing or VNC makes it possible to remotely access the graphical desktop environment of another machine. There are a number of projects out there that implement the VNC protocol. Typically, these projects provide two applications: a VNC server and a VNC client. The remote target machine runs the VNC server program. A VNC client instance connects to the target’s VNC server. The client application is a GUI application that renders the graphical display of the remote target. The image below illustrates the concept: ...

Are you a fan of the MMO RuneScape? Are you not a fan of the grinds RuneScape subjects its players to? If you answered yes to these two questions, it’s likely botting has crossed your mind. Put aside that botting is against the game’s rules. Creating a scriptable bot that can avoid RuneScape’s bot detection system presents a number of interesting technical problems. This article explores the creation of a rudimentary bot: an auto clicker bot. ...

The article “Making Cellular Textures” gives a good description of how you would go about generating textured images like the ones shown below. The authors’ descriptions and pseudocode provide the basis for the implementation of a CLI texture generator. This article describes such a tool and its performance when generating a number of different textures. Texture Parameters The goal of the tool is to generate a texture as a MxN grayscale PNG. The program exposes five key parameters that control the look of the output image: ...

ffmpeg is a powerful command line tool for processing video and audio files. ffmpeg can do just about anything you can imagine with media files. The trouble is in understanding how to invoke the program correctly. There are a few options that require some Linux and multimedia expertise to get right. This article covers a couple handy ffmpeg hacks that have made much of the audio/visual content on this website possible. The commands presented here are MP4 centric. That said, you can modify most of the commands to work with alternative formats (for example, WebM). ...

The Ulam spiral is a graphical depiction of a set of prime numbers devised by the mathematician Stanislaw Ulam. To quote the Wiki, it’s constructed by writing the positive integers in a square spiral and specially marking the prime numbers. The outcome is a square with distinct diagonal, horizontal, and vertical lines. This post will walk through the development of a Ulam spiral visualization tool. Creating a Ulam Spiral Take a look at the 4x4 Ulam spiral below: ...

The Caesar Cipher (CC) is a classic symmetric key algorithm dating back to the time of Julius Caesar. If you are new to cryptography, the Caesar Cipher is a great first crypto algorithm to learn. This post will walk through the details of implementing a CC encrypt/decrypt function. You’ll then get a look at the internals of a CC code cracker. Algorithm Description There are four key ingredients to a Caesar Cipher: ...