# Enchanting images with Inky Lines, a Pi‑powered polargraph

Post Syndicated from Helen Lynn original https://www.raspberrypi.org/blog/enchanting-images-inky-lines-pi-powered-polargraph/

A hanging plotter, also known as a polar plotter or polargraph, is a machine for drawing images on a vertical surface. It does so by using motors to control the length of two cords that form a V shape, supporting a pen where they meet. We’ve featured one on this blog before: Norbert “HomoFaciens” Heinz’s video is a wonderfully clear introduction to how a polargraph works and what you have to consider when you’re putting one together.

Today, we look at Inky Lines, by John Proudlock. With it, John is creating a series of captivating and beautiful pieces, and with his most recent work, each rendering of an image is unique.

## An evolving project

The project isn’t new – John has been working on it for at least a couple of years – but it is constantly evolving. When we first spotted it, John had just implemented code to allow the plotter to produce mesmeric, spiralling patterns.

But we’re skipping ahead. Let’s go back to the beginning.

## From pixels to motor movements

John starts by providing an image, usually no more than 100 pixels wide, to a Raspberry Pi. Custom software that he wrote evaluates the darkness of each pixel and selects a pattern of a suitable density to represent it.

The two cords supporting the plotter’s pen are wound around the shafts of two stepper motors, such that the movement of the motors controls the length of the cords: the program next calculates how much each motor must move in order to produce the pattern. The Raspberry Pi passes corresponding instructions to two motor circuits, which transform the signals to a higher voltage and pass them to the stepper motors. These turn by very precise amounts, winding or unwinding the cords and, very slowly, dragging the pen across the paper.

John explains,

Suspended in-between the two motors is a print head, made out of a new 3-d modelling material I’ve been prototyping called cardboard. An old coat hanger and some velcro were also used.

(He’s our kind of maker.)

## Unique images

The earlier drawings that John made used a repeatable method to render image files as lines on paper. That is, if the machine drew the same image a number of times, each copy would be identical. More recently, though, he has been using a method that yields random movements of the pen:

The pen point is guided around the image, but moves to each new point entirely at random. Up close this looks like a chaotic squiggle, but from a distance of a couple of meters, the human eye (and brain) make order from the chaos and view an infinite number of shades and a smoother, less mechanical image.

This method means that no matter how many times the polargraph repeats the same image, each copy will be unique.

## A gallery of work

Inky Lines’ website and its Instagram feed offer a collection of wonderful pieces John has drawn with his polargraph, and he discusses the different techniques and types of image that he is exploring.

They range from holiday photographs, processed to extract particular features and rendered in silhouette, to portraits, made with a single continuous line that can be several hundred metres long, to generative images spirograph images like those pictured above, created by an algorithm rather than rendered from a source image.

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# Some notes on eFail

Post Syndicated from Robert Graham original https://blog.erratasec.com/2018/05/some-notes-on-efail.html

I’ve been busy trying to replicate the “eFail” PGP/SMIME bug. I thought I’d write up some notes.

PGP and S/MIME encrypt emails, so that eavesdroppers can’t read them. The bugs potentially allow eavesdroppers to take the encrypted emails they’ve captured and resend them to you, reformatted in a way that allows them to decrypt the messages.

### Disable remote/external content in email

The most important defense is to disable “external” or “remote” content from being automatically loaded. This is when HTML-formatted emails attempt to load images from remote websites. This happens legitimately when they want to display images, but not fill up the email with them. But most of the time this is illegitimate, they hide images on the webpage in order to track you with unique IDs and cookies. For example, this is the code at the end of an email from politician Bernie Sanders to his supporters. Notice the long random number assigned to track me, and the width/height of this image is set to one pixel, so you don’t even see it:

Such trackers are so pernicious they are disabled by default in most email clients. This is an example of the settings in Thunderbird:

The problem is that as you read email messages, you often get frustrated by the fact the error messages and missing content, so you keep adding exceptions:

The correct defense against this eFail bug is to make sure such remote content is disabled and that you have no exceptions, or at least, no HTTP exceptions. HTTPS exceptions (those using SSL) are okay as long as they aren’t to a website the attacker controls. Unencrypted exceptions, though, the hacker can eavesdrop on, so it doesn’t matter if they control the website the requests go to. If the attacker can eavesdrop on your emails, they can probably eavesdrop on your HTTP sessions as well.

Some have recommended disabling PGP and S/MIME completely. That’s probably overkill. As long as the attacker can’t use the “remote content” in emails, you are fine. Likewise, some have recommend disabling HTML completely. That’s not even an option in any email client I’ve used — you can disable sending HTML emails, but not receiving them. It’s sufficient to just disable grabbing remote content, not the rest of HTML email rendering.

### I couldn’t replicate the direct exfiltration

There rare two related bugs. One allows direct exfiltration, which appends the decrypted PGP email onto the end of an IMG tag (like one of those tracking tags), allowing the entire message to be decrypted.

An example of this is the following email. This is a standard HTML email message consisting of multiple parts. The trick is that the IMG tag in the first part starts the URL (blog.robertgraham.com/…) but doesn’t end it. It has the starting quotes in front of the URL but no ending quotes. The ending will in the next chunk.

The next chunk isn’t HTML, though, it’s PGP. The PGP extension (in my case, Enignmail) will detect this and automatically decrypt it. In this case, it’s some previous email message I’ve received the attacker captured by eavesdropping, who then pastes the contents into this email message in order to get it decrypted.

What should happen at this point is that Thunderbird will generate a request (if “remote content” is enabled) to the blog.robertgraham.com server with the decrypted contents of the PGP email appended to it. But that’s not what happens. Instead, I get this:

I am indeed getting weird stuff in the URL (the bit after the GET /), but it’s not the PGP decrypted message. Instead what’s going on is that when Thunderbird puts together a “multipart/mixed” message, it adds it’s own HTML tags consisting of lines between each part. In the email client it looks like this:

The HTML code it adds looks like:

That’s what you see in the above URL, all this code up to the first quotes. Those quotes terminate the quotes in the URL from the first multipart section, causing the rest of the content to be ignored (as far as being sent as part of the URL).

So at least for the latest version of Thunderbird, you are accidentally safe, even if you have “remote content” enabled. Though, this is only according to my tests, there may be a work around to this that hackers could exploit.

### STARTTLS

In the old days, email was sent plaintext over the wire so that it could be passively eavesdropped on. Nowadays, most providers send it via “STARTTLS”, which sorta encrypts it. Attackers can still intercept such email, but they have to do so actively, using man-in-the-middle. Such active techniques can be detected if you are careful and look for them.
Some organizations don’t care. Apparently, some nation states are just blocking all STARTTLS and forcing email to be sent unencrypted. Others do care. The NSA will passively sniff all the email they can in nations like Iraq, but they won’t actively intercept STARTTLS messages, for fear of getting caught.
The consequence is that it’s much less likely that somebody has been eavesdropping on you, passively grabbing all your PGP/SMIME emails. If you fear they have been, you should look (e.g. send emails from GMail and see if they are intercepted by sniffing the wire).

### You’ll know if you are getting hacked

If somebody attacks you using eFail, you’ll know. You’ll get an email message formatted this way, with multipart/mixed components, some with corrupt HTML, some encrypted via PGP. This means that for the most part, your risk is that you’ll be attacked only once — the hacker will only be able to get one message through and decrypt it before you notice that something is amiss. Though to be fair, they can probably include all the emails they want decrypted as attachments to the single email they sent you, so the risk isn’t necessarily that you’ll only get one decrypted.
As mentioned above, a lot of attackers (e.g. the NSA) won’t attack you if its so easy to get caught. Other attackers, though, like anonymous hackers, don’t care.
Somebody ought to write a plugin to Thunderbird to detect this.

### Summary

It only works if attackers have already captured your emails (though, that’s why you use PGP/SMIME in the first place, to guard against that).
It only works if you’ve enabled your email client to automatically grab external/remote content.
It seems to not be easily reproducible in all cases.
Instead of disabling PGP/SMIME, you should make sure your email client hast remote/external content disabled — that’s a huge privacy violation even without this bug.

Notes: The default email client on the Mac enables remote content by default, which is bad:

# Secure Images

Post Syndicated from marcelatoath original https://yahooeng.tumblr.com/post/172068649246

By Marcel Becker

The mail team at OATH is busy  integrating  Yahoo and AOL technology to deliver an even better experience across all our consumer mail products. While privacy and security are top priority for us, we also want to improve the experience and remove unnecessary clutter across all of our products.

Starting this week we will be serving images in mails via our own secure proxy servers. This will not only increase speed and security in our own mail products and reduce the risk of phishing and other scams,  but it will also mean that our users don’t have to fiddle around with those “enable images” settings. Messages and inline images will now just show up as originally intended.

We are aware that commercial mail senders are relying on images (so-called pixels) to track delivery and open rates. Our proxy solution will continue to support most of these cases and ensure that true mail opens are recorded.

For senders serving dynamic content based on the recipient’s location (leveraging standard IP-based browser and app capabilities) we recommend falling back on other tools and technologies which do not rely on IP-based targeting.

All of our consumer mail applications (Yahoo and AOL) will benefit from this change. This includes our desktop products as well as our mobile applications across iOS and Android.

If you have any feedback or want to discuss those changes with us personally, just send us a note to [email protected].

# Secure Images

Post Syndicated from marcelatoath original https://yahooeng.tumblr.com/post/172037447286

By Marcel Becker

The mail team at OATH is busy  integrating  Yahoo and AOL technology to deliver an even better experience across all our consumer mail products. While privacy and security are top priority for us, we also want to improve the experience and remove unnecessary clutter across all of our products.

Starting this week we will be serving images in mails via our own secure proxy servers. This will not only increase speed and security in our own mail products and reduce the risk of phishing and other scams,  but it will also mean that our users don’t have to fiddle around with those “enable images” settings. Messages and inline images will now just show up as originally intended.

We are aware that commercial mail senders are relying on images (so-called pixels) to track delivery and open rates. Our proxy solution will continue to support most of these cases and ensure that true mail opens are recorded.

For senders serving dynamic content based on the recipient’s location (leveraging standard IP-based browser and app capabilities) we recommend falling back on other tools and technologies which do not rely on IP-based targeting.

All of our consumer mail applications (Yahoo and AOL) will benefit from this change. This includes our desktop products as well as our mobile applications across iOS and Android.

If you have any feedback or want to discuss those changes with us personally, just send us a note to [email protected].

# Raspbian update: supporting different screen sizes

Post Syndicated from Simon Long original https://www.raspberrypi.org/blog/raspbian-update-screen-sizes/

You may have noticed that we released a updated Raspbian software image yesterday. While the main reason for the new image was to provide support for the new Raspberry Pi 3 Model B+, the image also includes, alongside the usual set of bug fixes and minor tweaks, one significant chunk of new functionality that is worth pointing out.

## Compatibility

As a software developer, one of the most awkward things to deal with is what is known as platform fragmentation: having to write code that works on all the different devices and configurations people use. In my spare time, I write applications for iOS, and this has become increasingly painful over the last few years. When I wrote my first iPhone application, it only had to work on the original iPhone, but nowadays any iOS application has to work across several models of iPhone and iPad (which all have different processors and screens), and also across the various releases of iOS. And that’s before you start to consider making your code run on Android as well…

The good thing about developing for Raspberry Pi is that there is only a relatively small number of different models of Pi hardware. We try our best to make sure that, wherever possible, the Raspberry Pi Desktop software works on every model of Pi ever sold, and we’ve managed to do this for most of the software in the image. The only exceptions are some of the more recent applications like Chromium, which won’t run on the older ARM6 processors in the Pi 1 and the Pi Zero, and some applications that run very slowly due to needing more memory than the older platforms have.

## Raspbian with different screen resolutions

But there is one area where we have no control over the hardware, and that is screen resolution. The HDMI port on the Pi supports a wide range of resolutions, and when you include the composite port and display connector as well, people can be using the desktop  on a huge number of different screen sizes.

Supporting a range of screen sizes is harder than you might think. One problem is that the Linux desktop environment is made up of a large selection of bits of software from various different developers, and not all of these support resizing. And the bits of software that do support resizing don’t all do it in the same way, so making everything resize at once can be awkward.

This is why one of the first things I did when I first started working on the desktop was to create the Appearance Settings application in order to bring a lot of the settings for things like font and icon sizes into one place. This avoids users having to tweak several configuration files whenever they wanted to change something.

The Appearance Settings application was a good place to start regarding support of different screen sizes. One of the features I originally included was a button to set everything to a default value. This was really a default setting for screens of an average size, and the resulting defaults would not have worked that well on much smaller or much larger screens. Now, there is no longer a single defaults button, but a new Defaults tab with multiple options:

These three options adjust font size, icon size, and various other settings to values which ought to work well on screens with a high or low resolution. (The For medium screens option has the same effect as the previous defaults button.) The results will not be perfect in all circumstances and for all applications — as mentioned above, there are many different components used to create the desktop, and some of them don’t provide any way of resizing what they draw. But using these options should set the most important parts of the desktop and installed applications, such as icons, fonts, and toolbars, to a suitable size.

## Pixel doubling

We’ve added one other option for supporting high resolution screens. At the bottom of the System tab in the Raspberry Pi Configuration application, there is now an option for pixel doubling:

We included this option to facilitate the use of the x86 version of Raspbian with ultra-high-resolution screens that have very small pixels, such as Apple’s Retina displays. When running our desktop on one of these, the tininess of the pixels made everything too small for comfortable use.

Enabling pixel doubling simply draws every pixel in the desktop as a 2×2 block of pixels on the screen, making everything exactly twice the size and resulting in a usable desktop on, for example, a MacBook Pro’s Retina display. We’ve included the option on the version of the desktop for the Pi as well, because we know that some people use their Pi with large-screen HDMI TVs.

As pixel doubling magnifies everything on the screen by a factor of two, it’s also a useful option for people with visual impairments.

## How to update

As mentioned above, neither of these new functionalities is a perfect solution to dealing with different screen sizes, but we hope they will make life slightly easier for you if you’re trying to run the desktop on a small or large screen. The features are included in the new image we have just released to support the Pi 3B+. If you want to add them to your existing image, the standard upgrade from apt will do so. As shown in the video above, you can just open a terminal window and enter the following to update Raspbian:

sudo apt-get update
sudo apt-get dist-upgrade

As always, your feedback, either in comments here or on the forums, is very welcome.

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# One LED Matrix Table to rule them all

Post Syndicated from Alex Bate original https://www.raspberrypi.org/blog/led-matrix-table/

Germany-based Andreas Rottach’s multi-purpose LED table is an impressive build within a gorgeous-looking body. Play games, view (heavily pixelated) images, and become hypnotised by flashy lights, once you’ve built your own using his newly released tutorial.

#### LED-Matrix Table – 300 LEDs – Raspberry Pi – C++ Engine – Custom Controllers

This is a short presentation of my LED-Matrix Table. The table is controlled by a raspberry pi computer that executes a control engine, written in c++. It supports input from keyboards or custom made game controllers. A full list of all features as well as the source code is available on GitHub (https://github.com/rottaca/LEDTableEngine).

## Much excitement

Andreas uploaded a video of his LED Matrix Table to YouTube back in February, with the promise of publishing a complete write-up within the coming weeks. And so the members of Pi Towers sat, eagerly waiting and watching. Now the write-up has arrived, to our cheers of acclaim for this beautful, shiny, flashy, LED-based wonderment.

## Build your own LED table

In his GitHub tutorial, Andreas goes through all the stages of building the table, from the necessary components to coding the Raspberry Pi 3 and 3D printing your own controllers.

Find files for the controllers on Thingiverse

Andreas created the table’s impressive light matrix using a strip of 300 LEDs, chained together and connected to the Raspberry Pi via an LED controller.

The LEDs are set out in zigzags

For the code, he used several open-source tools, such as SDL for image and audio support, and CMake for building the project software.

Anyone planning to recreate Andreas’ table can compile its engine by downloading the project repository from GitHub. Again, find full instructions for this on his GitHub.

## Features

The table boasts multiple cool features, including games and visualisation tools. Using the controllers, you can play simplified versions of Flappy Bird and Minesweeper, or go on a nostalgia trip with Tetris, Pong, and Snake.

There’s also a version of Conway’s Game of Life. Andreas explains: “The lifespan of each cell is color-coded. If the game field gets static, the animation is automatically reset to a new random cell population.”

The table can also display downsampled Bitmap images, or show clear static images such as a chess board, atop of which you can place physical game pieces.

Find all the 3D-printable aspects of the LED table on Thingiverse here and here, and the full GitHub tutorial and repository here. If you build your own, or have already dabbled in LED tables and displays, be sure to share your project with us, either in the comments below or via our social media accounts. What other functions would you integrate into this awesome build?

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# LED cubes and how to map them

Post Syndicated from Alex Bate original https://www.raspberrypi.org/blog/led-panel-cubes-and-how-to-build-them/

Taking inspiration from a cube he had filmed at the 34th Chaos Communication Congress in Leipzig, Germany, polyfloyd gathered friends Sebastius and Boekenwuurm together to create their own.

## The build

As polyfloyd’s blog post for the project notes, Sebastius led the way with the hardware portion of the build. The cube is made from six LED panels driven by a Raspberry Pi, and uses a breakout board to support the panels, which are connected in pairs:

The displays are connected in 3 chains, the maximum number of parallel chains the board supports, of 2 panels each. Having a higher degree of parallelization increases the refresh rate which in turn improves the overall image quality.

The first two chains make up the 4 sides. The remaining chain makes up the top and bottom of the cube.

Sebastius removed the plastic frames that come as standard on the panels, in order to allow them to fit together snugly as a cube. He designed and laser-cut a custom frame from plywood to support the panels instead.

## Software

The team used hzeller’s software to drive the panels, and polyfloyd wrote their own program to “shove the pixels around”. polyfloyd used Ledcat, software they had made to drive previous LED projects, and adapted this interface so programs written for Ledcat would also work with hzeller’s library.

The full code for the project can be found on polyfloyd’s GitHub profile. It includes the ability to render animations to gzipped files, and to stream animations in real time via SSH.

## Mapping 2D and spherical images with shaders

“One of the programs that could work with my LED-panels through [Unix] pipes was Shady,” observes polyfloyd, explaining the use of shaders with the cube. “The program works by rendering OpenGL fragment shaders to an RGB24 format which could then be piped to wherever needed. These shaders are small programs that can render an image by calculating the color for each pixel on the screen individually.”

The team programmed a shader to map the two-dimensional position of pixels in an image to the three-dimensional space of the cube. This then allowed the team to apply the mapping to spherical images, such as the globe in the video below:

The team has interesting plans for the cube moving forward, including the addition of an accelerometer and batteries. Follow their progress on the polyfloyd blog.

## Fun with LED panels

The internet is full of amazing Raspberry Pi projects that use LED panels. This recent project available on Instructables shows how to assemble and set up a particle generator, while this one, featured on this blog last year, tracks emojis used on the Chelsea Handler: Gotta Go! app.

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# Petoi: a Pi-powered kitty cat

Post Syndicated from Alex Bate original https://www.raspberrypi.org/blog/petoi-a-pi-powered-kitty-cat/

A robot pet is the dream of many a child, thanks to creatures such as K9, Doctor Who’s trusted companion, and the Tamagotchi, bleeping nightmare of parents worldwide. But both of these pale in comparison (sorry, K9) to Petoi, the walking, meowing, live-streaming cat from maker Rongzhong Li.

#### Petoi: OpenCat Demo

Mentioned on IEEE Spectrum: https://spectrum.ieee.org/automaton/robotics/humanoids/video-friday-boston-dynamics-spotmini-opencat-robot-engineered-arts-mesmer-uncanny-valley More reads on Hackster: https://www.hackster.io/petoi/opencat-845129 优酷： http://v.youku.com/v_show/id_XMzQxMzA1NjM0OA==.html?spm=a2h3j.8428770.3416059.1 We are developing programmable and highly maneuverable quadruped robots for STEM education and AI-enhanced services. Its compact and bionic design makes it the only affordable consumer robot that mimics various mammal gaits and reacts to surroundings.

## Petoi

Not only have cats conquered the internet, they also have a paw firmly in the door of many makerspaces and spare rooms — rooms such as the one belonging to Petoi’s owner/maker, Rongzhong Li, who has been working on this feline creation since he bought his first Raspberry Pi.

Petoi in its current state – apple for scale in lieu of banana

Petoi is just like any other housecat: it walks, it plays, its ribcage doubles as a digital xylophone — but what makes Petoi so special is Li’s use of the project as a platform for study.

I bought my first Raspberry Pi in June 2016 to learn coding hardware. This robot Petoi served as a playground for learning all the components in a regular Raspberry Pi beginner kit. I started with craft sticks, then switched to 3D-printed frames for optimized performance and morphology.

Various iterations of Petoi have housed various bits of tech, 3D-printed parts, and software, so while it’s impossible to list the exact ingredients you’d need to create your own version of Petoi, a few components remain at its core.

An early version of Petoi, housed inside a plastic toy helicopter frame

A Raspberry Pi lives within Petoi and acts as its brain, relaying commands to an Arduino that controls movement. Li explains:

The Pi takes no responsibility for controlling detailed limb movements. It focuses on more serious questions, such as “Who am I? Where do I come from? Where am I going?” It generates mind and sends string commands to the Arduino slave.

Li is currently working on two functional prototypes: a mini version for STEM education, and a larger version for use within the field of AI research.

You can read more about the project, including details on the various interactions of Petoi, on the hackster.io project page.

Not quite ready to commit to a fully grown robot pet for your home? Why not code your own pixel pet with our free learning resource? And while you’re looking through our projects, check out our other pet-themed tutorials such as the Hamster party cam, the Infrared bird box, and the Cat meme generator.

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# Build a Binary Clock with engineerish

Post Syndicated from Alex Bate original https://www.raspberrypi.org/blog/engineerish-binary-clock/

Standard clocks with easily recognisable numbers are so last season. Who wants to save valuable seconds simply telling the time, when a series of LEDs and numerical notation can turn every time query into an adventure in mathematics?

#### Build a Binary Clock with Raspberry Pi – And how to tell the time

In this video I’ll be showing how I built a binary clock using a Raspberry Pi, NeoPixels and a few lines of Python. I also take a stab at explaining how the binary number system works so that we can decipher what said clock is trying to tell us.

I’ll be honest: I have to think pretty hard to read binary. It stretches my brain quite vigorously. But I am a fan of flashy lights and pretty builds, so YouTube and Instagram rising star Mattias Jähnke, aka engineerish, had my full attention from the off.

“If you have a problem with your friends being able to tell the time way too easily while in your house, this is your answer.”

Mattias offers a beginners’ guide in to binary in his video and then explains how his clock displays values in binary, before moving on to the actual clock build process. So make some tea, pull up a chair, and jump right in.

## Binary clock

To build the clock, Mattias used a Raspberry Pi and NeoPixel strips, fitted snugly within a simple 3D-printed case. With a few lines of Python, he coded his clock to display the current time using the binary system, with columns for seconds, minutes, and hours.

#### The real kicker with a binary clock is that by the time you’ve deciphered what time it is – you’re probably already late.

418 Likes, 14 Comments – Mattias (@engineerish) on Instagram: “The real kicker with a binary clock is that by the time you’ve deciphered what time it is – you’re…”

The Python code isn’t currently available on Mattias’s GitHub account, but if you’re keen to see how he did it, and you ask politely, and he’s not too busy, you never know.

In the meantime, while we batter our eyelashes in the general direction of Stockholm and hope for a response, I challenge any one of you to code a binary display project for the Raspberry Pi. It doesn’t have to be a clock. And it doesn’t have to use NeoPixels. Maybe it could use an LED matrix such as the SenseHat, or a series of independently controlled LEDs on a breadboard. Maybe there’s something to be done with servo motors that flip discs with different-coloured sides to display a binary number.

Whatever you decide to build, the standard reward applies: ten imaginary house points (of absolutely no practical use, but immense emotional value) and a great sense of achievement to all who give it a go.

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# Game night 2: Detention, Viatoree, Paletta

Post Syndicated from Eevee original https://eev.ee/blog/2018/01/16/game-night-2-detention-viatoree-paletta/

Game night continues with:

• Detention
• Viatoree
• Paletta

These are impressions, not reviews. I try to avoid major/ending spoilers, but big plot points do tend to leave impressions.

## Detention

longish · inventory horror · jan 2017 · lin/mac/win · $12 on steam · website Inventory horror” is a hell of a genre. I think this one came from a Twitter thread where glip asked for indie horror recommendations. It’s apparently well-known enough to have a Wikipedia article, but I hadn’t heard of it before. I love love love the aesthetic here. It’s obviously 2Dish from a side view (though there’s plenty of parallax in a lot of places), and it’s all done with… papercraft? I think of it as papercraft. Everything is built out of painted chunks that look like they were cut out of paper. It’s most obvious when watching the protagonist move around; her legs and skirt swivel as she walks. Less obvious are the occasional places where tiny details repeat in the background because a paper cutout was reused. I don’t bring that up as a dig on the art; on the contrary, I really liked noticing that once or twice. It made the world feel like it was made with a tileset (albeit with very large chunky tiles), like it’s slightly artificial. I’m used to seeing sidescrollers made from tiles, of course, but the tiles are usually colorful and cartoony pixel art; big gritty full-color tiles are unusual and eerie. And that’s a good thing in a horror game! Detention’s setting is already slightly unreal, and it’s made all the moreso by my Western perspective: it takes place in a Taiwanese school in the 60’s, a time when Taiwan was apparently under martial law. The Steam page tells you this, but I didn’t even know that much when we started playing, so I’d effectively been dropped somewhere on the globe and left to collect the details myself. Even figuring out we were in Taiwan (rather than mainland China) felt like an insight. Thinking back, it was kind of a breath of fresh air. Games can be pretty heavy-handed about explaining the setting, but I never got that feeling from Detention. There’s more than enough context to get what’s going on, but there are no “stop and look at the camera while monologuing some exposition” moments. The developers are based in Taiwan, so it’s possible the setting is plenty familiar to them, and my perception of it is a complete accident. Either way, it certainly made an impact. Death of the author and whatnot, I suppose. One thing in particular that stood out: none of the Chinese text in the environment is directly translated. The protagonist’s thoughts still give away what it says — “this is the nurse’s office” and the like — but that struck me as pretty different from simply repeating the text in English as though I were reading a sign in an RPG. The text is there, perfectly legible, but I can’t read it; I can only ask the protagonist to read it and offer her thoughts. It drives home that I’m experiencing the world through the eyes of the protagonist, who is their own person with their own impression of everything. Again, this is largely an emergent property of the game’s being designed in a culture that is not mine, but I’m left wondering how much thought went into this style of localization. The game itself sees you wandering through a dark and twisted version of the protagonist’s school, collecting items and solving puzzles with them. There’s no direct combat, though some places feature a couple varieties of spirits called lingered which you have to carefully avoid. As the game progresses, the world starts to break down, alternating between increasingly abstract and increasingly concrete as we find out who the protagonist is and why she’s here. The payoff is very personal and left a lasting impression… though as I look at the Wikipedia page now, it looks like the ending we got was the non-canon bad ending?! Well, hell. The bad ending is still great, then. The whole game has a huge Silent Hill vibe, only without the combat and fog. Frankly, the genre might work better without combat; personal demons are more intimidating and meaningful when you can’t literally shoot them with a gun until they’re dead. FINAL SCORE: 拾 ## Viatoree short · platformer · sep 2013 · win · free on itch I found this because @itchio tweeted about it, and the phrase “atmospheric platform exploration game” is the second most beautiful sequence of words in the English language. The first paragraph on the itch.io page tells you the setup. That paragraph also contains more text than the entire game. In short: there are five things, and you need to find them. You can walk, jump, and extend your arms straight up to lift yourself to the ceiling. That’s it. No enemies, no shooting, no NPCs (more or less). The result is, indeed, an atmospheric platform exploration game. The foreground is entirely 1-bit pixel art, save for the occasional white pixel to indicate someone’s eyes, and the background is only a few shades of the same purple hue. The game becomes less about playing and more about just looking at the environmental detail, appreciating how much texture the game manages to squeeze out of chunky colorless pixels. The world is still alive, too, much moreso than most platformers; tiny critters appear here and there, doing some wandering of their own, completely oblivious to you. The game is really short, but it… just… makes me happy. I’m happy that this can exist, that not only is it okay for someone to make a very compact and short game, but that the result can still resonate with me. Not everything needs to be a sprawling epic or ask me to dedicate hours of time. It takes a few tiny ideas, runs with them, does what it came to do, and ends there. I love games like this. That sounds silly to write out, but it’s been hard to get into my head! I do like experimenting, but I also feel compelled to reach for the grandiose, and grandiose experiment sounds more like mad science than creative exploration. For whatever reason, Viatoree convinced me that it’s okay to do a small thing, in a way that no other jam game has. It was probably the catalyst that led me to make Roguelike Simulator, and I thank it for that. Unfortunately, we collected four of the five macguffins before hitting upon on a puzzle we couldn’t make heads or tails of. After about ten minutes of fruitless searching, I decided to abandon this one unfinished, rather than bore my couch partner to tears. Maybe I’ll go take another stab at it after I post this. FINAL SCORE: ●●●●○ ## Paletta medium · puzzle story · nov 2017 · win · free on itch Paletta, another RPG Maker work, won second place in the month-long Indie Game Maker Contest 2017. Nice! Apparently MOOP came in fourth in the same jam; also nice! I guess that’s why both of them ended up on the itch front page. The game is set in a world drained of color, and you have to go restore it. Each land contains one lost color, and each color gives you a corresponding spell, which is generally used for some light puzzle-solving in further lands. It’s a very cute and light-hearted game, and it actually does an impressive job of obscuring its RPG Maker roots. The world feels a little small to me, despite having fairly spacious maps. The progression is pretty linear: you enter one land, talk to a small handful of NPCs, solve the one puzzle, get the color, and move on. I think all the areas were continuously connected, too, which may have thrown me off a bit — these areas are described as though they were vast regions, but they’re all a hundred feet wide and nestled right next to each other. I love playing with color as a concept, and I wish the game had run further with it somehow. Rescuing a color does add some color back to the world, but at times it seemed like the color that reappeared was somewhat arbitrary? It’s not like you rescue green and now all the green is back. Thinking back on it now, I wonder if each rescued color actually changed a fixed set of sprites from gray to colorized? But it’s been a month (oops) and now I’m not sure. I’m not trying to pick on the authors for the brevity of their jam game and also first game they’ve ever finished. I enjoyed playing it and found it plenty charming! It just happens that this time, what left the biggest impression on me was a nebulous feeling that something was missing. I think that’s still plenty important to ponder. FINAL SCORE: ❤️💛💚💙💜 # Eevee gained 2791 experience points Post Syndicated from Eevee original https://eev.ee/blog/2018/01/15/eevee-gained-2791-experience-points/ Eevee grew to level 31! A year strongly defined by mixed success! Also, a lot of video games. I ran three game jams, resulting in a total of 157 games existing that may not have otherwise, which is totally mindblowing?! For GAMES MADE QUICK???, glip and I made NEON PHASE, a short little exploratory platformer. Honestly, I should give myself more credit for this and the rest of the LÖVE games I’ve based on the same codebase — I wove a physics engine (and everything else!) from scratch and it has held up remarkably well for a variety of different uses. I successfully finished an HD version of Isaac’s Descent using my LÖVE engine, though it doesn’t have anything new over the original and I’ve only released it as a tech demo on Patreon. For Strawberry Jam (NSFW!) we made fox flux (slightly NSFW!), which felt like a huge milestone: the first game where I made all the art! I mean, not counting Isaac’s Descent, which was for a very limited platform. It’s a pretty arbitrary milestone, yes, but it feels significant. I’ve been working on expanding the game into a longer and slightly less buggy experience, but the art is taking the longest by far. I must’ve spent weeks on player sprites alone. We then set about working on Bolthaven, a sequel of sorts to NEON PHASE, and got decently far, and then abandond it. Oops. We then started a cute little PICO-8 game, and forgot about it. Oops. I was recruited to help with Chaos Composer, a more ambitious game glip started with someone else in Unity. I had to get used to Unity, and we squabbled a bit, but the game is finally about at the point where it’s “playable” and “maps” can be designed? It’s slightly on hold at the moment while we all finish up some other stuff, though. We made a birthday game for two of our friends whose birthdays were very close together! Only they got to see it. For Ludum Dare 38, we made Lunar Depot 38, a little “wave shooter” or whatever you call those? The AI is pretty rough, seeing as this was the first time I’d really made enemies and I had 72 hours to figure out how to do it, but I still think it’s pretty fun to play and I love the circular world. I made Roguelike Simulator as an experiment with making something small and quick with a simple tool, and I had a lot of fun! I definitely want to do more stuff like this in the future. And now we’re working on a game about Star Anise, my cat’s self-insert, which is looking to have more polish and depth than anything we’ve done so far! We’ve definitely come a long way in a year. Somewhere along the line, I put out a call for a “potluck” project, where everyone would give me sprites of a given size without knowing what anyone else had contributed, and I would then make a game using only those sprites. Unfortunately, that stalled a few times: I tried using the Phaser JS library, but we didn’t get along; I tried LÖVE, but didn’t know where to go with the game; and then I decided to use this as an experiment with procedural generation, and didn’t get around to it. I still feel bad that everyone did work for me and I didn’t follow through, but I don’t know whether this will ever become a game. veekun, alas, consumed months of my life. I finally got Sun and Moon loaded, but it took weeks of work since I was basically reinventing all the tooling we’d ever had from scratch, without even having most of that tooling available as a reference. It was worth it in the end, at least: Ultra Sun and Ultra Moon only took a few days to get loaded. But veekun itself is still missing some obvious Sun/Moon features, and the whole site needs an overhaul, and I just don’t know if I want to dedicate that much time to it when I have so much other stuff going on that’s much more interesting to me right now. I finally turned my blog into more of a website, giving it a neat front page that lists a bunch of stuff I’ve done. I made a release category at last, though I’m still not quite in the habit of using it. I wrote some blog posts, of course! I think the most interesting were JavaScript got better while I wasn’t looking and Object models. I was also asked to write a couple pieces for money for a column that then promptly shut down. On a whim, I made a set of Eevee mugshots for Doom, which I think is a decent indication of my (pixel) art progress over the year? I started idchoppers, a Doom parsing and manipulation library written in Rust, though it didn’t get very far and I’ve spent most of the time fighting with Rust because it won’t let me implement all my extremely bad ideas. It can do a couple things, at least, like flip maps very quickly and render maps to SVG. I did toy around with music a little, but not a lot. I wrote two short twines for Flora. They’re okay. I’m working on another; I think it’ll be better. I didn’t do a lot of art overall, at least compared to the two previous years; most of my art effort over the year has gone into fox flux, which requires me to learn a whole lot of things. I did dip my toes into 3D modelling, most notably producing my current Twitter banner as well as this cool Star Anise animation. I wouldn’t mind doing more of that; maybe I’ll even try to make a low-poly pixel-textured 3D game sometime. I restarted my book with a much better concept, though so far I’ve only written about half a chapter. Argh. I see that the vast majority of the work was done within the span of a single week, which is bad since that means I only worked on it for a week, but good since that means I can actually do a pretty good amount of work in only a week. I also did a lot of squabbling with tooling, which is hopefully mostly out of the way now. My computer broke? That was an exciting week. A lot of stuff, but the year as a whole still feels hit or miss. All the time I spent on veekun feels like a black void in the middle of the year, which seems like a good sign that I maybe don’t want to pour even more weeks into it in the near future. Mostly, I want to do: more games, more art, more writing, more music. I want to try out some tiny game making tools and make some tiny games with them — partly to get exposure to different things, partly to get more little ideas out into the world regularly, and partly to get more practice at letting myself have ideas. I have a couple tools in mind and I guess I’ll aim at a microgame every two months or so? I’d also like to finish the expanded fox flux by the end of the year, of course, though at the moment I can’t even gauge how long it might take. I seriously lapsed on drawing last year, largely because fox flux pixel art took me so much time. So I want to draw more, and I want to get much faster at pixel art. It would probably help if I had a more concrete goal for drawing, so I might try to draw some short comics and write a little visual novel or something, which would also force me to aim for consistency. I want to work on my book more, of course, but I also want to try my hand at a bit more fiction. I’ve had a blast writing dialogue for our games! I just shy away from longer-form writing for some reason — which seems ridiculous when a large part of my audience found me through my blog. I do think I’ve had some sort of breakthrough in the last month or two; I suddenly feel a good bit more confident about writing in general and figuring out what I want to say? One recent post I know I wrote in a single afternoon, which virtually never happens because I keep rewriting and rearranging stuff. Again, a visual novel would be a good excuse to practice writing fiction without getting too bogged down in details. And, ah, music. I shy heavily away from music, since I have no idea what I’m doing, and also I seem to spend a lot of time fighting with tools. (Surprise.) I tried out SunVox for the first time just a few days ago and have been enjoying it quite a bit for making sound effects, so I might try it for music as well. And once again, visual novel background music is a pretty low-pressure thing to compose for. Hell, visual novels are small games, too, so that checks all the boxes. I guess I’ll go make a visual novel. Here’s to twenty gayteen! # Create SLUG! It’s just like Snake, but with a slug Post Syndicated from Alex Bate original https://www.raspberrypi.org/blog/slug-snake/ Recreate Snake, the favourite mobile phone game from the late nineties, using a slug*, a Raspberry Pi, a Sense HAT, and our free resource! *A virtual slug. Not a real slug. Please leave the real slugs out in nature. ## Snake SLUG! Move aside, Angry Birds! On your bike, Pokémon Go! When it comes to the cream of the crop of mobile phone games, Snake holds the top spot. I could while away the hours… You may still have an old Nokia 3310 lost in the depths of a drawer somewhere — the drawer that won’t open all the way because something inside is jammed at an odd angle. So it will be far easier to grab your Pi and Sense HAT, or use the free Sense HAT emulator (online or on Raspbian), and code Snake SLUG yourself. In doing so, you can introduce the smaller residents of your household to the best reptile-focused game ever made…now with added mollusc. ## The resource To try out the game for yourself, head to our resource page, where you’ll find the online Sense HAT emulator embedded and ready to roll. It’ll look just like this, and you can use your computer’s arrow keys to direct your slug toward her tasty treats. From there, you’ll be taken on a step-by-step journey from zero to SLUG glory while coding your own versionof the game in Python. On the way, you’ll learn to work with two-dimensional lists and to use the Sense HAT’s pixel display and joystick input. And by completing the resource, you’ll expand your understanding of applying abstraction and decomposition to solve more complex problems, in line with our Digital Making Curriculum. ## The Sense HAT The Raspberry Pi Sense HAT was originally designed and made as part of the Astro Pi mission in December 2015. With an 8×8 RGB LED matrix, a joystick, and a plethora of on-board sensors including an accelerometer, gyroscope, and magnetometer, it’s a great add-on for your digital making toolkit, and excellent for projects involving data collection and evaluation. You can find more of our free Sense HAT tutorials here, including for making Flappy Bird Astronaut, a marble maze, and Pong. The post Create SLUG! It’s just like Snake, but with a slug appeared first on Raspberry Pi. # Physics cheats Post Syndicated from Eevee original https://eev.ee/blog/2018/01/06/physics-cheats/ Anonymous asks: something about how we tweak physics to “work” better in games? Ho ho! Work. Get it? Like in physics…? ## Hitboxes Hitbox” is perhaps not the most accurate term, since the shape used for colliding with the environment and the shape used for detecting damage might be totally different. They’re usually the same in simple platformers, though, and that’s what most of my games have been. The hitbox is the biggest physics fudge by far, and it exists because of a single massive approximation that (most) games make: you’re controlling a single entity in the abstract, not a physical body in great detail. That is: when you walk with your real-world meat shell, you perform a complex dance of putting one foot in front of the other, a motion you spent years perfecting. When you walk in a video game, you press a single “walk” button. Your avatar may play an animation that moves its legs back and forth, but since you’re not actually controlling the legs independently (and since simulating them is way harder), the game just treats you like a simple shape. Fairly often, this is a box, or something very box-like. Since the player has no direct control over the exact placement of their limbs, it would be slightly frustrating to have them collide with the world. This is especially true in cases like the above, where the tail and left ear protrude significantly out from the main body. If that Eevee wanted to stand against a real-world wall, she would simply tilt her ear or tail out of the way, so there’s no reason for the ear to block her from standing against a game wall. To compensate for this, the ear and tail are left out of the collision box entirely and will simply jut into a wall if necessary — a goofy affordance that’s so common it doesn’t even register as unusual. As a bonus (assuming this same box is used for combat), she won’t take damage from projectiles that merely graze past an ear. (One extra consideration for sprite games in particular: the hitbox ought to be horizontally symmetric around the sprite’s pivot — i.e. the point where the entity is truly considered to be standing — so that the hitbox doesn’t abruptly move when the entity turns around!) ### Corners Treating the player (and indeed most objects) as a box has one annoying side effect: boxes have corners. Corners can catch on other corners, even by a single pixel. Real-world bodies tend to be a bit rounder and squishier and this can tolerate grazing a corner; even real-world boxes will simply rotate a bit. Ah, but in our faux physics world, we generally don’t want conscious actors (such as the player) to rotate, even with a realistic physics simulator! Real-world bodies are made of parts that will generally try to keep you upright, after all; you don’t tilt back and forth much. One way to handle corners is to simply remove them from conscious actors. A hitbox doesn’t have to be a literal box, after all. A popular alternative — especially in Unity where it’s a standard asset — is the pill-shaped capsule, which has semicircles/hemispheres on the top and bottom and a cylindrical body in 3D. No corners, no problem. Of course, that introduces a new problem: now the player can’t balance precariously on edges without their rounded bottom sliding them off. Alas. If you’re stuck with corners, then, you may want to use a corner bump, a term I just made up. If the player would collide with a corner, but the collision is only by a few pixels, just nudge them to the side a bit and carry on. When the corner is horizontal, this creates stairs! This is, more or less kinda, how steps work in Doom: when the player tries to cross from one sector into another, if the height difference is 24 units or less, the game simply bumps them upwards to the height of the new floor and lets them continue on. Implementing this in a game without Doom’s notion of sectors is a little trickier. In fact, I still haven’t done it. Collision detection based on rejection gets it for free, kinda, but it’s not very deterministic and it breaks other things. But that’s a whole other post. ## Gravity Gravity is pretty easy. Everything accelerates downwards all the time. What’s interesting are the exceptions. ### Jumping Jumping is a giant hack. Think about how actual jumping works: you tense your legs, which generally involves bending your knees first, and then spring upwards. In a platformer, you can just leap whenever you feel like it, which is nonsense. Also you go like twenty feet into the air? Worse, most platformers allow variable-height jumping, where your jump is lower if you let go of the jump button while you’re in the air. Normally, one would expect to have to decide how much force to put into the jump beforehand. But of course this is about convenience of controls: when jumping is your primary action, you want to be able to do it immediately, without any windup for how high you want to jump. (And then there’s double jumping? Come on.) Air control is a similar phenomenon: usually you’d jump in a particular direction by controlling how you push off the ground with your feet, but in a video game, you don’t have feet! You only have the box. The compromise is to let you control your horizontal movement to a limit degree in midair, even though that doesn’t make any sense. (It’s way more fun, though, and overall gives you more movement options, which are good to have in an interactive medium.) Air control also exposes an obvious place that game physics collide with the realistic model of serious physics engines. I’ve mentioned this before, but: if you use Real Physics™ and air control yourself into a wall, you might find that you’ll simply stick to the wall until you let go of the movement buttons. Why? Remember, player movement acts as though an external force were pushing you around (and from the perspective of a Real™ physics engine, this is exactly how you’d implement it) — so air-controlling into a wall is equivalent to pushing a book against a wall with your hand, and the friction with the wall holds you in place. Oops. ### Ground sticking Another place game physics conflict with physics engines is with running to the top of a slope. On a real hill, of course, you land on top of the slope and are probably glad of it; slopes are hard to climb! In a video game, you go flying. Because you’re a box. With momentum. So you hit the peak and keep going in the same direction. Which is diagonally upwards. ### Projectiles To make them more predictable, projectiles generally aren’t subject to gravity, at least as far as I’ve seen. The real world does not have such an exemption. The real world imposes gravity even on sniper rifles, which in a video game are often implemented as an instant trace unaffected by anything in the world because the bullet never actually exists in the world. ## Resistance Ah. Welcome to hell. ### Water Water is an interesting case, and offhand I don’t know the gritty details of how games implement it. In the real world, water applies a resistant drag force to movement — and that force is proportional to the square of velocity, which I’d completely forgotten until right now. I am almost positive that no game handles that correctly. But then, in real-world water, you can push against the water itself for movement, and games don’t simulate that either. What’s the rough equivalent? The Sonic Physics Guide suggests that Sonic handles it by basically halving everything: acceleration, max speed, friction, etc. When Sonic enters water, his speed is cut; when Sonic exits water, his speed is increased. That last bit feels validating — I could swear Metroid Prime did the same thing, and built my own solution around it, but couldn’t remember for sure. It makes no sense, of course, for a jump to become faster just because you happened to break the surface of the water, but it feels fantastic. The thing I did was similar, except that I didn’t want to add a multiplier in a dozen places when you happen to be underwater (and remember which ones need it to be squared, etc.). So instead, I calculate everything completely as normal, so velocity is exactly the same as it would be on dry land — but the distance you would move gets halved. The effect seems to be pretty similar to most platformers with water, at least as far as I can tell. It hasn’t shown up in a published game and I only added this fairly recently, so I might be overlooking some reason this is a bad idea. (One reason that comes to mind is that velocity is now a little white lie while underwater, so anything relying on velocity for interesting effects might be thrown off. Or maybe that’s correct, because velocity thresholds should be halved underwater too? Hm!) Notably, air is also a fluid, so it should behave the same way (just with different constants). I definitely don’t think any games apply air drag that’s proportional to the square of velocity. ### Friction Friction is, in my experience, a little handwaved. Probably because real-world friction is so darn complicated. Consider that in the real world, we want very high friction on the surfaces we walk on — shoes and tires are explicitly designed to increase it, even. We move by bracing a back foot against the ground and using that to push ourselves forward, so we want the ground to resist our push as much as possible. In a game world, we are a box. We move by being pushed by some invisible outside force, so if the friction between ourselves and the ground is too high, we won’t be able to move at all! That’s complete nonsense physically, but it turns out to be handy in some cases — for example, highish friction can simulate walking through deep mud, which should be difficult due to fluid drag and low friction. But the best-known example of the fakeness of game friction is video game ice. Walking on real-world ice is difficult because the low friction means low grip; your feet are likely to slip out from under you, and you’ll simply fall down and have trouble moving at all. In a video game, you can’t fall down, so you have the opposite experience: you spend most of your time sliding around uncontrollably. Yet ice is so common in video games (and perhaps so uncommon in places I’ve lived) that I, at least, had never really thought about this disparity until an hour or so ago. ### Game friction vs real-world friction Real-world friction is a force. It’s the normal force (which is the force exerted by the object on the surface) times some constant that depends on how the two materials interact. Force is mass times acceleration, and platformers often ignore mass, so friction ought to be an acceleration — applied against the object’s movement, but never enough to push it backwards. I haven’t made any games where variable friction plays a significant role, but my gut instinct is that low friction should mean the player accelerates more slowly but has a higher max speed, and high friction should mean the opposite. I see from my own source code that I didn’t even do what I just said, so let’s defer to some better-made and well-documented games: Sonic and Doom. In Sonic, friction is a fixed value subtracted from the player’s velocity (regardless of direction) each tic. Sonic has a fixed framerate, so the units are really pixels per tic squared (i.e. acceleration), multiplied by an implicit 1 tic per tic. So far, so good. But Sonic’s friction only applies if the player isn’t pressing or . Hang on, that isn’t friction at all; that’s just deceleration! That’s equivalent to jogging to a stop. If friction were lower, Sonic would take longer to stop, but otherwise this is only tangentially related to friction. (In fairness, this approach would decently emulate friction for non-conscious sliding objects, which are never going to be pressing movement buttons. Also, we don’t have the Sonic source code, and the name “friction” is a fan invention; the Sonic Physics Guide already uses “deceleration” to describe the player’s acceleration when turning around.) Okay, let’s try Doom. In Doom, the default friction is 90.625%. Hang on, what? Yes, in Doom, friction is a multiplier applied every tic. Doom runs at 35 tics per second, so this is a multiplier of 0.032 per second. Yikes! This isn’t anything remotely like real friction, but it’s much easier to implement. With friction as acceleration, the game has to know both the direction of movement (so it can apply friction in the opposite direction) and the magnitude (so it doesn’t overshoot and launch the object in the other direction). That means taking a semi-costly square root and also writing extra code to cap the amount of friction. With a multiplier, neither is necessary; just multiply the whole velocity vector and you’re done. There are some downsides. One is that objects will never actually stop, since multiplying by 3% repeatedly will never produce a result of zero — though eventually the speed will become small enough to either slip below a “minimum speed” threshold or simply no longer fit in a float representation. Another is that the units are fairly meaningless: with Doom’s default friction of 90.625%, about how long does it take for the player to stop? I have no idea, partly because “stop” is ambiguous here! If friction were an acceleration, I could divide it into the player’s max speed to get a time. All that aside, what are the actual effects of changing Doom’s friction? What an excellent question that’s surprisingly tricky to answer. (Note that friction can’t be changed in original Doom, only in the Boom port and its derivatives.) Here’s what I’ve pieced together. Doom’s “friction” is really two values. “Friction” itself is a multiplier applied to moving objects on every tic, but there’s also a move factor which defaults to $$\frac{1}{32} = 0.03125$$ and is derived from friction for custom values. Every tic, the player’s velocity is multiplied by friction, and then increased by their speed times the move factor. $$v(n) = v(n – 1) \times friction + speed \times move factor$$ Eventually, the reduction from friction will balance out the speed boost. That happens when $$v(n) = v(n – 1)$$, so we can rearrange it to find the player’s effective max speed: $$v = v \times friction + speed \times move factor \\ v – v \times friction = speed \times move factor \\ v = speed \times \frac{move factor}{1 – friction}$$ For vanilla Doom’s move factor of 0.03125 and friction of 0.90625, that becomes: $$v = speed \times \frac{\frac{1}{32}}{1 – \frac{29}{32}} = speed \times \frac{\frac{1}{32}}{\frac{3}{32}} = \frac{1}{3} \times speed$$ Curiously, “speed” is three times the maximum speed an actor can actually move. Doomguy’s run speed is 50, so in practice he moves a third of that, or 16⅔ units per tic. (Of course, this isn’t counting SR40, a bug that lets Doomguy run ~40% faster than intended diagonally.) So now, what if you change friction? Even more curiously, the move factor is calculated completely differently depending on whether friction is higher or lower than the default Doom amount: $$move factor = \begin{cases} \frac{133 – 128 \times friction}{544} &≈ 0.244 – 0.235 \times friction & \text{ if } friction \ge \frac{29}{32} \\ \frac{81920 \times friction – 70145}{1048576} &≈ 0.078 \times friction – 0.067 & \text{ otherwise } \end{cases}$$ That’s pretty weird? Complicating things further is that low friction (which means muddy terrain, remember) has an extra multiplier on its move factor, depending on how fast you’re already going — the idea is apparently that you have a hard time getting going, but it gets easier as you find your footing. The extra multiplier maxes out at 8, which makes the two halves of that function meet at the vanilla Doom value. That very top point corresponds to the move factor from the original game. So no matter what you do to friction, the move factor becomes lower. At 0.85 and change, you can no longer move at all; below that, you move backwards. From the formula above, it’s easy to see what changes to friction and move factor will do to Doomguy’s stable velocity. Move factor is in the numerator, so increasing it will increase stable velocity — but it can’t increase, so stable velocity can only ever decrease. Friction is in the denominator, but it’s subtracted from 1, so increasing friction will make the denominator a smaller value less than 1, i.e. increase stable velocity. Combined, we get this relationship between friction and stable velocity. As friction approaches 1, stable velocity grows without bound. This makes sense, given the definition of $$v(n)$$ — if friction is 1, the velocity from the previous tic isn’t reduced at all, so we just keep accelerating freely. All of this is why I’m wary of using multipliers. Anyway, this leaves me with one last question about the effects of Doom’s friction: how long does it take to reach stable velocity? Barring precision errors, we’ll never truly reach stable velocity, but let’s say within 5%. First we need a closed formula for the velocity after some number of tics. This is a simple recurrence relation, and you can write a few terms out yourself if you want to be sure this is right. $$v(n) = v_0 \times friction^n + speed \times move factor \times \frac{friction^n – 1}{friction – 1}$$ Our initial velocity is zero, so the first term disappears. Set this equal to the stable formula and solve for n: $$speed \times move factor \times \frac{friction^n – 1}{friction – 1} = (1 – 5\%) \times speed \times \frac{move factor}{1 – friction} \\ friction^n – 1 = -(1 – 5\%) \\ n = \frac{\ln 5\%}{\ln friction}$$ Speed” and move factor disappear entirely, which makes sense, and this is purely a function of friction (and how close we want to get). For vanilla Doom, that comes out to 30.4, which is a little less than a second. For other values of friction: As friction increases (which in Doom terms means the surface is more slippery), it takes longer and longer to reach stable speed, which is in turn greater and greater. For lesser friction (i.e. mud), stable speed is lower, but reached fairly quickly. (Of course, the extra “getting going” multiplier while in mud adds some extra time here, but including that in the graph is a bit more complicated.) I think this matches with my instincts above. How fascinating! What’s that? This is way too much math and you hate it? Then don’t use multipliers in game physics. ## Uh That was a hell of a diversion! I guess the goofiest stuff in basic game physics is really just about mapping player controls to in-game actions like jumping and deceleration; the rest consists of hacks to compensate for representing everything as a box. # The disclosure on the processor bugs Post Syndicated from corbet original https://lwn.net/Articles/742744/rss The rumored bugs in Intel (and beyond) processors have now been disclosed: they are called Meltdown and Spectre , and have the requisite cute logos. Stay tuned for more. See also: this Project Zero blog post. “Variants of this issue are known to affect many modern processors, including certain processors by Intel, AMD and ARM. For a few Intel and AMD CPU models, we have exploits that work against real software. We reported this issue to Intel, AMD and ARM on 2017-06-01. See also: this Google blog posting on how it affects users of Google products in particular. “[Android] devices with the latest security update are protected. Furthermore, we are unaware of any successful reproduction of this vulnerability that would allow unauthorized information disclosure on ARM-based Android devices. Supported Nexus and Pixel devices with the latest security update are protected. # HackSpace magazine 2: 3D printing and cheese making Post Syndicated from Andrew Gregory original https://www.raspberrypi.org/blog/hackspace-magazine-issue-2/ After an incredible response to our first issue of HackSpace magazine last month, we’re excited to announce today’s release of issue 2, complete with cheese making, digital braille, and…a crochet Cthulhu? ### Your spaces This issue, we visit Swansea Hackspace to learn how to crochet, we hear about the superb things that Birmingham’s fizzPOP maker space is doing, and we’re extremely impressed by the advances in braille reader technology that are coming out of Bristol Hackspace. People are amazing. ### Your projects We’ve also collected page upon page of projects for you to try your hand at. Fancy an introduction to laser cutting? A homemade sine wave stylophone? Or how about our first foray into Adafruit’s NeoPixels, adding blinkenlights to a pair of snowboarding goggles? And (much) older technology gets a look in too, including a tutorial showing you how to make a knife in your own cheap and cheerful backyard forge. As always, issue 2 of HackSpace magazine is available as a free PDF download, but we’ll also be publishing online versions of selected articles for easier browsing, so be sure to follow us on Facebook and Twitter. And, of course, we want to hear your thoughts – contact us to let us know what you like and what else you’d like to see, or just to demand that we feature your project, interest or current curiosity in the next issue. ### Get your copy You can grab issue 2 of HackSpace magazine right now from WHSmith, Tesco, Sainsbury’s, and independent newsagents. If you live in the US, check out your local Barnes & Noble, Fry’s, or Micro Center next week. We’re also shipping to stores in Australia, Hong Kong, Canada, Singapore, Belgium, and Brazil, so be sure to ask your local newsagent whether they’ll be getting HackSpace magazine. Alternatively, you can get the new issue online from our store, or digitally via our Android or iOS apps. And don’t forget, as with all our publications, a free PDF of HackSpace magazine is available from release day. That’s it from us for this year; see you in 2018 for a ton of new things to make and do! The post HackSpace magazine 2: 3D printing and cheese making appeared first on Raspberry Pi. # Weekly roundup: Invinco Beat Post Syndicated from Eevee original https://eev.ee/dev/2017/12/18/weekly-roundup-invinco-beat/ I’ve been a bit all over the place! And I’m starting to go nocturnal again, oh no. • art: I started drawing a header image for my itch.io page, which for a year now has been barren, save for a promise that I would soon make it unbarren. I accidentally spent a good chunk of time toodling around with 3D modelling again, this time trying to aim for low-poly with pixel art textures. I tried a couple things, but the biggest success by far was Star Anise. • anise!!: Still not done, but asymptotically approaching done. Most of the time has been going towards the map, which has been rearchitectued several times, and which is bigger and more complicated than anything we’ve done before. Also did some regular old mechanical stuff, like doors and whatnot. • misc: I had MegaZeux on the brain and wanted to try out the Web Audio API, so on a total whim I wrote a little player for MegaZeux’s SFX strings. • ???: Ah! Not ready to talk about this one yet. # All the lights, all of the twinkly lights Post Syndicated from Alex Bate original https://www.raspberrypi.org/blog/all-of-the-lights/ Twinkly lights are to Christmas what pumpkins are to Halloween. And when you add a Raspberry Pi to your light show, the result instantly goes from “Meh, yeah.” to “OMG, wow!” Here are some cool light-based Christmas projects to inspire you this weekend. ## App-based light control #### Christmas Tree Lights Demo Project Code – https://github.com/eidolonFIRE/Christmas-Lights Raspberry Pi A+ ws2812b – https://smile.amazon.com/gp/product/B01H04YAIQ/ref=od_aui_detailpages00?ie=UTF8&psc=1 200w 5V supply – https://smile.amazon.com/gp/product/B01LZRIWZD/ref=od_aui_detailpages01?ie=UTF8&psc=1 In his Christmas lights project, Caleb Johnson uses an app as a control panel to switch between predefined displays. The full code is available on his GitHub, and it connects a Raspberry Pi A+ to a strip of programmable LEDs that change their pattern at the touch of a phone screen. What’s great about this project, aside from the simplicity of its design, is the scope for extending it. Why not share the app with friends and family, allowing them to control your lights remotely? Or link the lights to social media so they are triggered by a specific hashtag, like in Alex Ellis’ #cheerlights project below. ## Worldwide holiday #cheerlights #### Holiday lights hack – 1$ Snowman + Raspberry Pi

Here we have a smart holiday light which will only run when it detects your presence in the room through a passive infrared PIR sensor. I’ve used hot glue for the fixings and an 8-LED NeoPixel strip connected to port 18.

Cheerlights, an online service created by Hans Scharler, allows makers to incorporate hashtag-controlled lighting into the projects. By tweeting the hashtag #cheerlights, followed by a colour, you can control a network of lights so that they are all displaying the same colour.

For his holiday light hack using Cheerlights, Alex incorporated the Pimoroni Blinkt! and a collection of cheap Christmas decorations to create cute light-up ornaments for the festive season.

To make your own, check out Alex’s blog post, and head to your local £1/\$1 store for hackable decor. You could even link your Christmas tree and the trees of your family, syncing them all in one glorious, Santa-pleasing spectacular.

## Outdoor decorations

#### DIY musical Xmas lights for beginners with raspberry pi

With just a few bucks of extra material, I walk you through converting your regular Christmas lights into a whole-house light show. The goal here is to go from scratch. Although this guide is intended for people who don’t know how to use linux at all and those who do alike, the focus is for people for whom linux and the raspberry pi are a complete mystery.

Looking to outdo your neighbours with your Christmas light show this year? YouTuber Makin’Things has created a beginners guide to setting up a Raspberry Pi–based musical light show for your facade, complete with information on soldering, wiring, and coding.

Once you’ve wrapped your house in metres and metres of lights and boosted your speakers so they can be heard for miles around, why not incorporate #cheerlights to make your outdoor decor interactive?

Still not enough? How about controlling your lights using a drum kit? Christian Kratky’s MIDI-Based Christmas Lights Animation system (or as I like to call it, House Rock) does exactly that.

#### Eye Of The Tiger (MIDI based christmas lights animation system prototype)

Project documentation and source code: https://www.hackster.io/cyborg-titanium-14/light-pi-1c88b0 The song is taken from: https://www.youtube.com/watch?v=G6r1dAire0Y

## Any more?

We know these projects are just the tip of the iceberg when it comes to the Raspberry Pi–powered Christmas projects out there, and as always, we’d love you to share yours with us. So post a link in the comments below, or tag us on social media when posting your build photos, videos, and/or blog links. ‘Tis the season for sharing after all.

The post All the lights, all of the twinkly lights appeared first on Raspberry Pi.

# E-Mail Tracking

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2017/12/e-mail_tracking_1.html

Good article on the history and practice of e-mail tracking:

The tech is pretty simple. Tracking clients embed a line of code in the body of an email­ — usually in a 1×1 pixel image, so tiny it’s invisible, but also in elements like hyperlinks and custom fonts. When a recipient opens the email, the tracking client recognizes that pixel has been downloaded, as well as where and on what device. Newsletter services, marketers, and advertisers have used the technique for years, to collect data about their open rates; major tech companies like Facebook and Twitter followed suit in their ongoing quest to profile and predict our behavior online.

But lately, a surprising­ — and growing­ — number of tracked emails are being sent not from corporations, but acquaintances. “We have been in touch with users that were tracked by their spouses, business partners, competitors,” says Florian Seroussi, the founder of OMC. “It’s the wild, wild west out there.”

According to OMC’s data, a full 19 percent of all “conversational” email is now tracked. That’s one in five of the emails you get from your friends. And you probably never noticed.

I admit it’s enticing. I would very much like the statistics that adding trackers to Crypto-Gram would give me. But I still don’t do it.

# Roguelike Simulator

Post Syndicated from Eevee original https://eev.ee/release/2017/12/09/roguelike-simulator/

On a recent game night, glip and I stumbled upon bitsy — a tiny game maker for “games where you can walk around and talk to people and be somewhere.” It’s enough of a genre to have become a top tag on itch, so we flicked through a couple games.

What we found were tiny windows into numerous little worlds, ill-defined yet crisply rendered in chunky two-colored pixels. Indeed, all you can do is walk around and talk to people and be somewhere, but the somewheres are strangely captivating. My favorite was the last days of our castle, with a day on the town in a close second (though it cheated and extended the engine a bit), but there are several hundred of these tiny windows available. Just single, short, minimal, interactive glimpses of an idea.

I’ve been wanting to do more of that, so I gave it a shot today. The result is Roguelike Simulator, a game that condenses the NetHack experience into about ninety seconds.

Constraints breed creativity, and bitsy is practically made of constraints — the only place you can even make any decisions at all is within dialogue trees. There are only three ways to alter the world: the player can step on an ending tile to end the game, step on an exit tile to instantly teleport to a tile on another map (or not), or pick up an item. That’s it. You can’t even implement keys; the best you can do is make an annoying maze of identical rooms, then have an NPC tell you the solution.

In retrospect, a roguelike — a genre practically defined by its randomness — may have been a poor choice.

I had a lot of fun faking it, though, and it worked well enough to fool at least one person for a few minutes! Some choice hacks follow. Probably play the game a couple times before reading them?

• Each floor reveals itself, of course, by teleporting you between maps with different chunks of the floor visible. I originally intended for this to be much more elaborate, but it turns out to be a huge pain to juggle multiple copies of the same floor layout.

• Endings can’t be changed or randomized; even the text is static. I still managed to implement multiple variants on the “ascend” ending! See if you can guess how. (It’s not that hard.)

• There are no Boolean operators, but there are arithmetic operators, so in one place I check whether you have both of two items by multiplying together how many of each you have.

• Monsters you “defeat” are actually just items you pick up. They’re both drawn in the same color, and you can’t see your inventory, so you can’t tell the difference.

Probably the best part was writing the text, which is all completely ridiculous. I really enjoy writing a lot of quips — which I guess is why I like Twitter — and I’m happy to see they’ve made people laugh!

I think this has been a success! It’s definitely made me more confident about making smaller things — and about taking the first idea I have and just running with it. I’m going to keep an eye out for other micro game engines to play with, too.

# Eevee mugshot set for Doom

Post Syndicated from Eevee original https://eev.ee/release/2017/11/23/eevee-mugshot-set-for-doom/

A full replacement of Doomguy’s vast array of 42 expressions.

You can get it yourself if you want to play Doom as me, for some reason? It does nothing but replace a few sprites, so it works with any Doom flavor (including vanilla) on 1, 2, or Final. Just run Doom with -file eeveemug.wad. With GZDoom, you can load it automatically.

I don’t entirely know why I did this. I drew the first one on a whim, then realized there was nothing really stopping me from making a full set, so I spent a day doing that.

The funny thing is that I usually play Doom with ZDoom’s “alternate” HUD. It’s a full-screen overlay rather than a huge bar, and — crucially — it does not show the mugshot. It can’t even be configured to show the mugshot. As far as I’m aware, it can’t even be modded to show the mugshot. So I have to play with the OG status bar if I want to actually use the thing I made.

I’m pretty happy with the results overall! I think I did a decent job emulating the Doom “surreal grit” style. I did the shading with Aseprite‘s shading mode — instead of laying down a solid color, it shifts pixels along a ramp of colors you select every time you draw over them. Doom’s palette has a lot of browns, so I made a ramp out of all of them and kept going over furry areas, nudging pixels into being lighter or darker, until I liked the texture. It was a lot like making a texture in a sketch with a lot of scratchy pencil strokes.

I also gleaned some interesting things about smoothness and how the eye interprets contours? I tried to explain this on Twitter and had a hell of a time putting it into words, but the short version is that it’s amazing to see the difference a single misplaced pixel can make, especially as you slide that pixel between dark and light.

Speaking of which, Doom’s palette is incredibly weird to work with. Thank goodness Eevees are brown! The game does have to draw arbitrary levels of darkness all with the same palette, which partly explains the number of dark colors and gradients — but I believe a number of the colors are exact duplicates, so close they might as well be duplicates, or completely unused in stock Doom assets. I guess they had no reason to optimize for people trying to add arbitrary art to the game 25 years later, though. (And nowadays, GZDoom includes a truecolor software renderer, so the palette is becoming less and less important.)

I originally wanted the god mode sprite to be a Sylveon, but Sylveon is made of pink and azure and blurple, and I don’t think I could’ve pulled it off with this set of colors. I even struggled with the color of the mane a bit — I usually color it with pretty pale colors, but Doom only has a couple of those, and they’re very saturated. I ended up using a lot more dark yellows than I would normally, and thankfully it worked out pretty well.

The most significant change I made between the original sprite and the final set was the eye color:

(This is STFST20, a frame from the default three-frame “glacing around” animation that plays when the player has between 40 and 59 health. Doom Wiki has a whole article on the mugshot if you’re interested.)

The blue eyes in my original just do not work at all. The Doom palette doesn’t have a lot of subtle colors, and its blues in particular are incredibly bad. In the end, I made the eyes basically black, though with a couple pixels of very dark blue in them.

After I decided to make the full set, I started by making a neutral and completely healthy front pose, then derived the others from that (with a very complicated system of layers). You can see some of the side effects of that here: the face doesn’t actually turn when glancing around, because hoo boy that would’ve been a lot of work, and so the cheek fluff is visible on both sides.

I also notice that there are two columns of identical pixels in each eye! I fixed that in the glance to the right, but must’ve forgotten about it here. Oh, well; I didn’t even notice until I zoomed in just now.

The original sprites might not be quite aligned correctly in the above image. The available space in the status bar is 35×31, of which a couple pixels go to an inset border, leaving 33×30. I drew all of my sprites at that size, but the originals are all cropped and have varying offsets (part of the Doom sprite format). I extremely can’t be assed to check all of those offsets for over a dozen sprites, so I just told ImageMagick to center them. (I only notice right now that some of the original sprites are even a full 31 pixels tall and draw over the top border that I was so careful to stay out of!)

Anyway, this is a representative sample of the Doom mugshot poses.

The top row shows all eight frames at full health. The first three are the “idle” state, drawn when nothing else is going on; the sprite usually faces forwards, but glances around every so often at random. The forward-facing sprite is the one I finalized first.

I tried to take a lot of cues from the original sprite, seeing as I wanted to match the style. I’d never tried drawing a sprite with a large palette and a small resolution before, and the first thing that struck me was Doomguy’s lips — the upper lip, lips themselves, and shadow under the lower lip are all created with only one row of pixels each. I thought that was amazing. Now I even kinda wish I’d exaggerated that effect a bit more, but I was wary of going too dark when there’s a shadow only a couple pixels away. I suppose Doomguy has the advantage of having, ah, a chin.

I did much the same for the eyebrows, which was especially necessary because Doomguy has more of a forehead than my Eevee does. I probably could’ve exaggerated those a bit more, as well! Still, I love how they came out — especially in the simple looking-around frames, where even a two-pixel eyebrow raise is almost comically smug.

The fourth frame is a wild-ass grin (even named STFEVL0), which shows for a short time after picking up a new weapon. Come to think of it, that’s a pretty rare occurrence when playing straight through one of the Doom games; you keep your weapons between levels.

The fifth through seventh are also a set. If the player takes damage, the status bar will briefly show one of these frames to indicate where the damage is coming from. You may notice that where Doomguy bravely faces the source of the pain, I drew myself wincing and recoiling away from it.

The middle frame of that set also appears while the player is firing continuously (regardless of damage), so I couldn’t really make it match the left and right ones. I like the result anyway. It was also great fun figuring out the expressions with the mouth — that’s another place where individual pixels make a huge difference.

Finally, the eighth column is the legendary “ouch” face, which appears when the player takes more than 20 damage at once. It may look completely alien to you, because vanilla Doom has a bug that only shows this face when the player gains 20 or more health while taking damage. This is vanishingly rare (though possible!), so the frame virtually never appears in vanilla Doom. Lots of source ports have fixed this bug, making the ouch face it a bit better known, but I usually play without the mugshot visible so it still looks super weird to me. I think my own spin on it is a bit less, ah, body horror?

The second row shows deterioration. It is pretty weird drawing yourself getting beaten up.

A lot of Doomguy’s deterioration is in the form of blood dripping from under his hair, which I didn’t think would translate terribly well to a character without hair. Instead, I went a little cartoony with it, adding bandages here and there. I had a little bit of a hard time with the bloodshot eyes at this resolution, which I realize as I type it is a very poor excuse when I had eyes three times bigger than Doomguy’s. I do love the drooping ears, with the possible exception of the fifth state, which I’m not sure is how that would actually look…? Oh well. I also like the bow becoming gradually unravelled, eventually falling off entirely when you die.

Oh, yes, the sixth frame there (before the gap) is actually for a dead player. Doomguy’s bleeding becomes markedly more extreme here, but again that didn’t really work for me, so I went a little sillier with it. A little. It’s still pretty weird drawing yourself dead.

That leaves only god mode, which is incredible. I love that glow. I love the faux whisker shapes it makes. I love how it fades into the background. I love that 100% pure “oh this is pretty good” smile. It all makes me want to just play Doom in god mode forever.

Now that I’ve looked closely at these sprites again, I spy a good half dozen little inconsistencies and nitpicks, which I’m going to refrain from spelling out. I did do this in only a day, and I think it came out pretty dang well considering.

Maybe I’ll try something else like this in the future. Not quite sure what, though; there aren’t many small and self-contained sets of sprites like this in Doom. Monsters are several times bigger and have a zillion different angles. Maybe some pickups, which only have one frame?

Hmm. Parting thought: I’m not quite sure where I should host this sort of one-off thing. It arguably belongs on Itch, but seems really out of place alongside entire released games. It also arguably belongs on the idgames archive, but I’m hesitant to put it there because it’s such an obscure thing of little interest to a general audience. At the moment it’s just a file I’ve uploaded to wherever on my own space, but I now have three little Doom experiments with no real permanent home.