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Category: Technical

Two kinds of Randomness

Two kinds of Randomness

Game development is now as much art as science, or rather the art of science. Even something as simple as how and when to use randomness can profoundly impact the fun of a game. Enter the observation of two different kinds of randomness: input and output randomness.

Input randomness is randomness that is decided BEFORE a player makes their strategy and decisions. Examples would include having a random number of enemies generated before the fight starts. While the number is random, knowing how many will show up actually lets the user decide to use different strategies and feel more in control.

Output randomness is often a big contributing factor to frustrating parts of gameplay. Examples here would consist of attacking an enemy, only to find out your attack completely missed out of sheer bad luck or an usually bad hit roll. This kind of behavior, while mathematically correct, often leaves users feeling like they were ‘robbed’ and that the game is cheating.

Games are increasingly using input randomness as a way to give users control. Even games that rely on output randomness often put their thumbs on the scales so that you do not lose as often as you’d like. In Civilization, if your unit with a 33% chance of hitting misses twice in a row, it’s guaranteed to hit on the 3rd try – even though real randomness wouldn’t behave like that.

Anyway, this is a great video about the different kinds of randomness.

Using a Neural Net as compression for character animation

Using a Neural Net as compression for character animation

This was published in 2018, but it’s a fascinating dual purpose use of neural nets. Firstly, there was a massively increasing issue with character animation. Character animation is quickly becoming highly complex as it has becoming more realistic. The problem compounds when you want to make sure you can do things like crouch and aim at the same time. Or crouch and walk across uneven terrain while looking left or right. You can imagine all the different kinds of combinations of motion that must be described and handled. This all started taking massively more time to develop by artists; but even worse it was taking up more and more storage space on disk and especially in memory space.

Daniel Holden of Ubisoft wondered if he could use a neural net to not only reduce the combinations they had to handle into a net but also utilize the inherent nature of neural nets to compress data. It turns out he could – and he presents what he found in this excellent presentation.

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Really useful caustics

Really useful caustics

With the right set of curvatures, it’s possible to make a clear object project an image that’s not visible until light shines through it. Science educator Steve Mould explains the optical and mathematical properties of these uniquely engineered lenses. It turns out the problem has a lot to do with moving the minimal amount of dirt to build a structure and was studied extensively by mathematicians who called it optimal transport. These transport theory problems have a number of solutions and applications.

A similar effect can be created with mirrors and reflected light. Rayform specializes in the technique for a wide variety of luxury and architectural items.

Wavelet introduction

Wavelet introduction

Artem Kirsanov normally talks about neuroscience, but in the process also made a great introductory video on wavelets. Wavelets let you find structures which are present in a complex signal but often hidden behind the noise. Since wavelets can perform decomposition in both time and frequency domains it makes them tremendously valuable tools.

Major Valve Asset leak

Major Valve Asset leak

It appears someone has leaked a massive Valve asset repository. This is probably the biggest leak since the 2003 source code leak for Halflife (git). Instead of source code, this time it appears to be a massive package of used, prototype, early, and discarded assets for Team Fortress 2, Portal, Halflife, Counterstrike, and several other big Valve games.

Right now there is a big discussion going on at the VCC (Valve Cut Content) community discord server. They’re finding all kinds of crazy things in there, like prototype Counterstrike maps, female TF2 characters, and even some partially completed levels like this TF2 rocket-jump training map:

Update: It appears folks are now re-packaging the newly discovered maps:

cp_badlands_base_ik1

cp_PointBreaker:

Prevent Windows 10 from automatically upgrading you to Windows 11

Prevent Windows 10 from automatically upgrading you to Windows 11

Nobody seems to want to upgrade from Windows 10 to Windows 11. Now late 2022, only about 15% of users have upgraded or bought machines with Windows 11 – despite it being out for well over a year. Even the Steam Hardware Survey indicates a 28% install rate on some of the newest/highest end gaming systems.

There’s a whole host of gripes about Windows 11. There have been performance and compatibility issues that are not present on Windows 10. Others greatly dislike the UI changes (this is my big gripe). Still others mention being told their hardware is incompatible. However, you may, like many others, find yourself FORCED to upgrade to Windows 11 whether you want to or not. Windows has a nasty habit of pushing such upgrades without asking.

If you want to make sure you don’t get a Windows 11 upgrade but still keep getting Windows 10 updates, you can try this trick:

First, navigate to Windows Update, then hit Pause Updates on that page.

Run services.msc, find the Windows Update service and Background Intelligent Transfer Service (BITS), right click on them and pick Stop.

Next, browse to C:\Windows\SoftwareDistribution\, and delete the contents.

That is it. The two services will eventually restart on their own, and next time it checks for updates it will only get Windows 10 updates.

Edit – If you want an extra layer of assurance, run the tool InControl from GRC, this free utility changes a few Microsoft sanctioned registry keys to specify what version and feature update of Windows you want to remain on. There are also details on those registry keys for those that would rather manually configure it themselves: https://www.grc.com/incontrol.htm

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Completely isolated PC’s are vulnerable to data theft – via their switching power supplies.

Completely isolated PC’s are vulnerable to data theft – via their switching power supplies.

“Air gapping” is a security measure that involves a computer being physically isolated and incapable of connecting wirelessly or physically with other computers or network devices. It’s used in high security setups. The idea is that if the system is physically incapable of connecting to other systems or networks, it should be safe. Right?

A new attack method named COVID-bit uses electromagnetic waves from power supplies to transmit data from air-gapped systems. Using this attack, even if the computer is completely isolated and unplugged from the internet, the researchers demonstrated collecting information emanating from the device by a nearby smartphone or laptop over a distance of at least two meters – even if a wall separates the two.

Researchers created a malware program that regulates CPU load and core frequency in a particular manner to make the power supplies on air-gapped computers emanate electromagnetic radiation on a low-frequency band (0 – 48 kHz).

While the attack requires at least one instance of physical access to install the malware, such attacks have happened. Examples include the Stuxnet worm in Iran’s uranium enrichment facility at Natanz, Agent.BTZ that infected a U.S. military base, and the Remsec modular backdoor that collected information from air-gapped government networks for over five years.

Mordechai Guri explains the primary source of electromagnetic radiation in switched mode power supplies is due to their internal design and switching characteristics in the technical paper. “In the conversion from AC-DC and DC-DC, the MOSFET switching components turning on or off at specific frequencies create a square wave,” the researcher details. The electromagnetic wave can carry a payload of raw data, following a strain of eight bits that signify the beginning of the transmission.

The attack works against air gapped pc’s, laptops, and even a raspberry pi. The receiver can be as simple as a cell phone.

Definitely worth a read.

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Libby stinks, I want my Overdrive

Libby stinks, I want my Overdrive

Overdive Media pulled their app for PC Windows 10/11 in February 23, 2022. Unfortunately, their new app, Libby, doesn’t allow you to actually download and listen to the mp3’s on your Windows desktop.

I seemed to have 2 copies of the app and they do seem to still work as of Dec 2022.

Download links:

ODMediaConsoleSetup.msi version 3.6.0 – Copyright 2016 Overdrive, Inc.

ODMediaConsoleSetup.msi version 3.2.0 from software.informer

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