Author Archives: Vadym

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Haxe: Shorthand expression matching

This is a small post about a small, useful macro for Haxe.

As you may (or may not) know, Haxe has fancy enums (which are actually algebraic data types). That's nice. And you can do all sorts of fancy value matching on them, which is also nice.

What is less nice, however, is that the only conventional way to extract enum arguments is to "match" it, and thus in some situations you can only do code like this, 

var r = switch (expr) {
    case one(k): k;
    default: -1;
};

adding a couple lines of code in place of what feels like it could have been a single operator.

So I wrote a tiny macro which adds just that: 

var r = ematch(expr, some(k), k, -1);
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GameMaker: Using external version control

Over time, I have witnessed a particular scenario a few too many times:

  1. A person demonstrates complete unwillingness to learn how to use version control, be that due to "lack of need" or delightful claims of their existing approaches (which most often turn out to be manual backups) being sufficient or even superior.
  2. A person loses days, weeks, or even months of work due to human error and/or hardware failure(s).
  3. Noticeably bitter about the situation, a person attempts to continue defending their position.

Having spent far too much time arguing with people and explaining how to use version control, I have decided to make a blog post that would cover a few things on the matter:

  • Explain the advantages of version control over "simpler" backups.
  • Explain (step-by-step) the basics of using a common combination for version control being BitBucket (service) + Git (software) + SourceTree (GUI client).

While this tutorial is oriented on GameMaker: Studio users, it can also be easily applied for other tools.

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Understanding isometric grids

Isometric grid coordinate conversion demo
A GIF of the interactive demo seen later in this post.

Questions about the algorithms related to isometric grids are not uncommon. In fact, they are a little more common than you could expect them to be, given the relative simplicity of things.

So I have decided to write a little blog post on the two things important here:

  1. Converting local isometric grid' coordinates to global screen-space coordinates
  2. Converting global/screen-space coordinates to isometric grid' local coordinates
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Changing scroll speed in Firefox using CSS

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(live demo - compare scrolling speeds in Firefox)

For quite a while now, a thing that bugged me in Firefox was the inconsistent scrolling speeds across the pages. On some it would seem just fine, while on others you could have a list that scrolls at a ridiculously slow pace. My searches on the subject were inconclusive - while, of course, you can regulate the scroll speed via scripting, that definitely wasn't the case on all these pages.

The culprit, as it turns out, was pretty simple - while most of the browsers scroll the elements for an amount of (screen) pixels per key press or mouse wheel change, Firefox scrolls the elements based on the their font size. Which, on one hand, makes sense, but there's a catch - it's based only on the scrolling element's font size. Content' font sizes are ignored.

So that is why you get odd scrolling speeds - people most often set up styles for the actual content (paragraphs\labels\etc.) and not the scroller\container element.

Luckily, this also means that scrolling speeds can be adjusted easily - you change the container font-size to (100*X)%, and then add a rule to change it's child element sizes to (100/X)%:

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C#: Get current keyboard layout\input language

Get current input language on Windows with C#

On some occasions, you may want to get a "global" input language - that is, the keyboard layout used by the current foreground window\application\whatever. Basically, simulating the behaviour of the language panel on Windows.

The common use cases are on-screen keyboards, fullscreen applications, and widgets.

While I wasn't able to find a premade function that get this particular thing during my searches, it turned out not to be too hard to assemble:

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Top-down bouncing loot effects

GIF
In action

A little while ago, I was asked about what would be a good approach to creating an effect for a top-down game where coins would fly out of a smashed object. Not recalling any tutorials on the matter, I've made an example of this exact thing, and this is a post detailing everything related to such an effect.

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Adding hotkeys to switch to N-th screen on Windows

Keyboard shortcuts for switching between desktops on Windows

For quite a while, the multi-screen setup on my desktop was powered by Synergy.
Which, I should say, is pretty neat, aside of it's complete unwillingness to send non-English keystrokes to additional devices.

Slightly more recently I've switched to using a more conventional dual-screen setup.
Which, of course, is more convenient (being able to drag a window to the second screen without having to sync the related media first), one thing would seem to be missing — the "hotkeys".

Moving the mouse over an entire monitor (or two) only to click something and move it back is not all that exciting, and Synergy's keyboard shortcuts for moving the mouse to N-th screen (while remembering the old position for returning) were a welcome feature.

Windows, unfortunately, does not seem to have any "built-in" keyboard shortcuts for swithing to a given screen, but that can be easily fixed with help of an AutoIt script:

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C# + .NET: Minimalistic asynchronous UDP example

Recently I have been experimenting with networking in Unity3d.

As you may know, there are various systems to aid you with building networked applications in Unity, ranging in approaches and capabilities.

However, if you are more familiar with the regular socket APIs, or just need to port a bit of existing code, you would probably rather have a couple of simple methods to send and receive data.

So here's just that, using .NET's System.Net.Sockets.UdpClient to asynchronously receive and handle data as it arrives:

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C#: Implicit conversion from null to struct (and more)

MyStruct some = null; // some == MyStruct(...)

This is a small post about a rather specific construct in C# syntax, permitting to assign "null" to struct-typed variables (which are non-nullable) and treat this specific case as you please.

If you did not come here looking for this particular thing, you may or may not be in a dire need of the post's subject, but explanation may be of interest.

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