Entanglement

Entanglement?

Some time ago there was a game popular over there, called Entanglement:

There are a few implementations of this game under Android:

But there was no such game for iOS. And as I pursued my second M. Sc. degree, I have had a course “iOS development”, where we were learning to use Swift and iOS platform.

I decided to implement this game as my course project. In Swift. Originally the game was implemented in Swift 2 (there was no Swift 3 back those days).

And recently I decided to refactor the game a bit and update it to the most recent Swift version (which is Swift 3 at the moment of writing this post).

In this post I’ll describe some interesting decisions I made while creating this game.

libc.js: component interaction

libc.js

Recently I’ve written a post about functional programming techniques, coming into the world of front-end and the library I crafted as an experiment. That library, libc.js was highly inspired by Elm and Mithril. But it suffered two major features:

1. components were hardly able to be used in other components
2. the interaction between components was nearly impossible (or, at least, not very transparent)

What’s hidden beneath the next version of the library?

Speeding-up algorithms with SSE

Have you ever asked anyone if assembly language might be useful nowadays? So, here’s the short answer: YES. When you know how your computer works (not a processor itself, but the whole thing - memory organization, math co-processor and others), you may optimize your code while writing it. In this short article, I shall try to show you some use cases of optimizations, which you may incorporate with the usage of low-level programming.

Recently I was reading through my old posts and found out there is a gap in the article about SSE - the post did not cover some of the implementation caveats. I decided to fulfill this and re-publish a new version.

Functional web

In last couple of years the functional programming paradigm became very popular. A huge amount of libraries, tools, tutorials and blog posts appeared. Although the paradigm itself is rather old (lambda calculus was developed around 1930 and the Lisp language was introduced in 1950), its popularity blew up rapidly somewhere in 2014-2016 and that’s what is happening right now. Probably one of the most powerful influencers, giving FP (functional programming) that thrust is web development. Since Facebook introduced React, the community started incorporating many things from FP with React - including Redux and Immutable.js. But there are much more interesting things which were invented on this wave of FP popularity. One of them is Elm.

This is a story how I implemented invented yet another web framework wheel.

Clojure guards

Once I wanted to have something like a pretty “match” operator from Scala, but in Clojure. And hence there are no default options for it in Clojure out of the box, here are some alternatives I’ve found in the Internet.

Big O notation

The best big O notation explanation I’ve ever saw I’ve found on… Google Play Market! I was hanging around, looking for the suggested software and, for some reason, I’ve decided to install some educational application for programmers. And here’s what I’ve found…

Chicken in Blender

This is a chicken. This 3D model I’ve made in 3.5 hrs in Blender (with texturing).

Taking into account the fact I’ve started learning Unity 3D, I will possibly use this in the remake of my old Shoot Them! game. Like this (early preview, made with Unity 3D in ~3 hrs):

Two sides of web application. Part 3: Communication Layer

Article series

• Part 1: The Tools
• Part 2: Sketching
• Part 3: Communication Layer

Foreword

In this section we will implement the communication layer for our application. It’ll handle all the requests to/from our web server. Have no worries - we will create server application in the next section!

First resource

Let’s create a Session resource. Since we have no backend part, we should stub the data. We’ll use Angular Services. That’s easy: a service defines a function, returning, say, an object. That object will be used every time you call a service. And you may use not only objects - you may return functions, constants or literally anything from your services.

Two sides of web application. Part 2: sketching

Article series

• Part 1: The Tools
• Part 2: Sketching
• Part 3: Communication Layer

General architecture

The first thing we need to think of is how we’ll be gathering the information about users. It’s quite easy - we just need to get a request from a visitor. Of any kind - it may be a request to get an image, a file, a stylesheet or a script.

Then we’ll just parse headers from that request and save the extracted data in the database. The only problem here is: how to get unique key from each request?. We may use visitor’s IP address. It’s the easiest way.

Finishing the first scene

If you remember, we ended our coding excercises at place, where we almost created our first Newtonian body, but we did not actually have enough models.

We discussed collision shapes a bit. So let’s create one for our brand new model!

We have a nice ramp to work with. But how we can reconstruct the same shape in the terms of Newton? Newton offers a set of collision shapes for us:

• Sphere

• Box

• Cone

• Capsule

• Cylinder

• Chamfer Cylinder

• Convex Hull

• Trimesh

Obviously, not sphere, cone, capsule, nor cylinder make sense for us. We could use box shape, but then we simply ignore our inner faces (inside walls):

A bit better, but still the same situation with convex hull shape:

Generally, the way we create our Newtonian body is:

1. create collision shape
2. create blank Newtonian body
3. set body properties like collision shape, mass, inertia parameters, etc.
4. store the pointer to the graphical entity for that body in the userData property

And then Newton Game Dynamics will take your body into account when processing other objects in the NewtonWorld.