DDevelopment & Design

The experience of developing “Quak” during a hackathon.

In March 2019 we held a 2-day hackathon named “Ship IT!” in TouK. I was part of the team developing “Quak” – a 2D Liero/Soldat inspired game where players can immerse themselves into being a cute blob-like character while simultaneously laying waste to their opponent.

In this post I want to share our experience writing and designing the game, what kind of roles team members assumed and some of the technical choices we made.

Development

Working for a company that swims in JVM technologies – naturally we chose Kotlin as our development language. Our leader Rafał Golcz created a simple game engine in the ECS Model using the standard java game development library – libgdx and box2d for physics.

ECS stands for Entity Component System, and its main advantage over a standard object hierarchy (as games tend to be strongly object-oriented programs in principle) is its behavioural nature.

Instead of drowning in large inheritance trees and having potential “problems” with instantiation or making sure what kind of object goes where – we receive an elegant solution where the behaviour of every game object can be defined as a list of scripts that are attached to it. From design perspective it also allows for a more natural approach to creating specific objects (as in what properties an object has like dealing damage on impact, destruction on collision, bleeding).

Team Roles

Large gamedev companies (Blizzard, CD Project Red, Bethesda – to name a few) usually have strict roles for people working on their projects. Game directors, designers, writers, composers, testers, programmers, marketing teams, managers – all of which (except maybe for directors/managers) tend to be split between junior, senior and leads.

Developers are also often split according to their main responsibility: engine/tools development, gameplay programmers, special effect programmers. However, in smaller teams responsibilities tend to be way more relaxed. What I find really interesting is the natural emergence of similar structures during these 2 days of developing Quak.

We had a person responsible for art, another person for music and sound effects, 5 people who were actively developing various features for the game (controllers aka joystick and keyboard integration, weapons and missiles/bullets, collisions, character movement/controls, map loading, destructible terrain, blood splatter and camera shake effects).

At some point someone took the mantle of mapper and started creating the terrain you can see in the various screenshots in this article and a few others. What did wonders, in my opinion, was when one person became some sort of a Game Director and Designer’s hybrid. By making sure that everyone had a similar grasp of the direction the game was taking this person made sure that contradicting ideas and implementations didn’t emerge. I was this person.

Experience Itself

New features were “flowing in” as our leader noticed. Everything seemed to work seamlessly, every time someone wanted to push their changes to the repository they were met with the necessity of git pulling the changes which often introduced multiple new features. All of this added up made for a great passionate atmosphere, full of fast development and motivation. At some point we had outsourced testers from other projects to playtest early versions of the game as the sound of quacking echoed through the vast open-space of TouK.

Conclusions

During the project showcase Quak has been met with laughter and smirky remarks – great signs. We concluded that the game was a success – we delivered more than we thought we were capable of before the actual hackathon.

Making sure that the game is “juicy” (in gamedev slang – a game is juicy if love and care has been put into small details/finishing touches) at a relatively early stage with camera shake, visual effects like explosions or blood, sounds of duck quacking (as our bullets are all some kind of variation of TouK’s “duck” mascot) all made the game much more interesting to playtest and to develop – boosting the morale and work efficiency of the team.

Having little stand-ups every few hours to quickly discuss who is responsible for what and in which direction the game is going (what features to cut, which to implement, maybe some new ones?) as well as the aforementioned game director all made sure every member of the team knew what to do and in my opinion was the reason we managed to successfully finish the game. Quak has since then appeared at our stand during Scalar conference and was met with positive feedback.

It was an awesome experience but it wouldn’t be possible without a great team. Kudos to the entire Quak squad: Rafał Golcz, Robert Piwowarek, Agata Kłoss, Mateusz Mazur, Hubert Lipiński and Filip Majewski.

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DDevelopment & Design

Sample for lift-ng: Micro-burn 1.0.0 released

During a last few evenings in my free time I've worked on mini-application called micro-burn. The idea of it appear from work with Agile Jira in our commercial project. This is a great tool for agile projects management. It has inline tasks edition, drag & drop board, reports and many more, but it also have a few drawbacks that turn down our team motivation.

Motivation

From time to time our sprints scope is changing. It is not a big deal because we are trying to be agile :-) but Jira's burndowchart in this situation draw a peek. Because in fact that chart shows scope changes not a real burndown. It means, that chart cannot break down an x-axis if we really do more than we were planned – it always stop on at most zero.

Also for better progress monitoring we've started to split our user stories to technical tasks and estimating them. Original burndowchart doesn't show points from technical tasks. I can find motivation of this – user story almost finished isn't finished at all until user can use it. But in the other hand, if we know which tasks is problematic we can do some teamwork to move it on.

So I realize that it is a good opportunity to try some new approaches and tools.

Tools

I've started with lift framework. In the World of Single Page Applications, this framework has more than simple interface for serving REST services. It comes with awesome Comet support. Comet is a replacement for WebSockets that run on all browsers. It supports long polling and transparent fallback to short polling if limit of client connections exceed. In backend you can handle pushes in CometActor. For further reading take a look at Roundtrip promises

But lift framework is also a kind of framework of frameworks. You can handle own abstraction of CometActors and push to client javascript that shorten up your way from server to client. So it was the trigger for author of lift-ng to make a lift with Angular integration that is build on top of lift. It provides AngularActors from which you can emit/broadcast events to scope of controller. NgModelBinders that synchronize your backend model with client scope in a few lines! I've used them to send project state (all sprints and thier details) to client and notify him about scrum board changes. My actor doing all of this hard work looks pretty small:

Lift-ng also provides factories for creating of Angular services. Services could respond with futures that are transformed to Angular promises in-fly. This is all what was need to serve sprint history:

And on the client side - use of service:


In my opinion this two frameworks gives a huge boost in developing of web applications. You have the power of strongly typing with Scala, you can design your domain on Actors and all of this with simplicity of node.js – lack of json trasforming boilerplate and dynamic application reload.

DDD + Event Sourcing

I've also tried a few fresh approaches to DDD. I've organize domain objects in actors. There are SprintActors with encapsulate sprint aggregate root. Task changes are stored as events which are computed as a difference between two boards states. When it should be provided a history of sprint, next board states are computed from initial state and sequence of events. So I realize that the best way to keep this kind of event sourcing approach tested is to make random tests. This is a test doing random changes at board, calculating events and checking if initial state + events is equals to previously created state:



First look

Screenshot of first version:


If you want to look at this closer, check the source code or download ready to run fatjar on github.During a last few evenings in my free time I've worked on mini-application called micro-burn. The idea of it appear from work with Agile Jira in our commercial project. This is a great tool for agile projects management. It has inline tasks edition, drag & drop board, reports and many more, but it also have a few drawbacks that turn down our team motivation.