Tips For The Pragmatic Unity Developer

In the video below I’ve presented several productivity tips / hacks for the great Unity3d developer, that cultivates his / her essential qualities (impatience laziness hubris):

 

Sources & References

The three most essential plugins are DOTween, Text Mesh Pro and Console Pro.

Jet Brains IDE for C# preview here.

The “auto-save on play” script is here, The “no more hot reload script” is here, both by the same cool guy.

The scene object enable and disable script is this:

public class TheScene : MonoBehaviour
    {
        public GameObject[] activateOnStartup, deactivateOnStartup;
        
        void Start()
        {
            foreach (GameObject go in activateOnStartup)
            {
                go.SetActive(true);
                if (go.GetComponent<CanvasGroup>() != null)
                    go.GetComponent<CanvasGroup>().alpha = 1;
            }
            foreach (GameObject go in deactivateOnStartup)
            {
                go.SetActive(false);
                if (go.GetComponent<CanvasGroup>() != null)
                    go.GetComponent<CanvasGroup>().alpha = 0;
            }
        }
    }

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A Circular Range Control for Unity UI

I needed a circular range control to be for a project using Unity UI, and there seemed not to be one built-in, I created one. I wanted it to work on both desktop and mobile (touch). In building it I found out that to make it usable it requires quite a bit of tuning. [Read more…]

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Untangling GameObject State in Unity

In this short post and video I try to discuss and clarify a few points about GameObject state in Unity with respect to game, scene and “runtime” scope. It is a bit more complex than one may understand initially, so bear with me a little.

When you start developing scenes in Unity, it won’t take long before you start asking questions like:

How can I get the same GameObject in different scenes?

Why do static properties sometimes get reset across scenes?

Why when I reload a scene I get duplicated objects which are meant to be singletons?

How can I comply with the (highly practical) principle “Make the game runnable from every scene” when I have global instances from other scenes?

Here are some answers.

Here is the full schema I refer to:

GameObject State in Unity

While MonoBehaviour’s  life-cycle is quite well documented e.g. both directly in Unity docs here and also by third parties e.g. here, how to handle GameObject’s persistence in and across scenes may be more obscure.

So here are written (partial) answers to the questions above:

How can I get the same GameObject in different scenes?
Would be probably better to reword this as “how can I persist and share data across scenes” – and there are many ways to do that :-)

Why do static properties sometimes get reset across scenes?
Only static properties which are GameObjects present in the scene will get reset (typically singletons). Other static properties will be preserved across the virtual machine.

Why when I reload a scene I get duplicated objects which are meant to be singletons?
That is because you marked those objects with DontDestroyOnLoad and created them (also) in other scenes. Create them via code (not in hierarchy) checking before their existence.

How can I comply with the (highly practical) principle “Make the game runnable from every scene” when I have global instances from other scenes?
This is best done just as explained above: create the global objects in every scene via code if they don’t already exist.

 

Unity Execution Order

Unity Execution Order – from Unity documentation.

If you are in need of learning some good patterns in software game development, a really nice book is Game Programming Patterns. Here are also 50 Tips for Working with Unity (Best Practices) which I reread from time to time, understanding progressively more and more of them (but still not all :D).

Thanks to Daniele Giardini for some feedback on the state scheme above.

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Creating Match 3 Games in Unity

How to create quickly a match 3 game in Unity? Or any kind of match game? I have been working on an original match 3 game (an applied game actually) together with Unity 2D guru Daniele Giardini and I took some notes, which I present in the video below. This is not a tutorial: I just point out some concepts you will probably need to deal with.

Consider also that this is all done with Unity 5, which by introducing 2D, sprites (and also new UI) has made it much simpler to create this kind of games. And as in all my games, its actually Unity plus Gamelogic Grids component, as in my models (and probably in games in general) grids are pervasive.

Here is the video:

I started writing my tests from GameLogic match 3 sample project. The code project is based on GameLogic’s Grids for Unity component, and I’m using as much as possible the DOTween’ component for smoothing movements and effects.

The GameLogic fellows compiled an exhaustive survey of match games, including a wonderful infographic on match game structure spectrum:

2015-09-18 16_28_08-Microsoft Edge

Subtleties of match 3 game mechanics

explodingSubtleties of game design mechanics emerge once you are creating a prototype: sequential matching, peculiarities of click / swipe matching, generative universe (no need of generational AI) … discrete / continuous matches … .

If you believe that game design is basically a formal activity, mainly to do with mechanics (which actually I believe to be too simplistic) you need to be a developer at least at some level, because in building the prototype you understand the mechanics, with all its possible variations.

References

Match Game Mechanics: An exhaustive survey.

GameLogic Match 3 sample project.

Grids for Unity GameLogic FAQ.

Match 3 game draft in Unity tutorial with full code.

You Must Build a Boat.

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Simple Behaviour Trees for your game in Javascript and C#

A little while ago I tried to understand what Behaviour Trees are about, as in a couple of games I’m developing I have sets of NPCs that I have to manage and I would like to somehow decouple their behaviour from the main game flow. Here you can find a good explanation of behaviour trees.

Sample behaviour tree

Sample behaviour tree

Got this, I searched for implementations (I wanted both Javascript and C# implementations) and I didn’t like them because of the amount of code and classes required. Then on StackOverflow I found this very simple example:

Stack Overflow simple behaviour trees

Encouraged by this,  with Matteo Bicocchi we started writing our own implementations, as I simply could not believe that the code needed to be so complex 😉 . We first wrote the Javascript implementation, and the two main points we had to deal with have been:

1. Distinguish between the tree description and the instance tree being run: you need a concrete instance as you need to be independent of “tick” speed and need to be able for each instance to find what is the current node.

2. You need to handle single node completion asynchronously e.g. if you have a “chase” node, this may take a long time to resolve.

Now we have our implementation, its very simple code and can be useful in a wide variety of game development situations – surely its not a complete solution but it works fine.

Here is a simple Js Fiddle example you can play with directly in the browser.

Fiddle with behaviour trees

and here are full sources in both Javascript and C# on GitHub. The C# code is a simple port from Javascript, surely it could be refined (branch it!). It also contains two classes making the C# example run, its made with a for Unity (extends MonoBehaviour) but the code can be used anywhere.

The code is mostly commented in the Javascript version.

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Indie Development: Have Full Versioned Backups at Zero Cost

There is a simple way to have complete backups of all your sources versions, at no cost; it’s the kind of solution a single, destructured, minimal budget indie developer may use. This without any server or complex setup: just use a couple of tricks. I suppose here you are developing on Windows.

What does not work

The simplest way one can think is simply to set up your working folder as a folder in Dropbox (or any similar service), as that syncs online you’ll be fine. For versioning, Dropbox actually does version you files.

Now this can fail disastrously, because:

1. If you want to recover work that happened yesterday before you took the wrong path in your web application using this library that does not work, or before you imported that non compatible plugin in your Unity project, you don’t need to recover just one file: you need t recover a situation, with maybe hundreds of files to be recovered and Dropbox simply does not do that: history is at single file level, not groups of files (e.g. folders).

2. Working in Dropbox continuously modifying files means a lot of syncing going on, and your IDE may not always be happy about that, you are maximizing risk of source / project corruption, and as you cannot recover whole folders, you risk losing everything.

The TortoiseSVN menu for unversioned foldersA simple way that works

What would be cool would be to work outside the syncing folder and commit to a synced versioning server. And we also would like to have complete backups of the versioning server in the form of a single file so that we also have a history of that in Dropbox. We’ll get all this.

First notice (as once pointed out to me by Daniele Giardini) that with TortoiseSVN you can create a Subversion repository just as a local folder without installing any server; so you can setup your project to commit to a local folder based Subversion repository. Just do “Create repository here”,  see here for setup details. This is the key point; the only difference with a server is that you access this local repository with urls like file:///C:/SVNRepository/.

Create that folder repository in Dropbox, and each time you commit the Subversion repository will get your files and these will be backed up online. Still you are not safe, as any little file that gets corrupted in the Subversion repository folder will break all your versions, and as Dropbox keeps only the history of single files, you will have no way to recover a coherent working repository of all your versions. For that, just schedule a daily Windows job to zip and backup your repository as a zip file in your Dropbox. From that file you can recover all your versions. Done Sorriso

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A podcast & sources for (romantic) game polish and feel – DAG pod 22

In this podcast Daniele Giardini and Pietro Polsinelli (myself) discuss the notions of game polish and feel.

Here is the podcast:

There is also a video of the podcast here:

References

Game Feel: the book.

The game Goscurry.

football drama prototype

The Football Drama site.

DOTween

DOTween tweening component site. Easings http://easings.net/en.

Finally, Vlambeer talk on game feel.

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Making a sport game in Unity: model & prototype

I just published a video where I describe how to start modelling and developing a sport game, specifically football (soccer) in my case:

In the following notes some motivation for the work and references from the video.

What am I trying to do?

I am creating a game on football (not American Football), called Football Drama: this game is supposedly the story of the coach in the context of a Football Manager like game. The latest version of Football Manager for smartphones has a cool game play:

FM 15 on smartphone

One of the first thing I did in Unity is search for a plugin that would handle the match play part. Given the number of plugins available in the Asset Store and the popularity of football, I was pretty sure that my only problem would be picking the best plugin. Wrong.

I didn’t want to do thisimage

The only decent looking component I found is Soccer Project by “Astute Games”, which is ok but actually does nothing useful in my perspective, as it provides passive 3D models of players and little more.

The are simply no plugins covering modelling, movement and AI for football games in the Asset Store.

Maybe because “The barrier of entry on making a decent team sports game is really high.”, as they say in one of the few discussion of the theme indie & sports available online.

The Simple Soccer examplehttp://ecx.images-amazon.com/images/I/51jAoX1id6L.jpg

In chapter 4 of the book Programming Game AI by Example the author provides a nice implementation of a simple soccer game.

I’ve downloaded the Java sources and made the sample run in my IDE.

simpleSoccer

Here are some of the Java classes of this example:

image

Movements are regulated by physics:

image

Complete Java source code is here.

Not what I want for a sport game

This material is useful but what it is modelling is not football. seems more snooker to me Sorriso. I want a simple grid with squares as players and a state handling framework, where the (hierarchical) state machine can easily be extended. Movement is not determined by physics – the right metaphor is not snooker.

If you actually watch a football game, its a highly fractioned game of control and tactics, my reference for this development has been Cameroon vs. England (World Cup 1990):

Physics plays a role on long shots, but I will model that using tweening (the wonderful DOTween library by Daniele Giardini). I will call the model I need Football Grid.

Football Grid: The model

imageThe example is also using heavily inheritance to model all aspects of play. I instead will be happily mixing inheritance and composition, reducing inheritance to a minimum and modelling state with classes only when strictly necessary. A great book to learn about basic game programming patterns, if you are new to the topic is Game Programming Patterns.

The three states of game play: paused, preparing play, in play: this is simply an enum.

I used object hierarchy and modelling of states with class instances only when it is strictly useful, so e.g. in the case of a player state.

Here are the classes of my model:

image

2015-04-05 16_11_46-UnityVS.footballDrama - Microsoft Visual Studio

2015-04-05 16_20_15-UnityVS.footballDrama - Microsoft Visual Studio

Curve ball effects

2015-04-05 16_29_08-PowerPoint Slide Show - [MasterSlides.ppt [Compatibility Mode]]

To get these effects you can simply tween (I use DOTween) the ball differently along the X and Y axis:

DOTween curse transform

More?

Follow me on Twitter – I study game design, development (2D), applied games, and I post about progress on Football Drama.

Football Drama game design

Unity components used

DOTween tweening component

Game Logic Grids http://gamelogic.co.za/grids/

DOTween http://dotween.demigiant.com/

Thank you!

Image references

“Association football 4-4-2 formation” by MaxDZ8, based on work from Mario Ortegon – self-made, original file from Mario Ortegon. Licensed under CC BY 2.5 via Wikimedia Commons – http://commons.wikimedia.org/wiki/File:Association_football_4-4-2_formation.svg#/media/File:Association_football_4-4-2_formation.svg

“Association football 4-3-3 formation” by Threner. Licensed under CC BY-SA 3.0 via Wikimedia Commons – http://commons.wikimedia.org/wiki/File:Association_football_4-3-3_formation.svg#/media/File:Association_football_4-3-3_formation.svg

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Unity3d: Using A* and grids for entering a football field

Just played with the A* algorithm and a grid to make players enter a field and assume the initial 4-4-2 classical formation. Notice there are dumb and smart teams A bocca aperta [Read more…]

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Unity3d: Giving runtime prefab instances meaningful names

This is a short note about a minor issue you may meet in Unity3d when you are creating scene objects in code, say from prefabs.

In my case I am creating a soccer field borders on the base of a grid that may resize, so I want to create everything in code.

Unity3d object instance with meaningless nameI am as always giving meaningful names to variables (and you should too) and so it would be nice to get the instance to be named as the variable, without duplications and without – oh horror – writing the instance name as string, breaking code esthetic and refactorings. In the pic on the side you see what you get by default – not cool.

Actually in the rich and hackable C# universe as managed in current Unity3d this is possible: just this way:

image

Thanks to this post here. I used it this way:

image

imagegetting good names on the instances Sorriso

 

Note that this relies on unspecified behaviour and while it does work in Microsoft’s current C# and VB compilers, and in Mono’s C# compiler, there’s no guarantee that this won’t stop working in future versions. See the discussions here:

Getting names of local variables (and parameters) at run-time through lambda expressions

Finding the Variable Name passed to a Function in C#

Update: It seems like this might no longer be an issue from C# 6, which will introduce the nameof operator to address such scenarios.

If you have suggestions on how to automate getting good instance names at runtime (maybe with cleaner / lesser code) let me know!

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