Tag: Programming

Using Autofac With Unity3D

Autofac With Unity

Why Consider Using Autofac With Unity3D?

I think using a dependency injection framework is really valuable when you’re building a complex application, and in my opinion, a game built in Unity is a great example of this. Using Autofac with Unity3D doesn’t need to be a special case. I wrote a primer for using Autofac, and in it I discuss reasons why it’s valuable and some of the reasons you’d consider switching to using a dependency container framework. Now it doesn’t need to be Autofac, but I love the API and the usability, so that’s my weapon of choice.

Building a game can result in many complex systems working together. Not only that, if you intend to build many games it’s a great opportunity to refactor code into different libraries for re-usability. If we’re practicing writing good code using constructor dependency passing with interfaces, then things really start to line up in favour of using a dependency injection framework.

Getting Set Up

At the end of my autofac primer article, I provided a link to the Nuget package for Autofac. You’ll notice that there’s a version dependency for .NET 4.5, so if you’re not sure how to get Unity3D working with .NET 4.5, you’ll want to check this other article of mine. It’s very simple, so don’t worry!

Unity3D, at the time of writing this and using version 2018.1.1f1, there’s no native Nuget package support. I haven’t spent too much time investigating alternatives, but not to worry. I’ll explain a quick work around. The TL;DR is that we need the binaries from the Nuget package to be loaded up by Unity3D and we’ll miss out on the Nuget-y-ness for now. Not a huge deal since we’ll still have Autofac support!

  • Start a new Visual Studio C# project
    • Ensure that the .NET framework is at least 4.5 and more specifically, the version of .NET that you’d like to use in your Unity3D project
  • Open up the Nuget package manager in Visual Studio
  • Search for Autofac online in the package manager (it should be the same one I referred to above!)
  • Add this package to your visual studio project
  • Compile this visual studio project
  • Assuming you built in debug, go to the output folder (which is in bindebug if you didn’t change anything from default)
  • In the output folder, you’ll find “Autofac.dll”
  • You’ll want to add this into your Unity3D project’s “Assets” folder
    • I like nice folder hierarchies, so I’d suggest making a subfolder inside of “Assets” called “Third Party” or “Dependencies”… Something that’s obvious for what it means
    • Drop in the Autofac.dll file into there
  • Unity3D will add a corresponding *.meta file to go along with this

Great! We’re almost there. If you want to test it out, open up a script from Unity3D. This will launch a new Visual Studio instance if you haven’t opened up one for your Unity project yet. At the very top of your file you should be able to type:

using Autofac;

And the namespace should resolve! If not, sometimes this takes Unity3D a refresh operation to regenerate the project file on disc, so if you switch to Unity3D again and it starts doing some processing, switching back to Visual Studio might resolve this.

Using Autofac With Unity3D

Up until this point, we’ve proven we can reference Autofac. I’m not going to explain all the ins and outs for how you’ll want to organize your Autofac initialization in this post, but we can walk through a quick example!

  • Pick a game object on your scene
  • Add a new C# script to it
    • Call it whatever you’d like, but make sure you know how to open it
  • … now go open it in Visual Studio ūüôā
  • We should have a method in there called Start()
    • If not, feel free to add it:
    • private void Start()
      {
        // TODO: we'll add stuff here
      }
  • Let’s use this code to make a new class that you can put inside the same script file for now:
    • public sealed class MyAutofacObject
      {
      
        public MyAutofacObject()
        {
          Debug.Log("Constructor for our object!");
        }
      
        public void DoThing()
        {
          Debug.Log("Test!");
        }
      }
  • Inside this start method, let’s try doing something VERY simple to prove Autofac works!
    • var containerBuilder = new Autofac.ContainerBuilder();
      containerBuilder.RegisterType<MyAutofacObject>().SingleInstance();
      
      var container = containerBuilder.Build()
      var instance = container.Resolve<MyAutofacObject>();
      
      instance.DoThing();

Now if we run our game, here’s what should happen:

  • The script attached to the game object should run
  • The Start() method on the script should be the first thing that goes
  • The code we added should:
    • Make a new ContainerBuilder
    • Register our MyAutofacObject type as a single instance
    • Build the container
    • Resolve an instance of our type
    • Log out a message saying it’s in the constructor
    • Log out a message that says Test!

And voila! It’s simple, but it should demonstrate that Autofac is working!

Next Steps

This is a very contrived example of using Autofac with Unity3D. It proves that the code can be run, but it doesn’t do too much that’s useful. There are going to be many considerations you’ll need to make for how you want to organize your dependencies, register your classes/interfaces, and so on.

I’ll continue to add into this Unity3D series of posts, but let me know what else you’d like to know about using Autofac with Unity3D! I’d be happy to try and answer, or even create an article to help explain.

Thanks!


Part 1 – Exploring Graphs and Trees

Graphs and Trees - Delta State Algorithm

Graphs and Trees to Start

I was chatting with my colleague about generating maps for a 2D role playing game the other day after getting super excited explaining picking ProjectXyz back up and looking into Unity3D more. He was expressing interest in algorithms for procedural generation and storing data in trees or graphs as an optimal data structure for the scenario we were going over.

It stuck with me though. I’ve been putting a lot of thought into game state management and wanting to address it by using a generic layering/stacking approach. By that, I mean that I want to find a way to take base game state, allow mods or plugins to overlay their state, allow game patches to overlay their state, and then save game data to be overlaid on top of all of that. Conceptually, I believe I can create a generic system for doing this stacking of game data, which I’ll be referring to as my Delta State Algorithm, but I’ve been struggling with a starting point.

But the trees and graph concept stuck with me because the properties of trees and graphs that my colleague was referring to seemed to line up with how I envisioned this algorithm working. A graph or a tree just might be the right structure to represent this game state and the deltas between them, so I wanted to start mocking up some ideas.

A Map is a Game Object… And so is Everything Else?

Confusing subheader? You bet. But it’s because it was an odd realization.

I’ve been re-writing the same back end for an RPG for years now. Literally, it’s probably been at least 10 years that I’ve started, progressed, and scrapped such a game. But one thing I borrowed from Unity3D development was the idea of components and component-based design. I was far too married to object hierarchies, and these would eventually result in me having to refactor a TON of code. If you couple that with the fact I wasn’t using dependency injection properly (see this little primer article), it meant my refactoring efforts got to the point where it just made sense to start over.

So I was working with loading maps from TMX or Tiled map formats, and after getting these to load I was putting some thought into how I wanted to save/load my game objects. My game objects are essentially containers of components, and the containers have no properties at all. What does that mean in practice? My Actor/NPC game object class is the exact same class as an equippable item! It’s just “GameObject”. The difference between them is the variation in the components that I attach to them. In my mind, I figured I’d need some sort of hierarchical serialization paradigm where my game object would serialize itself, then the components would serialize themselves within that process, and if I could have components with components… You get the idea. But this could sort of be represented by a tree structure.

After the discussion with my colleague about trees and graph structures for maps, I connected some dots. Really the tiles and placed objects on a map were just… game objects as well. And that means that my thought process behind hierarchical serialization aligns well with some of the properties he was referring to for maps as graphs/trees. This suggests that “world state” for a game where everything is a “GameObject” with components attached to them (where some of those components can contain other GameObjects) could be represented by a graph or tree data structure

What About Tabulated and Listed Data Sets?

So we’ve come up with a starting point for “World Data” being represented by a graph. However, if we go back to my initial goal, I want plugins/mods/patches to be able to get applied to base “Game State” data.

What’s the difference between world and game state data?

These are just my terms so I should try and clarify. The world data is the data the player sees in the playable world. It’s the status of the objects and the maps they are interacting with. Game state data is the superset of this data and all of the other lookup data for loading content into the game. So this OTHER data includes things like the possible stats players and items can have, the types of monsters that can spawn (not the instances of the spawned monsters, because that’s the world state data), the possible dialog entries, etc… This type of data is really well represented in a relational database where we can create lists of data entries.

But if we take a step back, can’t that relational database content also be represented as a graph?

Could I have:

  • A node called “Stats” as a parent to a “Life” node that is a parent to a “StatRange” node, and “LocalizedNameResource” node?
  • A node called “BaseItems” as a parent to a “Sword” node that is a parent to a “DamageRange” node, “RequiredStats” node, and “EquippableSlots” node?
  • A node called “MonsterSpawns” as a parent to a “Skeleton” node that is a parent to…

You get the idea. I generally think about this data in a relational database paradigm (and perhaps it’s much faster to edit the data this way or look it up this way). However, if I can transform this data into the same type of graph structure I want to use for world state, then it means my delta state algorithm would work on not only world state data but also ALL game state data.

So Everything in the Graph? Always?

This is an important question, and I think one that without actually explicitly thinking about was causing me some headaches and keeping me from progressing down exploring more of my delta state algorithm.

I mentioned that some of the game state data feels better represented in a relational database. It might be much faster to add/remove or look them up when the data feels like it’s just a list of records when you contrast that with a graph. But why not have multiple storage mechanisms?

The delta state algorithm serves a very important goal: Layer deltas of data on top of a base set to get a new set.

That’s it though. So once I have that final transform of data that represents the new game state, who says I can’t transform it into a different format?

Maybe the world state is still better represented as a graph. So things like maps with tiles and game objects in the world still are super efficient to work with in graph form. Maybe things like dialog entries or definitions of player stats are better represented in a relational database… I could populate a database with the necessary data based on the graph data though. And the really cool part? A save game, which is probably the delta that changes the most, probably shouldn’t have the extra game state data in it (likely just has world state deltas represented). So… if a relational database is better suited for the remaining game state data, this could get generated and cached, and then only regenerated when different mods/plugins/patches are applied!

Concluding Thoughts

To summarize some of the major thoughts discussed in this article:

  • Game objects with components can be represented by nodes in a graph just like maps with tiles on them.
  • Other game state that feels better suited for relational databases can still be transformed into nodes in a graph for working with deltas.
  • Once a final game state is calculated (based on base state + deltas for mods/plugins/patches + delta for save game), data can be transformed back into the most suitable form to work with
  • Data does NOT have to exist in only one form! We can transform it as we need to work with it more effectively.

While this article was a bit of a brain dump, this the thought process that got the ball rolling for starting to design this delta state algorithm. In my next post in this series, I want to discuss a quick look at undo/redo approaches used in applications and how they might be similar (or different) to how the delta state algorithm might work.


Dependency Injection with Autofac – A Primer

Autofac Logo

Before Autofac…

I’ve written before about IoC and dependency injection, but these are older posts and my perspective and experience with these topics has fortunately been growing. I think they’re incredibly important when you’re building complex systems, but the concepts can offer some benefits in all of your programming! When you get in the habit of practicing this kind of thing, you can get some pretty flexible code… for free.

So a quick recap on what I mean by dependency injection here… I’m mostly focused on passing interfaces into constructors (and yes, I’m going to be using C# terminology as I do in most of my programming examples, but these concepts are generally the same in other languages). The benefits here:

  • You can write implementations that don’t depend on other implementations… Just an API.
  • Not depending on an interface means you can write mockable code for your unit tests. (I’ll follow up with a post on this to help provide examples)
  • You can swap out functionality by providing a different implementation of an interface and NOT re-writing core code
    • This can be a very powerful refactoring tool
    • This can allow creation of new functionality in a system simply by adding one small class instead of re-writing code

So that’s all good and well… So what do we use Autofac for?

When you might want to take the leap to Autofac

So you’ve been writing code now using interfaces in your constructor parameters. You’ve got nice modular code using composition. You have unit tests. Things are great.

There comes a point where you decide you need to break open a class in the depths of your system and provide it a new interface as part of the constructor. This is in line with the constructor parameter passing paradigm (nice alliteration, woo!) you’ve been using, so it feels good. You modify your constructor to take the new interface parameter. You change up your method to call this new interface’s API. You update your tests. It works!

Now you need to make the rest of your application work though, and it turns out because this class is created so deep down in your system, you need to find a way to pass this new interface implementation allllllllll the way down. And suddenly, you find you need to break open 10 other classes to pass this interface into the constructor. It’s a simple change in that it’s the same change in 10 spots… But it’s 10 spots. And it’s tedious. And you got lucky because you own this code and you don’t need to worry about breaking the constructor API for other people.

But it might be time to look into something like Autofac at this point because it can make this problem disappear for you.

Enter Autofac!

Autofac is awesome. The end.

But seriously, Autofac is one example of a dependency container framework. The idea with a framework like this is that programmers can register things to the container and then at a later point these things can be resolved. So you could:

  • Decide to take a particular implementation and register it so that it can be resolved by its interface
  • Decide if you want a registration to act like a singleton (and remember, a singleton does NOT have to have global access… it just means literally a single instance)
  • Run callbacks when an instance is created
  • … and so much more

In my opinion, the two major benefits of Autofac as they relate to this example are:

  • You can better organize the top level of your application to wire up specific implementations to use in your code
  • … Autofac can magically resolve the dependencies for you so it solves that nasty problem of passing down dependencies via constructors to deep areas of your code

You’ll need to be careful that you don’t abuse the container though! It’s considered an anti-pattern to use the container to manually resolve dependencies across various areas of your application (generally this is referred to as the Service Locator (anti)Pattern, but people go back and forth on why it’s good or bad). The “proper” use case is to resolve your single entry point class in one spot, call the methods you need on your entry point class, and let Autofac do its magic to resolve all of your registered dependencies.

Where Can I Get Autofac?

This is the easy part! You can use your Nuget package manager in Visual Studio to find the right package for your .NET framework dependency. Check it out at the Nuget Gallery!

What’s Next?

I have some examples I’d like to write about next for using Autofac including:

  • Using Modules for Organizing Code Dependencies
  • Patterns for Dynamically Resolving Modules Across Assemblies
  • How to use Autofac with Unity3D

But I’d love to hear what you want to know more about! Comment and let me know, and I’ll see what I can do.


Unity3D and .NET 4.x Framework

Unity

Unity3D Default .NET Framework

I recently wrote that I wanted to start writing more Unity3D articles because I’m starting to pick up more Unity3D hobby work. It felt like a good opportunity to share some of my learnings so that anyone searching across the web might stumble upon this and get answers to the same problems I had.

Unity3D as of 2018.1.1f1 (which is the version I’m currently using), still defaults to using .NET 3.5 as the framework version. Nothing wrong with that either. I’m sure there are reasons that they have for staying at that version, probably because of Mono and cross platform reasons if I were to guess, so I’m not complaining. For reference, this setting in Unity3D is referred to as “Scripting Runtime Version”. So if you’re googling more about this later, that’s what Unity calls it. For the libraries I was building to use as a game framework, I was using .NET 4.6 and discovered I was going to have a challenge getting them working in Unity3D.

If you want to see what your setting is currently set at, you need to check out the “Player” settings. This was kind of buried in the UI for me so I didn’t know it was a thing that could be adjusted. In Unity3D¬†2018.1.1f1, click Edit->Project Settings->Player. Here’s what it looks like:

Unity3D - Player Settings

In Unity, click Edit->Project Settings->Player

From there, you’re going to get “PlayerSettings” in your Inspector tab. You’ll need to expand the “Other Settings” to see your scripting runtime version:

Unity3D - Other Settings

“Other Settings” accordion control in PlayerSettings Inspector tab

Once you expand that, here’s the setting you’re interested in:

Unity3D - Scripting Runtime Version

Scripting Runtime Version – The selected .NET version Unity will use

Switching Unity3D to .NET 4.x

Now that you know where the setting is… it’s pretty easy ūüôā

Unity3D - Scripting Runtime Version

Use the dropdown to pick which .NET framework version you’d like to use.

You can read more about this setting over at the official Unity3D documentation pages:

https://docs.unity3d.com/Manual/ScriptingRuntimeUpgrade.html

This outlines what things are affected in different platforms and scenarios so YOU SHOULD READ IT to understand what will change.

Hope that makes things a bit easier for you to get up and running with .NET 4.x assemblies in Unity3D!


Delta State Algorithm Creation Series

Delta State Algorithm

Delta State Algorithm Motivation

This post will act as the table of contents for an algorithm I’m developing for calculating deltas between state for generic sets of data.

I figured this would be an interesting series to write about so I can document my thought process, trials, errors, and successes. At the end of this I plan to share working code that implements this algorithm so that you can use it in your own work.

Now that I’ve been not diving more into Unity3D development for my hobby programming, I’m getting to a point in game development where I need to manage state for data in a way that allows patches of state to be applied in a layered fashion. A couple of examples of this include:

  • Applying save game state to a base game state
  • Applying a patch to a base game state
    • Optionally allow save game state to be applied on top of this and completely override as necessary
    • Optionally allow save game state to be applied on top of this but “retroactively patch” existing save game data

I believe that I can design an algorithm that’s relatively simple that should allow the layering to work, but I have a lot of potential corner cases to figure out (especially when considering retroactively vs not for applying game patches). I’ll be exploring data structures to use and technologies to leverage for persisting this state.

It should be pretty exciting!

Delta State Algorithm Series

Just a reminder that if you’re interested in this series, you’ll want to use this page as the starting point. As I continue to add new content to this series, I’ll come back and update this page with links to the parts of the series. Ideally at the end I’ll have some working code I can share!

  • Part 1 – Exploring Graphs and Trees (TBD)
  • Part 2 – Undo/Redo Patterns (TBD)
  • Part 3 – Generic State Serialization to a Graph (TBD)
  • Part 4 –¬†¬†… TBD

API: Top-Down? Bottom-Up? Somewhere in the Middle?

A Quick Brain-Dump on API Desgin

I’ll keep this one pretty brief as I haven’t totally nailed down my thoughts on this. I still thought it was worth a quick little post:

When you’re creating a brand new API to expose some functionality of a system, should you design it with a strong focus on how the internals work? Should you ignore how internals work and make it as easy to consume as possible? Or is there an obvious balance?

I find myself trying to answer this question without ever explicitly asking it. Any time I’m looking to extend or connect systems, this is likely to come up.

Most Recently…

Most recently I started trying to look at creating an API over AMQP to connect my game back-end to a Unity 3D front-end. I had been developing the back-end for a little while now, so I had a pretty good idea for how things needed to work from that perspective. The front-end? Not so much really. I knew some basic actions that I was considering, so I tried coding up an early API for them.

A lot of my focus was around how I was going to implement the code on the back-end to make this API work. It resulted in some of the API calls looking a little bit gross. But the idea was that if I settled on an API that would make the back-end easy to implement, I could get it up and running faster.

After a little while, I feel like my API isn’t getting any cleaner from a consumer perspective, and funny enough, it’s not actually as easy to implement as I was hoping on the back-end. Which had me reflect on a work example…

Once Upon a Time at Work…

Well, it was only a couple of months ago, really. I was working with a colleague on integrating a new system into an existing code base. We decided we wanted to approach the API problem from a consumer perspective. We said “let’s make this as easy to call and use as possible so that people ACTUALLY want to use it”.

We set out with this mission, and created a pretty simplistic API. The challenge? There was a lot of heavy lifting and a bit of voodoo going on behind the scenes. But you know what? We hid the magic in one spot of the code (instead of having ugly stuff scattered all over the code base) and it ended up being a very usable API.

So…

So does this consumer-first, top-down approach to API design always work? I’m not sure. Some similarities/differences in the scenarios:

  • In my current situation, I have a back-end implemented and very minimal code implemented on the caller side. In the work example, we had nothing implemented on the back-end, and a ton of code implemented where the caller side would be.
  • In both examples, at least one of the caller side or back-end side was reasonably well understood. For my game, the back-end was pretty well understood. For work, the caller side was pretty well understood and we had experience with what we’d call a “failed’ back-end implementation (that we were actually setting out to redesign).
  • The work example was a relatively small subset for an API, but the game example was about to be a very specific implementation that I’d need to adapt into a pattern for all messaging in my AMQP system

So there’s a few things to consider there. I think I’m at the point in my game where I’d like to revisit how I’m forming this API and try it from a client-first perspective. Now that I know some of the catches, maybe I’ll shed some new light!

How do you approach API design?


What Makes Good Code? – Should Every Class Have An Interface? Pt 1

What Makes Good Code? - Should Every Class Have An Interface?

What’s An Interface?

I mentioned in the first post of this series that I’ll likely be referring to C# in most of these posts. I think the concept of an interface in C# extends to other languages–sometimes by a different name–so the discussion here may still be applicable. Some examples in C++, Java,¬†and Python to get you going for comparisons.

From MSDN:

An interface contains definitions for a group of related functionalities that a class or a struct can implement.
By using interfaces, you can, for example, include behavior from multiple sources in a class. That capability is important in C# because the language doesn’t support multiple inheritance of classes. In addition, you must use an interface if you want to simulate inheritance for structs, because they can’t actually inherit from another struct or class.

It’s also important to note that an interface¬†decouples the definition of something from its implementation. Decoupled code is, in general, something that programmers are always after. If we refer back to the¬†points I defined for what makes good code (again, in my opinion), we can see how interfaces should help with that.

  • Extensibility: Referring to interfaces in code instead of concrete classes allows a developer to swap out the implementation easier (i.e. extend support for different data providers in your data layer). They provide a specification to be met should a developer want to extend the code base with new concrete implementations.
  • Maintainability:¬†Interfaces make refactoring an easier job (when the interface signature doesn’t have to change). A developer can get the flexibility of modifying the implementation that already exists or creating a new one provided that it meets the interface.
  • Testability: Referring to interfaces in code instead of concrete classes allows mocking frameworks to leverage mocked objects so that true unit tests are easier to write.
  • Readability: I’m neutral on this. I don’t think interfaces are overly helpful for making code more readable, but I don’t think they inherently make code harder to read.

I’m only trying to focus on¬†some of the pro’s here, and we’ll use this sub-series to explore if these hold true across the board. So… should¬†every class have a backing¬†interface?

An Example

Let’s walk through a little example. In this example, we’ll look at an object that “does stuff”, but it requires something that can do a string lookup to “do stuff” with. We’ll look at how using an interface can make this type of code extensible!

First, here is our interface that we’ll use for looking up strings:

public interface IStringLookup
{
    string GetString(string name);
}

And here is our first implementation of something that can lookup strings for us. It’ll just lookup an XML node and pull a value from it. (How it actually does this stuff isn’t really important for the example, which is why I’m glossing over it):

public sealed class XmlStringLookup : IStringLookup
{
    private readonly XmlDocument _xmlDocument;

    public XmlStringLookup(XmlDocument xmlDocument)
    {
        _xmlDocument = xmlDocument;
    }

    public string GetString(string name)
    {
        return _xmlDocument
            .GetElementsByTagName(name)
            .Cast<XmlElement>()
            .First()
            .Value;
    }
}

This will be used to plug into the rest of the code:

private static int Main(string[] args)
{
    var obj = CreateObj();
    var stringLookup = CreateStringLookup();
    
    obj.DoStuff(stringLookup);
 
    return 0;
}
 
private static IMyObject CreateObj()
{
    return new MyObject();
}
 
private static IStringLookup CreateStringLookup()
{
    return new XmlStringLookup(new XmlDocument());
}
 
public interface IMyObject
{
    void DoStuff(IStringLookup stringLookup);
}
 
public class MyObject : IMyObject
{
    public void DoStuff(IStringLookup stringLookup)
    {
        var theFancyString = stringLookup.GetString("FancyString");
        
        // TODO: do stuff with this string
    }
}

In the code snippet above, you’ll see our Main() method creating an instance of “MyObject” which is the thing that’s going to “DoStuff” with our XML string lookup. The important thing to note is that the DoStuff method takes in the interface IStringLookup that our XML class implements.

Now, XML string lookups are great, but let’s show why interfaces make this code extensible. Let’s swap out an XML lookup for an overly simplified CSV string lookup! Here’s the implementation:

public sealed class CsvStringLookup : IStringLookup
{
    private readonly StreamReader _reader;
 
    public CsvStringLookup(StreamReader reader)
    {
        _reader = reader;
    }
 
    public string GetString(string name)
    {
        string line;
        while ((line = _reader.ReadLine()) != null)
        {
            var split = line.Split(',');
            if (split[0] != name)
            {
                continue;
            }
 
            return split[1];
        }
 
        throw new InvalidOperationException("Not found.");
    }
}

Now to leverage this class, we only need to modify ONE line of code from the original posting! Just modify CreateStringLookup() to be:

private static IStringLookup CreateStringLookup()
{
    return new CsvStringLookup(new StreamReader(File.OpenRead(@"pathtosomefile.txt")));
}

And voila! We’ve been able to extend our code to use a COMPLETELY different implementation of a string lookup with relatively no code change. You could make the argument that if you needed to modify the implementation for a buggy class that as long as you were adhering to the interface, you wouldn’t need to modify much surrounding code (just like this example). This would be a point towards improved maintainability in code.

“But wait!” you shout, “I could have done the EXACT same thing with an abstract class instead of the IStringLookup interface you big dummy! Interfaces are garbage!”

And you wouldn’t be wrong about the abstract class part! It’s totally true that IStringLookup could instead have been an abstract class like StringLookupBase (or something…) and¬†the benefits would still apply! That’s a really interesting point, so let’s keep that in mind as we continue on through out this whole series. The little lesson here? It’s not the interface that gives us this bonus, it’s the API boundary and level of abstraction we introduced (something that does string lookups). Both an interface and abstract class happen to help us a lot here.

Continue to Part 2


What Makes Good Code? – Patterns and Practices Series

What Makes Good Code?

It’s been a while since I’ve had a programming oriented post, and I figured this would be a great topic to write about. It’s been a topic I’ve been thinking about more and more over the last year and I’ve been experimenting with certain patterns and practices to see if certain things actually make code “better”. A lot of the information presented in this series will be completely based on my opinion, but I’ll try to back up my opinion with as many concrete examples as I can. If you have a differing opinion, I’d love to hear it in the comments.

I’d also like to call out that much of what I’ll be discussing is in the context of object oriented programming. To be¬†specific, there may be mostly C# examples used. If this isn’t something you’re actively doing, then don’t worry! It would be great to hear if you see parallels in the work you’re doing.

What Is “Good”?

So let’s start by defining what “good” or “better” means (and I’ll leave this high level and we can dive in afterwards)…

  • Extensible: Re-writing of code is minimized when adding more functionality. It feels straight forward to extend the code. Developers won’t do “the wrong thing” when trying to extend the code.
  • Maintainable: Many of the same qualities¬†that go with extensible. Fixing bugs or making tweaks¬†involves touching¬†few places in the code base.
  • Testable: It’s¬†straight forward to write coded tests that can exercise functionality of the code under test.
  • Readable**: ¬†Developers should be able to read code and understand what it’s doing.¬†The flow of execution¬†within and between different modules of code shouldn’t cause anyone a headache,

All of these describe qualities of the code. I could argue that you could write very maintainable, extensible, and testable code and it would be awful if it didn’t actually solve the customers’ needs. I’d like to try and leave this aspect out of the discussion, and focus on the actual patterns/practices that we can implement in code. I’d love to write something separate about writing code that actually solves a problem versus code that may potentially solve some possible problem at some potential point in the future (and yes, all of the uncertainty in that sentence was on purpose).

Why Should We Care?

It’s kind of a funny question, I guess, but I think it’s a fair one to ask. Why should we care what good code is? If we agree on the definition of good code, so what? Maybe those criteria for good code are obvious to some people. Maybe they weren’t so obvious to some people, but they still don’t really care. So why the fuss about what good code is?

If you’ve read other posts on DevLeader or you know me personally, you may know that I started work at a digital forensics startup a few years back in Waterloo Ontario. What you may not know is that that startup has grown significantly, and based on the accolades we’ve received as an entire organization, we’re actually one of the fastest growing software companies in North America in terms of revenue. I’m not trying to do the horn tooting without a reason though… I think one of the reasons we’ve been able to have such great success on the development side of things is because we’re always trying to improve.

We didn’t always write “good” code, and we certainly don’t always write “good” code right now. However, we’re always trying to figure out how we can get better. So¬†why might¬†WE care as developers at our office? I think it comes down to trade-offs.

In the real world of software development, you’re often faced with trade-offs. You can get a product out faster if you don’t test it. Or you can get a product out and test it, but maybe you had to take a lot of shortcuts in the code. Or maybe you can get all the features in the product and tested, but you can’t hit the deadline. There’s countless more combinations of trade-offs that we make in real software development every day.¬†I think that by understanding what “good” code means allows a team to recognize just what kinds of corners they’re cutting sometimes. When teams talk about introducing “tech debt”, there’s a better grasp around what type of debt you’re introducing. If you need to get some extra features and bug fixes in but they’re getting added with some tech debt, what could that end up meaning?

Even if you don’t agree with what my criteria are for good code, I think it’s important that you establish this within your team. If everyone can agree on what good code is, it makes constructive conversations about different implementations much easier. Just because¬†some new code is different doesn’t instantaneously make it scary and/or wrong… Maybe it’s a new way that emphasizes one of the criteria for good code a bit more than another implementation might emphasize. Perhaps it doesn’t… You can at least refer back to a reference point for what “good” is.

It’s also important to recognize that the criteria for “good” may change over time. Revisiting the definition periodically might allow you to recognize when your team is¬†redefining what “good” means to them.

Enough Rambling! Where’s This Going?

Right. Okay. I want to write some follow up posts that will focus on a few of the following items:

  • Does every class need an interface?
  • Does every class need a factory that can create it?
  • Unit tests versus functional tests
  • Is there a benefit to only passing interfaces to objects around?
  • Is there a way to enforce that interfaces HAVE to be passed around?
  • Is the single responsibility principle even helpful?
  • Mutability and immutability
  • Is it always good to follow patterns and practices in all scenarios?

And after I feel that I’ve covered enough on these topics, I’d like to circle back and revisit what “good” code is. It’ll be cool to see if the definition changes at all!

**Readability¬†was an after thought and I’m not sure how… I started writing the first example post for this series and QUICKLY realized I had omitted this.


Should My Method Do This? Should My Class?

Whose Job Is It?

I wanted to share my experience that I had working on a recent project. If you’ve been programming for a while, you’ve definitely heard of the single responsibility principle. If you’re new to programming, maybe this is news. The principle states:

That every class should have responsibility over a single part of the functionality provided by the software, and that responsibility should be entirely encapsulated by the class

You could extend this concept to apply to not only classes, but methods as well. Should you have that one method that is entirely responsible for creating a database connection, connecting to a web service, downloading data, updating the database, uploading some data, and then doing some user interface rendering? What would you even call that?!

The idea is really this: break down your code into separate pieces of functionality.

Easier Said Than Done… Or Is It?

The idea seems easy, right? Then why is it that people keep writing code that doesn’t follow this guideline? I’m guessing it’s because even though it’s an easy rule, it’s even easier to just… code what works.

The recent experience I wanted to share was my work on a project that has a pretty short time frame to prove it was feasible. It was starting something from scratch, so I had all the flexibility in the world to design code however I wanted to. I really made an effort to keep asking myself this one question: Whose job is it?

Every time I asked that question and found that it was not my current method’s responsibility, I would ask “Is this class really responsible for that”? I’d either go make myself a new method in my class or I’d just go immediately make a new class with a single method on it. It seemed like a bit of extra overhead each time I had to do it, but was it worth it in the end?

Absolutely. After the project had proven itself and development continued on, I was easily able to refactor code (where necessary) and mock out functionality in my coded tests. Instead of trying to write test setup code that required a whack of classes I needed to initialize, I could mock out a couple of interfaces and test with ease. It was also really obvious which pieces were responsible for what functionality.

Final Thoughts

If you want to get better at following the single responsibility principle, I think it starts with one question: Whose job is it? Try it out!


Multiple C# Projects In Your Unity 3D Solution

Unity

Problem:¬†Visual Studio and Unity Aren’t Playing Nice!

Disclaimer: I develop on Windows, so I have no idea if any of this even applies to other operating systems. I assume not. Sorry.

I just started poking around in Unity 4.6 and I’ve been having a blast. I’ve made it to the point where I want to actually start hammering out some code, but I came across a bit of a problem: I want to start leveraging other projects I’ve written in my Unity solution while I’m in Visual Studio, and things are blowing up. So, what gives?

Okay, so¬†let me start by explaining why I want to do this. I understand that if I’m making a simple game, I should have no problem breaking out my unity scripts into sub folders and organizing them to be nice and pretty. The problem I’m encountering is that I have existing projects under source control and I don’t want to copy and paste all of the code as scripts into my Unity folder. I also want to be able to create re-usable code for my future games, so I’d like to start breaking things out into libraries as I see fit.

So, if you’ve been playing around in Unity for a bit, you might say “Oh, well you’re a dummy! Unity can totally leverage your C# DLLs once you drop them into your asset folder”! And you’d be 100% correct. But that’s not the workflow I want.

The underlying problem here is this: Unity will re-write your solution and project file when you flip between Unity and Visual Studio. But I’m sure they have it that way for a reason.

The Goal: Visual Studio and Unity Should… Play Nice!

My ideal state would be something like this:

  • Work in visual studio as much as I’d like to new projects to my solution, and reference them accordingly
  • Flip back and forth from Unity and Visual Studio without having to reset things to compile/run again
  • Build from visual studio and have things end up in the right spot… NOT copy DLLs
  • Not copy+paste my entire project(s) already under source control elsewhere

Is this something that can be achieved though? I was pretty determined that I should be able to do *something* to have this working. Could I get it perfect? I wasn’t sure… But I knew I could make it better.

The Solution: Give and Take with Unity

My *almost* perfect sution, which I’ll walk you through, is this: Leveraging Visual Studio tools for Unity, modify the Unity solution as you see fit and use directory junctions (symlinks) to the build output directories of other projects.

  1. Let’s get Visual Studio tools for Unity installed. Visit that link and download the version that you need for the version of Visual Studio that you use. After installing, I opened up my project within Unity and I had to import the Visual Studio Tools package.Import Package
    After selecting this menu item, I was presented with a dialog for picking the items to import. I left it as is.Import Package2After importing these items, I could see that Unity had successfully added these entries under my Assets folder. Okay, now we’re getting somewhere. Next up, I wanted to configure Unity to not modify my solution every time I go back and forth from Unity to Visual Studio. This is the part that kills whether or not I’ve added projects to my solution. For me, it’s critical to have code I’m working on immediately accessible so that I can jump back and forth between projects. Lucky for us, this part is pretty easy. Go to the menu to access your new Visual Studio Tools menu item:

    VS Tools Configure
    Selecting “Configuration” opens up a really simple dialog. Let’s make sure “Generate solution file” is unchecked! It’s that easy.

    VS Tools Configure2
    Once we have all of this setup, we should be able to go into Visual Studio and add other projects to our solution.

  2. The¬†one thing that I *could not* get this solution to do is have Unity leave my main game project alone in Visual Studio. As a result, the rest of this walk through is allowing us to play by Unity’s rules. Unity is good at magically referencing all of the managed DLLs that you include within your assets folder. If you drop DLLs somewhere within “Assets” and switch to Visual Studio, Unity will likely have modified your main project to reference this DLL.My next step was creating a spot where I wanted to drop the build outputs of my extra projects I wanted to reference. In my Visual Studio solution, I have my original game project and some newly added projects I want to build from source. In Unity, I wanted these to end up in “Assets/Dependencies/bin”. No problem. Let’s make that folder structure (or your equivalent if you don’t like my naming):Bin Dependencies
    The next part is probably the “trickiest” part because it’s… well… unusual. You could technically stop here and manually copy DLLs back and forth, but I’m not about that life. I want things to happen automatically. For this, we’re going to use junction points. Browse to your newly created folder in an administrator command prompt. I say administrator because only certain users have permissions to create junction points. Your non-admin user might, but this is my “safe” way of instructing you. On the command prompt, we’re going to use “mklink” to create a junction. The command is “mlkink /D /J <NAME_OF_YOUR_PROJECT> <RELATIVE_PATH_TO_YOUR_PROJECT>”. For example, if you had a C# project you wanted to reference that was “MyCoolLibrary.csproj” and was located in the directory above your Unity project, you might use the command “mlkink /D /J MyCoolLibrary “……..MyCoolLibrarybindebug””. Note that I used two dots to go back up a directory several¬†times (since we’re inside of AssetsDependenciesbin and want to get outside of our Unity project). you should get a success message when your junction is created.

    Repeat this step for as many extra projects as you want to include. You can always come back and add more projects this way too, or remove¬†the junctions if you don’t want to include a project anymore.

    At this point, you’re technically done. If you build from Visual Studio, you should have your other projects’ DLLs end up in your Unity folder, and your main game project will be updated by Unity to reference these now!

  3. But… You’re not done if you use source control for your Unity project and have separate source control on your other projects. The scary thing here is that usually we don’t want our build outputs to be stored in source control… But if we do nothing else, your source control system will likely want to include the newly created “AssetsDependenciesbin” folder and any of the contents you’re building into there. I just modified my git ignore file (I’m sure there’s an equivalent for SVN or other source control) to exclude the contents of “AssetsDependenciesbin”.The reason I didn’t excluded dependencies all together is because I can add other folders and DLL references here that I don’t want to build (like… the normal way). This gives me the flexibility of building the projects I want to control and still be able to just reference other pre-built DLLs!

Summary

In three easy steps, you should be able to use Unity, Visual Studio, and multiple projects in one solution in a what-feels-like-normal way. Because there’s still some dynamic stuff going on with Unity updating your main project, you might find the odd time you need to build twice to fix up compilation problems. I’ve seen this happen maybe once or twice so far, but otherwise it feels like normal. It’s also ¬†important to note that you can’t escape the Unity project updating… don’t add references to your main project manually. That’s what that “AssetsDependencies” folder is for that we made.

Here are a few shots of what my setup looks like (proof that it works):

Solution Explorer

Unity Dependencies

And of course… it’s not the perfect solution. There’s still these things:

  • Unity gets mad at you for using junctions within your project. It actually tells you not to do this because you can mess things up. It’s working awesome for me right now though… So I’m going to just ignore this warning.
  • Remember step 3 where we ignored the AssetsDependenciesbin location in git? This actually ignored your junction points you created too. As a result, anyone else who clones your code will need to create junctions too. I’m working solo, so I’m not too worried about this step… But it’s definitely something that should be fixed up (again, I’m sure it’s doable, but I’m in no rush).

Hope that helps you feel more at home in Unity and Visual Studio! It certainly made it nicer for me.

 


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  • Nick Cosentino

    Nick Cosentino

    I have nearly a decade of professional hands on software engineering experience in parallel to leading multiple engineering teams to great results. I'm into bodybuilding, modified cards, and blogging about leadership/development topics over at http://www.devleader.ca.

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