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16. September 2014

 

It is getting more and more common for kids of younger and younger ages to show interest in game development.  In this day and age there is a wealth of information out there, possibly too much information at times.  This guide is intended to help parents or younger readers get started in the world of game development.  So, what exactly does this mean?  First it means I will focus on technologies that are appropriate to beginners.  Second, it means I am making no assumptions about your technical abilities, in fact, I am assuming you have none.  So if it ever feels like I am insulting your intelligence or speaking down to you, I am not!  On the other hand, if I am unclear or confusing at some point, please let me know and I will try to clarify.

 

 

How young is too young?

 

This is perhaps one of the most common questions asked.  How old do I ( or my child ) have to be to get started in game development?  This is a question with an impossible answer as all kids are different.  On the extremely low end of the range ( and using the right tools ), an incredibly motivated 6 year old would probably be able to have some success.  On the other range of the spectrum, a typical 12 year old should have the educational foundation and mental abilities to succeed.  The actual age is bound to be somewhere in the middle.

 

There are a few critical things to be aware of up front. 

 

The first is motivation.  Motivation is more likely to be the biggest hurdle to success, not mental ability.  If your child absolutely loves creating stuff ( loving to play video games is massively different than loving to create video games ) and is willing to trial and error, they are perfect for game development!

 

The second is managing expectations.  This is where we lose the most potential game developers out there, regardless to age.  Game development doesn’t have to be exceptionally hard, but it is certainly complex.  Your child is not going to be creating massive modern games like Call Of Duty or NHL any time soon.  Nor are they going to create an MMO ( online game like World of Warcraft ).  They need to start small, very small and work their way up from there.

 

A key way to put it is, if your child’s mindset is “I am going to create the next Minecraft”, they are going to fail and fail hard.  On the other hand, if their mindset is “I am going to create the next Minecraft, eventually”, they have perhaps the perfect mentality to succeed.  Knowing the difference there is critical.  Like almost any other skill, you need to start small and build on your successes.  Starting too big will just result in failure and frustration.  For the record, I believe I was about 8 when I started programming using Atari BASIC.

 

 

What is Game Development anyways?

 

This section is going to get slightly more technical, but not overly so.  Game Development is an umbrella term, it includes many different skills all coming together to create a greater whole.  Think about Game Development like you would an car maker.  There is no single skill involved in making a car, instead you have engineers, graphic designers, manufacturers, quality assurance and more all coming together to make a car.  In the case of a game however, it’s still possible for all of these different tasks to be performed by a single person.  There are a number of highly successful games out there that were written, drawn and scored by the same person.  It is important to realize though, this generally isn’t the case.  Basically what I am saying is game development isn't a single task, it’s multiple.  While your child may really enjoy one part, they may dislike another part.  It’s also important when looking at what tools to use to see if they come with art or sound examples to get your child started, so they don’t have to do everything all at once.

 

If you look at a modern game’s credits, you will literally see hundreds of different names and job titles contributed to the project.  When just getting started however, there are really only two tasks to focus on. Creating the game and creating the stuff that goes in the game.

 

Let’s look at the board game Monopoly as an example.  Two major sets of skills went in to making that game.  First you had to create the game…  design the board layout, make the dice rules, write up all the game cards, etc.  Then you had to create the contents of the games, the pictures that went on the board, the drawings on each card, the little plastic houses, etc.

 

In video games, it’s really no different.  You have the task of creating the game, generally called programming and the task of creating stuff to populate your game, be it art, animation or music/sound.  These skills are completely different but are generally required for a game.  This actual tutorial is going to focus mostly on programming, when a child is interested in game development, this is generally what they mean.  A child interested in being a game artist for example, has probably already got their face buried in a notebook, sketching away!  This by the way is the perfect approach for them too, as the difference between “an artist” and a “game artist” is miniscule.  If you do however want to explore computer art for games a bit closer, read this guide.

 

 

What is Programming?

 

So, chances when you are talking about game development you are actually talking about game programming.  What is programming?  The simplest definition I can give is programming is the art of telling the computer what to do.  In the case of game programming, this means doing stuff like “when the user pushes the UP arrow do this” or “when player health equals 0, draw that”.

 

Now how you program games, that’s a much trickier conversation and one of the biggest things that you will struggle with.  Perhaps more importantly, it’s the thing that is going to be most dependent on your child.  We don’t all think the same way and we don’t all express ideas the same.  In some cases a child might take to one particular style while a completely different child would possibly despise it. 

 

For the most part for game programming there are three different ways to tell the computer what to do ( and often a combination of all 3 ):

 

Visually – this is a very common approach for beginners and for game development in general ( Unreal Engine 4, one of the most commonly used commercial game technologies has a Visual scripting interface called Blueprint for example ).  In Visual programming languages you generally drag and drop to draw your game screen, then wire it all together in a flow chart like experience  Basically it’s the programming equivalent of creating a flow chart.  If your child is a visual thinker, this may be the best route for them.

 

Here is an example of a Visual game development tool, Construct:

 

Scripting Languages – With scripting languages you tell a computer what to do using small text files.  You often still draw your game using a visual editor like the picture above, but when actually telling the computer what to do, instead of filling in text boxes or creating flow charts, you use code.

 

Here is an example of the LUA scripting language, using a 2D game library named LÖVE:

image

This little bit of text tells to computer to load an image with the filename “whale.png” and then to draw it on screen.

 

Traditional Programming Languages – Finally a lot of game development is done in traditional programming languages.  Common names include C++, Java, C# and more.  I should start straight away by saying, I do not recommend young programmers start by using a traditional or more accurately, a compiled programming language for several reasons.

 

The big question you may have is, what’s the difference between a scripting and compiled programming language?  A lot of it is technical and beyond the scope of this article but most of it comes down to complexity.  Dealing with a compiled language leaves you dealing with a number of things you simply don’t have to worry about with scripting languages.  Things like compiling ( the act of turning the text you write into something the computer can understand ), linking ( can’t easily explain this one ) and more. 

 

Perhaps more importantly, it’s purpose.  Scripting languages are generally much more focused in what they do and are designed to make things easier for the developer.  Put in the simplest terms, scripting languages are generally a lot easier to learn and use.  If you do want to learn more about traditional programming languages, you can read this guide.  It is a much more technical guide than this one.  If your child is in their teens, this may be an appropriate place to start.  That of course isn’t to say that teenagers ( and older ) are too old for the stuff recommended below.

 

In the end you will often find game development tools offer both a visual system and a scripting language, where much of the game is created using drag and drop but portions can be controlled using a scripting language.

 

 

IDE, Library, what???

 

OK, one last topic to cover before we get into it.  There are a bunch of terms and expressions that get thrown around that might be confusing.  I am going to quickly cover some of them.

 

Language – This is the programming language used.  Just like we used English, Spanish, German etc to talk to each other, we use different languages to talk to computers.  In the example above the programming language was Lua.

IDE – Integrated Development Environment.  This is a bundling of a number of tasks all into a single application.  Not all suggestions will have an IDE, meaning you need to use different programs to do different things.  Generally an IDE includes a text editor, a programming language and various tools all in a single spot.

Library – Think of a library like someone doing a bunch of work for you.  Generally even the “simple stuff” isn’t actually part of the language, things like drawing on the screen.  Instead people write that stuff and make it available to you as libraries.  In some cases, like GameMaker or Construct, it’s all bundled together for you.  In other cases, like Lua, you pick a library to go with the programming language.  Each approach has advantages and disadvantages.  For example, Gamemaker bundling everything together makes life easier to get started, but with Lua, if they don’t like a particular library, they can simply use a different one.

Sprite – A sprite is a graphic used in a game, for example the player.  A sprite can be a single image or could contain multiple for animations.  The exact meaning of a Sprite changes from engine to engine, but is always a visible thing in the game that moves.  If you’ve played Super Mario Brothers, Mario, the turtles, fireballs, etc… would be considered sprites.  The world however, such as pipes and the sky, would not generally be considered sprites.

HTML 5 – This one can get a bit confusing.  HTML5 is the most current version of HTML ( Hyper Text Markup Language ) which is the language of the web.  When you load a webpage in your browser or phone, generally it’s an HTML document that you are looking at.  The confusing part is, HTML5 is actually an umbrella term for a number of technologies that work together to make the web work.  Those include HTML itself, which is a language that describes the contents of a webpage, CSS which is another language that describes how a webpage should look, and finally JavaScript, which is a scripting language that controls the logic.  People often use the terms HTML, HTML5 and JavaScript interchangeably, although this isn’t technically true.  HTML5 can be used to create games and doesn’t have to be run in a web browser.

Debugger – When your game doesn’t run correctly, it can be tricky to figure out why.  Some packages ship with something called a debugger, which is a tool to help you identify problems or “bugs” in your game.  It is a somewhat advanced feature for beginners, but at the point you need one, a debugger can be invaluable.  For additional information on debugging click here, although advanced warning, that is a highly technical article.

 

 

 

Kid Friendly Game Development Options

 

Now after all of that we get to the meat of the article… the actual suggestions for development tools to introduce your child to the world of game development.  This is by no means an all inclusive list!  For each example I will list what’s included, an example of how it works, positives and negatives, the costs if any and links to books available, if applicable.  One last very important thing to note…  any of these options is a valid one, there really isn’t a single ‘best” choice.  Tailor your decision to best match your kids interests.  If you first choice doesn’t work out, try a different one.

 

The following list is in no particular order.

 

Scratch

 

http://scratch.mit.edu/

Overview:

Scratch is an MIT backed project aimed at teaching kids aged 8 to 16 to learn how to program.  There is a massive community built around Scratch, which has been around since 2006.  There is a special focus on being family friendly.  Scratch is run entirely in the web browser, you simply go to the web page and start programming.  If you want to save your work, you need to register, but it’s a simply form and doesn’t even email you for verification.

 

Scratch is firmly in the visual programming languages category.  Your child works by dragging actors onto a scene, then controls them using Lego-like programming blocks.  The blocks are a good parallel to actual programming language structure, so if they switch to scripting or traditional programming, it will make immediate sense.  There is a good amount of documentation available and you can find literally thousands of sample scratch programs to learn from.

 

Perhaps the most valuable part of scratch is it comes preloaded with all kinds of content for your child to get started with.  However it also has the ability to import graphics and audio you create yourself or get from the community, allow an easy transition between programming and making game assets.

 

Screenshots:

Scratch running in Chrome:

image

 

Loading a new Sprite

image

 

Programming in Scratch:

image

The above is a script attached to the blue dog.  It’s in two parts, first is when the Green flag ( Go ) is clicked.  It makes the dog visible, moves to a certain position on screen, then moves by one step over and over.  The other waits until it gets the collide message from the other dog, when it does it goes back to the starting position, changes the scene then hides itself.  Each Sprite has it’s own script.  The programming blocks are drag and dropped from the programming palate:

 

The Programming Palate:

image

These are the blocks you use to program in Scratch.  Above are the “Looks” options.  As you can see, there are a number of different categories to choose from.

Includes or Alternatives:

Scratch is an all in one solution, so you need no other tools to work in Scratch.  It also ships with a large variety of sample scenes, backgrounds and sounds to start with.

Costs:

Scratch is completely free and run by sponsorship donations.

Books:

 

Comments:

Scratch also makes an iPad application called ScratchJr which is aimed at children 5 to 8.  It is also completely free.  Since there is nothing to buy, or download and you don’t even have to register to try Scratch, it is probably the easiest option to try out in this list.

 



 

 

Construct 2

 

https://www.scirra.com/

 

Overview:

Construct2 is another visual programming based game engine.  You create games in Construct2 using a drag and drop interface and control logic using a flow chart like event system.  If the functionality you need isn’t available in Construct2, you can create your own plugins using JavaScript, although this is certainly an advanced feature and is strictly optional, Construct2 is meant to be controlled using the event system.  The ultimate output of Construct2 is HTML5, which can be exported to run on a number of platforms such as mobile ( Android, iOS, Windows Mobile ), browsers and desktop.

 

Construct2 is a great deal more complex than Scratch, which has a two fold impact.  First, Construct certainly has a higher learning curve than Scratch, so it isn’t suitable for younger children and does not take a teaching approach.  On the other hand, it is meant to provide an easy to learn tool capable of creating professional games, instead of for learning.  This means there is a lot more runway before your child runs into any limitations.  There are many professionally shipped games that were created in Construct 2. 

 

There is a good deal of documentation available, including a complete references and a PDF manual available for download.  There is a very active community and strong forum for support.

 

Construct is an application installed on your computer.  Construct requires a computer running Windows.  There is no Mac option currently available.

 

Screenshot:

Construct 2 Main Window:

image

 

Event Sheets

image

This is the primary way of programming a Construct 2 game.  The example above is part of the code controlling how the player responds to input, taken from one of the included samples that shows creating a simple shooting game.

Behaviors

image

Behaviors allow you add quickly add predefined behavior to a game object.

Integrated Image Editor:

image

 

Includes or Alternatives:

Construct 2 is an all in one solution that contains everything you need to get started.  Out of the box however it does not contain a ton of content to get started with.  They do however have a free asset pack available for download. ( Warning, that is a direct download link.  Click it and the 38mb archive of assets will start downloading ).  If you move beyond the free version, you get more assets included.

If you do get into creating plugins, you will need to download the JavaScript SDK, which is available for free.  In this case you will need to provide your own text editing environment, Construct does not include one.

Costs:

Construct2 has tiered pricing.

  • There is a free version available to download.  The free version is only able to create games that run in your browser.  It also includes less bundled assets and has a number of limitations on the complexity of game that can be created.  This limits shouldn’t be too much of a problem at least initially.
  • The Personal Edition is currently 129USD, is able to create Desktop, iPhone and Android games and includes much more bundled assets like sounds, songs and sprites.
  • Finally, there is a Business Edition, which is exactly the same as Personal Edition, except it costs more and is required if you make more than 5,000USD from your Construct2 games.  Basically if you have this problem, it’s a good problem to have!

 

Books:

 

Comments:

None

 



 

Game Maker

 

https://www.yoyogames.com/studio

 

Overview:

GameMaker is an all in one game creation system that is a hybrid providing both a visual programming interface, as well as a scripting language, their own proprietary language GML.  GameMaker initially exports to Windows only, but for a fee can also create games for iOS, Android, Web, Windows Phone and more.

 

Programming in GameMaker can be done in a flow chart like manner, similar to Construct2.  It also adds the option of programming in their own scripting language GML.  This is both a plus and a minus.  The ability to program using a Scripting language in addition to the visual system gives the user a great deal of flexibility.  It is however a more complex process.  Since the language is proprietary to GameMaker, if they move to a different environment, a lot of their knowledge will be less useful.  That said, general programming concepts stay pretty much the same from language to language, so this isn’t as big of a problem as it might sound.

 

Other than assets to get started with, GameMaker quite literally ships with everything you might need out of the box, although the quality of the tools varies.  You are able to create graphics, sounds and levels in addition to programming, all in one single application.  GameMaker has been used to make some very successful commercial games such as the original version of Spelunky and Hotline Miami ( not for children ).

 

GameMaker is one of the more complex options on this list and is probably not appropriate for pre-teen level children.  For older children though, it offers a lot of flexibility and a ton of options should they wish to share or sell their games eventually.  Obviously this changes from child to child, so there is no hard set rule.  Just be aware, compared to say Scratch, the difficulty level here is much higher. 

 

Screenshot:

Main Interface:

image

Visual Programming:

image

Scripting:

(Script for firing a bullet)

image

Level Editor:

image

Sprite Editor:

image

Includes or Alternatives:

GameMaker is an all in one solution and contains everything you will need to make a game including code editing, image creation and editing, map designer and more.  It also includes a built in debugger, useful for hunting down problems.  The standard version however comes with very little in the way of included samples to get started with.  In fact, there are none.  However there is a very active community and tons of examples and tutorials available online.  The quality of the materials varies massively and curation by Yoyo Games is lacking, so finding the best starting material can be a bit of a challenge.  For all of the screenshots and code samples in this entry, I used material from this tutorial.

 

Costs:

GameMaker licensing can be a bit confusing, as their pricing structure has changed and not all material is updated.

The version you initially download is heavily restricted by the number of resources and scripts it can support.

You can however update to the Standard edition by simply registering an email address, which will be verified and you will then be sent a product key.

Then there is a “Professional” version for $100 USD that adds functionality for working with other developers ( you will not need at this point ).  The biggest difference is the Professional version can buy additional modules that support exporting to platforms other than Windows.  Each platform is generally $200 USD.  So for example, if you want to export your game to play on Android and iOS it will cost $500.  $100 for Professional, then $200 for each platform. 

Finally there is a “Master” version, which is basically Pro with all of the different export platforms enabled.  It’s $800USD currently.

For a new developer, the registered Standard edition is most likely good enough.  If you do need Professional, keep an eye on the Steam Store, it is made available for sale quite often.  To add to the confusion, the Standard edition you can download for free is $50USD on Steam.  DO NOT BUY IT!

 

Books:


Comments:

Note, it is not necessary to use the included tools.  For example, if you want to use another graphics program to create sprites, or to import graphics from another source, this is perfectly possible!



 

Lua with LOVE

 

http://www.lua.org/

http://love2d.org/

 

Overview:

Lua is a scripting language, while LOVE is a library for making games ( see the descriptions earlier for definition of a library ).  Lua was a programming language created for non-programmers and has become increasingly popular as a scripting language for commercial games, such as these.  That is one large advantage to choosing this option over say, Gamemaker’s custom scripting language, GML.  Lua is used elsewhere and fairly commonly, so it is a skill that will carry forward very well.    As a language it is fairly simple to learn.

 

LÖVE is the library you use to create games using the Lua programming language.  LÖVE provides pretty much all of the functionality you need to create 2D games including drawing graphics, playing sound, controlling input, loading files, etc. 

 

LÖVE and Lua isn’t a turn key solution like some of the others however, you still need a text editor to create and edit your scripts, a drawing program for creating art, and audio programming for recording sounds, a map maker for creating maps, etc.  Fortunately all of these things are freely available and I have recommendations below.  You do however have to download each one separately.  LÖVE however comes with no assets like graphics or sounds to get started, but sites like Open Game Art and FreeSound can help you get started.  It is however, yet another thing you have to locate and download.

 

The biggest negative about LOVE is the lack of platform support.  Currently LOVE can only create games for computers, although mobile targets are in the works.

 

Screenshot

Sample Lua/LOVE Code:

image

Zerobrane Studio:

image

Includes or Alternatives:

The LOVE library contains Lua, so all you need to get started is here with the getting started documentation here.  However that just gives you Lua and LOVE and nothing else.  You still need a text editor to create your code, plus art and sound programs.

 

For straight text editing, two very popular choices are Notepad++ and Sublime Text.

However, for Lua development I would recommend ZeroBrane Studio which is a more integrated development environment (IDE) that allows things like code suggestions and debugging.  Oh, plus it’s free, which is nice.

For art creation, Paint.NET, GIMP and Inkscape are three very popular free options, the last two however have a pretty hefty learning curve.

For creating levels and maps, Tiled is a very popular and free choice.

 

On the alternatives front, LUA is the scripting language for a number of popular game development tools including Corona, Gideros and Marmalade Quick.  None are as easy to learn as LOVE however, which is why I recommend LOVE over all.  They do however illustrate how learning Lua is a skill that transfers well to other projects.

 

Costs:

Both Lua and LOVE are free.  ZeroBrane is a pay way you like product.

 

Books:

Only one of these books is specifically about LOVE programming.

Lua also have a free reference manual available online.


Comments:

The name of the library is actually LÖVE with an umlaut over the O.  While cute, coupled with the commonness of the word love makes searching for help incredibly annoying.  When using Google, always add “lua” to search expressions.



 

Python with PyGame

 

https://www.python.org/

http://www.pygame.org/news.html

 

Overview:

Like the Lua and LÖVE option, this is a programming language and game library combination.  Very similar to the LÖVE library, PyGame is a very beginner friendly library.  Python is the programming language used in this pairing.  Python is a popular scripting language, although less so in game development.  It is an extremely popular language in the world of 3D graphics, such as at Pixar.   It is also quite commonly used by IT professionals to automate tasks, so even outside game development, Python can be a very valuable skill.  Python has been used to make several games.

 

PyGame also provides most of the common functionality you would expect in a game such as audio, input and graphics.  You also need to provide your own text editor, graphics, sounds, etc.  However unlike LÖVE, PyGame does ship with several examples and some sample assets to get started with.

 

Screenshot:

Python Code in PyCharm

image

Includes or Alternatives:

See the recommendations for LÖVE above, most of the same tools can be used.

ZeroBrane studio however is not an option for Python.  I would personally recommend checking out PyCharm, which has a free version available.  It is however a somewhat complicated editor.  Of course, you can still use whatever text editor you would like, such as the earlier recommendations of Notepad++ or Sublime Text.

 

Costs:

Python and PyGame are both free.  PyCharm is available in a free version.

Books:


Comments:

Python is a more complicated language than Lua, so its is recommended only for older children.  On the other hand, programming in Python is also much closer to programming in traditional languages, so the experience of learning Python will be closest to what professional programming generally feels like.

Sadly, there are two versions of Python, something that has plagued the language for a very long time.  Most of the time you want to use the 2.x version of the language.



 

HTML5 with various

 

https://www.gamefromscratch.com/page/Links-of-interest-for-HTML5-game-developers.aspx

Overview:

HTML5 is a somewhat confusing term these days.  Basically HTML is the language of web browsers while Javascript is the language that enables HTML to do stuff.  With each generation of web browser, the ability to create games has gotten more and more impressive.

 

Javascript is an interesting proposition for learning with as your kids probably already have experience in using a web browser.  Then can simply open a text file, type some code, save and load in the webpage and play.  It’s a very nice feedback loop.  Unfortunately there are some downsides here too.  While a pretty straight forward programming language, Javascript has some horrible flaws that make it hard to recommend to a complete beginner.  On top, each browser has tons of flaws, that also add a layer of complication on top.  Finally there are just so many options when it comes to HTML game development, unlike Lua or Python, that making a recommendation could actually take another article even longer than this one!

 

If you child is interested in working on HTML5 games, it is a good option to persue with the right library.  Two very good options, that provide game functionality and deal with some of the browser lunacy are Phaser and CreateJS, but there are literally hundreds of options.  Both of those libraries are straight forward, well documented and commonly used.

 

Like Python and Lua, HTML5 is not an integrated solution, so you need to provide your own text editor, graphics, etc.  However, pretty much every modern browser has build in tools to make development easier.



 

Stencyl

 

http://www.stencyl.com/

 

Overview:

Stencyl is a visually programmed game creation kit that bills itself as “the quickest and easiest way to make games”, which may actually be true!  In functionality it is very similar to Construct2, you program by drawing out your scene, then adding behaviors visually.  It is an all in one solution with an integrated image editor, although you can always import assets created in external tools.  There is no way to script in Stencyl, although you can create extensions using a programming language called Haxe, if there is functionality you need that is not available in Stencyl.  This however is advanced functionality and is probably beyond your child’s current ability level.  You can however download pre-made extensions from the marketplace.

 

Stencyl runs on Windows, Linux and Mac and by default can only create web (Flash) applications.  The ability to target other platforms like desktop computers (outside their browser), as well as iOS and Android is available for a cost (see below).  While it doesn’t ship with a ton of assets, it does make them very easily available.  In addition the help available online is very good.

 

Screenshot:

Stencyl:

image

Defining Behaviors:

image

Level Editing:

image

Program Flow:

image

Includes or Alternatives:

This is a pretty all in one solution.  Unless you delve into Haxe extension programming, basically everything is here with the initial download, or is linked directly from inside the application.

Costs:

Stencyl is available for free, but limited to applications that run in Flash, either in the integrated player or your browser.  Published games will have a Stencyl splashscreen when they load.

For $99, there is Studio that enables you to target desktop computers outside of the Flash player.  The splashscreen is removed in this version.

For $199, you gain the ability to target iOS and Android.

Books:

     

Comments:

None



 

Lego Mindstorm

 

http://www.lego.com/en-us/mindstorms

 

Overview:

Right off the top let me just say, this stuff is expensive Name Your Link'>Name Your Link'>really expensive.  However if your child shows an interest in robotics or is an avid Lego fan, this can be a very good introduction to programming.  Mindstorm Lego is basically a simple robot creation kit using lego.  The key part is it ships with a programmable piece that enables you to program your robot’s behavior.  Mindstorm enables a nice progression, your child can start by building in Lego, then start controlling the robot using the desktop or iPad application, then graduate to actually programming logic.

 

Lego Mindstorm enables you to simply control your creations, or program them using the EV3 software, a flow chart like process.  They do however make tools available allowing you to get as low leveled as you want to. 

 

Even though it’s somewhat off topic, I mention Mindstorm because it can be an ideal introduction to more (literally) hands on children to the concepts of programming.  Literally being able to see cause and effect in the real world can be very valuable.

 

Screenshot:

Programming Mindstorm:

mindstormProg

A Mindstorm robot assembled:

LEGO Mindstorm robot

Includes or Alternatives:

N/A

Costs:

Name Your Link'>Name Your Link'>Lots!

Books:

EBooks of the manual ( pdf link ) and teaching guide ( pdf link ) are available online.


Comments:

This is pushing the definition of “game programming”, but certainly is a very tactile introduction to many of the same skills that go into game development.  Also I have to say, had my parents purchased this for me as I child I would have considered nominating them for parent of the year awards.  When my daughter gets a bit older I am certainly buying this, but then, is it for her, or me? :)

 



 

Honourable Mentions

 

All lists must end at some point, and this one is no exception.  The following are other recommendations I have for parents looking to get their kids into game programming, but for whatever reason didn’t make the main list.  If nothing above appeals to you, be sure to check some of these options out.

 

Minecraft Modding

If your kids play games, there is probably a pretty good chance you have already been exposed to Minecraft.  Modding is the act of modifying an existing game and Minecraft happens to be a very popular game to mod.  Modifying an existing game can often be a great way, or at least motivation, for learning programming.  There is a HUGE community of people that mod Minecraft.  The downside is, it’s done in the Java programming language and it certainly isn’t suitable for young children.  If your child is very interested in Minecraft though, this could be a good approach to take.  You can learn more here.

 

GameSalad

http://www.gamesalad.com/

GameSalad is another visual game creation kit in the veins of Stencyl and Construct2 mentioned above.  It has been used to create professional games, there is a free version available as well as paid versions for other targeting other platforms.  I personally have no experience with GameSalad.

 

Codea

twolivesleft.com/Codea/

Codea is an iPad application for creating games on the iPad.  It currently costs $10USD.  It uses the Lua programming language and provides it’s own library for creating games that is very easy to learn.  It comes with code editing tools, debugger and tools to hook up with your computer.  You can later hook it up to a Mac and actually create a game for publishing.  However, typing code on an iPad keyboard is extremely unfun, so a bluetooth keyboard is pretty much essential.  It does however come with tons of examples and is actually a great option for a young developer who has an iPad, especially if that’s all they have.

 

Kodu or Project Spark

http://worlds.kodugamelab.com/browse

or

http://www.projectspark.com/#home

This is a game that is about creating games.  Basically it’s a game you can modify to do just about anything.  Kodu is a visual programming language created by Microsoft.  Project Spark is a modified version of Kodu being released shortly for the XBox One console.  It’s pretty far from normal game programming, but many of the concepts ( and the end result! ) are very similar.

 

Code Combat

http://codecombat.com/

Code combat is an interesting concept.  It’s a web based game where you control your character through programming.  As you progress in the game, it teaches harder concepts.  Basically you learn to program while playing a game.  It was originally created to teach Javascript, but has since added a number of other languages.  I believe it is completely free, so you’ve got nothing to lose by trying.

 

Alice

http://www.alice.org/index.php

Alice is a integrated programming solution designed to teach programming.  In their own words:

Alice is an innovative 3D programming environment that makes it easy to create an animation for telling a story, playing an interactive game, or a video to share on the web. Alice is a freely available teaching tool designed to be a student's first exposure to object-oriented programming. It allows students to learn fundamental programming concepts in the context of creating animated movies and simple video games. In Alice, 3-D objects (e.g., people, animals, and vehicles) populate a virtual world and students create a program to animate the objects.

Alice is maintained by Carnegie Mellon university and is completely free.

 

RPGMAKER

http://www.rpgmakerweb.com/

RPGMaker Ace is a product similar to GameMaker specifically for creating one type of games, Role Playing Games, generally along the Japanese style.  Their tagline is literally “Simple enough for a child; powerful enough for a developer.”  There are some commerically created games available that were written using RPGMaker.  If your child is really in to this style of game, RPGMaker could be a great introduction to game programming.  RPGMaker is $70, although quite often on sale on Steam.  Ironically enough, as I write this, it is on sale for 75% off.

 

 

Conclusion

 

Of course I only scratched the surface of the options available, but I think I got the majority of options in that list.  If you think there is something else I should have put in this document, let me know!  I tried to make this clear to people of all technical levels, but no doubt I’ve made mistakes.  If I lost you somewhere, please let me know and I will try to clarify.  The most important thing to remember, all children are different, so one approach that works for one child may fail with another.  Pick the option above that you think most fits with your child's personality, but if it doesn’t seem to be a good fit, remember there’s a dozen other options!

 

I hope that was useful.  Good luck.

Programming General Design Art


8. August 2014

 

I write a great many tutorials targeting newer developers and as a direct result I am exposed to a fair number of programming related questions.  I don’t mind in the least by the way, it’s why I run this site.

 

However, I notice one very common thread among those questions…

 

They often could have been solved with just a few minutes in the debugger.

 

Then it dawned on me.  Lots of newer programmers likely don’t know all that much about debugging.  Many are probably resorting to printing to the console to see how their program works.  For good reason too…  if you pick up say… a C++ book, it’s about the language, not the tooling.  Of course, there are dedicated books such as Beginning Visual C++ 2013 or the Eclipse IDE: Pocket Guide, but these tend not to be books beginners start with.  Hell, for someone just starting out, figuring out where the language begins and the IDE ends is challenging enough!

 

Which is all a shame, as basic debugging skills will make your life a hell of a lot easier.  Not only will it make solving problems much easier, but it will help a great deal in understanding how your language works.  Plus the most tragic part of all, it’s actually very simple and often incredibly consistent across tools and programming languages.

 

So, if you have no prior debugging experience, give me 20 minutes of your time.  I guarantee you it will be worthwhile, or your money back!

 

 

I am going to use a couple different languages/IDEs int this tutorial, but as you will see, the process is remarkably similar regardless to what language you use.  I am primarily going to start with Visual Studio, then illustrate how you can perform similar actions in other environments.  First a quick glossary of terms you are going to hear.

 

 

Glossary of terms

 

These are a few of the terms we are going to be covering during this tutorial.  Don’t worry over much if the following descriptions don’t make a lot of sense, it should be clearer by the time you finish.

 

Breakpoint

This one is critical, these are instructions that tell your code HEY, STOP RUNNING, I WANT TO LOOK AT SOMETHING HERE!  We will be using breakpoints extensively.  You can generally add/remove/enable/disable breakpoints.

 

Watch

This one is incredibly well named.  Basically these are variables you’ve said you want to keep a watch on the value of.

 

Local

Think of these like Watch expressions the IDE automatically made for you.  Basically every variable in local scope will be listed as a local.  Not all IDEs do this, but most do.

 

Expression Evaluation

This is powerful.  Basically you can type some code and see what result it returns, while your code is running.  Generally you do this once a breakpoint has been hit causing your code to pause and your debugger to be shown.

 

Call Stack

This is the hierarchy of function calls you are currently in.  For example, if you called myFunc() from main(), your callstack would look like

myFunc()

main().

 

Don’t worry, this should make sense shortly.

 

 

C++ and Visual Studio Debugger

 

I am going to start with Visual Studio/Visual C++ then show other platforms later on.  Once again, most of the process you see here is applicable to other environments.

 

Let’s start with this ultra simple code example:

void someFunction(int & inValue)
{
    inValue = 43;
}

int main(int argc, char ** argv)
{
    int i = 42;
    someFunction(i);
    return 0;
}

 

The code is extremely simple. We create a simple int, assign it a value, then pass it into a function that will assign it a different value. Now time to do some basic debugging.

 

The first thing you need to do is start debugging.  In Visual Studio, there are a couple ways to do this.  First thing, in C++, you need to tell it that you are building for debugging.  You see, when you make a debug build a few different things happen.  There are little bits of information added to your code that make the debugger work.  There are some other changes too, like memory being zeroed out, but those are beyond what we are talking about here.  The take away is, you need to build for debugging, then run the debugger, although generally this task is one and the same for you the developer. 

 

From the Visual Studio toolbar, you can do both:

image

Or, you can run from the Debug menu:

image

 

As you can see, F5 is also an option.  It’s worth noting, debug code generally runs a bit slower and bigger, so when you are finished development, you want to compile for release.

 

Ok, so that’s how we start the debugger, but in this code sample, it will simply start, run, then finish.  That’s not very exciting.

 

 

Enter the breakpoint!

 

Ok, now we are going to enter the wonderful world of breakpoints, your new best friends.  Let’s start by setting a breakpoint on our first line, where we declare i.  There are a number of ways of setting a breakpoint.  In the IDE you can right click the line of code you want to break on then select Breakpoint –> Insert Breakpoint, like so:

image

 

… for the sake of this tutorial, please just ignore Tracepoints, at least for now.

 

You can also set a breakpoint in the Debug menu, using Toggle Breakpoint, or by hitting F9:

image

 

The line of code you just set a breakpoint on should now have a red bullet in the margin:

 

image

 

Go ahead and press F5 to debug your program.  Things will go much differently this time, your code will stop executing on the line with the breakpoint.  You can hover your mouse over a variable to see it’s value:

 

image

 

In this case, you will see that the value is gibberish.  This is because i hasn’t been assigned yet.  Notice the little yellow arrow on the left hand side?  This is the line of code you are currently executing.

image

 

Stepping over the corpses of your vanquished foes

 

 

Now we need to navigate in the debugger.  This is done using a couple simple commands:

 

image

 

Step Into, Step Over and Step Out.  These are also available in the toolbar:

image

As you can see, you can also use the hotkey F11 and F10.  These keys change from program to program... if they didn’t, that would just make life too easy, wouldn’t it?

 

Now as to what these do…

Step Into, steps into the currently running line of code.  For example, if you are on a function, it will step into that function.  I will show this in a second.

Step Over jumps to the next line of code in the same scope.  Step out, jumps up on the callstack.  Again, I will explain this in a second. 

 

So what we want to do now is Step Over, and now it should look like this:

image

 

The little yellow arrow will now have advanced to the next line of code.  Notice now if we hover over the value of i, it is now 42 like we would have expected.  That is because the line of code has now executed.  This is a very important thing to realize… the line of code your breakpoint stopped on hasn’t executed yet.  So if you want to see what value is assigned to a variable, you generally want to set the breakpoint to the next line of code.

 

Now we want to “Step Into” the current line of code.  That is, we want to see what happens when someFunction() executes.  If we chose “Step Over”, we would jump to the next line ( return 0; ).  There is another important thing to realize here… even if you Step Over some code, it is still being run like normal, it just isn’t showing you it in the debugger.  That said, we want to see someFunction() in action, so choose Step Into or choose this icon:

 

image

 

Now the line of code jumps to the beginning of someFunction():

 

image

 

You can hover over parameters to see their value:

image

 

You can continue stepping in and over code like normal, or if you are done looking at someFunction ( or some other function someFunction calls ), you can choose Step Out to jump up on the callstack.

 

image

 

 

Callstack me, maybe?  No, I didn’t just make that pun did I?

 

 

Callstack… there’s that word again.  Now that we are actually in a bit of a call stack, let’s take a look at what I mean.

 

In Visual Studio, make sure the CallStack window is being shown.  This is controlled using Debug->Window->CallStack or CTRL + ALT + C like so:

image

 

A window like the following should appear:

image

 

The key to the name is “STACK”.  Think about it like a stack of plates at a cafeteria.  Each time a function is called, it’s like putting a plate on the stack.  The bottom most plate/function is the oldest, while the top most is the newest.  In this case, the call stack tells us that on line 9, in the function main, we called someFunction() and are currently running on line 2.  Speaking of “lines”, you have the option of toggling them on or off in Visual Studio ( and most other IDEs ).

 

The process of toggling line numbers on/off, isn’t incredibly straight forward.  That said, line numbers can be incredibly handy, so lets do it.  First select the menu Tools->Options…

image

 

Then in the resulting dialog on the left hand side scroll down until you find Text Editor->C/C++->General, then click the checkbox next to Line Numbers.  Obviously if you are using Visual Studio and a language other than C++, you need to pick the appropriate language:

 

image

 

Now line numbers will be displayed next to your code:

image

 

Ok… back to the callstack.  Double clicking an entry in the callstack brings you to that line of code.  In this trivial example, the utility is questionable.  However, when working with a real project, where the callstack might span multiple source files, it becomes a very quick and easy way to jump between source files and for seeing how you ended up where you are.  This obviously is a hell of a lot more useful when someFunction() is possible called from thousands of different locations for example.

 

 

Locals, no more witty titles after that last witless one…

 

Now let’s take a look at locals, a concept I mentioned earlier.  This is basically all the local ( non-global ) functions in the current scope.  While debugging inside someFunction, like so:

 

image

 

Open up the locals window.  Like before it can be toggled using the menu Debug->Windows->Locals:

 

image

 

Now you will have a new window, like so:

 

image

 

This is a list of all variables in the local scope.  Inside someFunction() there is only one value, it’s parameter inValue.  Here you can see that the current value is 42 and it’s data type is int reference.  As you step through someFunction, as values chance, they will be updated in the locals window. 

 

Step out of someFunction ( Shift + F11, or using the icon or menus listed above ), and you will see the locals change to those of main():

 

image

 

 

Now you see something somewhat unique to C and C++ ( and other languages with direct memory management ).  The value passed in, argv, is a pointer to a pointer of type char.  This is to say, it points to a pointer that points to the memory address of a char data type.  If that is greek to you at this point, don’t worry about it.  You will notice though that the locals window has done a couple very cool things.

 

First, you see a hex value:

 

image

 

 

This is the actual address of the pointer in memory.  After all, that is what pointers actually are, locations in memory.  This is incredibly useful in debugging, even if you yourself don’t use pointers, code you depend on might.  Look out for values like 0x0000000 or 0xFFFFFFFF.  If you look at the value of a pointer and it’s one of those values, your object wasn’t allocated or has been deleted.  These are some of the most common bugs you will find in C++ code.

 

The other neat thing that visual studio did was this:

 

image

 

The debugger was actually smart enough to go look at the data actually stored at the memory address this pointer points at.  Very handy.  You may also notice the triangle to the left of argv.  This is because there is more information available.  We will see this a bit more later.

 

 

Ok, now what?

 

So… what do you do once you have found what you were looking for?  You have a couple options.  Here they are from the debug toolbar:

 

image

 

Or using the following commands from the Debug menu:

 

image

 

One thing to keep in mind, when your programming is running, the options and menu’s available in Visual Studio are different.  For example, if you want to create a new project, you need to Stop Debugging before the menu options are even available.

 

 

Playing God with your Program

 

Ok, let’s rewind a bit and go back to the locals menu.  This time we are going to use a slightly different code example.

 

#include <iostream>
#include <string>

class MyClass{
public:
    int myInt;
    std::string myString;

    MyClass() :
        myInt(4), 
        myString("Hello World"), 
        myPrivateInt(5)
    {
    }

private:
    int myPrivateInt;
};
int main(int argc, char** argv)
{
    MyClass myClass;
    std::cout << myClass.myString;
    return 0;
}

 

Now let’s try setting a breakpoint on the final line of main, like so:

 

image

 

If you run this code, you will see:

 

image

 

You will have to ALT+TAB over to it, since debugger has given focus to Visual Studio.

 

Now lets look at some of the funky things you can do to a running program.  Now let’s set another breakpoint, this one on the cout line.  Remember, the code on the line you’ve breakpointed hasn’t been run yet!

 

image

 

Now restart or debug your program again.  It will hit the first breakpoint right away.  Now go look at the locals window again:

 

image

 

As you can see, data types composed of other data types, like myClass can be expanded to show all the other values that compose it.  Now let’s do something kinda neat.

 

You can change the values of a program as it is running.  Sorta…  For basic data types, it’s extremely straight forward.  For example, to change the value of myInt while debugging, simply right click it in the locals window and select Edit Value, like so:

 

image

 

You can now change the value:

 

image

 

From this point on ( during this debug session ), that value is now 42.  Of course, if the value is changed in code, it will of course be updated.  This allows you to tweak values interactively and see how it will affect your program’s execution.

 

With objects however, it is slightly more complicated.  In the previous case, we edited myInt which is a member of myClass.  But we couldn’t simply edit MyClass directly, as the debugger has no idea how.  Therefore you can’t just right click myString and select edit.  The debugger simply doesn’t know how to edit this data type ( this isn’t true for non-C++ languages ).  You can however modify the values that make up the string, like so:

 

image

 

As you can see, myString is of type std::basic_string, which is composed of an array of character values that make up the string.  So we can edit the character values to say… lower case our string.

 

image

 

Once again, Visual Studio is smart enough to understand the datatype.  So we could either enter the value ‘w’ or the ascii code 119.  Now if you continue execution of your program it will automatically run to the next breakpoint.  And if you look at the output, you should see:

 

image

 

One very important thing to note here… all of these changes are temporary.  They only last as long as the current debugging session.  The next time you run your program, it will run like normal.

 

 

I’m sick of these damned breakpoints

 

In that last example, when we selected Continue, we jumped to the next breakpoint, like so:

 

image

 

As you add more and more breakpoints to your code, they can make stepping through it incredibly annoying.  So, what can we do about that?

 

Well the first thing we can do is disable it.  Right click the red dot and select Disable Breakpoint, or select the line and hit CTRL + F9

 

image

 

And the breakpoint will be disabled.  Now it will show up as a hollow circle:

 

image

 

This allows you to re-enable it later, but until you do, the debugger will completely ignore the breakpoint.  You can re-enable it the same way you disabled it.  Right clicking and selecting enable, or by hitting CTRL + F9.

 

 

You can also remove a breakpoint complete in a couple ways.  First you single left click the red dot, and it will be removed.  The F9 key will also toggle a breakpoint on and off completely.  You can also right click and select Delete Breakpoint ( see shot above ).

 

Sometimes you want to remove or disable/enable them all at once.  You can do this using the debug menu:

image

 

Breakpoints are your friend, learn to love them!

 

I’m Watching You!

 

Now we are going to look at two final concepts, watches and expressions.  Let’s start with watches.

Until this point, we’ve only been able to look at variables declared in the local scope.  That’s all well and good, but what happens when we want to watch a value declared in a different scope?  Don’t worry, the debugger’s got you covered!

 

Consider this simple code example and breakpoint:

 

image

 

At this point in execution, your locals will look like:

 

image

That said, stringInADifferentScope has already been declared and allocated… how would you look at this value?

 

Well, there are two ways.  As you may be able to guess from the preamble, they are watches and expressions.  A watch is a variable you are keeping an eye on, even if its not currently local.  You can set a watch while debugging code by right clicking the variable and selecting Add Watch:

 

image

 

Now you can look at watches in the watch window using the menu Debug->Windows->Watch->Watch 1 ( or CTRL+ALT+W then 1 ).  You can have up to 4 sets of Watch windows in Visual Studio.  Now you can inspect the value of watched variables at any time:

 

image

If you watch a variable that isn’t in scope, it tells you:

 

image

 

When the variable notInScope comes back in scope, it’s value can be retrieved by hitting the refresh icon.

 

The other option is Evaluate Expression, which is called QuickWatch in Visual Studio.  It’s an incredibly cool feature.  You can invoke QuickWatch while debugging by right clicking and selecting QuickWatch…  or by pressing Shift + F9.

 

image

 

This opens a dialog that allows you to enter whatever value you want into the Expression tab, then press Re-Evaluate and it will look up the value:

 

image

 

The Add Watch button allows you to add the selected Expression to the watch window we just saw.

 

The cool thing about this you can actually call some functions on your object and get the results:

 

image

 

 

On One Condition

 

Back to breakpoints for a second, then I am done I promise.

Consider the following code sample:

 

image

 

This is a very common bug scenario, but you really don’t want to run through the debugger 100K times do you?  Generally with these kinds of errors, its only the last couple of iterations you want to look at.  Fortunately we have something called a conditional breakpoint.  This, as the name suggests, will only break if a certain condition is met.

 

Add a breakpoint like normal.  Add it to the line inside of the loop.  Now right click the red dot and selection Condition…

 

image

 

Now you can set the condition you will break on.

 

image

 

The breakpoint icon will now have a white plus in it:

 

image

 

Next time you run the code, it will only trip when the condition is hit:

 

image

 

Unfortunately, in Visual Studio, conditional breakpoints can make your code ungodly slow, so only use them when absolutely required.  In other languages and IDEs, this isn’t always the case.  I honestly think this is a bug in Visual Studio, as the above code should not require several seconds to evaluate, even with the additional overhead. 

 

 

One of the keys to happiness is a bad memory

 

One other thing that can be incredibly useful, especially in C++ is to look at a location in memory.  This functionality isn’t always available, depending on the language you are using.  In Visual C++, it’s incredibly easy and useful.  In the previous example, we filled an array of char with 100K exclamation marks ( at least, once we remove the = sign from <= :) ).  Let’s say we wanted to look at memory for data.

 

In the Debug->Windows menu, select Memory->Memory 1

image

 

A window will open up like this:

image

 

That is showing what’s in memory, starting at the address 0x00287764.  What you want is the address of the variable data.  In the address box enter the value &data.  (For non-C++ programmers reading this, & is the address of operator, which returns the memory location of a variable ). 

 

Now you will see:

 

image

 

As you can see, data is located at 0x006D781C and is full of exclamation marks ( shown on the right ), which is represented by ascii character code 21 ( as shown on the left ).  Looking at memory can often help you find nasty bugs.

 

 

Debugging in other languages/IDEs

 

The instructions above were obviously C++ and Visual Studio related, but you will find other than the windows looking a bit different, some slightly different names and different hot keys, the process is almost identical.  Instead of going through the same process for every language, I will instead point out where all of these things are located or what they are called.

 

 

 

Java in Eclipse

 

Starting/Stopping:

Just like in Visual Studio, there is both a debug and run mode.  In order to debug in Eclipse you need to run using debug.  There is a menu option available:

image

You can also right click your project in the Package Explorer and select Debug As->Java Application.

image

 

Or using the Debug icon in the toolbar:

image

 

When you debug in Eclipse, you will be prompted to open in Debug perspective:

image

 

A perspective is simply a collection of windows and toolbars to accomplish a given task… such as debugging.  You can switch between perspectives using the top bar:

image

Or using the menu Window->Open Perspective.

 

 

Setting a Breakpoint:

You can set a breakpoint in a number of ways in Eclipse.  In a source window, you can right click the side column and select Toggle Breakpoint ( or CTRL+SHIFT+B ).  This adds a breakpoint, or removes on if there is one currently added.

image

You can also toggle a breakpoint using the Run menu:

image

 

Step Into/Step Over/Step Out:

While running in Debug perspective, you can perform stepping using the toolbar:

image

You can also resume and stop your program using this toolbar.  The icons are Step In, Stop Over and Step Out, from left to right.

 

You can also step using the Run Menu:

image

You can also use F5/F6/F7 to control stepping.

 

Watch Window

In Eclipse, Locals and Watch are in the same view, “Variables”. 

image

 

Variables should be available automatically when you launch into Debug perspective.  However you can also open It using the menu Window->Show View->Variables.  Or Alt+Shift+Q, then V.

 

image

 

Local Window:

See above.

 

Evaluate Expression:

Evaluate expression is called “Expressions” in Eclipse and is available using the same menu you used to open Variables.

image

Once again, you can dynamically execute code and see the results using Expressions.

 

Conditional Breakpoints

To set a conditional breakpoint in Eclipse, add a breakpoint like normal.  Then right click the dot and select Breakpoint Properties:

image

Then in the resulting dialog, check condition and enter your condition logic in the box below:

image

 

 

JavaScript in Chrome

 

Starting/Stopping:

In Chrome ( and other browsers, IE, Opera, Safari and Firefox are all very similar in functionality ), there is no such thing as debug or release, unless I suppose you count minified code.  Simply set a breakpoint in your JavaScript and refresh the page.  You will however have to open Developer Tools to be able to set a breakpoint.  Do this by clicking the Chrome menu button, selecting Tools->Developer Tools

image

 

Or as you can see above, press F12 or Ctrl + Shift + I.  Memorize that key combo, trust me…

 

Setting a Breakpoint:

To set a breakpoint, in the go to a source file:

image

 

Then in the source listing, right click on the left column and select Add Breakpoint:

image

… bet you can guess how to set a Conditional Breakpoint… ;)

You can also toggle a breakpoint using CTRL + B.

 

Step Into/Step Over/Step Out:

Step Over: F10

Step Into: F11

Step Out: Shift + F11

 

Or you can use the toolbar:

image

 

 

Watch Window

Window is located on the right hand side of the developer tools and is called Watch Expressions:

image

 

Expressions and Watches are combined into the same interface.  You can simply add a new one by clicking the + icon, then type code accordingly:

image

 

Local Window:

Called Scope Variables in Chrome.  Located in same area:

image

 

Evaluate Expression:

See watch above.

 

Conditional Breakpoints:

Just like adding a regular breakpoint, but instead choose Conditional Breakpoint.

image

Then type your conditional logic code:

image

 

WebStorm / JavaScript

 

Ok.. I’m just being lazy here.  I remember I already wrote an article about debugging in WebStorm… recycling is good, no? ;)

 

Debugging your app in WebStorm

 

It actually covers 100% of what we just talked about above, except of course the memory view, as it isn’t applicable.

 

Ok, Done talking now

 

As you can see, across tools the experience is very similar.  Some IDEs are worse ( Xcode… ), some are very limited ( Haxe in FlashDevelop ), but generally the process is almost always exactly the same.  Of course, I only looked at a couple IDEs but you will find the experience very consistent in several different IDEs.  It’s mostly a matter of learning a few new hotkeys and window locations.

 

One area that is massively different in command line debuggers, such as gdb.  You are still doing basically the same things, just no nice UI layer over top.  A discussion of gdb debugging is way beyond the scope of this document and there’s tons of information out there.  Heck, there are books written on the subject!

 

Hopefully that process was useful to you.  A while back I posted an example where the debugger saved my ass if you want to see this actual process in action.  Debugging should be a part of your development process, it will make your life a hell of a lot easier, and your hair a hell of a lot less white.

 

Let me know if that wasn’t very clear, this tutorial may actually require a step by step video companion to go along with it.  If so, please let me know.

Programming


18. July 2014

 

So, as you may be able to tell from the title, I’ve run into a bit of a bug moment.  I am in the process of getting Blender exported models to work with the Three.JS library, as a follow up to this post.  As with all things programming related you are going to run into your share of problems.  This post actually walks through the process of identifying and fixing a bug.

 

The first lesson of bug hunting is always simplify.  Try to replicate the problem in as little code as possible.  What follows below is a blow by blow of  the debugging process.

 

First off, it’s a Three.JS project using TypeScript authored in WebStorm.  All of these points are important to this story.  Not to ruin an upcoming post with too much code, I’ll just give the applicable code.  The problem is in this code… if it’s in code at all that is.  Yeah, that’s a bit of a hint.

 

        var modelLoader = new THREE.JSONLoader();

        modelLoader.load("dice.jsm", function(geometry,materials){
            var mesh = new THREE.SkinnedMesh(geometry,new THREE.MeshFaceMaterial(
                       materials));
            mesh.position. x = mesh.position.y = mesh.position.z = 0;
            this.scene.add(mesh);
        });

 

Anyways, I started off by trying to load this model:

image

Exported from Blender to Three.JS JSON format.

 

When I run the code however I get the following in WebStorm:

image

 

Unexpected token /?

 

Hmmm, looks like something went wrong in the export process.  This is never a fun thing to debug, as the output of the above model is a JSON file 1.5MB in size.

 

So, it’s time to simplify.  I need a model with a texture, nothing more.  Let’s make something about as basic as possible.  So I hack together a quick textured model in Blender and export it.  This is the new model:

image

 

Ok, that is definitely simpler.  Now when I run it I get the exact same error.  Ok, this file should be a hell of a lot easier to debug.  Let’s take a look at the generated JSON file.  Oh, top type… right click the js file and tell Webstorm to treat it as plain text, otherwise it will clobber your CPU trying to parse the javascript!

 

 

{

	"metadata" :
	{
		"formatVersion" : 3.1,
		"generatedBy"   : "Blender 2.7 Exporter",
		"vertices"      : 8,
		"faces"         : 6,
		"normals"       : 2,
		"colors"        : 0,
		"uvs"           : [24],
		"materials"     : 1,
		"morphTargets"  : 0,
		"bones"         : 0
	},

	"scale" : 1.000000,

	"materials" : [	{
		"DbgColor" : 15658734,
		"DbgIndex" : 0,
		"DbgName" : "Material",
		"blending" : "NormalBlending",
		"colorAmbient" : [0.6400000190734865, 0.6400000190734865, 0.6400000190734865],
		"colorDiffuse" : [0.6400000190734865, 0.6400000190734865, 0.6400000190734865],
		"colorEmissive" : [0.0, 0.0, 0.0],
		"colorSpecular" : [0.5, 0.5, 0.5],
		"depthTest" : true,
		"depthWrite" : true,
		"mapDiffuse" : "crate.jpg",
		"mapDiffuseWrap" : ["repeat", "repeat"],
		"shading" : "Lambert",
		"specularCoef" : 50,
		"transparency" : 1.0,
		"transparent" : false,
		"vertexColors" : false
	}],

	"vertices" : [1,-1,0,1,0,1,-1,0,0,0,-1,0,1,0,0,0,1,1,-1,1,0,0,0,0],

	"morphTargets" : [],

	"normals" : [0.577349,0.577349,0.577349,0.577349,0.577349,-0.577349],

	"colors" : [],

	"uvs" : [[0.988679,0.99767,0.988677,0.016243,0.007251,0.016244,0.007252,0.
	997671,0.989755,0.017099,0.989755,0.998526,0.008328,0.998526,0.008328,0.017099,
	0.990714,0.989755,0.009287,0.989755,0.009286,0.008328,0.990713,0.008328,0.
	000516,0.993662,0.981943,0.993661,0.981942,0.012235,0.000516,0.012235,0.987766,
	0.997568,0.987766,0.016141,0.006339,0.016141,0.006339,0.997568,0.986807,0.
	986807,0.986807,0.005381,0.00538,0.00538,0.00538,0.986807]],

	"faces" : [43,0,3,2,1,0,0,1,2,3,0,0,1,1,43,4,7,6,5,0,4,5,6,7,0,0,1,1,43,0,4,5,1,
	0,8,9,10,11,0,0,1,1,43,1,2,6,5,0,12,13,14,15,1,1,1,1,43,2,3,7,6,0,16,17,18,19,1,
	0,0,1,43,3,0,4,7,0,20,21,22,23,0,0,0,0],

	"bones" : [],

	"skinIndices" : [],

	"skinWeights" : [],

  "animations" : []


}

 

Well, first obvious thing is to look for an offending / in this code.

Hmmm… there is none.  Well we wouldn’t make the big bucks if this was easy now would we?

 

Let’s go back to our error for a second:

image

 

Well, other than the fact we know we have a / where we shouldn’t, we also have the line of code that is going all explodey.  Let’s start there.  This is one of those things that makes WebStorm so freaking cool.  Just click the link “three.js:11960” and it will automatically download that script file and go to that position.  Let’s take a look at the resulting code:

image

 

Ok, that’s some pretty straight forward code.  Basically it’s a XML response function handler.  As we can tell from the above code, the callback executed all nice and dandy.  As you can see on line 11960 I’ve set a breakpoint to pause execution before our exception, let’s see if that gives us any insight.  If you don’t know about breakpoints and debugging, drop everything and learn.  You will literally become a better programmer overnight.

 

So… to the debugger!  Let’s see what the value of responseText is:

 

By hovering over it, everything looks fine, seems to match the file we are expecting:

image

 

That said, let’s take a look at the whole thing.  Now we are going to use a feature called “Evaluate Expression”.  Again, if you don’t know what this is, drop everything and go learn.  I really need to write a debugging tutorial…. 

 

image

 

Copy the value and paste it into your editor of choice.  Then scroll to the very bottom:

image

 

Oh son of a bi….

 

That my friend, is our bug.  See, Webstorm has the ability to generate something called a SourceMap, which helps the debugger translate your running code to the code you created, especially useful if you, like me, are working in a JavaScript generating language like TypeScript.  As you can see, sometimes this is not ideal however.  Basically when run, Webstorm was appending a source map to the bottom of our js file, rendering into invalid JSON and causing the parser to puke.

 

There are two immediate solutions to this problem.  First, we can disable source map generation.  This unfortunately is a project wide setting as far as I can tell, and I rather like the ability to debug.  The easier solution is to change it from a .js file to something different.  However, once deployed to a server this can have unintended side effects.  For example, IIS will not, by default, serve files without a registered mime type.

 

Oh, and for the astute, once I got past the problem be renaming the file extension, I did in fact discover two errors in my code.  The proper TypeScript code is;

 

        var modelLoader = new THREE.JSONLoader();

        modelLoader.load("dice.jsm", (geometry,materials) => {
            var mesh = new THREE.SkinnedMesh(geometry,new THREE.MeshFaceMaterial(
                       materials));
            mesh.position.x = 0; mesh.position.y = mesh.position.z = 0;
            this.scene.add(mesh);
        });

 

Why is an exercise for the reader. :)

Programming


13. July 2014

 

It’s funny the things in life that irritate the hell out of you.  This is one such example for me.  For HTML5 development, I generally use WebStorm as my IDE and Chrome as my default browser.  Webstorm has a plugin debugger that integrates directly into chrome.  However, whenever you run your application, there is this exceedingly annoying yellow bar across the screen saying “JetBrains IDE Support is debugging this tab”:

 

image

 

You can disable it by clicking the x, unfortunately each time you run your code it appears again.  It’s one of those things I just let annoy me, as opposed to looking in to a more permanent solution.  That, it turns out, was rather stupid, as this is fairly easily fixed.

 

In Chrome’s URL box, enter chrome://flags

image

 

Scroll down and locate Enable Silent Debugging and click Enable.

 

image

 

Relaunch Chrome and PRESTO, no annoying yellow bar!

 

image

General


13. July 2014

 

You may notice over time on GameFromScratch.com the way code is posted changes quite often.  There are a few reasons for this.  First and foremost, I most commonly use Live Writer when writing blog posts on Windows.  Originally I used a plugin that did code formatting like you see in the C++ tutorial series.  It was really flaky though and eventually just stopped working.  Short of a complete OS re-install there wasn’t any way to get it running again.  Obviously this wasn’t an option.  I switched to a different Windows Live Writer plugin for text formatting, but it only supported a couple of languages and I have probably done code samples for over a dozen language, so that was a bit of a deal breaker.

 

Quite often though, I am working on a Mac and that makes Live Writer a complete non-starter.  On Mac I use a program called MarsEdit, which has an OK RTF paste option and I can get code markup via Sublime Text like described here.  On Mac, code samples, such as in this series, were entirely dependant on the application I used.  Meanwhile on Live Writer I used a plugin called VSPaste, which in reality just pastes an RTF file from the clipboard to Live Writer, and generally it works OK.

 

The problem, in both cases, is if the RTF copy didn’t go as smoothly as I hoped.  Sadly this is quite often, posted code from IntelliJ ( with RTF copy plugin or using IDEA 14 which builds it in ) or WordPad for example just don’t work.  The line breaks don’t turn out correctly and it ends up looking like this:

public class DesktopLauncher {    public static void main (String[] arg) {        LwjglApplicationConfiguration config = new 
LwjglApplicationConfiguration();        config.width = 720;        config.height = 1280;        new 
LwjglApplication(new SetCenterIssue(), config);    }}
ïÿiªá€

 

… not exactly ideal.

 

The end result was to write my code in whatever IDE I am using, then paste it into Eclipse or Sublime Text and paste, whichever has the best formatting.  If that sound’s like a bit of a pain in the ass, well, it is.  In the long run I should look at using something like Gist for all code segments.  For now though I’ve found a nice little work around.  It’s still an extra step, but it’s much smoother.

The above example posted as HTML:

public class DesktopLauncher
{
    public static void main (String[] arg)
    {
        LwjglApplicationConfiguration config = new 
        LwjglApplicationConfiguration();
        config.width = 720;
        config.height = 1280;
        new LwjglApplication(new SetCenterIssue(), config);
    }
}

 

Or as RTF:

public class DesktopLauncher
{
    public static void main (String[] arg)
    {
        LwjglApplicationConfiguration config = new 
        LwjglApplicationConfiguration();
        config.width = 720;
        config.height = 1280;
        new LwjglApplication(new SetCenterIssue(), config);
    }
}

As you can see, it’s not perfect, in the case of an RTF paste, the background isn’t copied.  I am used to this already with Visual Studio paste, I manually go in and edit the generated HTML’s background color each time I paste a sample.

 

So, what am I using now?  A wicked little program named Highlight that is available for basically every platform out there.  The program has an amazing amount of versatility, and since it isn’t a plugin, it’s not going to break every time I look at Live Writer funny.  It’s available both as a command line utility or using a GUI and has an amazing amount of functionality.

 

The work flow is pretty simply… either point it at your source file, or copy your file to the clipboard.  Pick the language of choice ( it’s basically got all of them covered ), pick your formatting options, then paste it back to the clipboard.

 

Here is the main screen of Highlight in action:

image

 

The language choices… ( or, at least, some of them ):

image

Let’s just say, every language I could think of needing ( TypeScript, JavaScript, HaXe, C#, C++, etc… ) was there.

Then the code formatting options:

image

 

You can export to a number of different sources:

image

 

And for each output format, you’ve got a number of options, such as below for HTML:

image

 

So, if you need to paste code samples into a blog or other project, you owe it to yourself to check out Highlight.  It’s one of those products I wish I found 4 years ago!  For you command line warriors, there is a disturbing amount of flexibility available.  For example, you could recursively convert all .cpp files in a hierarchy of directories to SVG with a single command.

 

Oh and best of all, it’s completely free!

 

So, if you notice yet another change in the way code is formatted on GameFromScratch, this is why!  Hopefully it will be the last major change in a long time, and code samples should look more consistent across platforms from now on!

Totally Off Topic


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