I’m pleased to announce my latest book which explains how to write a retro-style text adventure in Java using object oriented techniques. I already have a book on programming adventure games in C#. The new Java book explains all the techniques described in that book so that you can parse user commands (e.g. “put the sword into the sack”), take and drop objects, move around a map, save and load games and so on. But it also goes much further, to explore more advanced techniques.
For example, it can use adjectives to distinguish between similar objects. Maybe there are three swords here. The user says “take sword”. The game may now reply “Do you mean the gold sword, the silver sword or the Elvish sword”? Or the player may write commands such as “Put the small gold ring into the big brown wooden box.”
I also explain how to use recursion to ‘unwind’ networks of objects into linear lists. For example, if you have a sack containing three boxes and each box contains three treasures, you would need to navigate a network of objects to locate each treasure. You can either do that recursively each time the player wants to interact with the treasure or you can create a linear list of treasures so that your code can iterate through that list (for 1 to 10, say) instead of recursing down the network of objects.
And I’ve added a ‘mass’ property to objects. The mass is defined as a value that indicates how difficult that object would be to carry. It’s not really ‘mass’ as a physicist would understand it! So a huge but very light kite might have the same mass as a small but very heavy gold brick. Every time the player picks up an object, the ‘mass’ being carried increases until no more objects can be carried. And it’s no good cheating by putting massive objects into low-mass containers (say, a sack) and then carrying that container. Thanks to recursion, my code calculates the entire mass of containers and everything they contain!
The Little Java Book of Adventure Game Programming is available in paperback or Kindle format, from Amazon stores worldwide:
If you've subscribed to my YouTube channel you'll know that I have lots of lessons on programming C, Java, Delphi, Ruby and more. Over the past few months I've been posting a series of videos to help people get up to speed with C# programming. These lessons can be followed in order if you are new to C# or you can just jump in to watch whichever lesson is of interest. This is the latest video...
The complete course is called The Little Course Of C# and you can view all the lessons (more to be added later on) HERE.
Recursive programming is surprisingly hard to learn for something that, in essence, is really quite simple. A recursive function is one that calls itself. So, you might have a function called x() which somewhere inside its code calls itself x() rather than some other function such as y().
Recursion is a very valuable technique when you want a function to do an operation a certain number of times until it’s run out of things to do. For example, if you want to count all the files in a set of subdirectories you can use recursion to keep looking for more subdirectories until there are no more subdirectories (or subdirectories of subdirectories) to recurse. Then you can count the files in each subdirectory. This sounds like it should be easy to do – and in essence it is. But unless you really understand how recursion works, it can be tricky.
I teach a whole course on recursion and I also have a book. Either one will teach you all you need to know to understand recursion – what the stack is; how frames are added to and removed from the stack whenever a function is called; how to save values from recursive functions; how to return values; how to avoid infinite recursion and more…
The code examples in the course and book are mainly given in C and Ruby. However, recursion works in a similar way in all mainstream languages. To prove this, I’ve translated most of the C code into Java. You can get all the free source code (C, Ruby and Java) just by signing up to my mailing list and I’ll send you the download link: www.bitwisebooks.com
Meanwhile, here’s a short lesson explaining how to write just about the simplest possible recursive function in Java…
So I loaded up Delphi (Community Edition) this morning and I saw an unhelpful dialog box telling me that the software had expired and prompting me to enter a valid serial. I found my serial number, entered it, but it wasn’t accepted. What was I to do? The damned dialog box didn’t give me any other options.
I did that. Or tried to. Every effort I made to log in failed with a warning that my session had expired. Maybe my browser (Chrome) was the problem? OK, so I tried in Firefox. Same error. In desperation, I tried the Microsoft Edge web browser. Amazingly, this time I managed to log in.
I now had to download the latest version of the software, uninstall my old version, install the new one, wait for a new serial number, enter that… anyway, eventually the installation went again successfully.
Look, I like Delphi. I’ve used its Object Pascal language ever since Delphi was first launched and before that I used its predecessor, Turbo Pascal, since the early 1980s. But, come on, chaps, this download-and-install palaver is nuts. You provide a free edition of Delphi (good) but you make it bomb out after a year and then you go to some lengths to make the reinstallation as painful as possible. It’s a positive incitement to use the open source Object Pascal alternative, Lazarus instead: https://www.lazarus-ide.org/index.php?page=downloads
The history of the free edition of Delphi is an odd one. From the launch of Delphi 1, way back in 1995, I was the Delphi columnist for PC Plus Magazine in the UK. I wrote Delphi programming columns every month for over ten years and readers could follow along using the free copy of Delphi that its developers, Borland, supplied on the PC Plus cover disk. Whenever a new version of Delphi was released, we had a new free copy on the cover disk.
Then the Borland programming team split away to form a company called CodeGear and they were quickly bought up by another company called Embarcadero. Sadly, Embarcadero didn’t seem to understand the importance of providing a free edition. I asked for one so that I could teach a course on Delphi. And for the first time ever, my request was refused. So I based that course on Lazarus.
In the meantime, Microsoft had decided that it would be a jolly good idea to provide free copies of its IDE, Visual Studio, to anyone who wanted one. Visual Studio doesn’t support Pascal as standard but it does support C# – a very good language that was created by Anders Hejlsberg, the man who had previously been responsible for Delphi before Borland made the unfortunate error or losing him and other members of his team to Microsoft.
Now let me be ruthlessly honest. Delphi/RADStudio is a fine programming environment. But it’s not as good as Visual Studio. Visual Studio is simply the best. Embarcadero must have noticed that the Delphi market was dwindling while C# was very much in the ascendant. Rather (too) late in the day they decided to release a free Community Edition of Delphi. OK, so better late than never.
But then they go and implement this incredibly infuriating expiry, download and update mechanism. This doesn’t stop you carrying on programming with Delphi after one year is up. All it does, is make you very annoyed with the software and the company for making the update process as inscrutable and infuriating as possible. I have no idea why they do that. It’s bad PR, it’s bad marketing, it’s just really bloody annoying.
OK, so I finally have Delphi reinstalled. But I now feel so ill disposed towards it that I think I’ll spend the rest of the day programming in Visual Studio!
As a passionate adventure game player and programmer, from the 1980s onwards, I’ve decided that the time has come to help other programmers embark on the noble quest of developing retro-style adventure games. I’ve already taught a course and written a book (available on Amazon US, Amazon UK and worldwide) on writing adventure games in C#. But if you’ve never written a game before you might still find it hard to implement all the features needed. Wouldn’t it be great if someone had already written a library of classes that encapsulated all the essential behaviour needed for a game – a parser to interpret text commands, Rooms to create a map, Treasures to create objects, actions to let the player look at objects, take, and drop them or put one object inside another one?
Welcome to BIFF!
BIFF is short for The Bitwise Interactive Fiction Framework. I’ve spent much of the last year writing this framework in Java and now I’m starting work on translating it into C#. The Java version of BIFF is currently more complete – it can handle reasonably complicated commands such as “Put the small golden egg into the big carved wooden box” or “Unlock the treasure chest with the magic brass key”. I will make BIFF for Java freely available later in the year.
Since many people have already read my C’# book or followed my course, I decided that, rather than wait until the C# release of BIFF has all the features in the Java version, I would release BIFF for C# in incremental stages so that existing readers and students can carry on developing their games using the new features. This necessarily means that the early releases will always be substantially incomplete. However, if you want to deepen your understanding of game programming, this is a great opportunity for you to try to modify the latest release by adding on additional features. You are free to modify BIFF as required as long as you leave my copyright notice in the comments of the source code.
To download the code of my C# adventure game book (whether or not you’ve actually bought it!) as well as the current release of BIFF for C#, juts sign up to my mailing list at www.bitwisebooks.com. Meanwhile, here is a short introduction to BIFF…
If you’ve read my book or followed my course on adventure game programming in C#, you will already know how to create a map of linked rooms which the player can wander around in order to take or drop treasures. You will be able to communicate with the game using simple English language commands such as “Take the sword” or “Put the coin into the box”.
But what happens if there are several swords in the current location? In that case, when the player enters: “Take the sword” you want to game to reply:
“So you mean the gold sword, the silver sword or the Elvish sword?”
And when there are multiple coins boxes here, the player should be able to enter:
“Put the small silver coin into the big carved wooden box.”
In order to do that, we need adjectives – “big, small, gold, silver, carved, wooden” and so on. To implement that I’ve begun to extend the code that was supplied with my book. My aim is to create a reusable game framework of ready-to-run classes that you will be able to use to program your own games. This code is in its very early stages at the moment. The main new feature is the addition of adjectives to the parser. I have not yet defined properties to match those adjectives for the treasures. That is, while you can say “take wooden box”, the game doesn’t yet check if the box you want to take really is wooden. I’ll add that in a future update.
The game framework is called The Bitwise Interactive Fiction Framework (BIFF) for C#. I’ll also shortly be releasing a version of BIFF for Java. To keep up to date with developments and download the source code for BIFF (and for my any of my books and YouTube tutorials), just sign up to our mailing list on: www.bitwisebooks.com.
In my recent review of the screencasting suite, Camtasia 2020, I said that “The latest release of Camtasia is less focussed on adding big new features than making the existing features easier to use”. Since writing that review I’ve become aware of one feature that makes Camtasia harder to use – well, for long-time Camtasia users at any rate. Because the new release no longer supports old Camtasia file formats. That means that if you made some recordings a few years ago and you want to load and edit them with Camtasia 2020, in all probability you won’t be able to do so.
Put simply, Camtasia 2020 no longer supports older Camtasia project files (with the extension .camproj) nor screen recording files (ending .camrec). I Googled for help on this and the only solution I found (in the Techsmith forums) was to use Camtasia 2019 to convert .camproj files and then load those into Camtasia 2020. But even if you do that, the individual clips (.camrec files) are invalid so in effect the conversion fails. I contacted Techsmith to see if the company had a solution to this problem. This is what the Camtasia project manager replied:
“You are correct that both camproj (projects) and camrec (recording) formats were retired in 2020. We replaced both formats many years ago (I believe TREC was introduced sometime in 2014 in version 8 of Camtasia) to introduce cross-platform project and recording support between Windows and Mac. You are also correct that the solution for opening camproj files is to open them in 2019 and then convert them to the tscproj format. Unfortunately, there was no easy or fast method of handling this for camrec to TREC format. We investigated to see if this would be worth the investment, but only a very small percentage of imports (something like 0.05%) were camrec format.
“Probably the easiest workflow for getting these older videos into 2020 will be to install Camtasia 2019, which will install the camrec shell extension. With this, you can right-click on camrec files in the Windows File Explorer and extract the video as an AVI. You can then bring this video into Camtasia 2020 (note that this will not include any cursor data though; if you need the cursor, you will have to produce the video from Camtasia instead).”
Mediaeval history is not a subject that I often discuss here but I am going to make an exception to that rule because I've discovered the best history videos I've ever seen (and that includes those made by TV companies such as the BBC or The History Channel). They are all freely available on YouTube and if you have the slightest interest in how knights managed to go into battle wearing armour, how they trained their horses, what they ate, how their swords were made - in fact, if you have any curiosity about what the Middle Ages were really like (not what they look like in the movies), I have this simple advice: subscribe to the Modern History channel today!
This is just one of their videos...
This channel is the creation of Jason Kingsley, the founder and CEO of the Rebellion computer games company. When not running his business, he lives the life of a mediaeval knight. His channel is one of the great gems of YouTube. He really brings history to life. He goes to an armourer to see how suits of armour were made. He puts the 'shield wall' battle strategy to the test. He has sword fights, he jousts. He doesn't just talk about things - he actually does them. I am blown away by this channel. It deserves to be much better known.
Camtasia is a long-established and widely-used screen-casting program, available for both Windows and Mac. It lets you record direct from your computer so it’s ideal for making software demos, tutorials and walkthroughs. Here I look at the newly released update, Camtasia 2020, which I tested on Windows 10.
Camtasia is a great tool for making screencasts. It lets you record from the whole screen, from a selected window or from a marked rectangular area. Optionally you can make a simultaneous recording from your webcam and there are even tool to add annotations – boxes, circles or free-form drawings – while you are recording. When you stop recording, your new video clip is added to the Camtasia editor. In the editor you can arrange multiple clips on a stack of tracks. Clips can be cut, moved, slowed down or sped up. Adjacent clips can be smoothly joined using transitions to fade one into the next or create dissolves and folding effects. You can zoom in or out, add annotations and callouts (text and speech bubbles), and apply various types of animation. You can do basic audio editing to change the volume and remove background noise. And, if you recorded your webcam video in front of a coloured backdrop (usually a green screen) you can remove the background colour so you appear ‘in the scene’ that you recorded from the computer screen.
The latest release of Camtasia is less focussed on adding big new features than making the existing features easier to use. For example, whereas previously each new project started as a blank workplace waiting for video to be added, there is now the option of picking a pre-designed template that sets up a project complete with intros, outros, animations and titles. You can also create your own templates and save those for re-use.
These are some of the downloadable templates that can be used when starting a new project
The theme management has been extended too. You can create themes to do things such as set the colours and fonts of annotations and callouts. Camtasia 2020 now lets you preview the effects of those themes in the Callouts panel.
A Favourites panel has been added to the workplace. This lets you group together the tools and effects you use most often. For example, if I find I frequently use the Fade transition but rarely any others, while I use the noise-removal tool but not the other audio tools, I can click a ‘star’ icon in the corner of each tool or effect in order to add it to the Favourites panel. Then when I need to add transitions, audio effects, visual effects and annotations, I can select them from the Favourites panel instead of having to load up half a dozen different panels and scroll down to find the item I need.
The editor has gained a few handy features too. You can now add placeholders to the timeline. These are like ‘empty’ clips. You can move, cut and resize placeholders and then add an actual piece of video by dragging it onto the placeholder. This also makes it easy to replace one clip with another. If, for example, you’ve already finished a project but decide to replace a single clip, you can change the existing clip into a placeholder then add a new clip to it without being forced to re-edit the rest of your project.
Tracks have an optional ‘magnet’ mode. This means that adjacent clips automatically snap to one another, eliminating any gaps. The timeline can be detached so that it can be used in its own floating window. This is particularly useful if you are editing on a multi-monitor system, since you can place the timeline fullscreen in the second monitor.
Here I'm editing on a dual-monitor PC. I've detached the timeline so that I can use it fullscreen (left) on my 2nd monitor
Track mattes are a new effect that can be enabled for media with ‘transparency’. In effect this removes the transparent areas from an image or video to allow clips beneath it to show through. If you want to share your customised changes to Camtasia – themes, shortcuts, templates and so on – the new package exporting tool simplifies this process by giving you the option of selecting the specific things you want to export. These are saved to a file and can be imported into an installation of Camtasia on another computer.
The official Camtasia 2020 demo
Although Camtasia can be used to edit and produce video recorded from any source (such as digital cameras), its real strength is in recording action from the computer screen. There is little change to the screen-recorder in this release apart from the ability to record up to 60 frames per second (the previous maximum was 30 fps but see HERE for a technical explanation of the actual framerate). It would have been nice to have had the option to record from webcam alone (without also recording from the screen) but this still isn’t possible. If you want to record a plain ‘to camera’ video you have to record the screen as well and then delete the screen-recording in the editor.
The Recording toolbar
While there are various free templates, themes and resources available for Camtasia, these have to be downloaded, one at a time, from the web site . It seems to me that it would have been better if they were installed by default or, at any rate, downloaded in a single step. To be honest, this would seem to be the perfect project for Camtasia’s new package import/export feature to let the user import all additional content in one go. Also, bear in mind that while some of these ‘added extras’ are free, others require a subscription. A subscription also gives you access to other resources such as royalty-free video footage, images, music loops and sound effects. The subscription costs £192.95 a year, so you would probably need to use quite a lot of the available content to make it worthwhile.
Which brings me to the subject of the cost of Camtasia itself. At around £241, it’s not cheap. Bear in mind that many general-purpose video editors (software aimed mainly at editing video recorded from a camera) now include a screen capture tool, including modestly priced software such as Cyberlink PowerDirector (about $99) or even free software such as OBS Studio.
Obviously, if free is what you are looking for, OBS Studio is the way to go. But while it is extremely powerful (and can be used for streaming as well as recording), it’s by no means as easy to use for recording and editing screencasts as Camtasia. If, on the other hand, your main requirement is a general-purposes video editor and only occasionally need to record from the screen, PowerDirector is a good choice.
But if screen-casting is your main requirement, Camtasia remains my top recommendation. The purchase price is justified if you regularly need to record and edit pro-quality screencasts. Given the relatively modest updates since the previous release of Camtasia, however, I can’t help thinking that the upgrade cost for existing users (£96.48) is a bit steep.
So, in short. Camtasia 2020 is an excellent screen-casting suite. The additions to this new release (as in the last couple of releases – see my reviews of Camtasia 2019 and Camtasia 2018) are useful but not extensive. While it’s not the cheapest software of its type, if you need an easy-to-use, fast and efficient screen-casting tool that lets you get your work done quickly, Camtasia would be a great choice.
There is a huge range of programming languages and a beginner may wonder where to start? Java, C, C++, C#, Python, Pascal, Ruby, Go, etc. The choices are overwhelming. In this video I give my thoughts on which languages would be good to start with - and which ones you should avoid!
Here's my latest video on programming a collapsible outliner using Delphi. In this one, I associate text notes with the branches (nodes) of a TreeView.
I’ve been programming in Delphi for over 25 years. What? Can that really be true? It doesn’t seem that long but Delphi’s just had its 25th birthday so it really must be. It was launched in 1995 and I was using the pre-release beta some months before that. I wrote the review of Delphi for PC Plus Magazine and for more than ten years after that I wrote the monthly Delphi programming columns for the same magazine.
Delphi was the successor to Borland’s hugely successful DOS-based Turbo Pascal and its less successful Windows Pascal (even I can hardly remember that – I think it was called ‘Borland Pascal With Objects’ or something equally unmemorable). At the time, Delphi was, in my view, far the best visual (drag-and-drop, design-and-code) environment for Windows. Its only real competition was Microsoft’s Visual Basic. The trouble is that no matter how visual you make Basic, it’s still Basic. Whereas Delphi used a very nice version of Pascal that had a reasonably modular unit-based system, good Object Orientation and also had low-level features for anyone who might be missing C.
To celebrate Delphi’s 25th birthday, I’ve just released a book for new or intermediate Delphi programmers. It’s called The Little Book Of Delphi and it’s available in paperback or as a Kindle eBook from Amazon.
There’s an interview with me (Huw Collingbourne) in the latest edition of the Classic Adventurer Magazine (#8) which you can download free here: http://classicadventurer.co.uk/
In the interview, I discuss everything from The Golden Wombat Of Destiny – the game I wrote back in the '80s – to my recent book, The Little Book Of Adventure Game Programming. There are numerous other articles in the magazine that should be of interest to anyone interested in retro/classic ‘Interactive Fiction’ games.
Regular readers will know that I am passionately keen on retro-style adventure games. Not only are they great fun to play but they are also great fun to program. Don't be fooled into thinking that an adventure game is a trivial program to write, however. It isn't. It requires you to use a very broad range of programming techniques: creating class hierarchies, overriding and overloading methods, generic lists, serialization to save and load networks of mixed data types. And much more.
I've recently started a YouTube series on programming games in Java. This complements my book, 'The Little Book Of Adventure Game Programming' which uses C# as the primary language.
Memory leaks are some of the trickiest things to track down when you are writing programs. Somewhere you allocate a chunk of memory and then later on, that memory isn’t freed when it’s no longer needed. Small memory leaks might not be a problem but when a program allocates huge amounts of memory, you can run into trouble. In a long programming career, I’ve seen people spend weeks trying to track down obscure memory problems. It’s usually quite easy to track down problems that cause your program to crash every 10 minutes. But once every ten days? Not so easy at all.
Of course, in modern garbage collected languages like C# and Java, memory leaks are no longer a problem – or are they? It’s certainly the case that garbage collection makes life a lot easier. In general, you don’t have to bother about freeing up memory – it’s done automatically. However, you can still get problems if you call system APIs or libraries written in another language where memory is not managed.
If you have (or think you have) a memory leak problem, then a tool to track down the source of the leak might be useful. One such tool is Deleaker. This comes with a 14 day trial period where you can use the full functionality of the tool. Deleaker helps you find and fix memory leaks in your C, C++ or Object Pascal programs developed using either Microsoft’s Visual Studio or Embarcadero’s RAD Studio/Delphi.
This is Deleaker’s own video showing integration with RAD Studio.
When installed, Deleaker can either be run from a menu item in your chosen IDE or it can be run as a standalone application so that it is available on a PC without the IDE installed. The licence allows a single user to run Deleaker on multiple PCs which is convenient if you need to use it both on your desktop computer and also on a laptop.
Here I have docked Deleaker into the Delphi IDE. You can keep its window ‘free-floating’ if you prefer.
Deleaker has a very nice integration with Visual Studio and Delphi and most of the time it works smoothly though it did crash Visual Studio on one occasion. You can also use it in standalone mode from the console – Deleaker attaches itself to the process you specify so as to perform its magic.
We tried it out on some very simple programs with a couple of memory leaks and it worked great. At the end of the run, Deleaker will identify the leaks and indicate the source of the leak. However, it doesn’t (and can’t) tell you where you should have freed the memory. But it’s a good start and with some extra coding diagnostics, you should be able to track down memory leaks reasonably easily.
In my experience, though, simple memory leaks are not the huge problem that they are sometimes made out to be. First, from my own experience early on in my programming career seeing other programmers get in real deep trouble, I’ve been absolutely fanatical about memory allocation. Because of that I’ve never had a serious problem. The other memory problem that Deleaker can’t help with is where you have accidentally reused some freed memory: you have two pointers to the same memory address and you’ve forgotten about the second pointer when you called free on the first. These can be very tricky indeed to track down.
But where Deleaker does score is keeping track of system resources such as GDI device contexts, handles and the like. It is surprisingly easy to lose track of these because they tend to exist for a long time in the program and the effects of not freeing handles are not obvious – you don’t see memory creeping up and your program slowing down dramatically until the whole of Windows starts to seize up.
Here Deleaker has produced a report of some leaks in a Visual Studio C project.
Overall, Deleaker is a nice, simple tool that fits in well with Visual Studio and Delphi and makes tracking down memory leaks much easier. It’s not a cure-all for poor programming practice, though. If you have a badly written program, it will tell you that you have a leak and the line that allocated the memory, but it’s up to you to find out where you should have freed it.
At the end of the day, while you have been careful about memory allocation and resource tracking (and in my case paranoid about it) – how you do you know that you have no memory leaks? Without something like Deleaker you won’t - and here Deleaker does shine in acting as a quality check keeping track of memory and non-obvious system resources: it’s always a lot cheaper to fix bugs before releasing software and any tool such as Deleaker that helps produce bug free software is well worth the money.
For this review Dermot Hogan reviewed Deleaker for Visual Studio (Huw Collingbourne tested it with Delphi)
