C / C++

C++ Programming Related Blog Posts

How I Made Reversi Magic For Android/iOS (And Games In General)

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A few weeks ago, I took a bunch of my old computer systems (Atari’s, GameBoys and Sega Systems) to my kid’s school to show them off as part of his “History Of Video Games” project he had worked on. Several of the kids ask me, as a games programmer, how I make them, and even my own kids recently have started asking questions about how I make the small games that I do, so I thought I would write this up showing how I made my Reversi Magic game to hopefully educate them a little bit, and also anyone else who might be interested in learning the process.

Firstly, I should start by saying that the various methods used by different people tend to be very different; I take a more OldSkool approach to writing games than say, some of the modern game programmers. Also, being that I work mostly in my spare time, at home, at night, in-between a full time job & managing the kids, some things get done with more priority than others. Someone with more resources/time etc. can probbably get things done a lot quicker. That being said, i’m always open to feedback so feel free to comment on this if you have some 🙂 Don’t shoot me if I do something differently than everyone else 🙂

Coming Up With Ideas

Before I start laying in any amount of code, I usually try to come up with an idea of where I want the game to go. Depending on the game and whats going on, there might not even be an idea yet. Ideas tend to come from existing games, so you might have a couple of web games that seem good, but if one had this feature, or copied ideas from this, it might be even better. If I have a general idea of what I want to work on, i’ll take an empty project file of mine (which consists of the game basics such as the menu’s and basic graphics, enough to be able to press Play, and just start adding game code right away) and modify it to work with a very crude, but simple engine showing the gameplay for this idea. This will be tweaked until the game is able to do what I was thinking of, then its evaluated for how well it plays.

 Some of these tests might seem pretty good, even with very basic graphics (often coloured blocks or re-used images). Others, will be quite bad. It’s not a bad thing if the idea doesn’t yet work, it just needs more refining. After working on a very basic idea, its often good to have a friend play with it and have them give you some feedback. You are trying to find an idea thats engaging to you and your players, so if your friend is very quickly bored, or finds the idea too challenging or confusing, then you need to head in another direction.

In this picture, this game (called Avalanche!) was put together in about 2 days altogether, to show off some ideas I had about a columns-based game, and matching snowflakes together to make some cool snowy explosions etc. In the end, I never released the game, but it was fun to work on the prototype.

In the past, I have prototyped as many as 30+ different game ideas, some better than others, until something comes up. Often, you’ll know when a good idea comes up as you’ll find yourself playing it for ages, while not getting bored of it. Also, your friends might like playing it too. They are also handy to come back on later as well, i’ve worked on some I haven’t touched in years, bringing some new changes and various elements to the table that turn it into a better game.

The Design Process

Once you have thought of a solid idea to work on, it’s often a good idea to do a brief design draft of where the game should be heading, so that you don’t fall off the wagon too easily. If you’re going a route that’s not recommended or you get stuck what to do next, you still have your plan to fall back on for guidance. Again, depending on the type of game you are writing, you can also define a list of specific behaviour rules here, that must be followed at all times. For example, if it’s a puzzle game, you would lay out the logic here exactly, so that you know exactly how it’s supposed to play. If its doing something its not supposed to, you can later analyze this logic to start tracking bugs. This is more important for larger games, or puzzle games that have a lot of different AI/Logic combinations.

Normally I do paper notes for almost all of my games, I still have notebooks with designs in them from my days of writing programs on the ZX spectrum games! One day, i’ll put all that stuff online, but it won’t be today hehe 🙂

Below is my notebook pages that I did for my Reversi Magic game, that’s currently available on Android, iOS and Kindle Fire. The notes were done a year or so ago. The idea was very simple, and I have always been interested in playing Reversi on the computer, with this game not being my 1st on the computer. The goal was to make a simple, easy to pick up game that anyone could familiarize themselves with, without having to learn any new rules or be bombarded with over-the-top graphics. Not all games require notes, but it doesn’t hurt to play with pen/paper every so often to make some design sketches. These 2 pages are the design spec that I originally set forward to complete:

 

The 1st page just covers some simple layout rules and goals that I would like to have the program meet, and the 2nd page shows some interface layouts for various orientations, and a few other design elements such as an idea I had for dynamic grid frames.

Applying Code

 Once you have a clear idea of where you want to go, you can start laying in code. I’m often asked which part of the game do I start on first? Most people always assume that the graphics are first. The correct answer is actually the AI/Logic of the game (how I do it anyways) with a little bit of graphics work to get the basic shape of what you are working on. The graphics for this game were actually quite simple to do. I use a CAD program called CoCreate, so I used it to make the rotating disk image and capture each of the frames for it. The picture on the left is a small version, with an added drop shadow to make the edges stand out a bit more. The actual images are a lot bigger, so they look sharp & crisp even on the iPad Retina displays. The backdrop is also translucent, so the shapes can be blitted anywhere.

I spent a full month of non-stop coding of the AI engine for the game. The tough parts were testing it to make sure it plays 100% compliant moves, so in the end, there would be a long debug report of the game, how the computer did, as well as opportunities that it took/missed so I could review and tweak the AI later. The AI algorithm itself is based on a combination mix of NegaScout & Min/Max game theories. The Min/Max algo will evaluate scores recursively for the Best/Worst possible scoring points, and NegaScout does some pruning to several paths in that tree, to ensure the answer it comes out with can be found faster. Combine this with some traditional elements of gameplay, a method of looking at grid moves to determine how risky they are, and you have a very powerful AI routine. You can learn more about the Min/Max methods Here in this great tutorial (with samples and images).

The next hardest part of programming the AI was to teach the computer not to be too hard on beginner players. Its programatically easy to make the computer as hard as nails when it comes to playing the game, but how do you adjust those levels so that they are somewhat forgiving to a new player? Again, with a reverse NegaScout algo, and a few other traditional playing rules implemented, the computer will now assist the player to some extent when playing its moves, so as not to dominate. Of course, there are always some people who are just not very good at the game (or Reversi in general), and as I have seen on the feedback for my games, they think the game is the fault and tend to leave negative feedback because of that.

Your game should also show assists/help to your players, for when they get stuck and cannot decide where to play a move. They also may not realize they can play a move in certain areas. In Reversi Magic, I added options that show you where you can place a tile, they actually cycle in and out as small transparent disks of your colour. Tap the disk to place your move. There is also an option that shows you where the opponent last moved, so if you are not following the board too closely, you can still see where they last played and how it affects your strategy. Both of these assist options can be turned off in the game Options screen at any time, though they are enabled by default for first time users of the game. In my original design, I had wanted to show how many disks were going to be flipped for each move that was shown as available, but as experienced players will tell you, playing for the best possible score every time is not the best playing strategy at all, so I eventually removed it.

Cleaning Things Up

Now that the majority of your code is done, the last part of the process is to apply the spit & polish needed before you release it. For me, this is usually when I will finalize all of my graphics, and add all of the last bits of fine tuning to the game. Normally, i’ll sit in a room with my Nexus 7 and play the game, write down all the stuff that I see that is annoying, or needs fixed (out of place text, menus that move too slow, playing effects that should happen that don’t, ways to improve the ingame experience etc. etc.) and then after I have the list, i’ll set forth on making the changes. If you are not already doing so at this point, its often a good idea to send out your game to some private testers. Friends/family often make a good choice, but you want to pick some who are open to give you criticizing feedback (and some who will actually give feedback!) Listen to their complaints and what they think might make the experience better. You might not be able to implement it 100% exactly as everyone wants it, but you might be able to meet in the middle, especially if several testers are reporting on one specific area/feature of the game (which normally means you should focus some effort on it anyways).

From Prototype, To Finished Game

 When you think that the game is ready, it can be released to the world. Be sure that before you release it, it has been tested thoroughly by your team, as there is nothing worse than having a game that gets launched on a platform such as iOS and theres a massive bug in it that prevents users from playing properly. I’ve been there, and its not a good feeling, as Apple are not very fast when it comes around to updating. The general public tend to do more crazy things with the game (seeing as there is much wider exposure to strange incidents) so putting your app through the ringer beforehand, making sure certain phone events don’t crash it, is extremely important. If you plan to release on tablets as well, be absolutely sure to test a range of different tablet resolutions, both in the Landscape/Portrait aspect. You should also make sure your graphics look good, as if someone on say a retina iPad has to look at your scaled-up low resolution logos, it makes for quite an eyesore.

In the above pictures, I have used my game Twinz! as an example of what the game may look like in prototype, to the final product. The left screenshot is from the prototype game I did in about 2005 or so. It was just a handful of images, a simple shaded image for the door shutters, and a small logo. The image on the right is taken from an iPhone running the released version of the game. As you can see, the screen’s real-estate has been cleaned up to make the size of the tiles more optimal, and get rid of the unused areas. This game runs great on tablets, and features high resolution tiles.

Whats Next?

After the launch, you can sit back and watch your total downloads go up for each market, and wait for your customer’s feedback. Most players are nice in that they will contact you directly about any bugs they might find, before they leave negative feedback, so if you do get not-so perfect app feedback, or bug reports, be sure to get right on top of them and prepare for an update in the future.

While I have yet to become mega rich or famous from one of my games, this is still a hobby that I love to do, and hope that one day at least one of my games will be successful enough that I can quit my job and focus on doing this full time 🙂

If you want to play any of the games mentioned above, or any other games of mine, please visit the app store for your preferred device and try them (there are free versions of all of my games): Amazon App Store (For All Kindle Fires), Apple App Store, Google Play

Should you find the info in this page useful for anything, show your support by buying a game! If you have questions, ask in the comments or send me a quick email. Thanks!

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Reversi Magic Updated For iOS / Android / Amazon Kindle Fire

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I have been spending a lot of time lately working on Reversi Magic, my Othello/Reversi game. Since the game was originally released last year, I have been spending time on optimizing the various parts of the game for AI, appearance, and also ensuring that it works on absolutely any device out there. The game has certainly come a long way since I originally started working on it!

The game’s AI functions make use of a NegaScout/PVS algorithm to determine the best possible moves based on a series of conditions, such as difficulty, board status and a few other things. The easy level is designed to be not too difficult, but good enough to keep you alert during play. As the levels get harder, the AI will step up it’s game and the Hard levels are quite tough to beat! I spent close to a full month working on AI code alone, and it was very educational for me. One day I should write up something on how the AI works, as someone else might find it useful in a different game.

embedded by Embedded Video

YouTube Direkt

Anyways, if you would like to give the Free version of the game a go, you can find it at your favourite App Store by clicking one of the links below:

appleappstoreAndroidMarketLarge

amazon-android-app-store

Screenshot Gallery for Reversi Magic:

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How To Link To All Your Apps On The App Store In iOS, and other App Stores

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While working on an update for one of my games, I ran into a problem where I wanted to create a link to every app on the App Store that I had written. Each of my games has a button for ‘More Games’ that currently just takes you to my website, where you can see the games, but what if this could be tailored to go directly to the app store page itself? This generates better install follow through, as the viewer can simply click the Install/Purchase buttons, without having to go anywhere else!

How To List All Of Your Apps On Google Play

Directing the viewer to a list of all of your published apps on Google Play is as simple as making a link to your Publisher Name, such as:

market://search?q=pub:Andy+Kellett

Or, if you wish to do it via the web, you can link to this (clickable) link:

http://play.google.com/store/search?q=pub:Andy+Kellett

If your Publisher Name uses spaces, replace them with a + instead. Feel free to check out some of my Android games at the store!

How To List All Of Your Apps On Amazon Kindle Fire

The Kindle Fire runs Android, however it does not run any of the Google services at all, and many developers make the mistake of accidentally using some of the services in their apps, which do cause problems. Nothing is more embarrassing when you release a lite version of your game, only to have the link to upgrade to the paid version not work. The Amazon method is extremely simple:

http://www.amazon.com/gp/mas/dl/android?p=com.fishguygames.WordSearchHunterFree&showAll=1

The com.fishguygames.WordSearchHunterFree is the package name of the originating request, although Amazon doesn’t appear to do much with this initially that you can see, it lets the system know where the request was generated from. You can also manually enter the above URL in a regular browser window, which will generate a new address that can also be used, such as the following:

http://www.amazon.com/s/ref=mas_dl?_encoding=UTF8&field-brandtextbin=FishGuyGames&node=2350149011

Both are 100% compatible from launch. If launched on a Kindle device, the 1st link will give you the option of viewing the app list on the web, or in the Amazon App Store. The 2nd link is only viewable on the web, even if launched on the Kindle, so for use within your App, I reccomend the top link. On Non-Kindle devices, the top link is auto-converted to the 2nd one for display purposes.

How To List All your Apps On iOS/Apple

Follow these simple steps to do the same thing on iOS for your Apple products:

SelectLinkLocation
Step 1 – Find your app in the App Store. Right click on your Publisher name, and choose Copy Link to copy the address to the clipboard, so you can paste it in the next step.

Edit The Link
Step 2 – Paste in the link, and change the http:// header (the link in the example is highlighted above) to itms://, as this will stop the app from redirecting as many as 3 times, and instead use the iTunes Store app directly, making the experience faster for the end user. This link can be used in any app and shouldn’t ever change.

App Store List
Step 3 – Test the code on different devices, to ensure it works the way you expect it to! If you wish to have the same effect from your website, just keep the URL as it was.

If you would like to play some of the various games I have written for iOS, Check Out My List Of Games for more information! This should open a window, which will then open your iTunes and take you directly to my developer pages!

I hope this post helps you!  Andy Kellett

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New Tool In Development – Litecoin Miner Status – Monitor Multiple Litecoin Miners At Multiple Pools!

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Project Update
This project has now been officially released. You can visit the project page (and download the tool) Here or get to it throught Discography tab at the top of the page. Thanks!

LTC Miner Status ScreenshotI have been working on a new tool for the last couple of weeks to assist Litecoin miners in their quest of mining. As a Litecoin miner myself in this new coin, a few pools started to pop up here and there and there was not much of a way to track what was going on. Hence my tool came along!

A common thing with any coin mining process is hopping, or switching from one pool to another. With my tool, you can see what you are doing across multiple pools, including how much LTC you have mined and how much you have been paid.

The interface is split into 3 main portions. The top part is a “ticker” of sorts that pages through the supported mining pools, showing you the current overall stats of that individual pool such as it’s overall mining speed, and the number of individual miners currently working there (and their combined KH/s speed). The middle field view shows the miners you have listed in that specific pool (If any) and what your miners are currently doing there. The base view is an overall view of your current mining summary across all of the supported pools. The tool is quick, easy to use, and sits quietly in the background keeping itself updated.

The tool is currently going through the last few days worth of testing with some close friends and miners, and I hope to have it released in the next couple of weeks once all the fine tuning has been done to it. If you are interested in testing out the tool, feel free to get in touch with me at andy [at] andykellett.com with your information. You can also find me on IRC , irc.freenode.net in #elitist, #litecoin and #rfcpool

Support For Many Pools!

At the time of the release, or unless someone suggests otherwise, the following mining pools will be supported from the initial launch of the application:

  • Elitist Jerks
  • Pool-X.eu
  • OzCoin 

Additional Mining Pools

If you own/run/reccomend another litecoin mining pool that you would like to see added to this program, let me know either by email or in the comments of this post and I will see what I can do to get it in. Your pool must support JSON statistics that can easily be accessed via the web. The tool supports all mmcfe-based pools, I just need to know your details.

The Program Is Beerware!

The program itself will be released as BeerWare, meaning if you like it and you find it extremely handy, you should donate some coin towards a beer or two for the developer! Pool owners who want their pools listed within the app are encouraged to donate a couple of extra beers as well, especially if your pool requires a lot of work to get added (custom JSON etc.) There will not be a charge to buy the program ever, and anyone who does try to sell it for money are trying to rip people off. It will always work the same if you choose to donate or not. Donation addresses to send coin to will be in the About section of the program in various different formats. All donations are truly appreciated 🙂

Donation Addresses

Some people are already asking for donation addresses to bribe with, they are as follows:

LiteCoin: LfrxgdK1PgJQPRkPVDqopQt3FaYVswmp74
BitCoin: 15s2vduLZSBUYDHPANgXVC9DPKz6BesZLj

More details will be released for the program as soon as they are available. Versions will also be made available for Mac & Linux in time. Feel free to comment or ask any questions in the comments section on this post. Initial testing only available to Windows users. Thanks! FishGuy876

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Dennis Ritchie, father of Unix and C, Has Passed Away

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Dennis RitchieDennis Ritchie, creator of the C programming language and co-creator of the Unix operating system, has died aged at the age of 70.

Thank-you for giving us a superior language, and being a pioneer in the age of computing. Rest in peace!

/* for Dennis Ritchie */
#include <stdio.h> 

main() 
{
    printf("Goodbye World");
}

ZD Net Article: http://www.zdnet.com/news/dennis-ritchie-father-of-unix-and-c-dies/6314570

Wiki entry on C: http://en.wikipedia.org/wiki/C_%28programming_language%29 

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CNC TouchScreen Prototype

Prototyping New CNC FlexIO Program

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CNC TouchScreen PrototypeI have been working on a new version of my FlexIO program for quite some time new, which has a lot of new features in it including use of wXwidgets for the GUI interface, better accuracy, and even more tools & control for the operator using it. This week I have finally began connecting stepper motors to it, and doing some real motor experiments.

There have been other significant improvements to the program as well, especially on the controller side. It is still using the Parker 6K4/ZETA4 Combo, only now with the new code the communication between the hardware and the controller is much more effective. It also does not need such a high end PC to run, as now there is no DirectX requirements, there doesn’t need to be any high refresh rates. This was a problem with the MicroATX computer used on Joshua, and a problem of the old program anyways. We all do crazy things when we have very little time to complete a project 🙂

Now that the new program is going through the final paces of it’s hardware testing, I hope to have this finished and out of the way within the next couple of weeks. I have a lot of other projects building up that I need to work on! Click on any image to see an enlarged version.

In the above picture: On the left are 3 ZETA83-135-MO Parker stepper motors, each connected to a ZETA4 controller box (the 3 stacked units to the right of the motors). These are then connected to the Parker 6K4 controller box (the large box to the right of the ZETA4 units, with 4 red LED’s on the top) which controls the motor’s movement. The 6K4 is then connected to the PC via an RS-232 connection, which receives instructions from FlexIO. During the development process, laying the motors out flat like this is a good way to test the motor communication & the programs ability to switch between motors and steps accurately and smoothly, without damaging any real hardware in the event that a problem might occur.

Screenshot of the current program interface for setting up the cable being processed:

FlexIO V3 Screenshot - 06/13/2011

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The Big Arrow - PilesOTiles

Creating A New Game & Framework In 30 Days – Piles’o’Tiles for Android/iPhone \o/

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The Big Arrow - PilesOTiles

Click To Enlarge The Image

It’s been a while since I did any work on my games, which really is a shame as I still play my own games from time to time, and people are still buying them and playing them too. So, I have decided that I would motivate myself with a “New Game In 30 Days” type blogfest, where I port the old game to a brand new format in the space of a month!

The first game I picked to port is my popular Piles’o’Tiles Mahjong game, its been long overdue to be overhauled and is still fairly popular amongst players. On top of porting the game, within the same period of time I plan to develop a re-usable game framework that I will use in all of my games, so after Tiles I can easily jump in and start porting my other games such as Jelly-Othelly, Crazy Crystals and my unreleased WordHunter games. I also have some ideas for a few new games, but need the framework before I put together some experimental test versions, and see how bad the idea sucks when it’s played for real!

The plan is to have tiles in an almost-ready state by the end of the month, and from there I can fix any small issues, tweak a few bits and pieces and then release not too long after, if it even takes that long.

Today is Day 4, and most of the screen switching framework is in place, graphics are loading and being processed accordingly, and most menu/gadget functions are in and working. Once a few little things are fixed, the next steps are to start adding actual game code, such as level rendering and a few other parts critical to testing the rest of the game itself. Once they work, then I can start on the menus and level selectors etc. before finishing with the finer details.

I will keep you posted as to how it progresses, and when I am ready to find some beta testers to take a look at it! The plan is to try and get it released for Android & Desktops at the same time with an iPhone version to follow not too long afterwards. Thanks!

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Android Development Finally Taking Shape!!

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Over the last few weeks, I have been helping my friend Paul port some of his code over to Android. Currently he releases games for PC, Mac, and iPhone and so the move to Android is a good one. Most of my involvement was working on sound, and the C to Java handling code. Lots of stress when digging through the error logs, but it has coming along very nicely! We started the process aiming for an Android 1.6 target, to ensure we can support the most amount of users across all devices.

I have also been tinkering with some of my own Android projects, moreso converting some of the games I have written to work on the new platform. So far its working out well, I have the basis for my framework in and working, and I am hoping to have the first of my games ready in about 2 months. I’ll post more about them here as I get them ready for testing or release.

In the meantime, check out some of Paul’s great games at http://www.shoecakegames.com 🙂

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New FlexIO Module – XYZ Movement Detection

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Added a basic module to the new FlexIO program this week to assist in detecting moved XYZ tables. A common problem I faced was after a drawing had been created for a part, the actual part itself had been moved in virtual space. Then when the bend file had been created, the tables were completely different because of the move. Because of this, how to correctly determine if the table is actually correct, or if there was an actual geometry change in the design that had been overlooked?

The module I created just looks for simple X/Y/Z direction movements, it gets a little more complex when looking for parts that have been rotated in 3D space, so the model doesn’t look for that yet. It works by asking for the first row of coordinates from the drawing, and calculates the differences between the X/Y/Z in the bend file. If its just a case of simple movement, the offset is applied to the remaining points and the new table when updated will then identically match the drawing (if there is no geometry change). If you start seeing some points being a little off, you can check in CAD to make sure there is no rotation, and put the difference to being a design change which requires the original part designer to submit a revision change.

It’s a start, and saves me a lot of time when verifying a large number of drawings at one time. Still lots of other verification code to add to other areas of the program 🙂

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Win32 – SDL Loses Sound When The Main Window Loses Focus – Fix

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So, I ran into an interesting problem this week while working on the “Alien Invasion” music disk that causes all sound to be disabled when the main SDL window would lose focus or become hidden. This could be a bit of a problem for a music disk, so I looked into trying to figure it out for myself.At first I tried the usual SDL culprits, which are the event system for handling focus, but no luck there.

After some poking around in the SDL source code, I was finally able to find a fix. In SDL_dx5audio.c you can change the following function to read:

void DX5_SoundFocus(HWND hwnd)
{
    // This makes sound audible regardless of focus being lost
    //mainwin = hwnd;
}

A better solution long-term in SDL will be to have an option to do this, rather than having to change the code, or just have this enabled by default. We’ll see! This was tested on 1.2.14 which is available to download from http://www.libsdl.org Hopefully someone else can find this useful too 🙂

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