Learn C Games Programming

Consider entering a game jam

Posted on August 25, 2020August 20, 2020 by David

Much as I like creating games, game jams are not really my thing as I like to spend time polishing and making them look good and that’s not really how you want to spend your 24-72 hours.

But clearly they are for others as the GMTK Game Jam in 2020 had over 5,000 entries! Here’s a GitHub staff pick of their favourite top ten entries.

What is a game jam? Well Wikipedia helps out “A game jam is a contest where participants try to make a video game from scratch. Depending on the format, participants might work independently, or in teams. The contest duration usually ranges from 24 to 72 hours. Participants are generally programmers, game designers, artists, writers, and others in game development-related fields.”

There are probably more game jams going on than you imagine. The itch.io website has a list of forthcoming game jams plus links to past ones.

How I track ideas

Posted on August 24, 2020August 20, 2020 by David

About twelve years ago I came across WOAS (= Wiki on a Stick). It was a single HTML file notebook with built in JavaScript and you opened it in a browser. It showed a simple interface and you could switch it into edit mode and start adding in text in markdown format. It was very easy to create links to pages in the document and add new pages.

And it was all saved in the document. Also very easy to find the text. It had one excellent feature which I miss, You could have a page self-encrypt using AES-256. Great for holding passwords etc.

I used WOAS to deign software and had at least one very detailed design with several hundred pages each with links to other pages. Sadly WOAS was eventually killed by the browsers themselves, preventing files writing to disk. It’s not the only example of a single-file Wiki but they all suffered the same problem. I think someone came up with a Java shim that did the file writing but it was never the same.

Now I use WikidPad, it’s written in Python and I think just runbs on Windows, (though you wouldn’t know it) which works like WOAS but internally it uses SQLite to hold the Wiki pages. You can even use their website WikidPad but you have to register first. That picture is a screenshot of WikidPad.

An example of a game idea

Posted on August 23, 2020August 17, 2020 by David

Sometimes I wake up in the middle of the night and my brain is bursting with ideas. I’ve just finished reading Shaman by Kim Stanley Robinson that’s set 30,000 years ago and came up with ideas for a tribes game very loosely based on that (Absolutely nothing to do with the plot of the book!) . I opened up my iPhone around 3:00 a.m. and these are the notes I wrote down in the Notes app.

I opened my email (Gmail) which picks up notes from my phone automatically, so I have the notes now here in my PC. They are as I wrote them so they are quite rough.

“Tribe game. All players start with a small village and 50 tribes people.
Can relocate, hunt, plant etc. Can raid other tribes. Can split tribes spread over land. Have children. Found religion. Use animals. New options as tribe progresses. Discover and trade gold, furs. Tribes can move to other places or settle and form villages.
Raids build up resentment between tribes. Enough resentment leads to war. But can reduce resentment by gifts of women, food, furs etc st festivals.
Can do crafts, paint, culture, spirituality, warfare, building. Each has 1-10 levels with names. Orders focus on an area.
Better food means stronger, smarter.
Periodic festivals. Tribes get together and share attributes.
Run for 1,000 years. 100 turns x 10 years. “

And that’s how they go into WikidPad. Then I start fleshing them out into a fuller multi-player game. Of course I come up with lots of ideas and few will make it into an actual game creation but its always a good idea to keep them. In the future it may yet become a game…

And how was the book? Very good.

How to create an Alphabet bitmap in CSharp

Posted on August 22, 2020August 20, 2020 by David

Here’s another short utility. I have been looking for a decent alphabet to look in my next game (called HogWash) . As before, I want to create a sprite sheet with letters. But every alphabet set that I found had issues with kerning. I kid you not, usually but not always with M, W, or even Q.

Even when I put together a sprite sheet manually, the editor didn’t quite get it right and letters didn’t quite fit the grid. So to simplify it, here;’s a 50 line C# program that takes the letters you supply in a string, combined with a font (Liberation Mono- from Red Hat) and a brush (black solid). It does a double loop that I exit with a goto (shock horror!) when it reaches the a terminating * in the string I supplied.

That is the graphic file above that the program below generated. As you can see the letters are far enough apart so no overlapping. Just put in your path where I have for the source and dest consts. You can use this technique for building sprite sheet.

// Author D. Bolton Learncgames.com You are free to use and copy this program as you wish but please leave this line in.
using System;
using System.Drawing;
using System.Drawing.Imaging;

namespace buildfont
{
    class Program
    {
        const int LetterWidth = 100;
        const int LetterHeight = 120;
        const string source = "Your path"
        const string dest = @"YourPath\letters.png";

        static Bitmap allLetters = new Bitmap(LetterWidth * 8,LetterHeight * 5);

        static void Main(string[] args)
        {
            BuildOneImage();
        }

        private static void BuildOneImage()
        {
            var font = new Font("Liberation Mono",95);
            var brush = new SolidBrush(Color.Black);
            var str = "ABCDEFGHIJKLMNOPQRSTUVWXYZ*";
            Console.WriteLine("Creating letters.png");
            var aty = 0.0f;
            using (Graphics g = Graphics.FromImage(allLetters))
            {
                var strindex = 0;
                for (var y = 0; y < 5; y++)
                {
                    var atx = 0.0f;
                    for (int x = 0; x < 6; x++)
                    {
                        string aLetter = str[strindex++].ToString();
                        if (aLetter == "*") goto Done;
                        g.DrawString(aLetter, font, brush, atx, aty);
                        atx += LetterWidth;
                    }
                    aty += LetterHeight;
                }
            }
            Done:
            allLetters.Save(dest, ImageFormat.Png);
        }
    }
}

A spot of market research

Posted on August 21, 2020August 25, 2020 by David

Raspberry-Pi — Image by Benjamin Nelan from Pixabay

This is market research for a side-project I’m working on. I’m developing a server and mobile clients to play multi-player games over WiFi. The server software would cost about $15/£12 and 1$ for the game client on Android/iOS. It will come with 8-10 games including card games such as Texas Holdem, and a board game or two. All games will be single-player as well (well not poker!). If it takes off I’d like to licence popular board games.

There will also be an SDK for creating new games and some financial arrangements for games to be sold through a “Pi bakery” i.e. app store. Games can either be included in the standard package or low cost add-ons.

I’m just trying to assess if there would be demand for it. If you have any comments or thoughts, I’ve posted this on the Raspberry Pi forums. as well.

It is often said that you shouldn’t give away ideas but I’ve decided to anyway. I really need to find out if anybody would buy this. If not then I have a plan B side-project waiting in the wings. But I do like this and I’ve already gone down the implementation route a bit.

Update

Sadly I have decided to ditch this side-project. I didn’t get great response; although there are 31 million Pis out there, getting people together especially with Covid is not easy. So I’m mothballing this for now. There is a B2B commercial possibility but I’ll come back to that in a year or two. Instead I am going onto my next project a mobile MMO.

A graphics editor in C

Posted on August 20, 2020August 14, 2020 by David

As the picture shows, no one has ever accused me of being artistic! Hey I can’t be good at everything (sometimes it feels like anything but it passes!) and I’ve long ago accepted that I never will be an artist.

But I can get by with graphics as I hope all the pictures on this site show. Either they are screenshots or comes from sites like pixabay.com and unsplash.com. Both are excellent sources of free images.

Sometimes though I have to do a lot of editing. MonoGame requires bitmaps for fonts. So I’ll take a free monospaced font and choose a size and create a sprite sheet from it.

But sometimes the tools I use are less than perfect. I never mastered or bought PhotoShop. Instead I used software like PhotoDraw 2 (from Microsoft in the early 2000s) or before that Macromedia Fireworks. But these are quite old and instead I’ve been looking around for something a bit newer.

There are quite a few open source graphics editors and if you look closely at my er artwork you can see at the bottom that this was taken from one such package called GrafX2. One reason for including it is that it’s coded in C and it reminds me of the granddaddy of drawing packages : Dpaint. As we’re talking over 30 years ago, I don’t know how many will remember it.

Monogame 3.8 is now out

Posted on August 19, 2020August 20, 2020 by David

These don’t come that often and this one has quite a few changes. You can read all about it on their What New page. The main changes as far as I am concerned is the .NET Core support, templates in VS 2019 (finally!) and distribution via Nuget.

Interesting though that the Pipeline tool is dead, Long live the Pipeline! It’s now called the MCGB tool. I think it’s more a rebranding than completely new or maybe it is (apologies if that’s the case). And I notice that text is a resource type that you can add BUT on Android, no point in compressing things because apks are compressed anyway. Here’s a big secret, apk files, like Java .jar files are just zip files. Yes you can view their contents with WinZip!

If you are a 3.7 MonoGame user (as I am), you should probably readthe migrating from 3.7 web page.

Geomorphing for the masses

Posted on August 18, 2020August 11, 2020 by David

This is very clever. The website Davesmapper.com lets you create different type of geomorphic terrain maps, whether it be dungeons, city or village or even the interior of a spaceship. You get a choice of tile sets according to what type of terrain you’ve picked. If you are artistic, you can upload your own designs. This mixing and mashing of tile sets can lead to some very odd looking cities with each tile a different style!

The view options controls lets you change how many tiles wide and high your map is, but watch out, the tiles are quite big so go above say 16 x 16 and you start to generate maps that are too big to export. The village at the top of the post was 2100 x 2100 pixels when exported.

The terrain maps generated are very nice. If you think these look a bit rough, it’s probably my fault. To speed up this website all images are both shrunk to typically 350-450 pixels wide and compressed and some images are possibly not quite as nice looking as their uncompressed originals.

This city below shows you the type of thing with two greenish tiles and a bluish one. You can untick the tile sets that you don’t want.

Geomorphic means it’s made of tiles that are almost always square and they fit together so that doors or passageways always join up.

Back in my D & D (Dungeons and Dragons, not drunk and disorderly!) dungeon mastering days (about 1979) I use to have a set of physical geomorph tiles. They were great but sadly lost along with my D & D toolbox that had all my figures.

There are some computer games where you might use geomorphic graphics; perhaps a procedurally-generated dungeon crawler.

Now for some mobile networking

Posted on August 17, 2020August 11, 2020 by David

Not the face to face type but actual networking. This is needed because I’m working on a game server. My mobile game (Manana Banana) will become networked enabled and thus multiplayer. C# is ideal for this type of thing but I’m not using the networking capability of MonoGame instead managing the whole lot myself.

Back a few years ago when I was a full-time mobile developer I wrote an app that was used by taxi drivers. It was a conversion of an Android App (I wrote it from scratch running on an iPhone based on the Android source code). There’s a curious architecture with such apps because not only is the a user interface but in the background the app was “chatting” over 3G to a central server (written in VB6 I kid you not) which sent an “are you alive?” message every six seconds to every driver’s phone.

It was not a traditional client-server architecture but the kind of system where the driver could send a message to the server or the server could send a message to the driver.

What this meant was the app was always keeping one eye on the 3G, getting messages and then it might for instance popup a screen saying “There’s a job from x to y. Do you want it?”. If the driver said yes then the app would receive details and show the driver the route to the pickup point. If the driver didn’t respond within 30 seconds or said no then the program would pass that back to the server,

What is a ConcurrentQueue?

C# has an advanced data structure called a ConcurrentQueue<t> which is a thread safe generic queue. I used two of these, one for a receive queue and one for a transmit queue in conjunction with a thread that never finished. All the 3G stuff was done using C# TCP/IP clients and ran in this thread. Messages that came in were put on the receive queue and could be popped off and processed in the main program. Messages to send out from the main program were put on the transmit queue and sent out in the thread. It was a very clean way of separating the main application running in the main thread from the 3G running in a background thread.

Compared to the Android program which was all running in one thread and polled the 3G, I was told by my drivers that my app felt much more responsive! The screenshot above was a very early image of it. It had a very simple UI where each screen of controls (Views in iOS parlance) was built up dynamically.

Also C#/Xamarin has a way of getting from a thread to the main thread on iOS. You cannot update any controls from any thread only from the main UI thread. There’s a method called InvokeOnMainThread for the Xamarin iOS controls. See this Microsoft/Xamarin documentation on how to use it. So that’s what I’ll be doing in my networked game.

Interestingly because I’m managing everything, the TCP/IP messages can be very small, under 20 bytes each. This allows a very high throughput.

Some awesome listings

Posted on August 16, 2020August 10, 2020 by David

Awesome stamp — Image by Pete Linforth from Pixabay

It has become a thing to label a big collection (usually open source) as awesome and there are several such collections around for many programming languages. In fact the C code collection’s first entry is to one of them.

That said they are pretty awesome, often having links to many related and useful open source projects. My only problem with the likes of GitHub and SourceForge etc. is the sheer quantity of excellent stuff on there. These awesome links are one way to “tame” them.

So now there’s a new link up top for C# and MonoGame links and a couple of entries to start it off.