Game | Learn C Games Programming Blog

Category: Game

The fun of game design

Posted on August 29, 2020August 25, 2020 by David

My new side project is a free to play multi-player mobile game about living the life of a celebrity. It’s brutally competitive and will accommodate up to 10,000 players in one game. It scales horizontally so multiple games can be run at the same time. It’s an idea I’ve had for years and now I’m on it.

The idea is that you start moving to the big city. A city where your dreams can come true by becoming famous in some field. Whether breaking into film, or sport, on TV, a famous writer and so on. But first as a wannabe, you have to get a job, whether its pumping gas, waiting on or one of a dozen jobs. And try to make your way up the greasy pole to the top of the A-List.

I have devised mechanisms for this. But there’s way more depth to the game than what I’ve said. The game is basically about decision making. Every action has consequences. If you go to this party, you might make friends with someone who can open doors that will give you more public exposure and earn celebrity points.

The game server generates events that you can attend. It’s a busy life attending openings, first nights, filming of videos, commercials, going to auditions, making guest appearances, signing books, partying, going to concerts, balls, awards ceremonies, opening fayres, launching ships, or more mundane things like product launches, endorsements, appearing in TV adverts and more.

All this has to take place in a game city. So the game server has to create a city populated with buildings, with jobs. Celebrities actually do jobs. Those books don’t write themself, or films make themself. Musicians have to record songs, go on tours. But you are also interacting with other players, helping them and helping yourself.

As a game designer and programmer I have to translate all this into code. In the past I programmed postal games. These were games where orders were sent by post, processed, results printed out and then mailed back. In this case, they’re entered on mobile and uploaded to a game server. Here a program will run at regular intervals and process a day’s activities. All those parties etc. have to be processed and the consequences determined. Did you make friends, did you get any new job offers? Have you accumulated some more celebrity points and moved up in the league table? Did you escape from being a wannabe to C-lister yet?

Then after that’s all done, the results and new decisions can be fetched onto mobiles and players decide what their next decisions will be… That’s what I’m designing and programming. Both the game server engine and the mobile clients.

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.

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.

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.

What is the best way to include text?

Posted on August 10, 2020August 3, 2020 by David

One of the games I’m working on needs to include a 1.9 MB text file (200,000 words). Now it’s not that big a deal but using 7zip I can compress it down to 400 KB and that’s 20% of the uncompressed size. So I’m thinking of including some C# code to decompress it.

But I did wonder if there was any kind of built in decompression, so you could add it to say Resources and have it decompressed automatically when read. I haven’t seen anything like that but it would be cool if if existed.

Ideas for multi-player games

Posted on August 7, 2020August 2, 2020 by David

Simple word game — Image by brainygames from Pixabay

One side-project I’m working on that uses the MonoGame library involves creating a bunch of simple multi-player games. I’ve started with that Poker game (Top Banana or Manana Banana as I’ve called it) and the next one will likely be a variation of the game Boggle but not called that and not based on a 4 x 4 grid as Boggle is. I’m not daft!

The danger with doing this and just copying existing commercial games is you might get sued or a nasty cease and desist letter/email come your way if you infringe someones copyright or (far far worse!) their trademark. If you have a bit of money, you might be able to license the game from the original designer/creator but that’s probably not at all cheap. Games like Fluxx, Acquire, Settlers of Catan and Ticket-to-Ride are favourites but not something I shall be doing until and unless I can afford to license them.

Some games like card games are in the public domain and I’ve no qualms about producing my own version. Scheduled in after It’s-Not-Boggle is one based on 3-card Brag which is very easy to play and quite fun. I’m also trying to come up with an idea based on word Searching or Sudoku but as those are primarily solo-play games and not quite so easy to do multi-player.

But I’m sure there are multi-player games, i.e. Texas Holdem Poker that are legal to create my own so if you know any I might do, add a comment!

Mobile game development progress

Posted on August 3, 2020July 29, 2020 by David

Development continues with the first game, which is a card game. I know the game as Top Banana, but I think that is the name of a commercial game, so for now the working title is Manana Banana. All it does currently is display the cards and backs as you can see. No photo this time, I learnt how to take snapshots on the phone (Hold down the power and Lower volume buttons at the same time) As it’s plugged in to my PC,. copying it across was not difficult.

This uses my virtual screen technology working on an 800 x 1400 virtual screen then scaling output onto the real screen which in this case on the Alps X27 Plus is 480 wide by 960 deep. As you can see I have a black rectangle at the top and the Android controls are visible at the bottom, neither of which I programmed for. I’ll get those fixed.

You play this game by clicking on the six top cards one-by-one and then tap the back of the card where you want to play that top card. So you end up with three poker hands. In this case I’d put the 7 and 9 on the top row for one pair, the two fives on the 2nd row also for a apir and the King and Jack for an Ace-high straight on the bottom row. The gap on the right will show the text of the hand so will say Pair, Pair and Ace Straight or something like that.

Next thing is making the cards clickable. That is the top six cards and the the three sets of two backs below. Once that’s done I’ll make that bit work then plug in the Jessie Chunn’s poker hand evaluation code to figure out what each hand of five cards is and more importantly give it a numeric score.

The gradient that covers the screen came from Unsplash.com.

Space Invaders done faithfully in C

Posted on July 30, 2020July 24, 2020 by David

I was around when space invaders came out in the late 70s and played it a bit, although I preferred Galaxian, Gorf, Defender and Battle Zone (3D Tanks on the moon- vector graphics).

This project (catchily named si78) though is a memory accurate re-implementation of the 1978 arcade game Space Invaders in C.

To build and run this (on a Linux box) you’ll need to download the invaders ROM which is available in one of the Mame sets. The game is written in the subset of C99 that is compatible with C++, and uses no compiler extensions apart from attribute packed.

Using Excel for level design

Posted on July 24, 2020July 25, 2020 by David

In the asteroids game and shortly in my MatchThree game, I’ll be creating a level data array of struct. This has a struct for each level containing a count of particular features for that level.

This is the struct and array for a level in asteroids.

struct level {
	int nums[4]; // how many of each size of asteroid
	int aliens; // how many aliens
	float factor; // from 1.0 to 1.5 - multiply asteroid speed by this
};

struct level levels[50];

This is the first 3 levels and level 50.

#include "levels.h"

struct level levels[50] = {
{ .factor = (float)1,.aliens = 1,.nums = { 0,0,3,3 } }, // Level 1
{ .factor = (float)1,.aliens = 0,.nums = { 0,1,3,3 } }, // Level 2
{ .factor = (float)1,.aliens = 0,.nums = { 0,1,3,3 } }, // Level 3
..
{ .factor = (float)1.5,.aliens = 3,.nums = { 4,4,5,5 } } // Level 50

I didn’t type any of this in. Instead, I created that spreadsheet above. It’s easy to work out difficulty levels in column H. The formula that calculates this is ins this on row 5. If you don’t know Excel, the $ in the factors means that as you copy this into successive row, it keeps the $ row value constant.

=(B5*B$4)+(C5*C$4)+(D5*D$4)+(E5*E$4)+(F5*F$4)+(G5*G$4)   - Row 5

=(B6*B$4)+(C6*C$4)+(D6*D$4)+(E6*E$4)+(F6*F$4)+(G6*G$4) - Row 6

So you can see its multiplying the values in rows 5 6 etc by the values in row 4. Having put that in place I could tinker with the values in rows 5,6 etc to make the difficulty level increase roughly at the same pace. The difficulty level for level 50 is 77.5.

This is what the Excel formula looks like to generate the C code, it’s in cell M5 in the spreadsheet and then copied and pasted down.

="{.factor =(float)"&G5&", .aliens="&F5&", .nums = {"&B5&","&C5&","&D5&","&E5&"}}, // Level "&A5

and this is what it looks like. C code that can be copied and pasted directly. It even includes the comment for the level number!

{.factor =(float)1, .aliens=0, .nums = {0,0,3,3}}, // Level 1

Creating a spreadsheet and C code from it this way saved a lot of typing but let me quantify the numerical difficulty which increases from 17.5 on level 1 to 77.5 on level 50. There’s no meaning to this value, it’s just a calculation.

A tictactoe (aka noughts and crosses) game in C

Posted on July 23, 2020July 16, 2020 by David

I was asked to write this a few month’s back and it took me 2 or 3 evenings. It’s 312 lines long in just one file. Hopefully there are enough sensible function and variable names to make sense of it.

It runs in a terminal. It was compiled with Visual Studio but should not need many changes to compile with gcc/clang. (I hope!).

I made extensive use of pointers. For instance this function uses pointers in a for-loop.

int InDanger(char piece, int * x, int * y) {

    for (*y = 0; *y < 3; (*y)++) {
        if (CountRows(piece, y,0)==2) return 1;
    }

    for (*x = 0; *x < 3; (*x)++) {
        if (CountCols(piece, x,0) == 2) return 2;
    }
    *x = 0;
    if (CountDiagonal(piece, x,0) == 2) return 3;
    *x = 2;
    if (CountDiagonal(piece, x,0) == 2) return 4;

    return 0; // no danger
}

I’ve added this to the GitHub C games repository and updated the C games source page.