Refresh Games - Gameboy Game Development in GBDK & Other Game Dev things

Ludum Dare 38- Hives Postmortem

So, with the compo entry complete last night and a few hours of sleep behind me. Now’s probably a good time to look at what is feel went well and not-so-well with the game during it’s short development cycle.

So, what went well?

Firstly I was happy with the theme of “a small world” I had an idea ready pretty quickly so could get stuck into the development of the game and it’s assets quite smoothly, despite the challenges associated with development on the classic gameboy (CPU, RAM, deciding whether to build with ROM banking in mind or not, etc.)

My homemade tools worked well (fairly well anyway).

Despite a couple of hiccups at the start with tile mapping (I had to fall back to manually doing this on a tile by tile basis) importing the graphics worked pretty reliably.

There is a FULL game loop, with side-fluff!

I (probably foolishly) worked on the non-gameplay parts for the first part of the game jam. Resulting in a fairly nice menu system with not much gameplay present, just basic player movement.

Despite my focus on different areas of the game initially, the resulting game (whilst simple and rather short) I feel is pretty nice. Not anything out there but challenging enough with multiple enemy types being added as you progress.

I accepted that the main game was pretty much done come the 2nd evening and spent most of the remaining 6 or so hours on adding more fluff including:

A proper high score table (with initials)

Fixing the levels on the SFX, adding more SFX and explosions when needed.

Adding fading transitions between the screens where appropriate

And, just becuase I was feeling particularly crazy ( and most older console games have this) a Demo mode.

The Demo player isn’t the cleverest as the fake joypad input is largely randomized, but with a little bit of logic to feel more authentic. It appears if you leave the title screen alone for 10 seconds and will play itself until you either press start or the beehives reach below a certain level of hit points.

Coding went well, the initial scope of the game was fairly small so it didn’t shrink that much compared to the original idea.

What Went Wrong.

Whilst I’m happy that the game is fairly complete, it is missing some elements which I’d like to add at some point in the future, including background music, power ups and more obvious gameplay progression as your score increases. (I mean, there’s more enemies and more types later on but it feels more Atari 2600 than it does Gameboy in parts)

The game length is okay for a game jam game but the action isn’t as exciting as it was in other gameboy games (which admittedly, I’ve spent more time on) such as, Infinitron or Formula Racing. I could fix this later with other elements being added, such as roughly targetted enemy shots and perhaps a boss-style enemy, ROM space permitting.

All in All

I’m fairly happy with the game made considering the time available. It fits the theme, is pretty much as complete as I could make this time around but I really, really need to learn or make a music tool that works well for me!

Just so I can implement the tracks in my ROMs with ease and not eat up much CPU (or ROM space) at the same time, expect bit-by-bit optimisation I guess!

Here’s to the next game jam ( and possibly some more tools to develop in the meanwhile)

Also, play the gameboy game yourself! Clicky Here!

Ludum Dare 38 Entry – Hives

Right, the Ludum Dare website seems to be in a bit of a usability pickle for me so I’ve uploaded the source code and Gameboy ROM here just in-case things have gone wrong somewhere, also, Pictures!

Brief Overview of the game also:

In Hives you take on the role of a bee who has been tasked to defend 3 hives in this side scrolling shooter.

Defend you hives from predators including wasps, bees and spiders, intent on destroy your hives with every contact they make.

Take them down with your Atomic Stinger fast to prevent further damage and repair hives with your personal shield.

Run into an enemy? No worries, another drone will soon be dispatched.

Record your progress on the high score board and hey, if you’re too shattered after Ludum Dare to even play the game, wait 10 seconds on the title screen for a quick demo.

ld38-gameplay-1

How high is your highscore?

Right, I recently came into a little problem regarding storing highScores and comparing between them. It sounds stupid as most people would probably think. “Well, duhhhh use greater than or less than”

Which is fine. but with the gameboy being 8 Bit, I’m storing my scores as arrays as scores up to 255 would be rather boring….

So, for example 9,001 would fit into an array of 4 lots of UINT8, for an easier time displaying things to the screen, without extra computation.

E.g.

score[0] = 9;
score[1] = 0;
score[2] = 0;
score[3] = 1;

score[0] = 9;

score[1] = 0;

score[2] = 0;

score[3] = 1;

In a game I’m making currently, scores can extend beyond the limits of a 16 bit integer also, so we’re using slighlty longer arrays to store things in, no biggie.

But. I’ve found a handy solution to my problem, along the lines of the following:

//SET UP OUR TEST SCORES
hiScore1[0] = 0;
hiScore1[1] = 0;
hiScore1[2] = 9;
hiScore1[3] = 6;
hiScore1[4] = 9;
hiScore1[5] = 9;

score[0] = 0;
score[1] = 0;
score[2] = 6;
score[3] = 9;
score[4] = 9;
score[5] = 9;

higher = 10;    // 10 = same score, 0 = lower than highscore, 20 = higher than highscore

i = 0;

   while (higher == 10){
   if (hiScore1[i] > score[i]){higher = 0;}
   if (hiScore1[i] < score[i]){higher = 20;}
   if (hiScore1[i] == score[i]){higher = 10;}
   if (i == 5){break;}
   i++;
   }

//SET UP OUR TEST SCORES

hiScore1[0] = 0;

hiScore1[1] = 0;

hiScore1[2] = 9;

hiScore1[3] = 6;

hiScore1[4] = 9;

hiScore1[5] = 9;

score[0] = 0;

score[1] = 0;

score[2] = 6;

score[3] = 9;

score[4] = 9;

score[5] = 9;

higher = 10; // 10 = same score, 0 = lower than highscore, 20 = higher than highscore

i = 0;

while (higher == 10){

if (hiScore1[i] > score[i]){higher = 0;}

if (hiScore1[i] < score[i]){higher = 20;}

if (hiScore1[i] == score[i]){higher = 10;}

if (i == 5){break;}

i++;

}

What the code above does is compare the arrays on an integer by integer basis and set another variable with the result, reliably!

I hope this helps someone out there who has a similar issue regarding setting up high-score boards on the gameboy as this seems to be a safe an fairly quick method.

I may well be missing another way that’s quicker all-around but this seems to work for me anyway 🙂

Expect a new game posted around the end of this month 🙂

Cartridges! Coming Soon-ishly!

Yes! I’ve finally found some lovely people from 8-bit Evolution to team up with who publish retro games! They’ve taken a liking to a few of my games in-progress so far and now they really need to be brought home over the finish line.

This is one of those geeky dreams of mine that I had since being on the playground in the 90’s, to have a game of mine on a Nintendo console, on an actual cartridge, complete with box and instruction booklet, the whole shebang!

So, I really need to tighten up some code on Formula Racing to make it as optimal as I can (again) in GBDK, get the password system in-place, sort out that difficulty curve, add some endings, some sorta music and that game will be done and ready for perusal. Also, I need to make some awesome box art like I made for They Are Everywhere 😉

It’ll be one of my game developer “awesome things to accomplish” things marked off the list and I never was sure which way to achieve it so I’m very grateful for 8-bit Evolution to reach out to me on this one.

And there I was considering some Sega Master System development instead. Well, maybe again in the future eh 😉

Gearing up for 2 Players!

Gameboy Development has been really good fun over the last 14 months and in total I’ve made over 10 games which are all playable in one state or another, which is nice!

I’ve played with some gameboy colour stuff and feel like I have a good handle on MBC1 style bank switching. Audio is coming nicely along the way and will keep on evolving over the coming months until I’m happy with both editor, exporter and GBDK implmentation.

But, one of the things that was in a lot of gameboy games was the ability to link up to another system, allowing for two player games. Normally in a versus mode scenario.

I WANT TO DO THAT!

And I want other people to be able to to do that also!

So, there are decidated functions and variables inside GBDK for handling such functionality allowing for not just link cable but other accessories to be attached, such as the gameboy camera and printer! I’ll look into those at a later date but for the moment, the next goal is to make a 2 player game!

Jams Jams and More Gameboy Jams

So, October has been a pretty intense month for game jamming, with two jams co-inciding with each other at the very start of the month the amazing GamesForBetter Jam hosted by the lovely SoGoodStudios and Sizeable Games, handily encompassed by GBJAM5 where developers make a game based around the general theme of the Gameboy. But, let talk about the Games For better Jam first, it was pretty eventful after all!Things started off in a fairly compromising fashion when I realised that I had packed literally everything I would need with the exception of a power cable for my laptop. Big mistake and thanks again to the lovely Jupiter Hadley for sorting me out with that one, you’re awesome!Our group constisted of 2 coders and 1 artist. What with both our coding skills coming from very different approaches I made the odd call to make a live demake of the PC game programmed by Tom who did a great job turning code and gameplay around with amazing speed onto the gameboy.

A fairly tall order for two days but I figured it would be pretty cool and unique way to tie things in for the GBJAM that was also running at the same time.

I was unable to get any code underway until ~midday on Saturday but we were able to get a really solid concept going of essentially a bullet hell shoot-em-up where you have two weapons, one is a standard peashooter, not too great but does the job, the other being a wider, more destructive shot from a slowly replenishing ammo source, which when fired can destroy bullets and most enemies. The trick being that using this too much will make more enemies indestructable, linking the game into the theme of anti-biotic resistance.

With time running out on the 2 days worth of Jam time, we had a really playable version on the PC with 10 seperate levels culminating in a boss fight which played really well but was a struggle to capture any real footage for oddly. The gameboy version lagged behind but had 10 very similar but slightly different levels and a few bugs.

It was a great Jam and the first time I’ve worked as part of a team in one of these events, it was great fun and whilst we didn’t get picked to be played at the event, I felt the game would be worth continuing development on for the rest of GBJAM5.

So, a trip back home from Plymouth, catching up on some sleep and a few play-throughs later, I’d decided what I wanted to add to the game.

Bosses
Bug-fixes
Pausing
Gratuitous Sampled Sounds
A pre-title screen to show off said sampled sounds as a little easter-egg.

Now being back in a home environment meant that coding time was more scarce as there are many other factors at play, not least the trips to work, awesome family times and the joys of housework. Late night is really the only option for coding @ home 😉

I had managed to write a tool in PHP in previous weeks to convert an 8-bit 8,000Hz RAW wave file into 4-bit, 4,000Hz but hadn’t really played around much with it, aside from verify that it worked. So, it really needed to be in the game in some form. Making a talking intro screen game boy announce “Game” “Boy” “Jam” “5” seemed a cool idea and fit in quite nicely with some more advanced bankswitching for me. It worked pretty well as a little novelty before the main game and I’ll work on making this play nicer (without game pauses) at some point.

Bosses were fun to play around with and got tougher as the levels progress. They use fairly simple movement patterns but fire a viscious amount of bullets on screen, some later bosses are supported with standard enemies to up the difficulty some more and all squeezed into the main ROM bank with space to spare.

There were some minor bugs with the GamesForBetter version but this was mostly just the score not resetting on replay and a couple of sound bugs due to me not resetting registers at the right point in the game loop at times.

Space Splosions and More Gameboy Tools on the way!

Yay! Space Splosionator 2086 was completed last Wednesday for the Workshop Wednesday challenge over at the lovely socoder forums and whilst it didn’t get as much time as I’d hoped to spend on it, plays pretty well, albeit in a tough as nails way.

The theme for the Jam was Hashtag so the game takes place in side a hashtag…in SPAAACCCEEE!

I know, awesome right? XD

What’s there in the game worked really well, there’s a starfield, lasers, targetting reticule and enemies that zoom into the screen and attack you, all complete with screen shaking effects!

It does essentially boil down to whack-a-mole, but it’s good fun for a few minutes 🙂

You can playit online via the gamejolt emulator orr, for a much better experience, use the BGB emulator and download the ROM instead!

http://gamejolt.com/games/space-splosionator-2086/186987

In other news I’ve made myself a tool to convert 8bit 8000Hz audio into 4bit 8000Hz audio for including wave sounds into gameboy games via sound channel 3.

I’ve shyed away from this channel before as I didn’t really get how it worked but now I’m playing with wave forms including triangle and sine waves to get more sound variety out from the gameboy!

I’d love to see if it’s possible to stream a low frequency sound whilst a game is playing. It’d be really low in quality (60Hz) but could be suitable for some applications, probably not vocals though. We’ll see!

So, August and me coding in GBDK didn’t really happen.

Yeah, yeah, I didn’t even update this blog either. For over a month!

But, that doesn’t mean I’m stopping gameboy development, far from it. There’s plenty of games I need to finish off before I move onto tackling 6502 ASM again in October / November.

There’s quite a list of them now, how does it always end up like this!

Formula Racing.
It’s nearly all done, but just needs a bit of polish and better ROM bank management.

I Shall Be Queen.
I’d really like to add that boss fight in there sometime soon. Then I’ll accept it as complete.

Shield Warrior VII.
It’s a small game I attempted to make for Ludum Dare 36 during the bank holiday weekend, but life and family fun was way more important. So, I need to finish this one off soon!

Ayasumi Todayachi.
A horizontally scrolling shmup with alternating weapons.

Space ‘splosionator 2086.
A quick Whack-a-mole type game. But in space!

They Are Everywhere.
I’ll come back to They Are Everywhere again sometime again. I feel it needs re-programming now I have a better knowledge of the system as opposed to in October last year.

Roll on September!

Bit Bit Jam 3 Post Mortem

Hiya. I’m Ryan Carson and this is a lil transcript for my video about “I Shall Be Queen” for the Gameboy and Gameboy colour, made in 1 week for the 2016 Bit Bit Jam. This is the first game jam I’ve entered which is entirely dedicated to retro console development and Has been lots of fun to take part in.

The chosen theme this time around was “Red Hot Princess Carnage” and resulted in quite a variety of games being made for systems dating as far back as 1976 / 7.

omgslimes — Early Dev Shot- Lots left to work on still here! I think this was on tuesday / wednesday…

A you can see I ended up making a double-dragon style beat-em-up where you play a princess character, out to steal control of the kingdom by yoinking the queens crown.

The game takes place over a total of 3 stages with enemies getting tougher as the game progresses, starting off with basic slimes, moving onto snakes, floating eyeballs and arrows being shot through the stage at you.As has been mentioned a few times to me now, hitting the enemies is considerably tougher than it should be, mainly down to the height of the enemies being less than your primary punch attack.

With a bit of skill, you can manipulate them to wander down into the punches and there’s always the simpler jumping kick and mana consuming ranged fireball you can throw with the select button.I started off with a simple base code consisting mainly of collision detection and fader for the monochrome gameboy and the rest of the code was written during the week.

I was really proud with the pixel work I could put into play with this game, particularly for the main character, although, using such a large sprite for her in-game meant I had to dedicate 18 tiles per animation frame. Not good when I need to consider enemies, power ups, etc.

I could have a maximum of 14 unique frames but ended up with a total of 10, comprising of:

1 Standing Frame
3 Walking Frames
2 Punching Frames
1 Jumping Frame
1 Kicking Frame
aaand 1 Death Frame

That’s still the majority of the 256 total available to me, leaving me with only 76 tiles to put enemies into!

I wanted to have some variety to the enemies with at least some animation so opted to make the enemies fit into 4 tiles per animation frame, with a maximum of 4 animation frames per enemy.

There’s 4 different enemies in-game, so that’s adding another 64 tiles, leaving only 12 (well..okay, 16, one enemy had just 3 frames to save on space)

The remaining tiles were dedicated to power ups, shadows, visible punches and kicks leaving a paltry 8 spare tiles at the end, I was really pushing the limits to what I could use here and many other scenes went the same way, it was tough trying to cram it all in!

Somehow it managed to fit in though and with a few sneaky tricks to reduce cpu usage, not checking for certain hit detections on every frame, etc, etc. Further code reductions to allow the main game code to fit inside one 16kb bank, the game squeezed into it’s available space.

I was hoping to add a boss fight with the queen towards the end of the jam but, despite having prepared some sprites, simply ran out of time and ROM space come Monday to add this so, had to replace it with some rather odd dialogue scenes.

All in all, I’m pretty happy with the way this game turned out. I’m tempted to round out the remaining bugs and add that boss fight at a later date but yeah, a few flaws but, it plays pretty well and looks better than I thought it would!

Heck, I even managed to add some requested scenes from a guy at work’s request, but you’ll probably need to view the code to figure it out 😉

Why not give it a quick play through at Gamejolt?

Click here to Play Me I Shall Be Queen

Oops, err yeah, the video, I’ll be uploading that one shortly ;P

More News on Formula Racing and other Gameboy Development stuff

Right, a few more changes have been going on under the hood of Formula Racing, including an overhaul of the A.I. which was a lot more predictable than in the current version, the A.I. can now branch into different paths depending on the track layout and is a lot less likely to crash into things as a result. So you really need to plan your overtakes now!

This has called for a redesign of some of the older tracks to handle this variant of the A.I. which has turned out to be a great blessing, with a lot of optimisation in the code now present to reduce CPU usage I’ve also weeded out some unneccessary lines of code and removed the speed overflow bugs that were present.

These bugs caused boost pads to stop the car and crashes to occsionally accelerate the car instantly to it’s top speed!

While this is all good, it’s resulted in the game becoming much tougher than before, unpredictable A.I. really puts things into a twist.

There have been some graphical changes to each course group also, billboards, trees and other elements being locked to each group help to give each track a slightly different feel, which is pretty nice!

The password system is almost there for Grand Prix mode and I’m working on a custom sound editor in the background just for the hell of it.

GBDK and sound can be a pain in the arse, there’s lots of ASM based solutions but GBDK could do with something, however basic it comes out initially. Unobfuscating the process could result in more games with soundtracks in, which would be nice!

There’s a couple of little A.I. bugs to sort out still but they should fit in nicely with the ~500byes remaining. I’m hoping to add a car explosion effect also in the remaining space!

Oh my gosh. it’s 1am, time to sleep, will post again soon!