The 13th edition of our 48 hour game jam starts on Friday September 17th!

As always, the event is about making a game, from nothing, in a weekend. Teams or solo devs, beginners and professionals are all welcome to participate. If you opt-in to the competition, you will get to be ranked against every other contestant! Or if you prefer a more relaxed setting, the unranked jam will still give you an opportunity to get plays and comments.

Schedule

Dates	Phase	Description
September 3, 7pm UTC	Theme submission and voting	You can submit theme ideas for the jam and vote for all other submissions.
September 10, 7pm UTC	Theme shortlist	Only the best 10 themes are kept. Rank them by order of preference in this final phase of theme voting.
September 17, 7pm UTC	THE JAM!!!	Start making a game solo or as a team, and simply submit it before the deadline!
September 19, 7pm UTC	End of ranked jam	The main competition ends here, exactly 48 hours after the start time. Submissions will remain open for an additional hour after the deadline.
September 20,10pm UTC	End of unranked jam	If you want to go for a relaxed weekend - or need more time - you can create a game in the 72 hours of the unranked jam.
October 3, 7pm UTC	Results	After two weeks during which all entrants are invited to play, rate and comment on other peoples games… The results are released and the winners crowned!

Rules

There are three divisions:

- Solo, in which you make a whole game alone in 48 hours
- Team, in which any number of persons can gather to make a game in 48 hours
- Unranked, a more open division which grants about 72 hours to finish the game. Useful for those not interested in the competitive aspect of the event, want to work on an existing project of theirs, or simply did not finish their game in time.

See the full rules for the Alakajam.

How to enter

All you need to do is:

1. Create an account on this website
2. Publish your game before the deadline

A lot of participants also post an "I am in" blog post presenting themselves or their team before the event. Describe what tools and frameworks and engines you will use to create your awesome game! Which themes do you like? Let us and the community know!

If you can, feel free to spread the word about the jam - the more we are, the merrier! glhf ;)

The next edition of our 48 hour game jam starts on Friday June 25th!

As always, the event is about making a game, from nothing, in a weekend. Teams or solo devs, beginners and professionals are all welcome to participate. If you opt-in to the competition, you will get to be ranked against every other contestant! Or if you prefer a more relaxed setting, the unranked jam will still give you an opportunity to get plays and comments.

Schedule

Dates	Phase	Description
June 11, 7pm UTC	Theme submission and voting	You can submit theme ideas for the jam and vote for all other submissions.
June 18, 7pm UTC	Theme shortlist	Only the best 10 themes are kept. Rank them by order of preference in this final phase of theme voting.
June 25, 6pm UTC	Countdown stream	An official stream is held on Twitch to launch the event! Cancelled?
June 25, 7pm UTC	THE JAM!!!	Start making a game solo or as a team, and simply submit it before the deadline!
June 27, 7pm UTC	End of ranked jam	The main competition ends here, exactly 48 hours after the start time. Submissions will remain open for an additional hour after the deadline.
June 28,10pm UTC	End of unranked jam	If you want to go for a relaxed weekend - or need more time - you can create a game in the 72 hours of the unranked jam.
July 11, 7pm UTC	Results	After two weeks during which all entrants are invited to play, rate and comment on other peoples games… The results are released and the winners crowned!

Rules

There are three divisions:

- Solo, in which you make a whole game alone in 48 hours
- Team, in which any number of persons can gather to make a game in 48 hours
- Unranked, a more open division which grants about 72 hours to finish the game. Useful for those not interested in the competitive aspect of the event, want to work on an existing project of theirs, or simply did not finish their game in time.

See the full rules for the Alakajam.

How to enter

All you need to do is:

1. Create an account on this website
2. Publish your game before the deadline

A lot of participants also post an "I am in" blog post presenting themselves or their team before the event. Describe what tools and frameworks and engines you will use to create your awesome game! Which themes do you like? Let us and the community know!

If you can, feel free to spread the word about the jam - the more we are, the merrier! glhf ;)

Hello everyone!

On Sunday, 13th of June at 16:00 UTC (18:00 Berlin Time)
Thunraz, Laguna and I are going to stream the awesome results of the Multiplayer Kajam.
https://www.twitch.tv/oobloodyorangeoo

We are looking forward to see you on stream! :)

Hello all!

Are you working on your game, hoping some day that it will be finished, trying to get it done? Join our secret game club, where you will find others who are working on their games as a sort of motivational club! Once a week, we have a meeting, in which we tell our stories, whether good or bad, and we support each other and listen to each others problems and show off our successes.

You can find more details hidden in the secret text document at http://laaph.com/tmp/gameclub.txt. If this sounds like a thing you would like to join, go to that link, follow the sekrit instructions found within, and ask me to add you to the server.

I hope to see you there!

Hi there Jammers!

The Deadline for the Kajam is approaching fast. Please submit your games until 2021-06-04 21:00 Berlin time.
Please add some instructions on how to set up your game for multiplayer session (e.g. which ports to forward (udp/tcp) of if specific config files need to be adjusted).

On 2021-06-05 we will have a dedicated gaming session where you are invited to join us in the Alakajam discord "general" voice channel to play all the submissions together. Of course you can also join if you did not participate in the Kajam. We will start at 18:00 Berlin time. Check this website for your local timezone.

So everyone: let's add the finishing touches to our games and then have a great time together. Looking forward to talk to all of you in person.

Hi there,

So there is finally some progress. Not so much on the gameplay side, but the underlying mechanics are getting fleshed out quite nicely.

As we are aiming for a SHMUP game, the client really needs to feel responsive. This will be achieved by some clever client side prediction. This will only roughly be described here. For a full introduction, I recommend you this awesome tutorial here.
Basically the server but also every client runs on it's own pace and a slow client should not block the server or other clients. This means that some sort of lock-step implementation will not work for us.
Due to network lag, the client will always be behind the server and there is basically nothing that could prevent it. The idea is that the client predicts the movement for a certain frame 60. Then it sends out the input state for this frame to the server. Simultaneously the gamestate for frame 55 has arrived (due to network lag this will always lag some frames behind).
The solution now is that the player locally stores the game state as well as the input state for the past frames.
The number of stored input frames as well as the framerate determines what input lags you can compensate.

If a mismatch between the locally computed frame 55 and the received frame 55 from the server is detected, the client code now needs to roll back its simulation to frame 55 and re-simulate the input up to frame 60. This will then be used to display the player position.

To simulate network trouble, you can use a tool like clumsy. This allows to add arbitrary lag, dropped packets, throttle, limited bandwidth or even message corruption to your in or outgoing network packets. It works for ipv4 and ipv6 and supports udp and tcp. This is very handy for testing purposes.

Progress!

After Game Center match making, I now have some interactivity: choose your ship's heading and thrust.

• It's a lockstep setup with input delay (currently two steps). Only input is synchronized between clients;
• Simulation updates every 0.1s (and waits if input doesn't come in);
• The "physics simulation" should be deterministic if Double acts the same on all iPhones/iPads.

Improvements:

• It's not a game yet: no win/lose condition;
• When it comes to network: current implementation uses tcp/ip and sends input as JSON to other clients. This should probably be optimized;
• There is no graceful end of game: only stop the process.

My current plan is to use the haxe programming language to create my kajam entry. In theory I can write a single codebase that can be compiled down to a headless (no graphics) server to run in the cloud, while having that same code be able to produce the playable version of the game. In order to get multiplayer support in the browser, I'll also be using websockets.

But more importantly I want to be able to quickly iterate on my entry during my free time, so I've set out to automate as much of the build and deployment workflow as possible. Nothing fancy, just a makefile that builds the server, deploys it to the remote server and launches it. I can then launch the client on my local machine and see messages passing between the server and client, which seems like a pretty important precursor to a remote multiplayer game. Testing with a local server on your development machine is OK but bypasses a lot of the issues that can occur with a 'real' server out on the interweb.

The test was successful but revealed that terminating the server on the remote server left a zombie process sitting on port 8000, which means that attempting to run the server again would fail as the port was unavailable. This behaviour didn't occur when hosting the server locally, so there's some instant proof that it's worth testing on as realistic a setup as possible. Hooray.

So I am joining the Multiplayer Kajam.

Tools that will be used:

• C++
• My self-written Jam Template, based on SFML
• Visual Studio & Visual Studio Code
• Aseprite for graphics

We will join in a team of three

• Thunraz
• BloodyOrange
• and Laguna

We started yesterday evening and already had some trouble with our ISPs. One was configured to use only IPv4, the other was configured for only IPv6 (with an ipv4 tunnel). We found a way around that, where the only restriction is that I cannot be the host, but we can work around that as local testing is still possible.

I wish everyone best of luck for the jam!

So, I finally managed to get working:

• Game Center Sign In in SwiftUI
• Matchmaking
• Start a match
• Exchange data between clients (just some strings with random data for now).

This means I can start making a multiplayer game!

Because Game Center is strictly peer-to-peer out of the box, I'll try and implement a deterministic lockstep mechanism. Hopefully the Swift Decimal type is stable accross architectures.