Chris McCormick

PodSixNet is a lightweight network layer I've written to make it easy to write multiplayer games in Python. It uses Python's built in asyncore library and the simplejson 3rd party library to asynchronously serialise network events and arbitrary data structures, and deliver them to your high level classes through simple callback methods.

Click here to download it

I wrote this library because I'm forever thinking up multiplayer game designs and then starting, but never finishing, a new multiplayer game library for every multiplayer game idea. In other words, I get bogged down writing low level code and eventually lose interest in my original idea as it proves tricky to implement. I decided to get the multiplayer game library written once and for all so that whenever I get an idea for a multiplayer game, I can now prototype it up rapidly. I'm quite proud of the fact that this library is only a handful of simple classes, and weighs in at just two hundred odd lines of code. This is of course because I built it on top of Python's already cool asynchat (used by Twisted) and simplejson.

Two example apps are included with the source to help you get started. The first one is a simple console based chat program, and the second is a pygame based collaborative whiteboard. For each example start one copy of the respective server, ChatServer.py or WhiteboardServer.py, and then start multiple copies of the client to test.

Would really love to hear about it if you use this in a game!

Need to settle an argument? Recently, I finished coding up this Rock Paper Scissors game that you can play online against someone else. Have fun.

It is said that when he was designing the first Mario game, the master Miyamoto had a screen full of plain square sprites and tested making one of them jump onto the others with what was to be the NES gamepad. He kept playing with the prototype until just the action of pressing the button and watching the squares jump, was itself fun, quite apart from any other aspect of the game.

This story might not actually be true, but it's in this spirit that I made a prototype for a platform game that I've been working on in my spare time. There are binaries for Linux, Windows, and Mac on PodSix Video Games, so check it out.

The point of this prototype was to try and prove the hypothesis that it is possible to have a platform game that is fun to play just by virtue of the jumping, collecting, and exploring mechanics with no shooting or killing, no puzzles, and no bad guys. Of course, I already knew this to be true from games like Nifflas' Knytt, but I also wanted to see if I could make it fun to jump around, collect things, and explore, without any additional game mechanics like Nifflas' climbing, and without nice fancy graphics or sounds. So what this resulted in was the most stripped back, minimalist form of a platform game that I could come up with. That said, I couldn't resist adding a few 8 bit style sound effects generated by sfxr just to enhance the experience a little bit. I hope that despite it's minimalism, it's still fun to play.

My other aim with this is to 'release early, and release often' which is a popular tenet of the free and open source software movements. It means that you get your releases out as early as possible so people can start testing them and finding bugs. So to that end, I'd love to hear your opinion on this prototype if you play it. If I make any progress on this game in the future, I'm going to try and make a release like this at each little milestone. Hopefully I'll get time to work on it quite often, and the full picture will come together over the next few months [but probably not, as things always take much longer to code than you think they will].

If you're interested in tinkering with the prototype, the levels are SVG graphics that were created in inkscape and had meta data such as portal destination and item name added with the 'Edit -> XML Editor...' menu option (ctrl-shift-X). So feel free to load them up, edit them, have a play around.

With this very basic, generic platformer code written it should be easier for me to create platformers from now on, and specifically the larger game project that I have in mind.

Have fun!

In order to test out a generic Python multiplayer game library that I'm working on, I had to come up with a game design for the simplest possible multiplayer game. I'll post the library's code here another time when it's stable and tested, but in the meantime here's the game design that I came up with:

It's a two player turn-based strategy game with the simple objective of destroying all of the other player's ships. There are two phases; the input phase, and the simulation phase. Each player runs the client on their own computer and they input their next moves simultaneously during the input phase. The moves are hidden from the other player until the simulation phase, which happens once both players are finished inputting their moves. Control of the ships is simple; click the blue circle and then click the playing field in order to define the path of each of your ships for that turn; click the red circle and click in the direction which you'd like the ship to shoot for that turn. When ships are hit with enemy fire their health bar will show up with it's value diminishing, and when it gets to zero the ship will disappear. You can also see the health bar of ships by hovering the mouse over them.

I've been re-visiting some code I wrote quite a while ago which generates a virtually infinite number of generic 2D RPG maps, with grass, sand, road, trees, and water, like this:

Here's the algorithm I have used, implemented in Python, using a Perlin Noise generator:

detail = abs(perlin.Noise2D(x / 300.0, y / 300.0))
desert1 = -perlin.Noise2D(x / 100.0, y / 100.0)
desert2 = perlin.Noise2D(x / 10.0, y / 10.0)
desertp = desert1 * detail + desert2 * (1.0 - detail)
waterp = perlin.Noise2D(x / 150.0, y / 150.0)
roadsp = (abs(perlin.Noise2D(x / 50.0, y / 50.0)))
treep = max(0, perlin.Noise2D(x / 300.0, y / 300.0)) + perlin.Noise2D(x / 3.0, y / 3.0)

oasis = desertp > 0.95
lake = desertp < -0.6
river = desert1 < 0.6 and abs(waterp) < 0.075
desert = desertp > 0.6 and desertp < 1.0 or desert1 > 0.8
roads = abs(roadsp) < 0.05
riversideRoads = desertp < 0.6 and abs(waterp) < 0.11 and abs(waterp > 0.08)
trees = treep > 1.15

if lake or river or oasis:
    DrawWater(x, y)
elif roads or riversideRoads:
    DrawRoad(x, y)
elif desert:
    DrawDesert(x, y)
elif trees:
    DrawGrass(x, y)
    DrawTrees(x, y)
else:
    DrawGrass(x, y)

One problem is that I couldn't find a decent perlin noise generator for Python that was easy to install, so I had to roll my own, and it's dog slow (apologies to any dogs who are reading this). I even tried re-implementing it as a Python extension in C but it was still only twice as fast. Psyco also did nothing to help the situation, which basically means it isn't slow because of bad optimisation but because the algorithm is very CPU intensive. The good news is that a few nights ago, while I couldn't sleep, I think I came up with a really quick way of generating random fractal based landscapes by caching the results of previous, higher order position lookups. If I'm right, it kind of turns the Perlin algorithm inside out to prevent redundant calculations. Of course, it will trade off speed for higher memory usage, but that's ok in this situation. I haven't tested my idea out yet, but hopefully I will get around to it and make my map algorithm much faster.

Another problem is that my existing maps won't wrap onto a torus without discontinuities, which means you have to have infinitely large maps for people to explore, which go on and on forever. I'd rather the maps wrapped so I could wrap them around planets and stuff. Fortunately, I think that with the judicious use of modulus operators my new algorithm should wrap pretty nicely.

Characters

I came up with these vector art characters which I think would be suitable for a 2D RPG style game.

They're SVGs made in Inkscape, which is highly scriptable, so I am thinking about prototyping a character creator screen which will allow you to deck them out in different colours, clothes, accessories, etcetera, and then use Inkscape to render variations in the background.