BulletML for C# and Monogame

This is a thing I’ve been workin on for awhile… Kenta Cho from ABA Games made a scripting language for bullet hell shooters a few years ago called BulletML. It’s pretty cool stuff. You can just write up an XML doc with the BulletML grammar and load it up in a parser and start shooting bullets all over the place. Even better, there are hundreds of examples out on teh internet that you can use.

There hasn’t been a very good C# port of BulletML… I found a pretty crummy one up on Github, tore it apart and put it back together. It’s quite a bit cleaner, more comments, better error checking, uses more of the features of C# and less of a straight port from the original C implementation ect etc

The sample program is up on github: BulletMLQuickStart

If you just want the BulletML parser it can also be found on github: BulletML

note that all the solution & project files are for Monogame & Xamarin Studio… eventually there will be Linux and Android ports. Way in the future might be Mac & IOS ports, but I don’t have access to a Mac for that 😛

Porting to Visual Studio and XNA will be left as an exercise for the reader 😉

It still needs a bit of work… the homing missile bits don’t seem to work quite right in all the examples, and it shoots more bullets than it should. It could also benefit from some better exception handling & error reporting.




Hey I added a new project to github for testing the FontBuddy:

FontBuddySample on GitHub

It just does some examples of each of the different font effects. Each is drawn with left, center, and right justification so you can see how they all behave:

FontBuddySample Screenshot

Note that since this is a different project, it uses the FontBuddy as an external project, located in ./externals/FontBuddy. You might have to pull this down separately or something, idunno I’m a bit new to using externals in git.


very handy GameTimer library

I put all the game timer code I use up on GitHub.  It’s super useful for doing stuff like speeding up gameplay, slowing down gameplay, hit pause, etc.

I’ve found that Timers in games are very hierarchical.  You’ve got the main clock, which is basically run off the cpu clock or whatever and never stops.  You’ve got a game clock which can be paused, or if the game is kinda sluggish or frantic you can tweak the speed this clock runs at.  Then you’ve got all the clocks that run off that, including character clocks, particle engine, physics clocks, etc.  If these are run hierarchically, when you pause the main game clock all the ones underneath it pause too.

Also when playing a network game, can send those clocks from the server to all clients, and all the players will instantly be synched up. Very neat trick!

Anyway, this is the way I do it. From readme:

A bunch of timer objects that can be used for time effects like hiererchical time, slowdown, speedup, hitpause, etc.
The most important thing is that these timers can be used hierarchically. You can pass one gameclock into the update function of another one, which updates based on that dude's time. So the timer chain might look something like this:
/ | \
Character1Time ParticleEngineTime Character2Time
So like the MainTime is a GameTimer.GameClock and is updated first from the XNA GameTime object. This one always runs at realtime, so you don't want to pause or slow it down. Can problably run HUD or menu transitions off this clock.
The GameTime is also a GameTimer.GameClock and would be used to run the gameplay itself. This one can be paused for the Pause menu, or slowed down/sped up if the game play speed needs to be changed. Since all the clocks below this one are updated off it, they will also pause/slowdown/speedup.
Under that, you could have the ParticleEngine running off it's own clock separate form the player characters. That way when the players are punching the snot out of each other, you can add some hit pause to add crunch and the particles will still be flying around.
Idunno, that's just example how I use it in my fighting games. I also send these timers over the network to sync up the server & clients.

Mono: Error CS0518

This a dumb problem I ran into today that might help someone… upgrading an XNA 2.x project to mono, got a bunch of errors:

Error CS0518 : The predefined type ‘System.whatever’ is not defined or imported.

Open whatever .csproj in a texteditor, there is as hidden xml tag in those old .csproj files that needs to be removed:


Tricks for importing content files into Monogame

Monogame is an open source replacement for the XNA game development library. It’s pretty neat, you can do a lot of cross platform stuff that XNA could never do. One of the biggest hassles though is that if you an existing XNA project and want to port it to Monogame, the content files need to be setup in a specific way and there’s really not an easy to do them all at once.

I’m gonna walk you through a couple simple copypasta find/replace tricks I’ve been using. Keep in mind, developing with Mono is always a moving target, so anything I post here is proooobably out of date by the time you read it 😉

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