Category: programming

Currently there are two anti-missile weapons in Gratuitous Space Battles. Point Defence Lasers and ECM beams. The point defence laser basically tracks incoming missiles and just zap them. They always hit (at the moment) and take one out. Of course, they can be overloaded,e specially by multiple-warhead missiles, but they are pretty cool. The other one (ECM beam) does exactly the same, but rather than destroy the missile it scrambles its guidance system and there is a cool wibbly wobbly effect as it veers everywhere. In the final game, the choice between them will probably be some sort of crew/power/cost/weight trade-off.

The thing they share though, is that they can ONLY target missiles that are aimed at their ship. You can’t have an ECM frigate at the spearhead of your fleet zapping all the incoming missiles to screen your capital ships from attack.

Clearly this sucks.

The solution isn’t trivial though. There are a LOT of ships in GSB and a LOT going on. if I’m to enable anti-missile weaponry to select from any missile on the map, that will involve a lot of processing. My mind is agog with quadtrees and other methods of limiting the amount of times each weapon has to do this:

for(each missile)

{

are_you_the_closest_one?

}

etc. It would normally be a trivial thing, but it’s something that isn’t in the game yet because it hasn’t really been necessary. The question is, do I write some big generic system that every piece of taregt selection will reference to find the nearest object? if so, that involves a fair bit of re-work, and it’s likely to be a several-cups-of-tea and a free morning sort of problem.

Stuff that is currently slow in really hectic games:

• The ‘smart’ sprite texture for the shield impact sprite gets created and destroyed a lot at runtime
• The sound engine spends a lot of time looking for free sound channels or cached sounds
• Drawing of blast textures for bullet turrets is slow somehow. Lots of small 2-primitive draws I suppose.
• Drawing Missiles and missile glares and trails
• Drawing debris

I love optimising, and the frame rate isn’t too shabby even with all hell breaking loose, but it would be cool to get it much better in the hope of adding some really gratuitous extra effects later on for fast cards.

I know that editors and level tools are part-and-parcel of most game development processes. Most games companies have at least one full-time tools programmer, who will work 8 hours a day for a year designing, coding and supporting the tools made to build the game. However, when you are a one-man-band, dedicating that amount of time to tools just isn’t viable.

There are several solutions. You can try and hit the happy medium where you spend enough time to get usable tools, but don’t let it eat too much into your schedule. You can produce really good quality tools that make game production a breeze, then realise you have not got close to finishing a game and you have to go get a day job again… Or you can just hack everything in manually using notepad and excel and worry about it later.

I’ve traditionally chosen the last option. I hate MFC, which is the ‘language’ that tools used to be built in, and I’ve never learned java or C#, which is what people often use now. That means that when I coded the few tools I use (like my particle-engine tool), I hand code them in C++ just like the games GUI. This takes ages.

Until now, I’ve been manually editing text files for the spaceship data. I have a master spreadsheet with lots of the data in, to make balancing easier, but there is a lot of manual staring at paintshop pro and memorizing pixel positions to type into notepad. Clearly this is mental.

So this weekend I made my very first steps towards a proper ‘spaceship-hull-editor’ for the game. This is still a makeshift hacked tool which won’t ship in the game, it’s just a quick tool to make it easier for me to tweak some of the graphics data, such as placing particle emitters for burning ship hulks. It’s a small step in the right direction I guess.

In non-tools news, I’ve been fixing a lot of very minor graphics glitches, the odd disappearing piece of debris or mis-aligned laser blast, or slightly crappy looking tractor beam graphic. The game is looking quite nice. Next week will be geared towards some online-integration, and some general gameplay code.

It’s the weekend, so rather than working on gamey stuff I’m making the battles look better :D. I’ve been improving the way the big ships explode so the drifting hulks fade in better, and the subsidiary explosions now blast in various directions. Turrets now smoothly track their targets, and there are various other small tweaks like highlight flares when bullet weapons fire.
My last niggly annoyance of the day is bullets, by which I mean laser pulses.
I draw all the bullets in one go, to make it extra fast, which is fine, but to do this I have to draw them AFTER I’ve drawn all the ships.
The thing is, the bullets are quite big, and when they ’emerge’ from a gun turret, they obscure it for the first frame. Ideally, I’d draw the bullet above the ship but below the turret so it would emerge naturally.
I think I’ll code a real horrid hack, which is to mark bullets as ‘n00bs’ for the first few pixels of their existence, and draw the n00bs separate from the main bullets.
That way I keep generally drawing them fast, but I also don’t get any anomalies when you hit pause and catch that 1 in sixty-off chance of seeing the frame where it looks wrong…

This is why game code looks like spaghetti. All those hacks are there for a reason I tell you!