MHGames

Just wanted to announce that I’ve finished the Android port of Jewels. It is now available through the Android Market, for free. The comments so far have been very positive, thank you. I’ll probably release an update later with some fixes and tweaks, but after that I think it’s time to start thinking about the next project.

I’ll write something about the porting experience from programmers point of view later; it definitely has been interesting as I have not done any mobile coding before this.

UPDATE on 13th of November:

Now that Jewels has been on the Market for a week, I’d like to share some statistics with you. Turned out that the game is a huge success (ok, it’s mainly because it’s Bewejeled, but interesting still), I had not anticipated this at all! At first I thought it’d break 5000 downloads before the last weekend (the game was released on Thursday). It did, Sunday the downloads were over 16 000. On Monday, it was over 32 000. And now, it’s over 100 000 installs, 92% of them active (i.e. still on users’ phones)!

Jewels is actually the second most popular (free) game in the Market right now with a average rating of 4.5 stars (596 ratings at the moment), only behind a Solitaire-game. Very nice. I’ve actually gotten more comments about Android-Jewels in a week, than I have from all my previous games combined during all these years, wow! So there’s definately market for good Android-games. I’m planning to make something a bit more original next,  so stay tuned.

Of course, it’s not all roses: I’ve released about a dozen updates but still there remains some mysterious bugs that don’t occur in most of the phones, but do in some.. Partly that is because Jewels was not originally writting  for phones (XNA as an environment is way simpler than Android!), and partly because I’ve probably screwed up something (my first Android app, after all). I will definitely try to design the next game to more solid and not so prone to these various bugs and crashes. But one thing bugs me: the Anroid phones are truly different from each other, although in theory the same code should work in most of them, in reality it won’t.. I’ve seeing reports of some really weird crashes that really should not be happening.

Hi, everybody! (“Hi, doctor Nick!” …sorry.)

Little background on today’s topic: When I first heard of the Google Android-platform some years back, I thought it was interesting but never actually expected to see proper devices (i.e. mobile phones) coming to reality. Now that there is several Android phones from a few manufacturers, I’ve been eyeing out the devices with great interest for a while now, I guess closer to a year actually. Waiting for them to arrive here in Finland. And, as you might have guessed already, they have arrived.

The Hero emerges..

So, I got myself a brand new HTC Hero! Obviously, the main interest for me was the prospect of developing software (ok, games) for the Android-platform. Also, it’s darn good phone as well, who would have thought of it? My previous phone was a few years old Nokia, just a basic model with no bells and/or whistles — so this is all new to me.

Why not iPhone, then? Well, there are several reasons I went with Android:

1. The development environment. It’s free, cross-platform and well integrated into Eclipse. Plus I get to write in Java, which I very much prefer over Objective-C.
2. I don’t need a freaking Mac for developing (as if the phone wasn’t expensive enough..)! I can use my old, cruddy PC instead. 
3. Android Market, while still in its early stages, has great potential. Plus not nearly as much competition as in the iPhones App Store (obviously this also means less customers, but things improve when Android-phones gain more market, I hope).

Read more…

Time for an update, I reckon.

Although PolyAnim is generally on hold due to the game project, I made a few optimizations (reducing garbage generation mostly, still quite high though) to it. As for the game, I’m still working on the engine side — BUT — I’ve written down some things on the game plot and other design! I have a vision of the game beginning, but the actual plot still needs to be thought up. Sooo yes, I don’t have much at all, but it’s a start. Luckily I don’t have too much pressures on the story side, as even if it ends up sucking donkey balls (excuse my language), it’s still infinitely better than the “stories” of my previous games combined!

Meanwhile, in the programming land…

It’s been so long since my last update, I’ve worked on so many things I don’t even remember them all. Instead of trying to remember the details, I’ll just list the things I do remember:

• First of all, I started using revision control for the source code (+ related resources). Instead of using the familiar Subversion, I decided to try something new and thus chose Git. All in all, this helps me keeping track of the things I do and also serves as a backup in case my computer decides to blow up. Git is nice since you can use it locally, on any directory without a server.
• VBO (Vertex Buffer Object) support. This means storing geometry to the GPU and rendering it in one batch. Basically it means better performance. Using VBOs I could optimize the text rendering by buffering the rendered glyphs into a batch, up until the buffer fills up (or the texture changes). The buffered glyphs are rendered in one go, and the process starts again.
• Particle systems! I started doing a “particle engine” a while back, got it done except for the different emitters. I still need to finish this up: complete the basic point emitter, add more emitters and add the ability to load particle systems from resources (perhaps a YAML or XML file). VBOs are used to render the systems, when supported by the GPU.
• Lighting system improvements. Lights can now have different effects on them, like flickering, fading and pulsating. The effects are defined in a YAML file of properties.
• Player character designs. I’m not sure if this guy ends up being the final character, but might be. I did a quick idle animation for him (need to adjust that a bit, though), I should add a walk cycle next as it’s quite boring to watch now. (The previous animation, test from PolyAnim, did walk!)
• And now for something completely different: Water effects. Yes. This is mostly eye candy (as Box2D doesn’t support buoyancy yet, I think the water is only going to be used for restricting player movements as in the player can’t swim..) so it made no sense to do it at this phase of development. But I did it anyway, I’m childish like that.. The water reflects the scenery above (provided the GPU supports Render-to-texture) and I even wrote a fragment shader to make it all wavy and twirling..

I have noticed a problem during the development of this game, which was not apparent on my previous game projects (since they were much shorter): I have this annoying tendency to start working on different (sub)projects even when the previous stuff is still not finished. That means I have heaps of unfinished subsystems in this engine, like the particles, scripting, triggers, etc. And I’m already thinking of doing the sprite system and other things as well! I mean, what the hell, it should be bloody obvious I should concentrate on the unfinished things and finish them.. Argh, hopefully I can sort this mess out. Speaking of which, I guess I should start coding the particle system to an usable state.

And of course, to all aspiring game developers: design the game first, damnit! Figure out the plot, setting, characters and whatnot BEFORE getting sucked in the bottomless fathoms of Teh Engine(tm)! Yes, I really should take my own advice some day!

Today’s subject: quad trees. Here is a nice little tutorial on the subject.

Until now I was using a naive method of rendering the level shapes (polygons and circles): I looped through them all, did a bounding box check* to see if they’re visible in camera, and rendered if they were. This works fine for small levels (and indeed for the current test level, although I keep adding more and more stuff to it — nevertheless it’s still quite modest in size), but for larger levels it can become a problem, especially on slower machines.

So I decided to add quad trees to speed up the level rendering process. The level shapes are stored in three different quad trees (one for collidables, one for background and one for foreground shapes). The trees are queried for visible objects, which then get rendered. Works nice and smooth, and the performance goes through the roof, right? Well… not quite.

Since the level shapes can have various opacities, it is important to render them exactly in the order that is specified during level creation (in the Inkscape SVG file). In the triangulation & convex decomposition process the original shapes get split up. It was not a problem during the naive approach — the shape parts were in a list and the original order was preserved. Quad tree on the other hand doesn’t necessarily preserve that order, to my great disappointment. It makes sense of course, I just hadn’t thought about it until I saw the effect: a few of the level shapes were rendered out of order.

At first I tried to come up with a way to partition the quad tree so that the order would stay correct, but that didn’t work too well. In the end I ended up just sorting the queried objects before rendering. That works perfectly, but introduces a new speed hit; the sort. So in all, the supposedly great speed increases of the mighty quad tree turned out to be only a modest gain, since I now need to sort the visible pieces.. Still, I’m confident that the quad trees were worth it, as the levels keep getting bigger and more complex it will surely show more greater effect. And at least I found that enormous bug in the bounding box culling!

Check out a few debug screens below, quad trees are the white lines.

*) I actually found one of the most stupid bugs I’ve ever done in the bounding box check code. It was actually checking bounds from the world origin (0,0) to the object lower right corner, instead of from the object upper left to lower right! That means that the bounding boxes got very big and only the objects to right and down from the camera view were culled properly.. Ouch.

Once again, I’ve been improving the platformer engine. I have done a lot of internal restructuring which isn’t directly visible on the screen. Remember, this project started as a quick hack testing JBox2D, so the oldest parts of the code were a total mess. Cleaning it up, I implemented modules, that the engine keeps processing. These modules (e.g. GameModule, MenuModule, OptionsMenuModule) are basically separate states and can be ran separately of each other. They also support transitions, so a title screen could fade into the main menu, which could then roll off the screen presenting the actual game. Currently I have an initial loading screen that fades into the game. Yes, all this doesn’t sound very exciting (and in reality it isn’t), but it makes the code much more cleaner and modular. Hopefully, one my biggest pet peeves — which is writing the menus after the game is complete — will be a more pleasant experience with these module supports in place. I still have some old physics related code there which needs some refactoring love, so there’s still work to be done..

I also did the different rendering path thing I was talking about earlier. The best rendering path allows for some neat shader effects, I did initial tests with a distortion shader — it was nice but didn’t work with the bloom effect, something I hadn’t realised before. I guess I will need to implement somekind of a post processing subsystem, that does the bloom among other effects. Oh well.

Another thing I added is an ingame profiler. While extremely simple, it still presents some very useful data so I can see what part of the game takes most time at runtime. So far the slowest thing is the text rendering. Luckily that won’t be a problem, since I don’t plan having much text on screen in the game (apart from dialogue, but that can be prerendered into a texture). In the current demo I draw the yellow text with a nice shadowy border around it — that is a very brute force approach which just draws the same string a bunch of times. That’s very slow. Also the text rendering could probably be optimized more, should the need arise.

I’ve been also improving the controller support (yes, the game will support game pads! That’s the first time in my [released] games — better late than never, right! ). The basic support was actually added months ago, I just forgot to mention about it earlier. It’s still pretty much unusable, since the buttons cannot be assigned: it just uses the first two buttons on the game pad. And that varies per model, a lot. On mine they’re positioned logigally, but on another pad they were almost unusable.. So the game needs a controller configuration screen, where the player can assign the actions to the preferred controller buttons. But that’s thinking way too much ahead, I need the game first!

One more thing: I made a simple test release of the engine, so that I could collect some data on how it works on different machines. (I mainly test it on two computers, which isn’t that much.) Head over to the JavaGaming.org forums and take it for a spin! Hopefully somebody confirms it works on Mac OS X as well.. [Update: Yes it does!] By the way, I will probably take the thing down in some time, since it’s still in very early stages and doesn’t have any gameplay in it anyways..

That is all this time, stay tuned for more! EDIT: I just realised I had used this very same line to end the previous posting.. Am I really this unoriginal!? Apparently, yes. Yes I am.