Performance

Welcome to the third installment of our series about the development of Payback for the Gameboy Advance. If you haven't read the first two reports then you'll find them here and here. Two weeks were set aside purely for optimising the game with the aim of reaching our original goal of an average of 15 frames per second (which is similar to other 3D games on the GBA such as V-Rally 3). I was pleasantly surprised that I managed to get it to 16 FPS, gaining a total improvement of 30% on top of what was achieved last month. A lot of those speed gains were achieved by reworking the engine, but I also optimised the triangle renderer's outer loop and setup routines, increasing throughput for the texture mapped version by around 8%:

As you can see, currently I haven't applied the optimisations to the routines that handle the transparency effects so it should be possible to get an additional speed gain in future.

The HUD

The other main area I've been working on this month is the HUD - i.e. the score, map, weapons indicator and mission briefing text. It would have been quite easy to re-enable the game's existing routines to draw these things using software rendering but I decided to rework the code to use the GBA's hardware sprites instead. This turned out to be quite fiddly and in the end I used almost all of the GBA's hardware features (rotation, scaling and alpha channelling). The advantage of doing all this is that performance is about 10% greater than it would have been if I had kept the existing software routines.

I also spent some time removing bugs, which means that the game is now fully playable on most levels. I'm planning to start testing it destruction within a couple of days.

What's next?

The main focus of attention over the coming month will be the audio mixer, sound effects and music. Also, I might get chance to start work on the multiplayer mode. [Note: The next status report is now available here.]

Last but not least, due to popular demand I've recorded a short video clip of the game in action which you can download using the link on the right. It was recorded using the game's replay feature - so don't worry that you might have to play the game from an awkward camera angle. The music is from the Amiga version of the game since audio hasn't been added to the GBA version yet. Also note that it was recorded on an emulator so performance will be better with the final code running on the real hardware.

Please feel free to email us with any questions, suggestions or enquiries. We do not yet have a publisher for the GBA version of Payback. For general information about Payback, please click here.