Java Sega Master System & Game Gear Emulator

 
I've updated the version on the preview page to Beta 1.
posted by Chris White at 9:31 PM

 
Today I improved the noise generation code again, in particular when the noise uses the same frequency as Channel 2. I also polished a few things ready for the public release which is out today. Go and download it from the Downloads section, and then tell me what you love and hate! Note that the 'preview' on this page is still the old version.
posted by Chris White at 6:46 PM

 
Here's a screenshot of the Controller Configurator. As you can see, you simply highlight the appropriate button to remap the key. There's also some nice transparency.

I've also implemented speed throttling, so that the emulator remains locked to 100% real SMS speed on faster machines.
posted by Chris White at 1:34 AM

 
The noise generator is now emulated, so the sound emulation is almost complete (just a few more tweaks to make, including emulating the voltage decay). Additionally, I uncovered some more interrupt related bugs. Fixing these corrected Shinobi, Fatal Fury Gear and others on the Game Gear.
posted by Chris White at 1:35 AM

 
Here's some screenshots of the GameGear emulation, with the new funky background image:

What else? Well, sound can now be logged to a WAV file. Today I also tried to implement the x1, x2, x3 size screen modes. Unfortunately I ran into some problems with these. Firstly, they were incredibly slow, and I also ran into some Java related problems. I could not seem to call setSize(x,y) to resize the window on the fly, as it would clip the display. The only way around this was to setSize(max_x, max_y) to begin with - which I don't want to do. Hmm..
posted by Chris White at 10:30 PM

 
The Texas SN76496 sound chip is now emulated, which means that JavaGear now has sound. The 3 square wave channels work well, and the noise generator channel is also working - but it doesn't sound totally correct yet (mainly due to a lack of documentation on how it works). I've put the next public release off for a period of time, as I'm in a period of intensive development - so I want to stablise and polish areas before making another release.

Other good news is that I've sped up the emulation by another 4% due to a couple of Java related display optimisations. A lot of homebrew demos now run at 50% with no frame skipping. Using sound emulation at 11025Hz reduces the speed by about 3%, which isn't too bad. I'm going to test on my university 800Mhz Linux machines when I next get a chance.
posted by Chris White at 10:47 PM

 
Well, I've been working on a few things in the run up to the public beta. Most importantly, Game Gear emulation is now working. Over the last few days, I've been ironing out some problems. A lot of ROMs were refusing to run, but that was because I hadn't emulated the Game Gear serial ports... they were returning 0xFF which caused some games to hang indefinitely.
posted by Chris White at 11:57 PM