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3.64 / 30-02-2012

Kega Fusion




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Kega Fusion is a closed-source Sega SG-1000, SC-3000, SF-7000, Master System, Game Gear, Genesis/Mega Drive, SVP, Pico, Sega/Mega CD and 32X emulator. It's packed with features but hasn't been updated in quite a long a while.

Note: On Windows 10, an incompatibility issue causes the emulator to freeze when attempting to switch to fullscreen mode. To fix it: right-clicking on Fusion.exe > Properties > Compatibility > check "Disable Fullscreen Optimizations".

Also, DPI scaling might affect the output resolution display. You might have to adjust it in compatibility also, if the emulator window is partially-filled. 


Last stable version: 3.64 (Windows), 3.63i (Mac OS X), 3.63x (Linux)

Development: Inactive for over 8 years, but extremely accurate. 

Windows: Nothing reported

Linux: Nothing reported

Mac: Os X+

Most Recent Changes


- Reversed buttons in the SMS;
- Added ability to display full-screen SMS emulation GG games;
- Improved emulation of some SMS and Sega CD games;
- Added emulation drive from SF7000;
- Improved emulation of sound;
- Minor changes and fixes.

Show Previous Changes


Made some changes to the config options. Hopefully this fixes a problem some people were having where Windows would fail to size the window correctly, although I cannot reproduce this problem.

* Moved SMS controls into main controls window, matching the other builds.

* Fixed a couple of problems relating to SMS controls.

* Fixed preferred country detection order - at some point a couple of them
got switched somehow.

* Various SMS fixes.

* A few minor 32X bugfixes and tweaks.


Not much, mainly just a few tweaks and minor bugfixes.

Seperate SMS controls (finally) allowing for support of SMS Paddles and Light Phasers. The reason I haven't done this before is down to the UI. I don't much like the current solution, either, but it's functional for now.

State Slots now report if they are already in use, by request.

Allow changing state slots, and saving states (but not loading) during Netplay. I'm not sure what use this is, but it was often requested.

Added support for a couple of Custom SRAM games that were recently discovered.

Windows Live Messenger status updates. (thanks Gerrie!)

Many small behind the scenes bugfixes that you probably won't notice, and I've mostly forgotten...


Various fixes for problems found in the last version, plus a couple of extras.

* Moved menus around a bit - the Country and CD Drive menus are now part
of the Options menu. This fixes problems with the old menus not fitting
properly in 320x240 mode, and is also a bit less cluttered.

* Timing was out by a small amount after I removed test code. It should
now be back to where it was supposed to be, removing minor glitches from
a few games.

* Problems with Vista-specific code reported by a few people should now
be fixed. Please report any problems with this as soon as possible.

* Windowed VSync is not required, or desired, under Vista. Fusion now will
default to ignoring the VSync flag when running windowed in Vista. There
is an INI file option to re-enable it just incase this causes problems
for anyone.

* Vista-specific code can also be disabled via another INI file option,
incase this causes problems, or you're trying to run Fusion under Wine,
Darwine, or Crossover.

* Sound effects in Primal Rage 32X are working again.

* AVI output now should not affect what you see on screen.

* Screenshot options - you can now select to save screenshots at various
stages. Final is what you'd get from earlier versions, Corrected is non
filtered but aspect corrected, and raw is not aspect corrected.

* Minor modifications to Render Plugin stuff.

* Upped the number of Render Plugins again, to 48. Please don't ask for
any more, there isn't, and probably never will be, anything like 48
different plugins that are actually worth bothering with.

* Modifications to Full Screen Resolution after noticing that default
resolutions for large widescreen monitors were sometimes not appearing
in the list. Should be fine now.

* A few more behind-the-scenes fixes.


Well it's been a long time. Lots of really bad things have happened, often working on Kega felt like the last thing I wanted to be doing.

Still. Work on it I did. Lots of changes and additions over the last two years, most of which I've forgotten about again, but here's the stuff I can remember:

* Fixed Sound/Timing Issue with Fahrenheit SCD/32X.

* Fixed a typo which corrupted a register in the YM2612 SSG/EG section.

* Removed a few pieces of test code that were not supposed to be left in,
and affected timing of various things under certain conditions.

* LOTS of behind-the-scenes fixes and improvements, which I've totally
forgotten, but you will notice them and remind me at some point ;-)

* Rewrote controller code, should fix problems with some USB controllers.

* Rewrote Menacer emulation which made it easier to add Konami Justifier
emulation. Just the first Justifier is emulated for now. You'll
definitely want to calibrate it in games that use it.

* Added SegaCD SaveStates that actually, you know, work.

* Added support for more games that use custom SRAM, and fixed some that
were already emulated, but got broken at some point.

* Added support for all unlicensed Genesis games that I know of.

* Added support for the Sega Virtua Processor (SVP). Thanks to the reverse
engineering work by the amazing Tasco Deluxe, and the proof of concept
emulator by Notaz, I was able to write and debug my ASM core for this in
just two days.

* Removed some filtering in YM2612 SuperHQ mode (you won't actually notice)
and instead added a "Filter" option to the sound menu. This filter is
very close to that in a real Model 1 Genesis/MegaDrive. Most people will
want to leave this off (me included) but I know some people wanted it.

* Removed 11025Hz option. It was causing me problems, doesn't work well on
most newish hardware, and sucked anyway.

* Added preliminary Sega Pico support. There's a lot more I plan to do with
this. For now, just load as a Genesis ROM. Mouse is required for Pico,
along with the following controls: START switches between StoryWare and
trackpad, B is the pico red button, A and C turn pages, and U/D/L/R are,
well, U/D/L/R.

* Added ability to create 128K SegaCD RAM carts to keep SpinelSun happy ;-)

* Added two controller sharing options for Netplay. Everybody can now share
controller one, or all controllers. The latter isn't very useful, but why

* Added "Nearest Multiple" option to the Video Menu. The various Aspect
modes do what they have always done when this option is enabled, but now
when it is disabled, they will allow non-multiple stretching while still
keeping the aspect ratio correct.

* Added "Use NTSC Aspect" option to the Video Menu. This used to be done
automatically under certain conditions, now you have full control.

* Added Pause Emulation feature.

* Added Frame Advance feature.

* Added No Frame Skipping feature. You should pretty much ignore this and
let Kega do what is best. But it does also trigger a special case mode
when you have VSync enabled, and you hit Fast Forward. Normally, VSync
is ignored during Fast Forward, or else Fast Forward wouldn't actually
do very much. With No Frame Skipping enabled, it will still do VSyncs.
This might be useful to you if your video mode is running at some odd
refresh rate. Note that the sound could well sound awful if you do this.

* Added AVI Logging using custom Kega Game Video 1 lossless codec. This is
needed because logging RAW video causes poor performance even on highend
machines, and using any of the available codecs either doesn't compress
well enough to fix that, or does compress well enough, but can't keep up
with 60fps, so you get poor performance either way. The codec is able to
use hints from the emulator to aid in compression, allowing pretty good
compression while taking very little CPU time. The codec to allow you
to play back and convert the files is included in the archive, and can
be installed via right clicking on the INI file and telling the OS to
continue with the install. Tested on XP and Vista64, should work fine
on 9x and Vista32.

Note that these AVI files are not really meant to be shared as they are,
it's just a way for you to log video without horrible laggy gameplay.
Convert them to Xvid or something using the excellent VirtualDub program
(Google it.) I'll open up this codec sometime later incase it's useful
for other purposes/programs.

* Disabled BIOS use where possible during Netplay games, to prevent out
of sync errors when people had different combinations of BIOS/NO BIOS/
Different BIOS.

* Netplay Games should now automatically change your country code to that
of the host.

* Added Fast 32X Timing option. This is mainly for development. If you
don't know what this is for, leave it disabled.

* Added CartBoot option, which is enabled via INI file only. Again, if
you don't know what this is for, leave it disabled.

* Kega Fusion now runs beautifully under Vista.


- Fixed Netplay Connection issue.

- Fixed Netplay Dialogs in Fullscreen mode.

- Config of Player 1 (the Host) is now copied to other players in Netplay.

- Re-added another deleted line, the sound effects in Ecco work again.

- Fixed a Timing issue, Street Racer works again.

- Fixed DMA issue with Powermonger.

- Fixed SMS NMI issue.

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