Blitz Coder#1 - Space Invaders Emulator
Having been a big fan of emulation since I first used a ZX Spectrum emulator on my Commodore Amiga 500 computer in the early 90's, I decided that it was time to learn how emulators worked and write my own one.
An intel 8080 based Taito Arcade Platform emulator is a great base level emulator to learn how emulators work and was a really fun coding project to do.
I wrote the initial basic emulator five years ago but I am lousy at finishing projects so I decided to change the habit of a lifetime and add multiple games along with game artwork and polish this up and for once, get a project completed and released.
An intel 8080 based Taito Arcade Platform emulator is a great base level emulator to learn how emulators work and was a really fun coding project to do.
I wrote the initial basic emulator five years ago but I am lousy at finishing projects so I decided to change the habit of a lifetime and add multiple games along with game artwork and polish this up and for once, get a project completed and released.
The emulator contains nine different official and unofficial versions of SPACE INVADERS including a few of the better so called 'Super Space Invaders' bootlegs.
The emulator supports a number of other features including optional bezels, backdrops, simulated colour overlays and simulated scanlines. I have tried to make it as configurable as possible with as many useful options available as I could think of.
So download, play and relive the peak of late 70's arcade videogaming.
The emulator supports a number of other features including optional bezels, backdrops, simulated colour overlays and simulated scanlines. I have tried to make it as configurable as possible with as many useful options available as I could think of.
So download, play and relive the peak of late 70's arcade videogaming.
Known Issues:
Space Invaders Colour (romset sicv) high score save doesn't work.
Forcing the previous high score into the ROM area to be read into the RAM area (which works with all other official Space Invaders games) causes the game to reset when a credit is added and a game is started.
It's almost like the game has a high score hack detector in the code. I figure that somewhere in the RAM area, there is a counter that is set to 0 if no game has been played and another value if a game has been played.
It probably works something like: "If game_counter=no_games_played and high_score>0 and start_game=Yes then reset Program_Counter to 0.
Might try a debug log to see what is actually causing the game to reset and then work back from there.
Invader sounds timing goes out of sync when the Invader sounds are playing fast i.e. near the end of the each level.
I have tried numerous different ways of triggering the Invader sound samples however they are always slightly off on timing when they are playing fast.
After trying a few "dev" programs triggering the invader sounds at an increasingly faster rate, I have concluded that it's a limitation of the programming languages sound playing functions and nothing to do with the actual emulator, so there's not a lot I can do about it...
Forcing the previous high score into the ROM area to be read into the RAM area (which works with all other official Space Invaders games) causes the game to reset when a credit is added and a game is started.
It's almost like the game has a high score hack detector in the code. I figure that somewhere in the RAM area, there is a counter that is set to 0 if no game has been played and another value if a game has been played.
It probably works something like: "If game_counter=no_games_played and high_score>0 and start_game=Yes then reset Program_Counter to 0.
Might try a debug log to see what is actually causing the game to reset and then work back from there.
Invader sounds timing goes out of sync when the Invader sounds are playing fast i.e. near the end of the each level.
I have tried numerous different ways of triggering the Invader sound samples however they are always slightly off on timing when they are playing fast.
After trying a few "dev" programs triggering the invader sounds at an increasingly faster rate, I have concluded that it's a limitation of the programming languages sound playing functions and nothing to do with the actual emulator, so there's not a lot I can do about it...
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