Oscilloscope Star Wars

Here's a picture and video from Moose2000 showing how he hacked MAME so that it could be displayed on an oscilloscope being driven by a sound card. There aren't many details on exactly how he did it but it is still pretty cool. I guess if you are looking for authentic vector monitor action an oscilloscope does make a good readily-available solution. I wonder what Asteroids would look like on one.

EDIT: I don't have to wonder. There is a video of Asteroids too!

I received this description via YouTube:

"Hi Scott.
There's really not much to say about it beyond the fact that it's an oscilloscope connected to the soundcard line out.

I hacked the vector driver in mame to render each frame to the sound card. Games like Star Wars and (especially) Asteroids really don't have much going on in a frame, and are easily achievable at audio frequencies.

There's no direct control over beam intensity on my oscilloscope, so instead I vary the speed of the beam. If you turn the brightness right up on the scope, you can see the beam moving from one line to another. To play the game, you turn down the brightness so that only the slowly drawn lines are visible.

Soundcards output an AC signal - any DC component gets cancelled out. What this means when controlling a vector display is that if you have a lot of lines on the left side of the screen, the display will drift to the right to keep it centred. To get around this, the code tracks where the beam is spending its time during each frame, and then draws little dots at the corners of the display to make it balance.

Cheers,
James."

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