With this patch applied, xmame 0.94 does vgaxy-style output for display on an oscilloscope in xy mode. Use at your own risk. This can damage (burn) your scope if you're not careful. The Z-axis amplifier can damage your VGA card if it is improperly assembled.

It's best to use "-vectorres [your screen resolution] -nooverlay -norotate", and fullscreen mode. Move the mouse pointer to the edge of the screen so it doesn't interfere with the display.

Depending on the game and your screen resolution, you'll need to change the 'intensity=' line in vector.c:vector_draw_pixel() so that the vectors all fit in the framebuffer.

If your scope's input bandwidth limit is 20MHz, then you need at least 4*20 = 80MHz dot clock. I use 150MHz.

The Z-axis amplifier is discussed here.

The version of xmame I used can be found here but it'd be better on my link if you download it from the real website. 

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  File "/home/jepler/gamma.unpythonic.net/index.cgi-data/_lib/local_code.py", line 414, in markup_showfiles
    string.join(file_list, u'') +
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