> It's pretty simple. The internal layout for seawolf has an overlay that gives the > entire screen a blue/cyan cast. Just ignore the periscope lamps, only the stuff used > for the "Color Overlay" view would be needed. You can adjust the colour to taste.
You dont need a overlay or .lay file at all. Enable HLSL and push red_ratio, green_ratio in .ini file and lower blu_ratio just a little. You can also use the sliders menu in options while in game, by changing "Signal Exponent" red, green and blue values accordingly.
I recommend MAME 0.179 for vector games. It is the last version where vector games looked really good, as you can make the points of a vector "visible" and adjustable. A very remarkable characteristic of a vector game.