Software:demoscene:Copper by Surprise Productions (1992) - Wengier/dosbox-x-wiki GitHub Wiki
1992 demoscene entry.
[dosbox] memsize=1 machine=vgaonly allow hretrace effects=true [cpu] core=normal cputype=386 cycles=4000 [sblaster] sbtype=sbpro2
This demo employs a lot of VGA raster trickery, in addition to the usual changing the color palette per scanline to make copper bars. The most dangerous trick not likely to work with today’s monitors is to make the picture waver by changing the position of the horizontal sync pulse once per scanline. That trick may happen to work with older VGA CRT monitors, but will cause modern flat panels and scan converters to blank the picture.
The demo will autodetect and use the Adlib FM synthesizer of your sound card. The detection however is CPU speed sensitive. If the cycle count is 13000 or higher, detection will fail, and you will hear no music. Music tempo is tied to the VGA refresh rate. If the refresh rate is anything other than 70Hz music will play too fast or too slow.