light gun for the speccy
how did it work?
i can see how the wii thing deos the stuff with its sensor bar, but as remeber the speccy thing didn't have one. i know you had to centre it when you turned it on, but how did it know where it was supposed to be shooting?
and has anyone done any modern games for it?
i can see how the wii thing deos the stuff with its sensor bar, but as remeber the speccy thing didn't have one. i know you had to centre it when you turned it on, but how did it know where it was supposed to be shooting?
and has anyone done any modern games for it?
Post edited by mile on
Comments
That 'sensor bar' isn't a sensor at all. It's just two infra-red LEDs a fixed distance apart. There's an IR camera in the tip of the Wiimote that tracks the position of these bright spots and how far apart they are, and from that works out where it's pointing. You can see what the camera sees on one of the config screens, with two white dots floating around. It also contains accelerometers to detect movement when pointing away from the bar.
Someone's done a neat hacked head tracker where you actually fix the Wiimote above your monitor and wear a pair of engineer's glasses with LEDs in the corners.
The best demonstration of how light guns work is Time Crisis on the Playstation. They use a single light sensor behind a lens. The old Grandstand TV game used one, and would bounce a white dot around the screen on a darker green background. It was sensitive enough to tell when you were pointing at the dot and when you weren't, although if you turned the brightness up on your TV it would register anywhere. But the later versions are much more accurate and sensitive.
What they do, is turn the screen bright white for one frame of the TV image. But, it takes the TV 1/50 second to display this, line by line. So the computer waits and times from the start of the TV drawing the picture, counting line-by-line, until the light gun registers a bright light. The line it's on gives the Y-position. It can then work out how much of that line has been drawn (which requires much more precise timing), and so get the X-position of where the gun is pointing. You can also take a couple of readings over the next few lines and take an average, to get a more accurate X-position.
However, LCD, Plasma, High-Definition, 100Hz - all these new TV technologies mean that the light gun is a thing of the past.
- IONIAN-GAMES.com -
thats what the call it in the mannual, lying gits. :D
Yes I was very annoyed that my Dreamcast light gun wouldn't work on my LCD TV....back to school shootings instead I guess..
- IONIAN-GAMES.com -
he he.
nice explination by the way, i didn't realise it was all so complicated.
Light-pens worked in a similar way. If you ever used one, first the screen would go white as it located the pen on the screen, then it would place a large white dot under the pen and use that to track the pen position. You had to be careful not to move it too fast, or it would lose track.
Commodore machines could do this better as they had an extra interrupt that could occur on each line of the display, and so do the timing more accurately. The Speccy only had the one interrupt, which occurred at the start of each frame refresh.
- IONIAN-GAMES.com -